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A STUDY OF THE REMOVAL OF HEAW METALS IN THE ENVIRONMENT
THROUGH PHYTOREMEDIATION

By

Karen A. Gould

A Thesis

Submitted to
Michigan State University
In partial fuiﬁllment of the requirements
for the degree of

MASTER OF SCIENCE
Division of Science and Mathematics Education

2005

ABSTRACT
A STUDY OF THE REMOVAL OF HEAW METALS IN THE ENVIRONMENT
THROUGH PHYTOREMEDIATION
By

Karen A. Gould

This unit was taught to an eleventh grade Integrated Science class at Flint
Southwestern Academy, in Flint, Michigan. The intent of the unit was to educate
the students on the implications of hazardous materials in the environment and
the use of plants as an alternative remediation device to clean contaminated
sites. Through the utilization of experiments and models that provided hands-on
experience and solutions to a real world problem, this goal was successfully met
by addressing the requirements of the State Educational Benchmarks regarding
environmental issues. Through the execution of a series of habitat models that
utilized plants and animals, toxicity was explored using heavy metals as a
reference, as well as the pathways that the toxins take in the environment. The
analysis of collected data from the models indicated that as concentrations of the
contaminant increased, the living organisms began to experience stress,
especially if they did not have mechanisms that allowed for survival. In searching
for a solution to the issue of toxicity and current practices of remediation, the idea
of plant application for removal of metals was investigated. As the class worked
with the experimental models, they gained knowledge, as indicated by their post

test scores which had a range of 38-54% increase over pre test scores.

Copyright by
Karen A. Gould
2005

ACKNOWLEDGEMENTS

The completion of this degree was not possible without the supporting hands of
many individuals, who either with intent or by default, had a great impact on me,
making the road traveled less arduous. Foremost, I would like to extend my
deepest appreciation to Dr. Merle Heidemann and Dr. Ken Nadler. Your
patience and easy giving of “what you know" has shaped me into the educator
that l have become, altered my thinking in only the best way. Thanks too, to Dr.
Clayton Rugh for helping with the development of an environmental model that
brought nature to the classroom. Margaret and Linda - many thanks. To my
classmates Deb, Angie and Ken — thank you for your brains, your patience and
mostly, your laughter, when I had forgotten how.

This wonder that fuels my work was ignited by my parents. My Dad Dale,
who weaved tales of nature and opened the door to thinking. outside of the box,
and my Mom Joyce, whose faith and encouraging words helped me to see
“possible” and started the way of looking for answers. Thanks to my family for
their love and encouraging words, Bud and Gary, you remain with me still and
Annie — a deep bow of appreciation for walking the road, cooking dinner, and
wiping tears. JEA, your silence and space meant more to me than you know.

Finally, I am truly grateful to Southwestern Academy for supporting the
research and I am honored and humbled by the students of the Integrated

Science Class (2003-2004) for being willing.

iv

TABLE OF CONTENTS

LIST OF TABLES ................................................................................ vii
LIST OF FIGURES .......................................... . ..................................... viii
INTRODUCTION ................................................................................... 1
IMPLEMENTATION .............................................................................. 14
RESULTS ........................................................................................... 32
DISCUSSION ...................................................................................... 44
REFERENCES .................................................................................... 57
APPENDICES A-R ................................................................................ 60
APPENDIX A: MICHIGAN CONTENT STANDARDS AND
BENCHMARKS .......................................................................... 61
A-1: MICHIGAN CONTENT STANDARDS ........................................ 61
A-2: FLOW CHART OF CONTENT STANDARDS AND MAIN UNIT
IDEAS .............................................................. . ......................... 62
APPENDIX 8: CONSENT FORMS ................................................. 63
APPENDIX C: PRE AND POST TEST ............................................. 66
C-1: PRE AND POST TEST ......................................... E ................. 66
C-2: PRE AND POST TEST OBJECTIVES ....................................... 68
APPENDIX D: HEAW METAL EXPERIMENT ................................... 70
D-1: STUDENT SHEET ................................................................ 70
DZ: INSTRUCTOR SHEET ......................................................... 80
APPENDIX E: MINERAL NOTES ................................................... 84
APPENDIX F: SELF SUSTAINING MECHANISMS ............................. 86

F-1: SELF SUSTAINING MECHANISMS READING ........................... 86

F-2: SELF SUSTAINING MECHANISMS QUESTIONS ....................... 90
APPENDIX G: FIELD TRIP QUESTIONS ......................................... 91
APPENDIX H: MACRO/MICRO NUTRIENT NOTES ........................... 92
APPENDIX I: RESEARCH OUTLINE .............................................. 94
APPENDIX J: REMEDIATION NOTES ............................................ 96
APPENDIX K: TOXOLOGICAL EFFECTS OF HEAW METALS ON RED
WORMS .................................................................................. 102
K-1: STUDENT SHEET .............................................................. 102
K-2: INSTRUCTOR SHEET ......................................................... 106
APPENDIX L: BIOACCUMULATION ACTIVITY ............................... 110
APPENDIX M: NOW YOU SEE IT, NOW YOU DON’T ...................... 112
M-1: STUDENT SHEET .............................................................. 112
M-2: INSTRUCTOR SHEET ......................................................... 114
APPENDIX N: SOIL PERCOLATION DEMONSTRATION .................. 116
APPENDIX 0: REMEDIATION UNIT EVALUATION ......................... 120
APPENDIX P: RUBRICS ............................................................. 122
P-1: PAIRED STUDENT T-TEST RESULTS .................................. 122
P-2: REMEDIATION UNIT GRADING RUBRIC ............................... 124
P-3: PRE AND POST TEST GRADING RUBRIC ............................ 125
APPENDIX Q: COPYRIGHTED SONG PERMISSION ..................... 128
APPENDIX R: UCRIHS LETTER OF PERMISSION ......................... 129

vi

LIST OF TABLES

TABLE 1: PHYTOREMEDIATION UNIT OUTLINE .................................... 17

TABLE 2: RESULTS OF TESTING FOR ACCEPTANCE OR REJECTION OF

NULL HYPOTHESIS ............................................................................. 33

vii

LIST OF FIGURES

FIGURE 1: FLOW CHART OF CONTENT STANDARDS AND MAIN UNIT
IDEAS ............................................................................................. 18

FIGURE 2: COMPARISON OF PRE AND POST TEST SCORES ................. 33

viii

Introduction
Rationale
In response to teaching in a public school system for seven years, and
ﬁnding a general sense of apathy and lack of knowledge regarding
environmental issues, a contamination and remediation unit was
developed. Although exhibited by a young adult population, the absence
of solid knowledge regarding human impact on the environment is a mirror
of society as a whole. As industrialization has replaced an economy
based on agricultural practices, humans have moved away from a sense
of connectedness to the Earth, and consequently have lost a sense of
ownership and responsibility to the land on which they live (Botkin and
Keller, 1982). Complicating the issue further, the adoption of a linear
system of thinking - one in which events occur in a straight line, ignorant
of webs of interaction have contributed to a massive global environmental
I crisis. Application of “band-aid” measures that treat the symptoms as
opposed to correcting root causes, allowing governmental decisions to be
made that favor business at the cost of exhausting natural resources, and
believing that as humans we control nature have also added to this crisis
state (Chiras, 1994). Essential to changing the current state of
environmental health is educating young people (who will become
tomorrow’s leaders and decision makers), and assisting them in

developing a sense of interconnectedness to the world in which they live.

The basic tenet of the unit was to demonstrate the application of
phytoremediation techniques in the context of contaminated soil treatment.
Although the 1980’s brought the development of the Superfund Act
(created by the Comprehensive Environmental Response, Compensation
and Liability Act — CERCLA) which addressed the clean-up or remediation
of contaminated sites through legal processes, public involvement has
diminished in recent years (Botkin and Keller, 1982). Coupled with
reduced federal dollars, many of the techniques that have been used in
the past have suggest environmental irresponsibility. For instance, ocean
dumping and incineration of wastes have increased pollution due to
changes that occur during the recycling process and have resulted in
chemicals that are as harmful to living organisms as the original toxin, i.e.
acid rain (Botkin and Keller, 1982). Consequently it has become
necessary to develop alternative techniques that not only‘stop further
contamination, but assist in the degradation of toxins while beneﬁting the
environment. Thus the study of phytoremediation (using metal tolerant
plants to sequester or remove heavy metals from soil) was introduced in
the classroom, focusing on the mutual beneﬁt of removing the
contaminant, as well as creating a healthier habitat for the organisms‘that
live in an affected area. Through the application of problem based inquiry
and cooperative learning, the students gained an understanding of how
heavy metals and other pollutants enter the environment and become

toxic.

EQEE;

Believing that as educators it is our responsibility to raise the
awareness of our student population, and reﬂecting on the need to cover
benchmarks that are not commonly addressed (evolution "L4 and
ecosystems Ill.1 - lll.5) the remediation unit focused on the impact that
human activity has on both habitat and the organisms that live within that
space. Expanding on the concept of utilizing environmentally friendly
remediation techniques, the unit was taught in an Integrated Science
class, a curriculum that was designed to prepare the students for
standardized tests by reviewing all of the benchmarks from 8th - 10th
grade and fulﬁlling the third year science requirement for those students
who were not candidates for advanced sciences.

Taught primarily to minority students who often experience
decreased academic success due to personal and cultural learning
A differences, low academic rewards for efforts put forth, and lack of general
support from their peers and family base, the classroom environment was
designed to address these speciﬁc issues (Golba, 1998). As stated by
Kathleen Cotton, schools that are effective in teaching urban youth, “were
characterized by features that focused on basic skill acquisition for all
students, high expectations of students, teachers who took responsibility
for their students’ learning and adapted instruction to make sure that
learning was taking place (in a) safe and orderly school environment”

(Cotton, 7/2004). Additionally, students within an urban classroom often

have limited involvement with the natural world, lacking hands-on
experience with agricultural settings, wetlands, water systems and the soil.
Of particular interest to the students in my classroom was the inﬂuence of
industrial activity (in this case General Motors and several iron works
plants) on the general health of local land and water ways. These local
industries assist in the degradation of environmental quality because they
release carcinogenic chemicals, as well as heavy metals into the
surrounding area. This same area is where the students live and work,
which increases the likelihood of the student population being exposed to
those chemicals (i.e. metals) that are largely neurotoxins, absorbed
through inhalation and the gastrointestinal tract, via daily living. The
presentation of the hazardous material naturally led into the investigation
of techniques used to remove these substances. Taking into consideration
soil type, which can prohibit or exacerbate the accumulation of metals,
traditional removal techniques include site caps which prevent the toxin
from becoming airborne, sequestering the toxin in a landﬁll or applying the
relatively new technique of using plants to remediate a hazardous site.
The problem with teaching phytoremediation in an urban setting is that
there are no local ﬁelds to explore where the technique is being applied,
thus the learning becomes theoretical unless alternative teaching methods
are used. An additional challenge is engaging the students and increasing
their connection of personal responsibility for sustaining a healthy

environment. In response to these challenges inquiry based and

cooperative learning techniques and theory were applied within the
classroom.
Teaching Theory

Current scientiﬁc teaching methods recognize the difﬁculty in
reaching a population of students who are removed from daily
experiences that activate investigative thinking. Additionally, diverse
student populations create the necessity of using examples, models and
teaching tools that hold some relationship to the student’s personal life
(Clark, 1999). Problem or inquiry based Ieaming meets this challenge
because it “encourages students to solve or ﬁnd solutions to real world
problems (in this case contaminated sites) by themselves or in groups,
rather than relying on Ieaming primarily through lectures or textbooks”
(Sonmez & Lee, 2003). As with guided inquiry, the teacher acts only in
guiding or assisting the students with the investigations (Martin, 2002).
Proposed Solution
Working from this theory, two long term models (one a wetland tank and
the other a Red worm soil column) were established in the class that
represented habitats that had been contaminated with a heavy metal,
similar to industrial waste. There were no deﬁned answers as to why the
wetland plants were experiencing stress, indicated by growth retardation,
poor photosynthesis or plant death. The class relied on their group’s
support to ﬁnd solutions by activating prior knowledge (Sonmez & Lee,

2003). Providing the student’s with the opportunity to direct their own

learning while developing critical thinking skills through investigation also
aided in building their conﬁdence.

The interdependency on each other as a source of both inspiration
and knowledge is especially crucial to not only building self esteem within
each individual, but also in developing shared understanding among
students that hold very different background information and experiences.
The class as a whole was split into 5 groups of 5-6 students that
progressed through the unit together. The groups were developed based
on communication skills that were exhibited among members, the mixing
of varying cognitive ability and learning styles (auditory vs. motor) and the
tolerance level each member had for the other members. Because
knowledge is built on preexisting frameworks of reference, by grouping the
student’s with similar communication skills, but different backgrounds of
experience, the group’s members were able to assimilatenew information
that they learned from the class work, as well as from each other (Ginn,
1997). As a collective (cooperative) group moving through the Ieaming
exercises each member was able to contribute his or her best ideas which
in turn increased the understanding of the whole group. By helping
teammates learn the students themselves created an “atmosphere of
achievement” for the entire group (AbiSamra, 2001). Using cooperative
Ieaming in the classroom has been documented to improve academic
achievement, individual behavior and attendance, as well as increase self-

conﬁdence and motivation, both to the individual and the entire class.

Moving away from individual competition, cooperative learning incites an
atmosphere of support, one in which the entire group beneﬁts from the
actions of all members of a team. Reducing the threat of not reaching a
goal, in this case academic success, by relying on the strengths of
individuals, self esteem builds due to each member feeling that his/her
input is both valuable and valued (Johnson and Johnson, 1989). This is
especially the case when teaching a class that has special needs or
inclusion students in attendance, as in the case of Southwestern Academy
where the unit was taught. Often individuals with disabilities are “tracked”
out of technical or main-streamed courses because it is believed that they
cannot function safely in a laboratory setting (Schwartz, 1987). The
school is the POHI (Physically or Othenrvise Health Impaired) center for
the Flint District, incorporating all levels of physical/mental ability into a
general education classroom. This incorporation includes individuals with
dependencies on medication to function daily, visual and auditory
impairments, and physical impairments that require the use of motorized
wheelchairs. This incorporation generally beneﬁts all students, but also
creates an atmosphere that could potentially cause separation among the
class because of prejudice and judgment. This potential issue is therefore
addressed by the incorporation of cooperative Ieaming groups.

One characteristic of this Ieaming technique is heterogeneity, in
that groups are developed based on differences between team members

as opposed to likenesses. Applied to the classroom, a team member that

is lower functioning due to medication can excel in the group because
helshe is contributing the ideas that helshe knows the best. Further, the
entire group processes information to assess their level of productivity in
meeting a set goal, becoming accountable for their own individual
responsibilities and recognizing the interdependence that is established in
being a member of a team. In regard to the unit, the students acted as a
team in constructing the two models, delegated individual responsibilities
in collecting twice weekly data, and when confronting a problem in the
investigative process, discussed the matter collectively. Once
established, the connectivity between team members was evidenced in
independent work such as discussion panels. Instead of individual
opinions being criticized, the class more readily accepted each others
views and used them as spring boards for deeper understanding. The
face to face interaction that the cooperative groups experienced
developed trust among team members, as well as communication and
leadership skills (Johnson & Johnson, 1989).

“ConstructiviSm in science and mathematics education has held a
broad inﬂuence on the educational ﬁeld; curriculum, National Science
Education Standards, in a broader audience, politics, applied as a world
view” (Matthews, 2005). While having its origin with Piaget and presently
asserted by Ernst von Glasersfeld, constructivism is taught in educational
theory classes and commonly used within the science classroom. Relying

heavily on the intake of information that is gathered by the senses,

constructivism allows the individual to interact with his/her environment by
seeing, hearing, touching, smelling and tasting. These messages provide
learners with information that. allows them to create a picture of the world,
thus bringing out a personal experience that resides within the individual
(Lorsbach & Tobin, 1992). Although a general theory may be taught in the
classroom, its meaning and therefore its application is inﬂuenced by the
learner. Knowledge becomes personal and ownership of the process
increases because of the development of independent thought processes.
A form of pragmatism, constructivist learning emphasizes practical results
in exploring science, as opposed to theoretical ideology. Esoteric
information becomes real as the learner applies the information on a
personal level and identiﬁes with it. This increased connectivity enmeshes
the learner in the investigative process, granting the student permission to
further seek answers to commonly posed problems. For instance, in the
analysis of the heavy metal lab (wetland tanks) the students identiﬁed with
long term exposure to a toxic substance and projected the outcome on a
human level, even though the lab speciﬁcally dealt with plants. Further, by
constructing meaning from the experiment, although the idea was not
speciﬁcally addressed, the students were able to conceptualize tolerance
of a metal and predeterrnine an outcome when applied to a different
situation. This skill is the beauty of the constructivist theory. Perhaps the

most difﬁcult aspect of using constructivism as an instructor is in “helping

learners to construct models for themselves, to appreciate their domains
of applicability and, within such domains, to use them” (Matthews, 2005).

Regardless of the challenges that constructivism presents to the
instructor, the theory is vital and necessary for generating an interest and
commitment to maintaining a healthy environment, to an otherwise
disinterested group of individuals. Though state benchmarks mandate
that environmental concepts be taught within the classroom, often the
student remains aloof to the necessity of becoming educated in both the
cause and effect relating to the release of hazardous material. Further,
the students do not perceive that they can become empowered to make a
difference when governmental decisions (on this topic) are handed down
to the general populace. Constructivism allows the student to use
previous conceptions and change them to ﬁt their current schema of
knowledge, to trouble their own thinking in rectifying a conﬂict and
connecting the student to the current situation or problem (lshii, 2003). By
creating personal reference to a situation the student moves from a place
of apathy to a commitment to the outcome, in this case the sustainability
of the Earth. Combined with the esteem that is gained from cooperative
learning, and the success experienced in inquiry based exploration,
students carry not only science lessons with them into the world, but life
lessons as well.

Finally, as enunciated by Jean Piaget, cognitive structures change

through the process of adaptation, assimilation and accommodation. The

10

interpretation of events in terms of existing cognitive structure and the
changes that ensue to make sense of the circumstances gives way to a
gain in knowledge and more importantly, a growth of personal experience
(www.tip.psvchologv.org, Piaget, 2/2005). Applied to the classroom, this
would indicate that when the students are tested before a learning unit
and then retested, a substantial percent of growth should occur.
Target Group

A more in depth perspective of the daily activities of the classroom
is included in the implementation of the unit, and with that, a clearer
understanding of the commitment made by the students to move through
the material. The unit was taught in the Flint School District, a school
system that is located within an urban environment and has a total of
18,955 students. While the district was at one time a showcase for
educational practice with expanding student populations, employee
wages, and building growth, it has in recent years suffered due to
decreased economic stability of the area. This has in turn resulted in lower
student population and diminishing educational resources. Within the
district there are yearly lay-offs of teaching and support staff, and
instability within the Board of Education members. Additionally, the
unemployment rate in Genesee County was 8.3% as of October 28, 2004,
markedly above the state average of 6.2% (US. Census Bureau). The
economic depression is evident in the student body with 69% of the

district’s students qualifying for free or reduced lunch.

11

The impact of the economic status of the area is evidenced in the
extremely high mobility rate. Nearly 40 % of all enrolled children in the
district either change schools within the district in an academic year or
leave the district altogether. Not only do the students experience housing
changes, but their academic foundation is altered as they move from
classroom to classroom where the same subject may be taught at a
different pace or in a different timeframe. Consequently, they may be
exposed to the same subject/topic repeatedly or they may continually be
exposed to new information, never having the opportunity to gain mastery
of the subject.

The depressed state of the district is also experienced in the
curriculum. Although one of the ﬁve district high schools is designated as
a “magnet school”, offering advanced classes in science, and the district
has a high school academy, current environmental sciences such as
forensic science, environmental studies and ecology are not offered. The
issue with the lack of alternative science offerings is that most
standardized tests require a general knowledge of these subjects to be
successful on the exams. Due to the time constraints of a school year that
is only 189 days in length, and the necessity of covering approximately 33
State Benchmarks in science, alternative studies though required, are
often overlooked. The unit was taught at Southwestern Academy, the only
high school in the Flint District that requires the students to carry a

minimum of a 2.5 grade average. Although the Academy has relatively

12

high expectations of its 905 students, has the lowest (10%) mobility rate of
the district, and the greatest diversity (67.7% African American, 28.9%
Caucasian, and 3.4% Asian, Latino and American Indian), there is not the
reassurance that all students will experience success. This is evidenced
in the “prerequisite” for enrollment into the Integrated Science class
(where the unit was taught) in that the student’s must have achieved a
grade of either an E or a D in their 9‘" and 10th grade science classes.
This type of academic background leaves the students with compromised
scientiﬁc knowledge, as well as limited laboratory skills and low academic
achievement. With this in mind, the unit was designed to address the
student’s needs, while achieving the goal of increasing the student’s
understanding of contamination, the techniques used to address these

issues, and the impact that human’s have on their environment.

13

Implementation

The implementation of the use of plants as an environmental remediation
technique and related topics, and the effect that heavy metals have on
living organisms within a habitat is outlined in the following pages. The
unit spanned seven school weeks, although the last week was shortened
by Thanksgiving break. Table 1 outlines the daily activities in a general
manner, with more description given in the text, as well as in Appendices
A and B.

Remediation of toxic sites is rarely taught outside of an environmental
science class, although it is expected that high school students are
familiar with the process according to the Michigan Science Content
Benchmarks (lll.5.4, Ill.5.6,lV.1.1) (Appendix A). This unit was designed to
address the pathways that contaminants take and their subsequent impact
on the environment. Designed in the summer of 2004 at Michigan State
University, all of the experiments were newly created, focusing on
increasing student understanding of the subject, as well as improving
laboratory skills and communication techniques, both verbal and written.
The study was focused on metal toxins and the use of plants to remove or
sequester these contaminants as an alternative to traditional remediation
techniques such as landﬁlls and hazardous site caps. Activities such as
leaky pipe joints; run-off from farms, backyards, and golf courses;

untreated or inadequately treated sewage and nutrient over load (due to

14

over fertilization) were used as examples of human actions that contribute
to chemical overload in drinking water, as well as natural water systems
and soils.

Taught in a constructivist manner, the 11‘". grade class of 13 males
and 14 females was broken into groups of 5-6 individuals, based on the
ability of the members of the group to support each other in the learning
process. The participating class, Integrated Science, is designed to revisit
and reinforce all of the Michigan State Benchmarks that are taught to
public education students from middle school through the 10"1 grade high
school standards. The unit required six weeks, focusing primarily on two
in-depth models that simulated environmental conditions. Most of the
class activities inVolved the observation and testing of the models.
Research, notes and class discussions added dimension to the students
understanding and knowledge base. Much of the fundamental knowledge
regarding the environment as a system and the interdependency of all
parts had been previously taught, at least minimally in 10th grade biology.
This foundation allows for a more expansive, current - issue based
classroom. Although speciﬁcally designed to ready the students for
standardized test situations such as the ACT and MEAP, the instructional
premise is that if the students are taught basic science knowledge that is
applied to everyday human issues, the knowledge and learning become
less institutionalized, and the students attain success. One of the greatest

challenges that we faced as a class was that we had no text books for

15

either reading or conceptual images. Consequently, a number of days
consisted of note taking, class discussion, reading adopted reference
material and interpreting instructor generated drawings.

The principal assessment tool that was used to measure student
comprehension and knowledge growth was a pre and post test. The series
of ten questions addressed key concepts that formed the foundation of the
unit. All of the questions were constructed responses, which provided the
students with the opportunity to express their own individual
understanding of contamination, remediation and its impact on the natural
world. This information was analyzed statistically using a paired student t
-test and used to measure the success of the unit. However, a journal
which contained the student’s observations, personal opinions, laboratory
reports and data analysis was also considered in the student’s ﬁnal grade,
and analysis for this project. Appendix P-1 shows the journal rubric,
expectations and point scale. The students were encouraged to record
their daily thoughts about the laboratory work in which they were involved,
evaluate their own growth, and answer their own questions through
classroom investigations. Not only did the journal keep all of their work in
a central location, it provided a guide to the progression of the
investigations and illustrated a more advanced approach to record
keeping (when compared to 9‘" and 10th grade science classes).

Appendices D-O includes student assignments and reference notes for

16

both the students and the teacher, and the pre/post test is found in

 

 

 

 

 

 

 

 

 

Appendix C-1.
Monday Tuesday Wednesday Thursday F riday
Heavy Tank Professional Tank Field Trip Protocol,
W Metal Lab Construction, Development ConStruction, Heavy Metal
K Introduced Journal Entry Mineral Deﬁnition/discussion
Unit Expectations Requirement Self-sustaining
1 intent, Notes mechanisms
Pre-Test
Field Trip Plants Placed Remediation 8 Macro/micro Soil Test from Bull
W to Bull in Tanks, Contamination Nutrient Frog Pond
Frog Pond Planting Discussion, Bull Notes, Plant
K Techniques Frog Pond Physiology
Taught Questions- Drawing (lab
Analysis books)
2
Tank Research Remediation Remediation Plant Count, Soil
W Monitoring Computer Lab Notes/Discussion Notes Test Protocol, Red
K CuSO4 - Finished, Worm Lab
addition to Scorecardcom Discussion Construction
3 tanks of Local
Impact
CuSO4 to Plant Count, Red Worm Scorecard, Red Worm
W Worm CuSO4 Water Count, toxicology Population Count
K Jars, Tank Test, Bio- Toxicology pathways
Care accumulation Pathways - Association
4 Activity Student Activity, EPA
Discussion Reading
Red Acid/base Lab, Red Worm Computer Plant Prep. for
W Worm and Soil Population Research CuSO4 Presence
K Plant Percolation Count, Computer Project Test, Final Plant
Count, Demo Research Project and Worm Count,
5 CuSO4 Research Project
Water test Due
Final Red Final Plant Data Analysis of Thanks— Thanksgiving
W Worm Count, Heavy Metal giving Holiday
K Count, Deconstruct Lab, Data Holiday
Compile tanks, CuSO4 Analysis of Red
6 Class Presence Test Worm Population
Data in Water/Plant
W Post Test
K Discuss
7

 

 

 

 

 

 

Table 1: Phytoremediation Unit Outline

Activities and Experiments conducted over a seven week period.

17

 

 

(Phytoremedlatlon\
Unit

 

 

x e 2.

 

 

( Content Standard r\
Constructing New
Knowledge

 

 

 

 

ﬁwestigating real worlh
models

Field trip to remediation

 

 

 

Investigating and
Gathering lnforrnation

 

L
Generation L1, L2, LA

 

K Biololgy ".6 \

Develop awareness and
sensitivity to natural
world
Toxic effect on living
things

 

 

 

 

 

gathering information

 

( Investigating and I

 

 

Evolution lll.3 \
Adaptation of living
things to toxic habitat
Ecosystems lll.5
Habitat change and
cycling of toxic

 

 

 

site
L

 

J \

 

K Cooperative Leaming\
Groups
Inquiry —based Learning

 

 

 

/ Wetland Tank Modem
Red Worm Habitat

Computer research into
local contamination

 

 

\ J

 

\ J

j k materials

Figure 1: Flow Chart of Content Standards and Main Unit Ideas

The Flow Chart above connects the main ideas of the unit to the Michigan
Content Standards and Benchmarks. The descriptions are condensed,

and explained in greater detail in the body of the text.

18

Week One

The song “Rescue Me” performed by Dougie MacLean opened the
unit. The song was written from the perspective of a farmer who after a
number of poor harvests and some investigation, learns that the
individuals who had farmed the land for generations before him had used
pesticides that had poisoned the land and inﬁltrated the water supply of
the surrounding area. This song demonstrated that contamination is not
always deliberate, that it is a global issue and that the aftermath of
chemical exposure can be toxic and far reaching for years after the
contamination event. After hearing the music students were encouraged
to express their opinions and voice prior knowledge that they had about
pollution, and the idea that as human beings there is a personal
responsibility in making choices that are not harmful to either the
environment or the organisms that inhabit it. This introduction and the
discussion that followed set the stage for studying phytoremediation of
heavy metals. A pre-test taken the ﬁrst day indicated that over half of the
students had no awareness of heavy metals, soil types or remediation
techniques.
Tank Construction

The remainder of the ﬁrst week was spent the constructing model
and basic knowledge that would be used throughout the unit. The
objective of the model was to recreate a living environment that mimicked

a natural habitat that had been contaminated by a heavy metal (copper

19

sulfate). The tanks for the Heayy Metal lab (Appendix D-1) were
assembled in groups of 5-6 student’s using 5 gallon ﬁsh tanks, wooden
dowels and landscape fabric to illustrate a water/land environment and
required two days to construct. The students used the remaining class
time to discuss journal entry expectations and to copy reference notes on
plant and human mineral requirements (Appendix E). On the ﬁnal day
students were given questions (Appendix B-2) they would be required to
ask/answer on the ﬁeld trip scheduled for the following Monday, students
were also provided with a ﬁeld trip protocol and natural wetland history. As
an overview assignment, the class read an essay “Self- Sustaining
Mechanisms in an Ecosystem” (Appendix F) and answered questions
relevant to the passage. This work gave them a background on both the
biotic and abiotic factors that are active in an ecosystem, so that when
they went to Bullfrog Pond the following week, they would be able to
identify those parts of the system. The radish and lettuce seeds that were
to be placed in the land/water tanks were germinated over the weekend.
Week Two

The second week of the unit began with a ﬁeld trip to a wetland that had
been reclaimed after 100 years of farming wheat and corn. Under the
Food, Agriculture, Conservation, and Trade Act of 1990 (P.L.101-624)
(www.water.usgs.gov/nmspmNVSP2425ll§gislation.html) land owners of
agricultural ﬁelds drained of their wetlands who are willing to reestablish

the area to its natural state receive tax deferment and assistance in

20

replanting native grasses and ﬂowers. Guided by a representative of the
Soil Conservation Department of Michigan, the students spent the school
day gathering water and soil samples, both from the marsh site as well as
the reclaimed ﬁeld. Included in the ﬁeld trip was the opportunity to tour
some of the 100 acres, noting varying stages of succession on the land.
This led the students to not only answer the required questions, but also to
generate their own questions based on observation. The following day the
soil from both sites was removed from the collection test tubes and dried
in labeled petri dishes.

Plant Placement

The students were assigned to teams of 5-6 students, based on both the
ability to cooperate with each other and the interrnixing of cognitive levels
so that all participants could learn from each other. Each group was then
assigned plants, so that as a whole the class would conduct a group
experiment over a three week period of time. The plant species varied,
based on their ability to withstand exposure to heavy metals. All groups
“planted” 40-50 individual Lemna minor (a metal tolerant water plant), one
group planted lettuce (a metal intolerant plant), one group planted radish
(a tolerant plant), two groups planted both lettuce and radish (one group
would contaminate with copper sutfate, the other would not), and the ﬁnal
group received only water plants. The groups were instructed to place

approximately 60 of their assigned plants into the soil side of the tank

21

models, paying close attention to seed depth and over population in one
area of the tank.

The students recorded the experimental data in their journals and also
recorded any impressions or opinions that they had developed in
response to the tank activity. Because the experiment spanned three
weeks, a pattern had to be established as to when the plants from both
the water and land environment would be counted and when soil testing
for the presence of copper sulfate would be conducted. Once the
seedlings had broken the soil surface, counting the plants and conducting
the copper sulfate tests occurred every ﬁve days and the tanks were
aerated using a motorized aerator every three days to reduce the
possibility of an anaerobic environment. The next two days included group
discussions of the Bullfrog Pond ﬁeld trip questions, the purpose of
remediation techniques as applied to contaminated sites, the deﬁnition of
contamination, and the transcribing of notes (Appendix J) that generalized
the need for speciﬁc macro/micro nutrients by plants to maintain health.
Additionally, the students illustrated the basic structure of a plant which
assisted in creating a model of contaminant uptake. Finally, the students
conducted rapid result soil tests on the samples taken from Bullfrog pond.
These results were recorded in their journals, along with their responses
from the ﬁeld trip questions

Week Three

22

Contamination

The week started with the students spending the day monitoring the
plant growth in their tanks, recording observations of changes, and adding
300 ml of 0.1 M copper sulfate solution to the land portion of their group’s
tanks, taking care not to saturate the newly emerged plants with the heavy
metal solution. Discussions included where situations that were modeled
by the tanks would occur in nature, in particular in the students
environment. The Flint River is a major water system that is present in the
area where the students live so most of them had some exposure to the
physical structure of a water/land interface. This exchange of ideas fed
into the next day’s activity of computer research on polluted sites in
Genesee County. The students accessed Scorecardorg in the computer
lab, a web site that lists all of the industrial businesses that have
contributed in some way to polluting the environment. Although the
students had no formal assignment associated with this activity, they had
the opportunity to view the great number of factors that affect an area and
contribute to the overall “wellness” of their environment. Listed on the
website are the documented chemicals and their effect on human health,
the location of the contamination and the proposed protocol for cleaning
the area. This gave the students a greater understanding of human
exposure to toxic substances due to unsafe industrial practices and
generated interest in the best practices for removing hazardous

chemicals. The next two days the class took notes on remediation

23

techniques (Appendix B-5), focusing entirely on the use of plants to
remove substances from a contaminated area. This activity threaded the
previous knowledge of plant physiology to application, and the students
began to understand the uptake mechanism of the plants and how they
either sequester or breakdown the toxins. The notes were used to extend
class discussion on remediation, and how landﬁll use is not always the
best technique to remedy a contamination problem. The students spent
the last day of the third week counting their tank plants, noting not only
numbers, but physical condition of the plant such as color, size and leaf
growth. The protocol for copper sulfate test was reviewed and the R_eq
worm Lab (Appendix K-1) was read aloud by class members.

Redworm Lab Construction

The intent of the lab was to demonstrate the effect of varying
concentrations of a toxin on organisms that live within a habitat. This
activity also showed that organisms can develop some level of tolerance
based on the organism’s physiological mechanisms to tolerate or remove
a toxic substance. I demonstrated for the class how to construct the red
worm habitats, and to save time I mixed 0.125 gm, 0.250 gm, 0.375 gm,
and 0.500 gm of copper sulfate per 100 ml. of water in large labeled
beakers so the students could concentrate on measuring and applying the
solution to the soil in the habitats. After observing the demonstration, the
groups began to construct the red worm vessels. One member of each

group weighed soil for ﬁve different trials, two other members gathered,

24

counted and weighed the required red worms, and the remaining team
members gathered and labeled jars. All of the information from the
various team members was gathered and recorded in each individual
member’s lab sheet. The teams decided to let the worms adjust to their
new environment before changing any components of the experiment, so
the habitats were constructed with the understanding that the copper
sulfate solutions would be added on the ﬁrst day of the following week.
Observations and opinions were noted in the student’s journals.
Week Four

The fourth week was spent maintaining and testing the developed
experiments. The groups measured required copper sulfate solutions,
loosened the soil from the red worm habitats, observed the worms (4-5
per habitat) general condition and added the solutions to the jars. One of
the jars was maintained as a control, with only water added. All of the jars
were left with open tops to permit oxygen exchange for the worms. The
ﬁnal minutes of the class were used to aerate the water/land tanks, and
make observations regarding plant conditions. The next day the students
reviewed the protocol for the testing of copper sulfate presence in the
water portion of the water/land tanks of the Heaﬂ Metal Effect on Plants
La_b (Appendix D-1), and I explained and demonstrated the proper
procedure for testing the water (Appendix A-1 teachers edition). Once the
students had gathered the needed equipment and had obtained an

adequate water sample, they placed one drop of the testing sample in a

25

spot well and one drop of distilled water in an adjacent well to be used as
a control and tested with ferric thiocyanate an indicator of copper sulfate.
The students looked for presence of copper sulfate which signiﬁes the
movement of a heavy metal contaminant through the environment. Most
groups showed some degree of copper being present, and all members of
the group made note of the color changes (with the clearness of the
solution indicating concentration of copper) and concentration numbers in
their journals. As this lab progressed for 2 more weeks, the concentration
of copper sulfate in the samples increased due to leaching through the
environment. This suggests a greater likelihood of lethal effects on the
water plants (Lemna minor). Ending the day, students acted as individual
components of an ecosystem which had experienced the accumulation of
a toxin (Bioaccumulation Activity, Appendix L). The following day the
students removed their worms from their jars, massed and counted all of
them and noted in their journals any observable changes. Many of the
groups worms had started to die, with the remaining worms showing
increased lack of movement and discoloration in their body. This
procedure was to be followed every two days, with the exception of the
weekend. Students recorded deaths in their lab charts, and the soil in the
jars was stirred to ensure proper aeration. The remainder of the class
session was spent discussing toxic pathways such as industrial spills,
pesticide and fungicide applications on lawns and ﬁelds, and toxins that

reach the soil and water through the air. The students generated most of

26

the ideas and were encouraged to visualize the path that the toxins took
once they were released in the environment. This informal process
created an atmosphere of relaxed imagination, and resulted in innovative
ideas, all of which were recorded on the board for futureuse. The next
class period was spent utilizing the information that had been gathered
from the previous work (week 3) in the computer lab with Scorecardorg.
Comparing the known hazardous material in the local environment, the
students used the ideas that they generated on the previous day about
contamination pathways and cross referenced the information.
Constructing Knowledge

Beginning with a ﬂow chart, the students mapped the source of the
contamination, the type (physical state) of toxins that were produced, the
contaminant release point, and the known effects of the toxin. They went
on to generate a Venn Diagram that illustrated the interrelatedness of the
point of release and the possible pathways that the toxin could take, such
as water systems, air pollution or land contamination. In the center of the
diagram was where the information crossed over and listed which
organisms would be affected by the toxic exposure. Although this was a
difﬁcult mental exercise, the students were successful in utilizing the
information gathered from the computer and applying it to a real life
situation. Finally, the students repeated the process of weighing and
counting their red worms, and ﬁnished the day by reviewing and writing in

their journals.

27

Week Five

The ﬁrst day of week ﬁve was a maintenance day in which students
repeated the copper sulfate water tank test, counted and observed tank
plants, weighed and counted red worms, recording all of the information in
their journals. The next day opened with an acid/base precipitation lab,
“Now You See It. Now You Don’t” (Appendix M1). The purpose of the lab
was to show that the acidity of an environment contributes to the
bioavailability of metals for plant uptake. The solutions were prepared to
save time (teachers version Appendix A-4). Basically, the students
counted the drops of sodium hydroxide and hydrochloric acid needed to
force the solution to ﬂocculate with the addition of a base and return to the
original clarity by adding an acid. The test was repeated to match the
original experimental results of ﬂocculation and clarity, but adding a buffer,
realizing that the addition of the buffer created the need for a greater
amount of both the base and the acid. The questions following the lab
asked the students to apply this experiment to an everyday situation
where a buffer was present. Post lab discussions covered the importance
of lowering the pH in the soil of a contaminated site to assist plants in
removing or “taking up” metals from the ground. This exercise brought the
lesson back to remediation and was reinforced with a demonstration on
soil percolation. “Bottled Water — What is 99319 on with the GrorLd”
(Appendix N) was originally designed to be conducted as a student based

lab, but the constraints of time dictated that the lab be transformed into a

28

demonstration. This demonstration showed the type of soil substrate
that a hazardous substance moves through dictates the degree of
contamination exposure to an ecosystem. The students massed, counted
and observed their red worms the next day.

Research Project

Utilizing the background information gained regarding contamination and
heavy metals, they embarked on a research project. Based on a series of
questions (Appendix I), they used the computer to gather the information
about heavy metal toxicity, its effect on plants, the sources and pathways
of the contamination and remediation techniques used to remove these
substances from the environment. Although this paper was originally
intended to be an informal assignment, the end result was a research
paper that included the students opinions. This type of inquiry allowed the
students to develop their own opinions while following a more forrnal
guideline. The grading rubric for this assignment is found in Appendix I.
The last day of week ﬁve was spent completing the research document,
weighing and counting the red worms, and reviewing the processes
needed to complete the plant count from the tank experiment.
Additionally, all of the plants were counted and pulled from the tanks and
ﬁnal observations made. The healthiest of the surviving plants were
separated out, placed on a labeled watch glass and dried for ﬁve seconds
in a microwave. This process assisted in removing the water from the

plant material, with the remainder of the water being removed over a two

29

day period through air drying. All groups then placed the watch glasses on
a shelf that had been labeled with their group name, and left them there to
dry over the weekend.
Weeks Six and Seven

The ﬁnal two weeks of the unit was interrupted by the Thanksgiving
holiday, but the core work with the long-tenn experiments was completed
in week six. Groups counted and weighed their worms, recording physical
states of the worms as well as deaths and amassing the information on an
overhead projected data sheet. All groups had recorded some worm
death, with the numbers increasing as the concentration of the copper
sulfate increased. This experiment clearly deﬁned for the students the
association between contaminant concentration and the impact on living
organisms. This was evidenced by their written responses to the lab
questions which were completed on the third day of the week. The next
day the students deconstructed the plant tanks, and prepared for the ﬁnal
testing of copper sulfate concentration in the plants that were removed
from the soil and water (Appendix D-1). All groups tested positive for the
presence of copper sulfate in their plant material, with the radish and
Lemna showing the greatest copper concentration. The lab concluded
with a series of questions that used the degree of student comprehension
as an assessment to the success of the experiment (Appendix C-2). The
students completed the week by compiling data, as wellas discussing the

results of the water/soil tank experiment.

30

Returning after the Thanksgiving holiday, the groups reconvened
for ﬁnal discussions on the success of the plant uptake of contaminants in
the tank environments and how phytoremediation could. be used as an
alternative technique for sequestering hazardous substances. The unit
was ﬁnished when the students completed their post test, placed their ﬁnal
opinions in their journals and turned in all lab work/joumals for
assessment (Appendix P-1).

To support the implementation of this teaching unit a pre and post
test were given to the students to indicate growth in knowledge that would
justify the amount of time spent in teaching the remediation unit.
Additionally, journals were used to give structure to daily activities, as well
as to reinforce Southwestern Academy’s commitment to “writing across
the curriculum”. By utilizing both of these assessments, the pre/post test
that gaVe statistical data and the journals that indicated an increase in

writing ability the class was able to fulﬁll the expectations of the school.

31

Results

Pre and post test comparison and analysis of the phytoremediation unit
can be found in the following pages. Each of the questions in the pre and
post test addressed a speciﬁc objective that was taught in the unit, and the
students answered each question as a constructed response (objectives
for constructed responses in Appendix C-2, rubric in Appendix P-3). All of
the students showed improvement in their test scores, some signiﬁcantly
more than others. Student performance per question as an overall class
average is presented in the ﬁnal pages of this chapter. Figure 1
graphically summarizes student performance per test question. Table 2
summarizes the results of the Paired Student t-test, which indicates the

rejection of the null hypothesis.

32

 

lpretest Iposttest

 

anon-v.1

"O’N'IOO

Figure 2: Comparison of Pre and Post Test Scores.
n=20

 

Table 2: Results of testing for the rejection or acceptance of the null
hypothesis.

In the analysis of the paired student t—tests, 0.05 was used as the limit for acceptable
data. The probability for all test questions was below the acceptable limit, indicating that
the data was valid.

33

The average improvement of student performance was 47%. The topic
that showed the greatest improvement in understanding was the recycling
of plants that had been used for phytoremediation, which showed a 58%
gain over the pretest. The topic that showed the least amount of
improvement was the naming of examples of natural remediation sites,
which had only a 38% increase in comprehension. Due to the question
being written in a constructed response manner, most of the students
responded in giving part of the expected answer, but did not provide a
comprehensive response. Each question will be analyzed separately and
discussed, and the paired t—test results will be provided. For all of the pre
and post test questions, the null hypothesis was rejected with the p value
ranging from 0.000 to 0.012, indicating that there had been a gain in

students’ understanding for all objectives.

Question 1: What is meant by “heavy metals”? How do they differ
from other metals?

This concept was not part of the students prior knowledge. Over half of the
students left this question blank on the pretest and only 40% of the class
recognized that heavy metals had a higher density than other metals.

This idea was vital to the unit in that copper (considered a heavy metal
because of its ability to accumulate in the environment) was used in both
the Red Worm Lab and The Water/Land Interface Lab as the hazardous

contaminate. On the post test however, 80% of the students answered the

34

question correctly with responses such as “metals with high density at a
low concentration, which become toxic to the environment”, and “heavy

metals are dense metals that effect [sic] the environment”.

Question 2: Deﬁne toxic.

Fifty percent of the students answered this question correctly on the pre
test, in part because the term “toxic” has a relatively broad application to
life and most of them had prior knowledge. The critical idea in this
question, however, was that any substance can become toxic if it is able
to reach a concentration that causes it to accumulate and leaves the
affected organism unable to tolerate its presence. Not only was this
concept taught in both of the major labs (Red Worm and Water/Land
Interface) but was reinforced in the “Bioaccumulation Activity”. As a result
of these lessons, 90% of the class correctly responded to this question
with responses such as “something that is poisonous to humans and other

organisms” and “something at low concentrations that is harmful”.

Question 3: Describe how a substance can become toxic.

This question relied on the understanding that any substance can become
toxic if it is able to reach a level of concentration within a system
(organismal or environmental) where it cannot be disposed or removed
from the system, if the substance is not inert. The concept also

established a connection between a substance entering the environment

35

and the techniques used to remove or sequester it. In analyzing the pre
and post test data, there was a 51% increase in correct answers, with the
pretest showing 22% comprehension and the post test showing 73%. Key
to the students understanding of this idea was the Red Worm lab, in which
the student’s observed and collected data of the effects of varying

concentrations of copper sulfate on the health of the worms.

Question 4: Name three different ways that heavy metals are known
to enter the environment.

The expected responses to this question were broad, in that there are
multiple ways for a contaminant to enter the environment. However, there
are general pathways that are the result of human activities such as 1
industrial contributions, car exhaust, fertilizer application and the
destruction of natural remediation sites like wetlands. As with question #3,
the student’s showed an increase in regards to understanding, with a gain
of 54% of correct answers for the overall class. While some of the
students’ named the phase that the heavy metal may be found in “solid
and liquid” as a pathway, most of the students successfully listed the
activities that contributed to environmental pollution, such as “landﬁlls, oil
spills, agricultural activities”. It is interesting to note that despite the ﬁeld
trip to a restored wetland the students did not readily name agricultural
activity as a contributing source. In part, this may be due to the class

having an urban background.

36

Question 5: Explain why lower organisms, such as plants and
invertebrates are the ﬁrst living things to be affected by toxic
contamination.

This concept was also not a part of the student’s prior knowledge, as it is
an ecological idea that is not taught in a general biology class. The
question was not intended to imply that all plants are lower organisms,
rather to activate the students thinking of living organisms that are not
human. With that, 25% of the class responded to this question correctly
on the pretest, with a 48% growth shown on the post test or 73% correct
responses. The basic point of this question was to assess whether the
students realized that by the time a toxic material is shown to affect the
human population, multiple organisms and plants have already been
exposed to the substance. More importantly, based on the laboratory
exercises, the students should have made the connection between the
toxic substance being present and how the plant or organism deals with it.
This was successfully shown in the post test responses, such as “toxic
contamination can occur in the soil and water. Plants take up the toxin

through their roots”, and “they are closest to the environment”.

Question 6: Describe the different soil types and explain why soil
composition affects the toxicity of a contaminant.
The general responses given by the students indicated that they had

gained an understanding of particle compaction and that the amount of

37

space between these particles leaves room for contaminants to
accumulate. The change of 40% between the pretest percentage of 13%
and the post test percentage of 53% supports overall success of the
student’s comprehension on this subject. However, on the post-test most
of the students were unable to describe the different types of soil. This
was possibly due to the lack of laboratory activities that related to the
subject. Other than one comparative demonstration between sand, soil

and a sand/soil mix, the class was not exposed to varying soil types.

Question 7: Deﬁne remediation and explain why it is important.
Thirty ﬁve percent of the class had some idea of how remediation was
deﬁned and its implications to human health prior to the unit being taught,
as indicated by the pretest. As this was an idea that was central to the
unit it Was expected that the class would gain a solid understanding of the
process of containing and removing a toxin from an area. With the post
test result of 83% correct answers and student responses such as
“cleaning the environment” and “allowing things to remain alive”, even the
lowest performing student gained some understanding of the community

beneﬁt of remediation.

Question 8: Deﬁne phytoremediation and explain how plants are able
to “take up” metals through their roots into the shoots, stems and

leaves.

38

This question addresses a more sophisticated understanding of
remediation in that it requires the student to not only comprehend the
technique of remediation, but speciﬁcally the use of plants in this process.
Additionally, basic plant physiology must be used to successfully answer
this question. With that, only 7% of the class was able to answer this on
the pretest, indicated by only three of the 20 students answering the
question at all. However, there was a 53% increase in correct answers on
the post test, with 60% of the class responding in an expected manner.
This was encouraging, because it signiﬁed a comprehensive
understanding of a number of concepts, namely, that once a contaminant
enters the environment there are a number of processes that can be
utilized to remedy the situation. This understanding was exhibited by
student responses that included, “the plants take them (toxins) up through
their reots, taking them into their stems and leaves, and removing them

from the soil”.

Question 9: Give an example of a natural remediation site that can be
found in nature.

It was expected that this question would have the greatest gain in
acceptable answers when compared to all other test questions. This
expectation was based on the fact that all of the students that took the pre
and post test also went on the ﬁeld trip to a local wetland. They discussed

at length the role that a wetland plays in the remediation or cleaning of a

39

contaminated area. It was surprising that there was only a 38% increase
in the test scores, the lowest gain of all ten questions. On the pretest only
three students attempted to answer the question, resulting in a 10%
correct score. The post test did show a gain, with 48% of the students
answering correctly. With hands on Ieaming, it was expected that the
students would show greater growth than they did. In review of the student
answers, there appears to be a misunderstanding of the term “natural
remediation sites” since “a water treatment plant” was a commonly given

response.

Question10: Can plants used for phytoremediation be recycled?
How?

The ﬁnal question of the test was basically an extension question, one in
which the students were required in the post test to use the knowledge to
which they had recently been exposed and extend it into an unknown
situation. The post test indicated that all of the students gained
knowledge, either through the lessons that were taught in the unit or their
own research that they had conducted on heavy metals and
phytoremediation techniques. This gain in understanding was exhibited
by an overall increase of 58% in test scores, changing from the 2% pretest
scores to the 60% post test score. Only one student attempted to respond
to this question on the pretest. Although there were six students that did

not respond on the post test, most of those who did received full credit for

40

their answers. None of the class remembered the discussion that focused
on the technique of removing the metals from plants used for remediation
and the “reclaiming” the metals for future use. However, some did state
that “because the plants could release the toxins into the air

(phytovolitilization) they could be reused for cleaning the ground”.

Remediation Unit Evaluation

A unit evaluation was given to the students as a measure of what the
students felt was most helpful and what components of the unit they
disliked. None of these questions were rated on a point scale, so the
results were compiled from the survey as the “most frequently given
response”. This is a subjective evaluation, but worthy of consideration as
it allows the students to voice their opinion and aides in judging the most

effective techniques used to teach the unit.

Question1: Did you learn anything about how toxins in the environment can harm
living organisms?

All students answered yes to this question.

Questions 2: Are there natural systems in the environment that can clean toxins
out of
the soil and water?

90 % of students answered yes.

41

Question 3: List three things that you learned from this unit
a. Adaptations by living organisms
b. Soil toxicity and toxicity of chemicals in the environment
c. Plant removal of toxins
d. Tolerance of worms
e. Ability of the environment to clean itself
f. Effect of toxins on water and how to keep it clean

9. Industrial impact on environment

Question 4: Did your opinion of the impact of humans on the environment change
after this unit? If yes, how?
10 students answered yes, 14 answered no. None of those responded indicated how

their opinion had changed.

Question 5: Did you know before the unit that plants have the ability to clean up
contaminants from the environment?

5 students had prior knowledge, 19 did not.

Question 6: If you had to decide if an area was contaminated, what part of the
environmentlhabltat would you look at ﬁrst and why?
3. Soil — 10 student responses
b. Water - 7 student responses

c. Plants - 3 student responses

Question 7: What activities that you were involved In helped you learn the most?
Why? '
a. Bullfrog Pond - 13 responses “easier to understand”

b. Red worm Lab - 12 responses “adaptation”, “how toxins effect the soil”, “fun”,

42

“hands-on”, “taught how to keep the worms safe”.
c. Wetland Tanks — 5 responses “watched the plants groW', “a real environment”
d. Soil Column Demo. — 0 responses
e. Precipitation Lab -1 response “hands-on”

f. Research Paper - 3 responses - no reason given

Question 8: What was the best part of this unit and why? (Ranked In order of
preference)
3. Redworm lab
b. Bullfrog Pond Field Trip
c. Tanks
d. Research

All students responded that these activities were fun and the easiest way to learn.

Question 9: What was the worst part of this unit and why? (Listed in order of most
commonly given answer)

a. Worm death

b. Research

c. Tanks difﬁcult to understand

(I. Time involved (length of labs)

e. Work too advanced

f. Clean up

9. Notes

Question 10: Give one suggestion to make this unit better when it is taught again.

The responses that the students gave mirrored the responses from question 9.

43

Discussion
Environmental concepts and ideas are most commonly taught in 10th
grade biology class, with very little attention given to citizen responsibility
and action. Additionally, as a tax payer we are required to support
environmental clean-up procedures, but generally as a whole we remain
uneducated (Chiras, 1994) about where and how our tax dollars are being
spent. It is in this vein that the phytoremediation unit was developed for
Integrated Science. The primary objective was to educate the students on
a subject that is not usually taught in a traditional science classroom, with
the possible exception being environmental science. The hypothesis in
developing this unit was that students would learn about the cause and
effect relationship between humans living on the planet, toxic waste that is
generated and remediation options that are available. The general take
home‘lesson was that all systems operate under the assumption of
balance and that when any part of the system undergoes a change, the
system as a whole is affected. In this case, the wetland was the general
system and the change occurred when copper sulfate was placed in the
models (a water/land tank, and a red worm/soil system). The students
observed changes in the organism’s health, reproductive ability, growth
rate and consequently, death rate. They conducted tests to determine if
any of the metal was displaced or taken up by the plants that were present
in the tank models, and ultimately conducted population studies on both

the plants and the worms in both of the models.

44

As the students moved through the unit they gained skills in long term
record keeping and improved their ability to record laboratory
observations. Additionally, they developed advanced laboratory
techniques in regards to chemistry, perfecting research techniques and
broadening their overall knowledge about human impact on the natural
world and the importance of caring for all organisms within the system.

The original intent of the unit was to focus on the use of plants as a
remediation technique in removing heavy metals from the environment. As
the unit progressed however, it became increasingly clear that as a whole,
the unit was broader in its scope. Not only did the unit target the success
of plants (to live) in the presence of a toxic substance, but it also
encompassed the ability of living organisms (in this case, red worms) to
accommodate these same substances. Basically, the unit developed into
some aspect of a population study. While this was not intended and
certainly not expected, it was a welcomed beneﬁt of learning and
instruction. When the students realized that organisms who dwell in the
soil are one of the ﬁrst to be affected when a toxic material is introduced
into their habitat, they immediately made the connection to a broader view.
That is, a toxic substance that harms or kills plants and invertebrates, may
eventually harm humans and other mammals. Many of the discussions
that followed the unit centered on the human body and its ability to adapt
to exposure to a toxic material. The students used their previous

knowledge of body systems by tracing the pathways that a toxin would

45

take, and the organs that were responsible for the sequestering and
removal of the material. Subsequently, they also gained a more realistic
point of view regarding the fragility of life.

The unit centered around two relatively long-term studies, one a
model of a water/land interface and the other a small scale model of a red
worm habitat. While the wetland tank model was intended to span a four
week period of time, due to the constraints of a holiday weekend and the
interruption to the testing schedule, the experiment was shortened by one
week. After the subject of toxins was introduced on the ﬁrst day and the
pre-test was given, the students began to construct the tank models for
the wetland tank experiment. Most of the subsequent activities took
longer than expected, resulting in a number of the projected activities
being dropped from the unit. Basically, the students had no experience
with self directed Ieaming and to a certain extent felt lost without-the
instructor directing them throughout every procedure. However, as the
unit progressed, they became more conﬁdent in their ability and took the
initiative to complete the tasks at hand. For instance, the students had no
idea how to plant seeds into the soil or that rocks were needed for
aeration on the bottom of the tanks to ensure that the plants would receive
proper oxygen for growth. Also, it was not until the second week that the
class began to show a personal interest in the plants and the effect that
the copper sulfate was having on them. As the plants broke the surface of

the soil, the class realized that they were dealing with living organisms.

46

To save time in the future, adult plants would be used so that the root
systems would be established sooner allowing the copper sulfate to be
added earlier to the tanks and extending the experiment into the fourth
week. One other issue that created some anxiety among the class was
the complexity of the chemical test for the presence of copper. The
students had not been exposed to advanced chemical testing (keeping
track of ferric thiocyanate and sodium thiosulfate), were not familiar with
the equipment (spot plates). Because they were hesitant to reread the
directions, a number of the tests had to be repeated. One possible
solution would be to start training the class on laboratory procedures
earlier in the year, so that they would feel conﬁdent in their ability.

In retrospect, this lab was successful in teaching phytoremediation,
in that, when the class compiled their data, it was clear that the tanks that
had land plants in them, and particularly radish, had the greatest Lemna
survival rate. This was the point of the experiment. When metal tolerant
plants are placed in soil that has been contaminated, they successfully
slow the percolation of the toxin into the surrounding areas (represented
by the Lemna), ultimately retarding the death rate of surrounding plants.
In answering the post lab questions the students generally answered in full
statements and with vocabulary that they did not have prior to the
experiment. The only consideration for future use would be to conduct

this lab after plant physiology and tolerance mechanisms had been taught,

47

so that the students held some prior knowledge to generate solutions that
apply to the model.

The students were required to enter information into their
lab/composition books on a frequent, if not daily basis. It became clear
that they did not have a background that included writing their own
opinions down on paper, and for the ﬁrst few days stumbled on exactly
what to say. Initial writings included “we had to put rocks and sand in the
tank and ﬁlled it up with soil” and “we put blue stuff in the tanks”, but
eventually progressed to “the tanks are doing good [sic], we put copper
sulfate in the jars to see how long the worms can live in there. I think if will
be a few days” and “today we took the mass of our worms and we noticed
that our mass was getting both higher and lower”. This exercise could
have beneﬁted from having the students engage in journal writing and
scientiﬁc observations prior to the unit being taught so that theywere both
familiar and comfortable with the process. The lack of journal entries also
reﬂects the students’ general apathy in following through with long term
assignments and required reading of experimental procedures. A
consistent theme throughout the unit was that the class did not reread
procedures and data requirements which ultimately led to some of the
groups having to repeat tests so that reliable data could be collected.
Again, this issue could be rectiﬁed by practicing the skills prior to utilizing

labs that require long term observations.

48

The ﬁeld trip to a restored marsh/recovering agricultural ﬁeld
(Bullfrog Pond) was a huge success. The director of the outreach program
sponsored by the Genesee County Soil and Conservation Ofﬁce, Gary
Huffman was both knowledgeable and patient with the class as he took
them on a tour of the grounds, answering their questions and assisting
them in conducting soil and water tests. Upon returning to the classroom,
the students retained the information that they had learned, evidenced by
correctly answering ﬁeld questions that they had been asked. The hands-
on experience aided the students in understanding the notes (because it
gave them a point of reference) on both nutrient requirements for plant
growth and sustaining mechanisms, an activity that focused on
maintaining the balance within an ecosystem. On the post unit survey the
ﬁeld trip was ranked as one of the classes’ favorite activities, in part I
believe, because the students were able to construct their own personal
meaning. One difﬁculty that presented itself with the soil testing from
Bullfrog Pond was that the rapid soil test capsules that were used in the
soil testing did not dissolve well and the directions were difﬁcult for the
class to understand. In repeating this exercise, I would type the directions
out for greater ease of understanding and perhaps use a more traditional
nitrogen, phosphorus and potassium test that did not rely on encapsulated
chemicals. Additionally, on the post test, the question that referred to this
experience (#9) had the lowest percentage of growth when compared to

the pretest. I found this confusing, given that the class had the

49

opportunity to directly interact with a natural wetland/remediation site.
However, it is possible that post ﬁeld trip discussions did not reinforce the
natural remediation site concept.

Throughout the unit the acquiring of skills was heavily dependent
on class discussion and the voicing of individual opinions. The ﬁrst class
discussion was at best halting, but as the students relaxed with each other
and their cooperative teams, they became more vocal. At the end of each
activity the class was encouraged to discuss their concerns and
understandings. Not only did this 'create continuity among class members,
but allowed each individual to take responsibility for their learning, and
impart their knowledge to the class as a whole, ﬁlling in the “blanks” for
other team members. This was very important for the Integrated Science
class because a requirement for entry into the class is that the student
maintained a C or lower grade average in their previous science classes.
Consequently, many of the students did not have strong backgrounds in
basic information such as plant physiology, an issue that was rectiﬁed by
fellow classmates. The cooperative sharing of information was also
evidenced in the groups conducting the Red Worm lab. This lab was
shorter in length (two weeks) and provided invaluable base knowledge
that the students were able to apply to the wetland tanks. The
development of a foundation of knowledge that allows the student to
“access that knowledge and apply it to a new situation” (Sonmez & Lee,

2003) is a basic tenet of problem based learning. Due to the shortened

50

length of the lab, the class observed the effect that higher concentrations
of copper sulfate had on the worms’ health (higher concentrations resulted
in increased worm death) and transferred the knowledge to the wetland
tanks, watching for the same expected results. The wetland tanks were ill-
deﬁned problems. The class had no textbook to rely on for information
regarding plant physiology, and although they engaged in note taking that
provided them with reference for plant structure, nutrient requirements and
uptake mechanisms, the class as a whole had no predeﬁned expectation
of what would happen to the plants once exposure to a toxic chemical had
occurred. Hence, they relied on questions that were posed by the
instructor to guide their observations and pursued various problem ﬁnding
solutions that were generated by their teammates (Sonmez & Lee, 2003
and Martin, 2001). This lab ended up being one of the favorite activities of
the class. Although on the post unit survey there were a number of
comments about the Red Worm lab being messy, in general the teams
excelled at the twice weekly counting and weighing of the worms. The
class members became quite competitive with each other in regards to
worm longevity and felt a sense of compassion (this was often vocalized)
when the worms died. Most importantly, although the lab was designed to
teach the basic principle of metal tolerance and toxic concentration, it was
also successful in teaching the impact of hazardous substances on
population size and the necessary environmental conditions for good

health, such as adequate water and habitat maintenance. The only

51

suggestion for future use would be to use a greater amount of soil (500-
750 grams) so that upon the addition of the copper sulfate, the worms
would not die due to an overabundance of moisture. Although there was
no way to prove that some of the worm death that was experienced was
due to this oversight, the class as a whole agreed that perhaps the worms
had drowned, because the jars that were used did not contain drainage
holes. This issue could be corrected by using plastic containers in which
drainage holes could be drilled.

A number of the activities that were developed on campus during
the research aspect of my Master’s classes were not implemented due to
time constraints. One of these that I feel would be beneﬁcial to teaching
the unit was the testing for iron presence in both the soil and the water of
the wetland tanks. The importance of including this activity in the unit is
that the students begin to understand that some metals are naturally
present in the environment and do not necessarily build to toxic
concentrations. Other developed experiments such as the percolation lab
had to be conducted as a demonstration rather than as a class
experiment, to save time. In the future, I would use the percolation lab
and combine it with the pH experiment so that the class had a solid model
of how metals can move through a soil column and accumulate, based on
the acidity of the soil. Also, a paper making lab was developed as an
introduction to the unit, with the intent of teaching the class recycling

methods, how matter recycles, but is not destroyed, similar to toxins in the

52

environment. In re-teaching this unit, I would deﬁnitely use this activity to
heighten the student’s interest in the subject. Additionally, one of the most
important changes that I would make to this unit is the placement of it in
the school year. The research was conducted approximately ﬁve weeks
into the ﬁrst semester, at the beginning of the biology unit. In retrospect, I
would teach this unit again at the end of the biology portion of the class so
that the student’s had full review of all of the biology benchmarks and
standards, and could access this knowledge. In an ideal world this unit
would be taught as a focal point of an environmental class. Currently, I am
in negotiations with the district to adopt such a class into their curriculum.
Finally, the computer research that the students conducted was a
success. This was true regardless of the student’s academic ability,
evidenced by the average grade of a B. Although the class moved as
groups through the remediation unit Ieaming new information, individuals
were given the opportunity to express their own knowledge in independent
activities. Using information that had been gained from researching local
environmental hazards, each student investigated different metals that
were released into the environment discussing the implications to human,
plant and soil health. By “constructing personal meaning” the students
built on previous knowledge that they acquired during class investigations
and readings and applied it to a new situation. This is the basis of the

constructivist theory of teaching and Ieaming.

53

The class was able to integrate this new information into their existing
knowledge and use it as a springboard for their research paper.

The combined activities supported a greater personal
understanding for the class. As one student wrote in her journal “you can
relate this to your own world”. Future activities that would also increase
personal knowledge include providing protocols for EPA clean-up sites so
that the class would understand how remediation decisions are made on a
governmental level, developing a rubric for neighborhood investigation of
local contaminants and inviting an environmental activist to visit the
classroom to encourage the students to become involved in maintaining
the health of the Earth. These suggestions would extend the Ieaming that
had been gained in the classroom to a real world experience, thus
enhancing personal understanding and activating a sense of responsibility
from the student to the community. 0

As an overview of the unit and its success, it is necessary to look at
the results of the data analysis on the pre and post tests, and the ﬁnal
computed class grades. The average grade earned for this unit, which
spanned one marking period in length, was a C. While this is not an
outstanding average, it reﬂects the ability of the class as a whole. This
grade was computed based on a compiled rubric (Appendix P-2) that
included all of the activities of the unit. The largest loss of points came
from not completing the lab questions and failure to turn in a research

paper. In part, some of the responsibility for this failure falls on my

shoulders, due to time constraints and not allowing the students adequate
class time to work on completing their labs. l wrongly assumed that the
students would take responsibility and ﬁnish the work. outside of class if
they had not completed the assignment. In reviewing the results of the
pre and post test questions, there was not one question that did not gain
in percentage of correct answers. The students had never learned about
contamination and remediation prior to the unit, nor had they had the
opportunity to conduct experiments that were of a more advanced nature.
The two questions that had lower than a 40% increase in correct answers
were the description of soil types and the effect that the soil had on the
accumulation of toxins, and the description of a natural remediation site.
The soil question had a designed percolation experiment that would have
reinforced the understanding of the class. This was changed to a
demonstration, which did not assist the students in developing a greater
understanding of the topic. Also, the naming of a natural remediation site
should have had higher test results (38%) based on the ﬁeld trip. The
problem may have occurred because the ﬁeld trip was taken in the
beginning of the unit, and the topic was not formally revisited as the unit
progressed. All other test questions had a gain in correct answers of over
40%, with question #3 (describing how a substance becomes toxic) and
#4 (describing three different pathways a heavy metal can enter the
environment) experiencing the greatest growth. At 51% and 64%

respectively, these two questions attest to the student’s comprehension of

55

how any substance, when found in concentrations great enough to cause
harm, can enter the environment and cause toxicity.

Although the original intent of the unit was focused on the use of
plants to clean a toxic site, and is evidenced by a gain of 53% in correct
answers given to question #8 (that asks the student to deﬁne and give
examples of phytoremediation), it is clear that the learning extended
beyond remediation. On a biological level, the students learned that any
substance in concentrations that are beyond the tolerance level of the
exposed organism can cause harm or death. As a population study, the
class gained knowledge of how small numbers of organisms that are
affected by a toxin indicate a larger problem. Lastly, is the lesson that
some organisms have built in mechanisms that allow them to tolerate a
toxic substance and to sequester that substance so that it can no longer
move into the environment and continue to cause damage. i

When I stand back and reﬂect upon the unit I realize that as an
instructor I expected a great deal of concentration, commitment and
dedication from the students to accomplish the goals I had set before
them. The laboratory testing was college level and the class did an
exceptional job of conducting the chemical tests. Generally, when using
this unit in the Fall of 2005, I will relax and enjoy the process, integrate
more of the activities that were developed and not used, and spend more

time on teaching the class on how to become environmental activists.

56

References

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16 Feb. 2005 < http://www.nadabs.tripod.com?coople‘arning.html>

Arnold, D, Hazuka, N.,Herring,D., Murray, D., Williamson, S.
Phytoremediation: Controlling Pollution With Plants. July 2004 <http://
www.fetc.org>

Bianchi, L. 2004 Demographic School Proﬁle 2004-2005. Ofﬁce of
Research Evaluation, Flint Community Schools, Nov. 23, 2004

Botkin, D, & Keller, E. Environmental Studies: The Earth as a Living
Planet. The Charles E. Merrill Publishing Company. Columbus, Ohio
1982

Chiras, D. 1994 Environmental Science: Action for a Sustainable Future.
The Benjamin/Cummings Publishing Company, Inc. California, 6-10, 74-
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Cluis, C. 2004. Junk-greedy Greens: phytoremediation as a new option for
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“Constructivism” Teaching Philosophies 5 Aug., 2004 -
<http:l/clab.cecil.cc.md.us/facumrldistanceleaming/teaching.htm>

Clark, J. 2003 Minorities in Science and Math. 21 July, 2004
<m_tp:l/www.§temworks.org/digests/dse99-02.html>

Cotton, K. Educating Urban Minority Youth: Research on Effective
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<h_ttp://www.nwrel.org/scpd/sirs/5/tppsvn4.html>

Department of Environmental Quality, Trace Element Monitoring in
Michigan’s Ecosystems July 2004
<http://www.deg.state.mi.us/docgments/deg-osep-ftp-tm.pdf>

Edugreen. Health Impacts of Water Pollution 15 July, 2004
<http://edugreen.teri.res.inlexplorelwater/health.htm>

Environmental Protection Agency. Bioaccumulation Summary: Copper
July, 2004 <http:l/www.epa.gov/ost/cs/biotesting>

57

Environmental Protection Agency. 2001. A Citizen’s Guide to
Phytoremediation. July, 2004 <http:/lwww.epa.gov/superfund/sites>

Extreme Health. Toxic Heavy Metals: Sources and Speciﬁc Effect. 15 July,
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Feigl, F. Qualitative Analyse mit Hilfe von Tupfelreaktionen: Spot test in
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Global Network of Environment & Technology. 2002. EPRI Sows Seeds of
Plant-Based Waste Cleaning Systems. 5 July, 2004
<h_ttg//wwwgnet.org/pewslnewsdetail.cfm?Newsl9120751 &Klevword+phy
toremediation>

Golba, A. 1998. How Does Education in Urban Schools Compare to
Suburban Schools? 24 June, 2004
<http:/Iwww.iusb.edu/1'ournaI/1998lP§per5.htmI>

 

Haury, D. 1993. Teaching Science Through Inquiry. 25 April, 2005.
<http:llwww.ericdigest.orgl1993/inguiry.htm>

lshii, D. 2003. Constructivist Views of Learning in Science and
Mathematics. Eric Digest. Se-03-02

Johnson, D. & Johnson, R. Cooperation and Competition: Theory and
Research. Interaction Book Company. Edina, Minnesota. 1989

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Martin-Hanson, L. 2002 Deﬁning Inquiry. The Science Teacher Feb,
2002. p. 34-37

Matthews, M. Constructivism In Science And Mathematics Education. 16
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Metal Scavenging Plants to Cleanse the Soil. 1995. Agricultural Research,
USDA-ARS Nov., 1995 p. 4-9

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<http:llwww.orbo.com/miclimb/DocPieces/st3hs.pdf>

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Natural Resources Conservation Service. What is Soil? 13 July, 2004
<http:/Isoils.usda.gov/educationlfactslsoil.html>

Paradise, C. A Standardized Soil Ecotoxicological Test Using Red Worms
(Eisenia fetida) The American Biology Teacher 63:9 2001.

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http://[pi.edu/dept/chem-enngiotech-EnvironlMlSC/phvtorem.html

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Water at Hazardous Sites. Environmental Protection Agency EPA/540/S-
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<http:/I149.152.32.5/Plant physiolpgv/minerajshtmb

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AUTHENTIC Science Problems. The Science Teacher Jan., 2002 p. 24-
29

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<h_ttp:/Iwww.access.wvju. eduL/classfmv/biotecltebcwebpage/Teacher%20T
axonomylENVlR....>

59

APPENDICES A-R

60

Appendix A: Michigan Content Standards
A-1: Michigan Content Standards and Benchmarks

Content Standard l

Construct new scientiﬁc and personal knowledge.

Reconstruct previously learned knowledge.

Reﬂect on the nature, adequacy and connection across scientiﬁc
knowledge, show how common themes apply in a real world context.

Reﬂection I.I.H.1
Ask questions that can be answered investigated empirically

Reﬂection I.I.H.2
Conduct scientiﬁc investigations

Reﬂection I.I.H.4
Gather and synthesize information from books, and other sources.

Reﬂection I.I.H.7
Identify and use safe procedures in science activities.

Biology II.H.6
Develop an awareness of and sensitivity to the natural world.

Evolution lll.H.4

All students will compare ways that living organisms are adapted to
survive and reproduce in their environments and explain how species
change through time.

Ecosystems lll.H.5

All students will explain how parts of an ecosystem are related and how
they interact.

All students will explain how energy is distributed to living things in an
ecosystem.

All students will investigate how communities of living things change over
a period of time.

All students will describe how materials cycle through an ecosystem and
get reused in the environment.

61

A-2: Flow Chart of Content Standards and Main Unit Ideas

 

F Content Standard IN
Constructing New
Knowledge

 

 

(Phytoremediation

 

k J

 

k

 

ﬁwestigating real worb
models

Field trip to remediation
site

 

Unit

 

ll

(Reflectionllxl, 1.,2 LN

Investigating and
Gathering Information

 

 

 

\ J

K Biology ".6 [D

Develop awareness a

sensitivity to natural
world

Toxic effect on living
things

 

 

L J

 

F Investigating and \

 

 

 

 

 

 

k

(Cooperative Leaming\

Inquiry —based Learning

 

J

 

F Evolution 111.3 \

 

 

 

 

 

 

 

J k

62

gathering information Adaptation of living
things to toxic habitat
Ecosystems Ill.5
Habitat change and
cycling of toxic
k J materials )
meﬂand Tank Modem
Red Worm Habitat
Computer research into

“—1 local contamination

 

J

Appendix B: Consent Forms

Parent and Student Consent Form
Collection of Data for Master’s Thesis

Dear Parent/Guardians and Students:

During this semester I will be implementing a unit on the use of
plants to clean contaminated areas in the environment. I have developed
this unit as the major portion of my Master’s thesis at Michigan State
University. The students will actively learn about environmental issues,
test models in the classroom, and gain a greater understanding about their
ability to make a difference in regard to environmental decisions. An
important aspect of this work is obtaining data about the effectiveness of
this unit, which will in turn be the foundation of my thesis.

In order to evaluate the learning process, data will be collected from
pre and post tests, research information that the students have generated,
as well as responses from laboratory experiments and surveys that will be
given throughout the unit. With your permission I would like to include
your child’s data in my thesis. Your child’s privacy will be protected to the
extent that is allowable by law, and at no time will the students’ name be
used or connected to any part of my thesis paper.

Your child will receive no penalty in regard to their grade should
you deny permission for the use of their data. They will be expected to
participate in the classroom activities and assignments, however, their
data will not be used in my thesis work. At any time during the unit you
may request that your childs’ data not be analyzed, and your request will
be honored.

Please complete the attached form and return it to me as soon as
possible. Should you have any questions feel free to contact me at
Southwestern Academy, 810-760-1400 or by email at
kgould@ﬂintschools.org. If there are any questions that you have about
your rights as a study participant, please contact

Sincerely,

Karen A. Gould
Science Teacher - Southwestern Academy

63

Please complete the following form and return it to me no later than
October 1,2004. '

OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

l voluntarily agree to have
participate in this study.
(print student name)

Parent/Guardian Signature Date

 

 

l voluntarily agree to participate in this study.

Student Signature Date

 

64

CONSENT FORM REGARDING RELEASE OF STUDENT
INFORMATION

Please print while completing this form.

 

Student’s Name Hour Grade

 

Student’s Home Address

I. Permission to Display Photograph, Audio, Visual or Electronic
Images:

I give permission (or do not give consent) for photographs, audio, visual or
electronic images of my student, to be used by the Flint Community
School District for exhibition, public display, publication, publicity
materials, a news media story, or photographic release. I understand that
my student’s full name may be used with such display except that only my
student’s ﬁrst name will be used on the District’s website.

I give my consent

I do not give my consent

ll. Permission for News Stories:

I give consent (or do not give consent) for quoted statements given by my
student, or photographs, audio, visual or electronic images of my student,
with possible identiﬁcation by full name, to be used for the purpose of
news stories or interviews about Flint Community Schools or educational
experiences by our area news media.

I give consent

I do not give consent

 

Signature of Parent or Responsible Custodian/Guardian
Date

 

Printed name of Parent or Responsible Custodian/Guardian

Please complete this form and return to Southwestern Academy

65

Appendix C: Pre and Post Test
C-1 Pre and Post Test

Name:

 

Contamination and Remediation

The following questions are designed to help both of us develop an
understanding of the knowledge that you have brought with you to this
class. Remember that this is a tool, not a judgment about what you know.
Answer the questions to the best of your ability, using past knowledge and
analytical reasoning.

1. What is meant by “heavy metals”? How do they differ from other
metals?

2. Deﬁne toxic
3. Describe how a substance can become toxic.
4. Name three different ways that heavy metals are known to enter the

environment?

5. Explain why lower organisms, such as plants and invertebrates are the
ﬁrst
living things to be affected by toxic contamination.

6. Describe the difference in soil types and explain why soil composition
affects
the toxicity of a contaminant.

7. Deﬁne remediation and explain why it is important.

8. Deﬁne phytoremediation and explain how plants are able to “take up”
metals
through their roots into the shoots, stems and leaves.

66

9. Give an example of a natural remediation site that can be found in
nature.

10. Can plants used for phytoremediation be recycled? How?

67

C-2 Pre Test and Post Test Objectives
The students will be able to summarize these major ideas.

1. What IS meant by “heavy metals”? How do they differ from other
metals?

Heavy metals have a higher density and tend to accumulate 1n the
environment, include living organisms, at a higher rate than other metals.

2. Deﬁne toxic

“Toxic” refers to any substance that can cause harm or death when it
reaches a critical concentration, a level that is not tolerated by the
organism

3. Describe how a substance can become toxic.

Any substance can become toxic if it accumulates, either in the
environment or within an organ system, and cannot be disposed or
removed from the system.

4. Name three different ways that heavy metals are known to enter the
environment?

Heavy metals occur naturally in the environment, where they are generally

tolerated. Other contributing pathways include: industrial waste (liquid,

solid, gaseous), human activity private life (car exhaust, lawn application

of fertilizer, septic chemicals, etc.) break down of natural containment

areas, pollution.

5. Explain why lower organisms, such as plants and invertebrates are the
ﬁrst

living things to be affected by toxic contamination.
Toxicity is dependent on concentration of substance and the organism’s
ability to remove the toxin from its system. Lower organisms are generally
smaller in size, their vascular systems are smaller and they live directly in
(contact) with the source of the contamination. Due to their inability to
move away from the source of toxicity, they are affected ﬁrst and most
often harmed in the greatest way, when contamination occurs.

6. Describe the difference in soil types and explain why soil composition
affects

the toxicity of a contaminant.
There are three main soil types - sand, peat, loam and a mix of all three.
Depending on the area of the world (geographically), soil types are
different, due to environmental factors such as water exposure, glacial
activity, salt concentration, etc, The larger the particle size, the larger the
air space between particles. This air space also allows for solid/liquid

68

contaminants to move and be stored in one area. The sandier the soil, the
greater the “holding ability” of the soil.

7. Deﬁne remediation and explain why it is important.

Remediation is the process of containing and cleaning an area that has
been contaminated by a toxic substance. This can be accomplished a
number of ways, and it beneﬁts the environment because it stops the
contamination from spreading to other habitats and harming other
organisms.

8. Deﬁne phytoremediation and explain how plants are able to “take up”
metals

through their roots into the shoots, stems and leaves.
Phytoremediation is the use of plants to contain a toxin in a contaminated
area by sequestering the toxin, in this case, heavy metals, through their
root systems. Once the metal has entered the root system, it is taken up
into the plant through the vascular system and is either contained or
volatilized by the plant.

9. Give an example of a natural remediation site that can be found in
nature.

A wetland is a natural remediation site. Contaminants are removed and/or
contained by the roots/shoots of the plant and the water is cleaned by the
respiration of the plant. Other examples of natural remediators include
poplar trees, weeping willow, cat tails and duckweed. ’

10. Can plants used for phytoremediation be recycled? How?

Plants that contain metals and other contaminants that have been
sequestered can be recycled. Burning the organic material and collecting
the ore is one example. Plants can also be removed from the
contaminated area and buried in a landﬁll, adding to the organic structure
of the soil.

69

Appendix D: Heavy Metal Experiment

D1: HEAVY METAL EFFECT ON PLANT SURVIVAL
WETLAND TANK MODEL .

Purpose: The purpose of this lab is to demonstrate the effect that
remediative plants have on an area that is contaminated with heavy
metals. The model is that of a soillvvater interface, similar to a soil bank
and static pool in nature.

Objective: The students will gain a greater understanding of the natural
cleaning system that exists in wetland areas, the effect that metals have
on a site inhabited by plants and the impact that plants have on a
contaminated area.

Materials:

This lab is designed as a group project in that all of the class will
contribute to the constmction of the class models. Thus, the materials are
listed as it applies to the entire class.

5 - 5.5 gallon aquarium

5 dowels, cut to ﬁt the inside of the aquaria (lengthwise)

Landscape fabric

Marine epoxy — quick setting

Potting soil — 1 large bag (20 lbs.)

Peat - 1 cubic foot

Sand - 20 lb bag

Small rocks — enough to cover the bottom of the tank at a 2 inch depth
(used for aeration)

Plant food — 15,30,15 mix works well

Duckweed ( Lemna minor) —-250 plants total

Radish seeds — (any plant from the Brassica family will work). Two
packets is sufﬁcient, pre-germinated

Lettuce — (any plant that is a fast to germinate). Two packets of seeds are
sufﬁcient, pre-germinated.

Grow lights

2000 ml of pond water or tap water

Copper Sulfate - 0.1 M (25 grams CuSO4 per 1 L H20) - 3000 ml total
Ferric thiocyanate solution - See instructor

0.1 N sodium thiosulfate solution

1 N HCI

Spot plates

70

Procedure: Building the model

. Each group of 4-5 students will be given 1 aquarium and 1 dowel.
Measure the width of the tank, ﬁnd the mid-point, and place a mark.
Measure the height of the tank, ﬁnd the mid-point, and place a mark.
Repeat the process on the other end of the aquarium.

2. Measure and record the length of the aquarium. Measure and record
the distance to the bottom of the tank from your mid-mark, the distance
from the mid-point of the ﬂoor of the tank to the edge and the distance
from the edge of the ﬂoor to the top of the tank. Total these numbers and
add three inches. You now have a general (rectangular) size for your
landscape fabric. Measure out on your fabric the width and length needed
for the aquarium and cut this rectangle out. .

. Using the marks that you made as a guide, place epoxy on the marks on

the inside of the tank, as well as the ends of the dowels. Move the dowel
into the tank (turning diagonally to place inside) and place the ends of the
dowel on the marks. Hold the dowel steadily in place until the epoxy has

set, approximately 3-6 minutes. See diagram below.

. Place the landscape fabric inside of the tank, matching up the width of the
fabric with the dowel length. Pull the fabric under and then over the dowel
creating a hem for the dowel to rest in. You can either staple the fabric
edge to the fabric length or stitch it by hand. When you have completed
this, the fabric should be attached to the dowel, drape down the ﬂoor of
the aquarium, up the side of the tank and have a 2-3 inch hang over the
edge. See diagram below.

. Holding onto the landscape fabric, place rocks (to the depth of nearly 2
inches) on the inside of the fabric, leaving one side without rocks and the
fabric side with rocks. Sprinkle sand on top of the rocks until they are
covered. Sprinkle sand to about 1/2 inch depth (2 cm) on the non-fabric
side. This creates an area that will allow for air spaces.

71

 

The top drawing is an example of the ﬁnished tank.

The bottom drawing is a representation of the tank prior to adding soil,
plants and water.

72

eeeeem

Mix soil in the following proportions: 40% peat, 40% potting soil and 20%
sand. The total amount of soil needed is approximately 12 cups or 3000 g
of soil per tank. Either mass the soil or use a measuring cup. Loosely
place the soil on the fabric side of the aquarium. Once the soil has
reaches a level equivalent with the dowel, begin to slowly add more soil so
that it angles up the side of the tank. Complete this packing and angling
until all of the soil is used.

Slowly add ‘/2 teaspoon fertilizer to 2000 ml of water (you can mix this in a
two liter pop bottle). Swirl the solution slowly to dissolve the solid. To the
sand only side, add the water/fertilizer mix, being careful not to over
stimulate the sand bottom. Sprinkle a small amount on the soil side. This
amount of water is added to all of the tanks.

Labeling tanks — each tank will be labeled as follows
Lemna, lettuce, radish, CuSO4
Lemna, lettuce, radish, no CuSO4
Lemna, radish, CuSO4
Lemna, lettuce, CuSO4_
Lemna, no plants, CuSO4

Establishing the design model

. Each group will be given a different mix of plants to place in their

aquarium, based on the label the group was given. Gently plaCe 50 Lemna
plants (easy to distinguish by their single root) into the (water side) tank.
The radish/lettuce tank has two tablespoons of each type of seed, and the
remaining tanks have the radish or lettuce seeds (two tablespoons)
according to the aquarium label.

Sow the seeds in the soil by making small indentions. Once seeds are
placed in the soil, sprinkle with water to wet. Allow plants to germinate
and take root (under grow lights) - this may take 3-5 days. After the land
plants have started to show stem growth, add (by sprinkling with a
watering can or jar that has holes punched in the metal top) 600 ml of
CuSO4 to four of the ﬁve tanks, on the soil side. Follow the labels on the
tanks!

On the data table place the starting date. Once a week or every ﬁve days,
observations will be made as to the health of the plants (color, wilting, etc.)
and the Lemna will be counted. This information will be placed in the data
table.

73

The following chemical test will be conducted (once every 5 days) to
determine the presence of copper sulfate in the water. Follow the
directions carefully.

Copper Presence Test

Obtain an eyedropper bottle containing ferric thiocyanate and another
containing 0.1 N sodium thiosulfate solution from the instructor.

Each group will withdraw 1 ml of test solution from their aquarium, using a
pipette.

Working with a spot plate, place one drop of distilled water in one plate
well and one drop of the test water in the next plate well.

To each well add 1 drop of sodium thiosulfate solution. One team
member will watch the clock, one member will stir the test solutions in the
plate (as drops are added) and one member will add 3 drops of ferric
thiocyanate solution to each test well. As soon as the ferric thiocyanate
solution is added begin timing, counting the seconds until the test water
turns from a blood red to a clear colored solution.

Comparing the time of color dissociation to the chart below, estimate the
concentration of CuSO4 in the test water. Record time and estimated
concentration in the data table. Carefully rinse the test plates with water
and wash hands.

 

 

 

 

 

 

 

Concentration of copper Time to reach clear
sulfate solution

0.1 M CuSO4 (10'1 instantaneous
M)

0.01 M CuSO4 (10'2 instantaneous
M)

0.001 M CuSO4 (10'3 instantaneous
M)

0.0001 M CuSO4 (10‘I 3 seconds
M)

0.00001 M CuSO4 (10'5 30 seconds
M)

 

 

 

This chart is the result of diluting the original concentration of CuSO4 by
one tenth per application. This was accomplished by adding 1 ml of
CuSO4 to 9 ml of H20 (0.01 M). From the remix 1 ml was taken out and
added to 9 ml of H20 to achieve 0.001 M, and so on.

. Repeat the observations and copper testing once a week for three more
weeks. All information is placed in the data table.

. At the fourth week, plant material will be harvested. Each group will pull 2
of their land plants (4 total for the radish/lettuce mix), as well as a number

74

of the surviving Lemna. Each plant will be placed on a watch glass and
put into a microwave for 5 seconds, driving the water from the tissue.
Remove the plant material, allowing it to air dry until crisp (1-2 days).

. Macerate the plant material until it is ﬁnely ground. Place the material into
a microfuge tube or a small test tube that has a cap'or rubber stopper. It
may be beneﬁcial to puncture a hole in the top of the cap to allow for the
escape of gas, after inverting the tube. Add 1 ml of 1 N HCL to each tube,
invert to mix and let stand for 24 hours (allowing solids to fall to bottom).

. Pull off efﬂuent with a pipette. Using the procedure for the “testing for
copper presence”, test all plant material (radish, lettuce and Lemna) for
copper concentration. Place information in data table.

. All data information will be compiled into a class data table. The results
will be used to create a bar graph that illustrates the effect of land plants
on the metal concentration in the water.

10.Answer the questions following the experiment. If you are missing any

information from your data table, please ﬁll in your table using a group
member’s data.

 

75

NAME
HOUR

 

 

DATA TABLES FOR EFFECTS OF HEAW METALS ON PLANT GROWTH

 

Copper
Concentration
IN WATER

Initial

Week
one

Week
Two

Week
Three

Week
Four

Change

 

Lemna, CuSO4

 

Lemna, radish,
lettuce, CuSO4

 

Lemna, radish,
lettuce, no CuSO4

 

Lemna, radish,
CUSO4

 

 

Lemna, lettuce,
CUSO4

 

 

 

 

 

 

 

 

Copper
Concentration
IN SOIL

Initial

Week
one

Week
Two

Week
Three

Week
Four

Change

 

Lemna, CuSO4

 

Lemna, radish,
lettuce, CuSO4

 

Lemna, radish,
lettuce, no CuSO4

 

Lemna, radish,
CUSO4

 

 

Lemna, lettuce,
CUSO4

 

 

 

 

 

 

 

76

 

 

 

Lemna Count
mumbers)

Initial

Week
one

Two

Week

Week

Three

Week
Four

 

Lemna, CuSO4

 

Lemna, radish,
lettuce, CuSO4

 

Lemna, radish,
lettuce, no CuSO4

 

Lemna, radish,
CUSO4

 

 

Lemna, lettuce,
CuSO4

 

 

 

 

 

 

 

 

Copper Present in Plant
Material at End of Study

Radish

Radish
Root

Lettuce

Lettuce
Root

 

Lemna, radish, lettuce, CuSO4

 

Lemna, radish, CuSO4

 

 

Lemna, lettuce, CuSO4

 

 

 

 

 

Lab Questions

. What does the model used in class represent in nature?

 

. Deﬁne “heavy metal”. Why is copper considered a heavy metal?

 

 

 

 

Why was the copper put into the soil as a liquid? What would have

happened if it had been put into the soil as a solid (its natural form)?

 

 

 

 

 

77

Change

 

 

. Explain how plants take up nutrients (remember that copper is a micro
nutrient) from the soil.

 

 

 

 

. Explain how a nutrient can move from being beneﬁcial to being toxic.
Hint: what has to happen to the concentration of the nutrient and how the
organism handles it?

 

 

 

 

 

. Looking at the class results, which tank model had the greatest lemna
growth? Why did these results occur?

 

 

 

. Looking at the class results, which tank model was the most toxic to the
Lemna? Why did these results occur? ,

 

 

 

 

 

 

. If you were to compare the concentration of copper in the water to the
concentration in the soil, what do you think you would ﬁnd? Describe a
way that you could test the amount of copper in the soil.

 

 

 

 

 

78

9. Which plant was the most tolerant of the copper? How did you know this?

 

 

 

10. What part of the plant was exposed to the metal? When you tested the
plants for copper presence, you used the stem, shoot and leaves. Was
this the best choice? Why or why not?

 

 

 

 

 

11.You work for an environmental group and have been notiﬁed that there
has been a cadmium leak into a local lake. It has leached out from an
underground tank, and you are expected to clean it up.

What is cadmium?

What type of element is cadmium?

How would cadmium affect the water plants and the land plants?

What animals could you look at to tell you how much cadmium is in the
area? Hint: what about their behavior?

Describe a clean up model that would take care of the problem. Be
certain to give reasons for your choices

99.69»

i”

79

D 2: Heavy Metal Effect on Plant Survival
TEACHERS EDITION

Remediation of contaminated sites is a topic that is relevant to high school
students. Although they may not see the connection to their existence,
the problem of contamination is an issue that will have to be addressed by
the next generation. This experiment is a 5 week project that could be
started either as an introduction to a heavy metal chemistry or to an
environmental unit. It is not necessary to give a lot of background
information prior to the set-up of the design model, as plant physiology,
nutrient uptake, contamination pathways, and remediation models can be
taught as the experiment progresses.

The key point of this lab is that there are alternatives to moving
contaminated soil into landﬁlls, and that hazardous waste is not “someone
else’s problem”. Phytoremediation or the use of plants as a natural
cleaning tool is not a new science. However, it is not generally taught in
the classroom and its validity is important. The students should walk away
form this experiment with a clearer understanding of heavy metals, their
impact on living organisms, how macronutrients (some of which are
metals) can become lethal toxins, normal plant function and how that
function lends itself to remediation. By creating 5 different modeled
environments, the students will be able to clearly see the effect of
contamination by comparing the health of the plants (color, total numbers,
death, etc.) with each tank. An indication of toxicity to the Lemna is that
the fronds begin to tum white.

Five 5.5 liter aquariums are used for the models. The control tank
contains all three types of plants and no copper sulfate. If the classroom
doesn’t have the space for ﬁve aquaria of this size, clear plastic
shoeboxes could be used, but the volumes of the soil, plant seeds and
copper would need to be adjusted accordingly. Landscape fabric works
well as a retaining wall for the soil because it allows water (and
contaminants) to move across the interface into the water without soil loss.

The construction of the model is as follows: a dowel should be cut
to ﬁt inside the length of the tank and securely adhered to the walls at a
midpoint (height and width). The fabric width matches the dowel length
and is folded over the dowel and stitched (or stapled, but is less secure).
The length of the fabric should be long enough to drape down to the ﬂoor
of the tank, across the tank bottom, up the tank wall and have an over
hang of 2-3 inches. In this pouch 2 inches of mid sized rocks, covered
with ‘/2 inch of sand and then 8-10 cups of soil are added. The mix of the
soil is 40% peat, 40% potting soil and 20 % sand. If the soil is packed too
tightly, anaerobic conditions occur and the plants won’t grow well.
Although it is suggested to put 50 Lemna into each tank, that could be
changed at your discretion. The hardest part of this step is that the

80

students tend to not be exact in their Lemna count because the plants are
so small. If the lettuce and radish seeds are pre-germinated they will
sprout faster and will be stronger when the copper is added.

The brassica family is known to be metal tolerant and includes
cauliﬂower, broccoli, radish and mustard. Lemna is also metal tolerant,
and is actually a water plant known to take up metals. This is an important
point because it reinforces the idea that all organisms have a level of
concentration tolerance, in which a substance moves from being beneﬁcial
to lethal. In regards to the lettuce, it was chosen because it is a fast
growing plant, but again, it is personal choice as to what plant family to
use.

Copper sulfate is added to the soil side of 4 of the 5 tanks in one
dose of 600 ml of 0.1 M CuSO4. If you were testing the total concentration
of copper in the water and soil over a period of time, you could add more
than one dose, however for this lab the focus is on the movement of the
metal across the soil/water interface and the effect of the copper on the
land/water plants. Additionally, the effectiveness of metal uptake by the
radish is also tested by the plant solids being macerated and subject to
the copper presence test. It is expected that only the radish shows copper
presence, but it is possible that the duckweed will also test positive, due to
its uptake ability.

The root system of the land plants and their ability to hinder the
movement of metal should be considered and discussed, as this is a vital
point in phytostabilization. As the weeks progress, it would be beneﬁcial
to discuss and teach the various phytoremediation techniques such as
phytovolitilization and phytodegradation.

Finally, when adding water to the all of the tanks it is helpful to use
pond water if collecting Lemna from the wild. Generally the Lemna are
healthier and reproduce at a greater rate because they are already
acclimated to their environment.

Expected Results: This lab will demonstrate that radish tolerates,
grows and takes up metals (when macerated is positive for copper),
lettuce is intolerant and dies in the presence of metals and Lemna, while
tolerant of metal (may be positive for copper), is limited by its presence.
Also, the presence of mated plants in the soil slows down contamination
into other areas of the environment when the soil is contaminated ﬁrst.

In analyzing the data, a collective data table that is displayed on the
board, an overhead or a computer screen should be generated so that the
students can compare plant numbers across all of the test models. From
this data a bar graph will effectively demonstrate the impact of the metal
on Lemna numbers and the students can determine the environmental
conditions (plant root systems, type of plants, plant tolerance, etc.) that
created their results.

81

CHEMICAL “RECIPES”
Copper Sulfate - Mol. Wt.= 249.68 grams

0.1 M CuSO4 - 25 grams solid copper sulfate dissolved in 1000ml (L) of water
3000 ml needed - 600 ml per aquarium

Copper Presence Test Solution
Sodium Thiosulfate - Mol. Wt = 248.18 grams
0.1 N N328203 — 1.24 grams solid dissolved in 100 ml

Place the solution in an eyedropper
One eyedropper per group

Ferric Thiocyanate

1.5 grams - ferric chloride
2.0 grams - potassium thiocyanate
*dissolve both solids in 100 ml of water

Placed the solution in an eyedropper
One eyedropper per group

Procedure

0 Put one drop of test solution (aquarium water) and a drop of distilled water
in adjacent depressions of a spot plate

a Place one drop of ferric thiocyanate into both spot wells, stir with glass rod
to mix

a Place three drops of sodium thiosulfate in each well and stir with a glass
rod to mix

a The time of decolorization of a copper-free solution is 1.5 - 2 minutes.
The decolorization of the test solution containing as little as 1 microgram
of copper is almost instantaneous.

82

The chart below was calculated using a dilution gradient of 0.1 of the
copper sulfate solution. It creates a scale that the students can compare
the time of their solution decolorization with the standard.

 

Concentration of copper sulfate Time to reach clear solution

 

 

 

 

 

 

 

 

0.1 M CuSO4 (10'1 M) instantaneous
0.01 M CuSO4 (10'2 M) instantaneous
0.001 M CuSO4 (10'3 M) instantaneous
0.0001 M CuSO., (1 O‘TVI) 3 seconds
0.00001 M CUSO4 (10'5M) 30 seconds

 

83

Appendix E: Mineral Requirement Notes
The Role of Minerals in the Human Body

Minerals are inorganic elements that play vital roles in the health of
a human being. These elements are extracted from the soil by plants,
which in turn are taken up by humans either through eating the plants or
by eating the animals that have eaten the plants.

Minerals account for about 4% of the bodies’ weight and almost all
of them are parts of organic molecules. What this means is that the
minerals are a part of something else — iron is part of hemoglobin,
phosphorus is part of phospholipids, potassium is part of the nervous
system and is vital in sending nervous impulses.

Minerals are present in all cells and make up part of the structure of
the body, like the teeth and bones. There are two different classiﬁcations
of minerals in the body — MACROMINERALS AND MICROMINERALS.
Macrominerals get their designation because they comprise 75% of the
total minerals in the body. Calcium, phosphorus, potassium, sulfur,
sodium, chlorine, and magnesium are all macronutrients - and the trend?
Most of them are metals!

Microminerals get their designation because they make up a
smaller portion (trace) of the total minerals in the human body. In fact they
make up less than 0.005% of the adult body weight. Iron, manganese,
copper, iodine, cobalt and zinc are all considered microminerals. Do you
see a trend? Again, most of these are metals!

The main point to all of this is that for human bodies to function at
full capacity, for nerve impulses to work, for intestines to digest, to grow
strong and for muscles to move, it is necessary to keep a certain level of
these minerals in the body. As with anything, when things become
imbalanced a system has to change to accommodate the imbalance and
often this is with sickness, or death. Just the right amount of potassium
for instance, and you can remember what you had for lunch. Too much
potassium and your system “thinks” its having a stroke.

See the following page for table of nutrients.

84

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Macromineral Amount Function
Needed

Calcium 800 mg Structure of bones and teeth, needed for
nerve impulses

Phosphorus 800 mg Structure of bones and teeth, needed in
most metabolic reactions, and for protein
synthesis

Potassium 2500 mg Helps regulate pH and cellular pressure,
needed for nerve impulse conduction,
and muscle contraction

Sulfur Not est. Part of amino acids, insulin, biotin,
polysaccharides

Sodium Not est. Helps osmotic pressure, regulate water
balance and helps with nerve impulses.

Chlorine Assoc. Helps with osmotic pressure, regulate

wlSodium water balance and helps with nerve

impulses

Magnesium 300 mg Needed for metabolic reactions, reactions
in the mitochondria and assoc. with ATP
production

Microminerals

Iron 1-2 mg Part of hemoglobin, enzymes and
catalyzes vitamin A

Manganese Not est. Needed for normal growth and
development of skeletal system,
connective tissue

Copper 2 mg Needed for the making of hemoglobin,
development of bone, making melanin

Iodine 0.001mg_ Big in helping to make thyroid hormones

Cobalt Not est. Thought to be necessary in the making of
enzymes

Zinc 15 mg Part of enzymes involved in digestion,

 

 

respiration, bone and liver metabolism
(function)

 

'T his is not a complete list of functions. The information was adapted
from “Human Anatomy and Physiology“, written by John W. Hole, Jr. *

85

 

Self Sustaining Mechanisms in Ecosystems

Ablotlc Impact
air. water, land
pollution
Human Activity Aesthetics.
economics.
heath.
98M
BIotIc lnpact
plant.
humans,non-
human

Part of the responsibility of Ieaming to live on a self-sustaining planet is to
learn to correct past mistakes. This must happen not only on an individual
level, but also on an industrial level that will require change in daily
activities and the way we think of life in general. We are interrupting
natural systems and it is necessary to change relationships of humans to
the environment. We, as guardians of the Earth’s health, must look to the
past and anticipate changes that may occur due to our interaction with the
environment in which we live.

There are two paths that human activity can take that effect the
environment: changes in abiotic and biotic factors. We will look at how we
alter these factors, and the impact of those changes.

Abiotic Factors

Abiotic factors are those components of an ecosystem that are not
living, that when altered, can cause situations not easily tolerated by living
organisms. The most common is chemical disruption, such as sewage
that adds nutrients to waterways that alter the natural state of
homeostasis. Pollutants can be produced by other activities introducing
possible toxic substances that some life forms cannot handle. An
example of human produced pollution is chloroﬂuorocarbons (by products
of aerosols) that eat at the ozone and increase global warming due to
increased ultraviolet radiation. While awareness has been raised on a
global level, CFC’s are still produced and their impact is still being felt.

Wastewater treatment plants release a wide range of compounds
into rivers. The by-product of the chlorination process used to sterilize
treated wastewater, the release of these chemicals can prove to be toxic
to ﬁsh and other aquatic species. Another example of human pollutants
results from the use of pesticides, chemicals that control fungi, insects,
viruses and weeds. Although the application of these chemicals might be
into the soil, they can also be carried to other areas through wind and
water dispersion. Poisoning beneﬁcial species, large ranges of living
organisms can be affected by the topical application of pesticides.

One of the best studied pesticides is DDT
(dichlordiphenyltrichloroethane). Formerly used by the United States and
still in use in other countries, DDT contaminated both aquatic and
terrestrial ecosystems and was passed through the food chains from one
organism to another. DDT was stored in the body fat of top-level
consumers, such as osprey and peregrine falcons, and was deposited in
their eggshells, which resulted in thin eggshells that could not support the
embryos of the birds. Populations of the birds declined rapidly until their
numbers were near extinction.

The DDT incident illustrates a concept known as biomagniﬁcation,
the accumulation of relatively low concentrations of a chemical within a
food chain that results in the concentration increasing as it moves up
through the trophic (feeding) levels. By the time the chemical has reached
top-level consumers, it has become a toxic concentration.

Regardless of the application site, human pollution can branch out
into soil, water or air contamination. Due to unfavorable abiotic conditions,
species can be reduced or eliminated, which in turn creates an
unbalanced ecological system.

Biotic Factors

Human activity can also directly affect, deplete or destroy resources
used by other species, thus impacting them directly. Building dams that
divert water away from naturally occurring streams and rivers, building
housing projects over wetlands and laying concrete over land that has a
natural drainage system are all examples of directly altering ecosystems
and the organisms that live within them.

87

The introduction of competitors is one of the most common
impacts we have on the biotic community. Many ornamental plants that
are placed in yards are non-native species. These plants compete with
native species for resources, and may possess adaptations that allow
them to tolerate chemicals that the native species cannot. The result is
that the competitor thrives at the expense of the native organism. While
the loss of these organisms may seem inconsequential, purple loosestrife
is not a natural water puriﬁer, a characteristic that the native species
holds. Thus plants such as cat-tails have been depleted and the
ecosystem the previously was free of contaminates due to the presence of
the wetland plants is now becoming increasingly toxic. In other words, we
are killing ourselves by our ignorance.

The introduction of competition into an area can also occur in an
aquatic environment. In the late 1980’s, ships coming into the Great
Lakes from the Atlantic ocean carried in their ballasts (systems in the ship
interior that emptied excess water so the ship could stay aﬂoat) Zebra
Mussels. This exotic species of aquatic mussel attached to pretty much
anything that couldn’t move away from it, and they reproduced at an
alarming rate because there was no efﬁcient predator for them.
Consequently, the Zebra Mussels population bloomed, and native species
of mussels and other small invertebrates became stressed because the
competition for food and habitat was too great.

Other factors that contribute to biotic issues are the introduction of
disease organisms. Although pathogens are a natural part of
ecosystems, they are usually held in check by modulating factors.
However, humans have unwittingly introduced pathogens into
environments that have no natural control, resulting in the loss of species.
The American chestnut tree was virtually eliminated between 1910-1940,
because of the introduction of a fungus that was carried by the Chinese .
chestnut tree. Having no resistance to the fungus, the American chestnut
became diseased and its numbers were permanently damaged.

Simplifying Ecosystems

Tampering with the abiotic and biotic factors in an ecosystem tends
to simplify the system by lowering species diversity. All components of an
ecosystem are reliant on one another. Whether the relationship is
predator/prey, mutualistic (both species beneﬁt from the presence of the
other) or just the toleration of other species, when one of the factors is
altered, the system because it works as a whole, must adjust to
accommodate the change. Chemicals applied to one area of an
ecosystem for instance, will ﬁlter to other areas, either through soil or
water movement, exposing any species of plant or animal that “gets in the
way”. The removal of these species through sickness or death causes the
system to become unbalanced, leaving itself open for viruses, insect
predation and greater competition. These species that do survive the
exposure may become genetically altered, creating a legacy of genetic

88

mutations that leave future generations ﬁghting for survival, unable to
adapt to the change in the environment.

Take Home Message

In general, for any ecosystem to remain healthy and thriving it must
maintain a balance. While natural disturbances such as ﬂoods or high
winds may alter larger total populations, the slow or methodical altering of
environments through human manipulation has a greater effect on the
viability of an ecosystem.

For homeostasis to occur, all parts of a system must be able to
adjust to changing living conditions. The imbalance occurs when one
component of an ecosystem is devastated (such as contaminated water
supply from the soil) and unable to tolerate the disturbance, while another
component of the system thrives.

Humans make decisions that affect their lives directly. We tend not
to think of the “ripple effect” that happens when we either intentionally or
unintentionally change a “part of the whole”. One decision (such as not
regulating industrial run-off) that does not take into account the overall
effect will harm something. That is not in question. Some living
component of the system must make way for the incoming changes. Our
responsibility is to determine how much effect the decision will have on the
environment, what living organism will be affected, how long will the
exposure last, and how long will it take to clean the area once the decision
has been made.

As responsible inhabitants of the Earth, these are tough questions
that we must ask, and be prepared to answer.

“Adapted from “Environmental Science, Action for a Sustainable Future”
Fourth edition, Daniel D. Chiras

89

F-2: Self Sustaining Mechanism Student Questions

Questions for “Self Sustaining Mechanisms in an Ecosystem”

Answer in complete sentences, following essay format.

1. Describe what is meant by abiotic factors.

2. Give an example, other than the one in the reading, of human impact
on abiotic factors in an ecosystem that you are familiar with.

3. Deﬁne biotic factors, giving an example from the reading.

4. Explain how something (such as a toxic chemical) can accumulate
through the food chain. You will need to use your prior knowledge of food
chains to answer this. Also, use your text for background information.

5. Which is more important — making a decision regarding the
environment on a local (just affecting Flint or Michigan) level or making a
decision regarding the environment on a global (affecting the whole Earth)
level? Why do you think that a decision that you make here in Flint,
Michigan could affect someone or something in England or China?
Defend your answer with sound scientiﬁc reasoning.

90

Appendix G: Field Trip Questions
Bull Frog Pond Questions

1. What process happened to allow the wetland to be re-established
(what steps were taken to make the pond come back to life)?

2. What is the impact on the ground (soil) from years of farming? What is
left ever, even though no farming is done on the acreage any longer?
How does this impact humans?

3. Why would the State of Michigan want a wetland to be re-established?
What purposes do they serve?

4. How long does it take for a wetland to come back to life?

5. What does a wetland do naturally, to an area of soil? Why is it
considered a beneﬁt?

Answers vary according to the student’s interpretation.

91

Appendix H: Macrolmicro Nutrient Notes

Essential Elements for Plants

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Element Chemical Form Avail. To % of Plant’s Dry
Symbol Plant ' Weight
Macroelements
Hydrogen H H20 6
Carbon C CO2 45
oxygen 0 02‘ C021 H20 45
Nitrogen N N03' 1 .5
Potassium K K+ 1 .0
Calcium Ca Ca“ 0.5
Magnesium Mg? Mg“ 0.2
Phosphorus P H2PO4'2, HPO..'2 0.2
Sulfur S 804'2 0.1
Micronutrients
Chlorine Cl CI' 0.01
Iron Fe Fe”, Fe+3 0.01
Boron B BO3'2, B407 0.002
Manganese Mn Mn+2 0.005
Zinc Zn Zn+2 0.002
Copper Cu Cu", Cu“T 0.006
Molybdenum Mo MoO.{2 0.00001

 

 

 

 

Macronutrients are elements that are required by the plant in greater
quantities than micronutrients. But in studying the chart above, you can
see that the amounts needed for survival are small, regardless of the

nutrient.

Plants have an incredible ability to concentrate ions (elements that

 

have lost or gained an electron), absorbing them until they are at a much
higher concentration than the surrounding area. This is accomplished by
the roots, which diffuse the ions down a concentration gradient, where
they enter the xylem, which in turn distributes the ions to various parts of
the plant.

Some plants are assisted in the process of taking up metals by the
chemicals that they secrete. Phytochelatins (ﬁ-toe-key-la-ton) are a class
of chemicals produced by the plant that attach to metals in the soil and
make them more soluble (able to dissolve). Plants that are used to
remediate or clean up a polluted site often have a greater number of
phytochelatins.

92

It is important to note that the presence of root hairs (small hair like
extensions that radiate out from the root) helps the plant to take up water
and nutrients. The root hairs increase the surface area of the plant,
creating a bigger area that can be exposed to the soil.

On the other hand, the root hairs also do a good job of taking up
metals in the soil. Although metals are needed by the plant to survive, too
much of anything can kill an organism, which is the case with heavy metal
exposure. The difference between metals and heavy metals is that heavy
metals have a relatively high density and are toxic or poisonous at low
concentrations. If the plant is not tolerant or has low tolerance to metals
in the sell, this uptake can be lethal to the plant.

Some plants, however, have a high tolerance of heavy metals and
successfully store the heavy metals in their roots, shoots, stem and
leaves. This creates a situation in which the plants are capable of
remediating a contaminated site, either by being purposefully planted in an
area or moving into an area naturally through succession. This is known
as phytoremediation (phyto = plant).

Adapted from: “Plant Physiology. Mineral Requirements”
10/2004 http:/l149.152.32.5/Plant physiology/mineralshtml

93

9:599)?“

NP’

Appendix I: Research Outline
RESEARCH PROJECT

This is a short research project. The purpose of this assignment is for you
to gain a clearer understanding of the effect of heavy metals on the
environment. The questions below will help to guide you as you look for
information on the intemet.

What are common environmental toxins?

What is a heavy metal?

What are the effects of heavy metals on plants?

What is the effect of exposure to heavy metals on living organisms?

What are the causes of heavy metal contamination (how do they get into
the environment)?

What does hazardous waste do to the environment?

What are our options in removing the toxins from the environment

Suggested Searches

Decontamination techniques for heavy metals
Heavy metals in the environment

Impact of heavy metals on living organisms
Pathways for heavy metal contamination

All of the questions from the guideline must be answered in your paper.
You are writing a document that creates a picture of how toxins (in this
case heavy metals) get into the environment, their impact on both abiotic
and biotic factors, and options for removing these contaminants.

The paper will be written in paragraph form, following traditional
essay format. Any direct statements taken out of your reference source
must be put into quotation marks and all resources that are used must be
listed on a reference page.

Web site suggestions
www.soils.wisc.edgu
www.environmental-center.com
www.deq.state.mi.us.gov

www.epa.gov

www.usgs.gov
www.lenntechcom/heava-metals.htm

www.luminet.net/~wenonah/hydro/heavmet.html

94

Grading Rubric for Research project

Questions answered

Comprehensive understanding of subject for reader

Essay format followed, including references 60
points

Some questions answered

Understanding not complete for reader

Spelling errors, improper sentence structure 50
points '

Unclear understanding of subject by reader

Many spelling errors, run-on sentences, no references 40
points

95

Appendix J: Remediation Notes
REMEDIATION, THE TRUTH ...................
Generally speaking

Phytoremediation (fy-toe-re-me—dee-a-shun) is the process of using
plants to completely or partially clean contaminants from the following:
Soil

Sludge - “junk” that has collected at the bottom of a water system
Sediment - soil and solid matter that has collected at the bottom of a lake
or nver

Ground Water — reserves of water found beneath the ground - “fresh
water pools”

Surface Water - water at the surface of a water body, whether it is a river,
pond, reservoir, lake, or stream

Waste Water - water that is the result of human activity — industry and
residential

“Contaminant” refers to a chemical that even though on its own it is NOT
toxic or only slightly harmful, when combined with other things and put in
certain situations, can develop into a harmful substance. A number of
factors inﬂuence the toxicity of a chemical such as:

Concentration — the amount (mass/volume) of the chemical in a given
area ‘

Physical state - solid, liquid, or gas form (of chemical)

Environmental state - did the chemical come in contact with the soil, air or
water

Climatic conditions - air temperature, atmospheric water content, ground
temperature

Type of organism that is exposed - some organisms have a greater
tolerance to chemicals than other organisms due to size, coping
mechanisms, etc.

Phytoremediation depends on a plant’s natural processes to work.
This means that the functions used by a plant to live can naturally process
toxins out of the environment. Each process has a different function,
which in turn creates a different outcome or result.

These processes include:

Uptake - bringing water and chemicals into the plant

Metabolism- sugar processing and respiration

Exudates - enzymes/chemicals released by the plant into the soil -
generally makes sell more acidic by taking up metals, which release
protons into the sell

96

Physical/biochemical impact of roots

Requirements for plants to take up chemicals:
Root system that takes up water and chemicals in soil
Xylem — a tube moves chemicals up from the roots, extracts chemicals
taken in at roots
Diffusion across the cell membrane that causes turgor pressure (osmotic
pressure) — remember wimpy vs. strong celery
Oxygen — the plant has to breathe to survive and function
Chemical must be in solution — either in ground water or soil solution - this
means “you can’t separate the chemical by passing it through a ﬁlter”
How hydrophobic a chemical is (how much does it not like water)?
(the more hydrophobic a chemical is, the more bound to the root system —
the less likely to be taken up by the plant)
How easy or hard does the chemical go into solution?
How polar (charged) is a chemical?
How much mass does the chemical have (its molecular weight)?

DIFFERENT TYPES OF PHYTOREMEDIATION EXPLAINED

Phytoextraction - IT IS A REMOVAL PROCESS

Contaminant uptake by roots, with accumulation in the above
ground part of the plant, usually followed by being picked and properly
disposed. ‘

Applies to:

Metals - Ag, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, & Zn
Metalloids — As, Se

Radionuclides - Sr, Cs, U

Non-metals

Target:
Soils — metals usually don’t change when taken in to plant
Sediments 8. sludges

Also known as:
Phytoaccumulation
Phytoabsorption
Phytosequestration

97

Occurs:
Root zone

Limited by:

Sorption of metals to soil particles — dependent on pH of soil, and solubility
of metals '

Narrowness of application - less successful with organic compounds
Disposal of biomass — once contaminant is taken up in plant, then what?

Phytostabilization - IN-PLA CE INA C TI VA TION OR
IMMOBILIZA TION

The use of vegetation to contain soil contaminants in situ, through
changing the chemical, biological and physical conditions of the soil.

Applies to:
Soil, sediments and sludges - reduces transport of contaminants
Increases absorption and accumulation by roots
Reduction of erosion (wind & water) — slows movement of toxins
May reduce or prevent generation of leachate

Target:

Metals — lead, chromium and mercury - roots stabilize by changing
metals from soluble to insoluble oxidized states .

Occurs:
Root zone

Advantages:
Soil removal is unnecessary
Disposal of hazardous materials or biomass is not needed

Cost and amount of disruption to surrounding area is less than with
other remediation techniques

Ecosystem is restored due to vegetation

Disadvantages

Needs long term maintenance of plants — they should be self
sustaining (needed because the toxins can re-release into the
environment)

Requires a metal tolerant plant with roots that grow into the
contamination zone AND can change the conditions of the soil

Possibility of transfer of toxin to a broader environment - heavy metals
should not be considered

98

Rhizoﬁltration - Removal of contaminants in water by plant roots
Removal of contaminants in surface, ground and waste water by
plant roots, by adsorportion onto the roots or absorption into the roots.

Applies to:
Large bodies of water with low concentrations of contaminants (ppb)

Target:
Metals - Pb, Cd, Cu, Fe, Ni, Mn, Zn, Cr(V|)
Radionuclides — Sr, Cs, U

Occurs:

Root zone

Above water plant
Terrestrial plants - roots

Advantages
Can be conducted in situ to remediate surface water bodies

Disadvantages
Monitoring and altering pH require time
Most studies have occurred in a laboratory - not much ﬁeld testing

Rhizodegradation - Destroys or detoxiﬁes organic contaminants
(PAHS)

Enhances naturally occurring biodegradation in soil through plant
roots
(and released chemicals) to destroy or decontaminate an organic
contaminant - petroleum, pesticides, fertilizers.

Applies to:
Soils contaminated with organic compounds

Target:

Organics - fertilizers, polycyclic aromatic hydrocarbons, pesticides,
petroleum(oil) spills, industrial waste

Occurs:

Roots - releases chemicals that breakdown organic molecules into carbon
and water or non-toxic compounds

Roots stimulate microbial activity to assist in the degradation process

99

Advantages

Destruction of the contaminant in situ — on site

Movement of contaminant to the plant or atmosphere very unlikely

No recycling of the plant is necessary — the plant breaks down the toxin

Disadvantages

Limit of the depth that the root can move into the soil and affect the
contaminant

Phytodegradation - contaminant destruction process
thin the plant the contaminant is degraded through uptake and
subsequent break down by the plant

Applies to:
Soil

Sediment
Sludges
Ground water
Surface water

Target:

Organic compounds

PCP

DDT 8. PCB’s — pesticides
TNT - explosive — metals
Herbicides

Chlorines

Occurs:

Through out the plant

Roots — release chemicals that break down contaminants

Poplar trees, water plants, willow trees are examples of degraders

Advantages
Successful metabolism of otherwise “untouchable” compounds

Disadvantages

Transformation of compound into a more toxic form and re-release into
environment are concerns

Phytovolatilization - contaminant removal process

Uptake of contaminant by plant, and release of volatile component
into atmosphere (gas part of molecule).

100

Applies to:
Ground water
Soil
Sediment
Sludges

Target:

Mercury

Selenium

Organic compounds - TCE

Occurs:

Roots to leaves — carries contaminants from root contact, throughout the
plant and releases the less toxic form of the compound into the
atmosphere

Original compound is transformed through plant metabolism

Disadvantages:

Possible transfer of contaminants to atmosphere that can be
toxic/harmful to animals and humans

Adapted from “Phytoremediation of Contaminated Soil and Ground Water
at Hazardous Waste Sites” by Bruce E. Pivetz, United States
Environmental Protection Agency Ground Water Issue

101

Appendix K: Red Worm Experiment
K1: Student Sheet
Toxicological Effects of Red Worms through Soil Transport of Heavy Metals
A Laboratory Experiment
STUDENT SHEET
As we have discussed earlier, any substance that is at a

concentration too high to be tolerated by living organisms is considered a
toxic substance. In this experiment we will be testing the impact that

copper sulfate, 3 heavy metal found in fungicides, algaecides and as a by

product of industrial processes, has on an environment.

The organisms that we will be testing are red worms or leaf worms.
These worms live in the leaf litter of the forest or under the top layer of
dead leaves in your yard. They also burrow deeper into the soil, breaking
down large chunks of soil into smaller parts and contributing to the
aeration (air spaces) of the soil, which helps microorganisms live.
Although the red worms appear to be small in size and removed from the
human experience, they are an excellent indicator of the health of the
environment. When chemicals have an impact on small organisms (those
lower on the food chain), then it is important to recognize how more

advanced organisms can be affected too.

Metals can ﬁnd their way into the environment through various

pathways. Metal ores occur naturally in the Earth’s crust, the application

102

of chemicals onto our lawns and ﬁelds, and the waste products of

industrial processes also results in an accumulation of metals.

In this experiment, you will create a model of a soil environment by
putting soil into a container that has been embedded with worm food and
then contaminating the soil with copper sulfate. You will place live red
worms into this environment, and observe the effects that the metal has
on the livelihood of the worms. Ultimately, you will gain a better
understanding of tolerable limits, critical concentrations and the impact
that “too much of a good thing” can have on an individuals’ life.

Purpose:

Through observations and measurements, the student will gain a
greater awareness of the impact of heavy metals on red worms in a
modeled soil environment.

Materials:
Material list is based on groups of 3-4 students
5 - 1 quart mason jars or 5- 3.8 liter plastic containers, both of these need
lids
270 grams (dry weight) of soil for mason jars, 500 grams (dry weight) of
soil for 3.8 L containers
1-2 tablespoons of worm food per container - bread crumbs
6-8 red worms per container
Copper sulfate solution

Procedure:

. Place soil containers in a row and label one container with one label,
ending with each container having a different label. The labels are as
follows

0.125 gl500 g, 0.2509/5009, 0.375 gl5009, 0.500 915009 and control
(no

CuSO4, only 500 grams of soil).

. Weigh out 270 grams of soil for the quart container or 500 grams of soil for

the 3.8 L container. This amount should be added to all of the containers,
including the control.

103

. Sprinkle the newly added soil with the worm food, mixing equally. Sprinkle
the soil mixture with water so that it is no longer dry, but do not wet it so
heavily that it turns into mud.

. Obtain the copper sulfate solution from the instructor, or mix the solution in
the following proportions: place 0.125 grams of CuSo4 into a graduated
cylinder and add enough water to the cylinder to equal 100 ml. Allow the
CuSO4 to begin to dissolve, aiding the process by slowly swirling the
mixture. Slowly pour the dissolved copper sulfate solution over the soil of
the container marked 0.125 gm/5009m, mixing the soil with a spatula after
all of the solution has been added.

. Repeat the mixing of CuSO4 and 100 ml of water, dissolving slowly,
adding to the correct container of soil slowly and mixing with a spatula for
the remaining proportions: 0.250 grams, 0.375 grams, and 0.500 grams.

. Take 6-8 red worms from the container and gently place them on a
weighing paper on the gram scale. Take the mass of the worms and
record the total number of worms, total mass of worms and the general
appearance of the worms in your data table. Gently place the worms in
the soil, allowing them to move deeper into the soil on their own. Repeat
this procedure for each of the containers, until you have weighed 5
containers worth of worms.

. Every two days you will gently move the soil around with a spatula to
check for behavioral health, such as movement and color. Record the
date and your observations in the data table.

. On the 5‘" day you will lay newspaper or some equivalent type of paper on
the lab bench. Gently shake the soil onto the paper emptying the entire
contents of the container on the table. Using a weighing paper, place the
worms on the scale so that you can measure total mass. Record this
number in your data table, along with behavioral observations and body
count

. Using the newspaper as a funnel, pour the soil back into the container.
Finish this work by adding the worms back into the soil.

10. Repeat the emptying and massing exercise with all four remaining

containers, being certain to record your ﬁndings in the data table.

11.Follow the procedure for observing on day #7, and on day #10, empty the

contents of the container on newspaper once again, as in step #8.

12.After taking the ﬁnal mass and a ﬁnal body count, remove the dead worms

and dispose of them, along with the soil, in a plastic bag. Those worms
that survived should be placed in a garden or a ﬂower- bed.

104

1. Rinse out the containers with detergent and wash your hands moroughly.
2. Proceed by analyzing data, graphing results and answering lab questions.

Name:
Team Members:

 

 

Data TableforExperImentObservationsandWonn Counts

 

Team
#1
Contain Start Day 3 Day 5 Day 7 Day 10 Change
or Day
Control
Worm
Count
Total
mass of
worms
0.125
_gm
Worm
Count
Total
mass of

 

 

 

 

 

 

 

 

0.250
_gm

Count
Total
mass of

 

 

 

0.375
_gm
Worm
Count
Total
mass of
worms
0.500
_gm
Worm
Count
Total
mass of
worms

 

 

 

 

 

 

 

 

 

 

 

 

 

 

105

K-2: Instructor Sheet Red Worm Experiment

Toxicological Effects on Red Worms through Soil Transport of Heavy
Metals

INSTRUCTOR SHEET

Metal toxicity through various pathways into the environment
affects a broad range of organisms. This assay focuses on the effect of
copper sulfate (found in fungicides, algaecides, root inhibitors, and as a
by-product of industrial processes) on red worms, which are common soil
inhabitants. While the red worms may be small in size and appear to be
removed from the human experience, they are in effect an excellent
indicator for metal toxicity, regarding behavior, reproductive ability and

mortality.

It is the intent of this experiment to give the student a better
understanding of how all organisms are affected by the presence of a
substance that, outside of tolerable limits, has a lethal effect. This
intolerable limit is called a “lethal concentration” and is applicable to any
substance that is found in great concentrations. This applies to any
nutrient or gas that takes an organism past the point of being able to
process it through their system in a healthy manner.

This lab can be performed over a four week period of time, or in as
little as two weeks, depending on the concentration of metal that is placed
into the model This lab will be written for the two week class period,
extending the testing period will only change the data table. It assists the
student in gaining observation skills, assessing organism behavioral
issues such as reproduction and mobility, and determining the
mathematical limit of chemical concentration that results in death of the
experimental organism. It is suggested that students work in groups of 2-
4, limiting the amount of material needed, as well as encouraging group
cooperation.

106

Materials:

0 4 quartl3.8 L plastic shoe boxes (1 quart mason jars can also be used
if there are a larger number of students that will be conducting the
experiment — adjustments in soil and metal volume must be made) -
each student group will use 5 containers

0 Red worms - 6-10 per assay

0 Soil — a normal mix of 30% peat, 30% sand and 40% potting soil. 270
grams required for 1 quart mason jars and 500 grams for 3.8 liter
plastic containers

0 Copper sulfate — The coppersulfate solution can be premixed for the
students or can be done by the students themselves, based on student
ability. Preparation of the solution is as follows: 0.125 g per 100 ml of
water, 0.250 g per 100 ml ofwater, 0.375 g per 100 ml of water and
0.500 g per 100 ml of water. If mixing in large quantities, be certain to
check for dissolution of the copper. This solution will be placed in the
containers prior to the worms being placed inside, and should be
mixed thoreughly throughout the soil.

0 Bread crumbs for worm food

Procedure:

1. Mix the soil in equal amounts of 30% peat, 30% sand and 30% potting
soil. Estimate the total amount of soil needed so that each container holds
270 g ofsoilforthe1quartmasonjars or5009 ofsoil (based on dry
weight of soil) for the shoe box containers. It is advisable to mix 10%
more soil (amount) than is needed.

2. Students should weigh the soil, dry, before placing in the container.
Each student will measure soil for 4 containers. Place soil and worm food
into each container.

3. Label each container with the appropriate metal concentration.

4. Copper sulfate solution is placed in each container (with the ranges of
0.125mg CuSOJ100mI of water, 0.250 mg CuSOJ100mI of water, 0.375
mg CuSOJ100mI of water, and 0.500 mg CuSO4/100ml of water) taking
note of required concentration and mixing thoroughly throughout the soil.

5. Count out 6—10 worms per container, per group. Each group should
weigh and record the total mass of their worms.

107

6. Before worms are placed in the containers, students should note (in the
data table) behavior such as mobility, ﬁle color of the worms and relative
size (based on student opinion).

7. Place worms in each container that has had the soil loosened to allow
for the worms to move deeper in to the mix. '

8. Students will make observations every 2 days, loosening the soil to
check for mobility. On the 5'" day, students will remove the soil from the
container, placing it on paper (newspaper works well), using plastic
gloves. Remove the worms and place the soil back into the proper
container. The mass and total count of the worms will be recorded, as well
as any behavioral changes, such as slower movement and death. Any
worms that have died should be discarded.

9. Continue observations for 4 more days, keeping to the two day
schedule. On the 10‘” day of the experiment, the soil should once again
be emptied onto newspaper and the worms removed charting weight and
total body count. It is expected that as the concentration of the copper
sulfate increases, so will the mortality rate of the worms. Consequently,
the 0.500mg/g concentration may have a 100% death rate. Again, all
information should be recorded in the data table.

10. Surviving worms can be placed back into a natural environment , such
as a garden or ﬂowermd. Dead worms should be discarded along with
the contaminated soil. It is safe to place the soil/newspaper in a bag and
discard it in a trash container.

11. Student data should be plotted on a line graph so that a relationship
between concentration and mortality can be established.

108

Class Discussion

Once the data has been analyzed, students should be able
to discuss the impact that metals have on organisms living in a
contaminated environment. Although red worms were used as the model,
the implication that survivability is dependent on the concentration of the
toxin is evident.

It is critical that the students understand that toxicity to a small
organism (whose existence is necessary for the rest of life, in this case
keeping the soil healthy) indicates the possibility of toxicity to higher order
organisms through bioaccumulation. Also, key to the discussion is that a
lethal dose does not always have the greatest impact on a population.
Slow growth rates or decreased reproductive ability also affect a
population, which in turn can have a greater impact than less of
individuals. ,

Further discussion of the laboratory techniques could include
remediation techniques that may inhibit the metals impact on the worm
population, such as plant cover or the increase of available space so that
the impact of the toxins is diminished. Additionally, because each
organism responds to a toxin in a different manner, the experiment could
be changed to test different populations or types of toxic substances, such
as yard fertilizer.

109

Appendix L: Bioaccumulation Activity

 

BIOACCUMULATION ACTIVITY

The purpose of this activity is to demonstrate, using the students, the
theory of bioaccumulation. Although books are used as the model for
toxins in the environment, it gives the students an idea of the “density” that
occurs when contaminants build in an area.

Procedure:

Each student will hold a book that is approximately equal in weight. Their
textbooks are a good idea.

Standing in a circle (if space permits) or outlining the room, one student
begins the “building” by passing their book to the person next to them.
The second person adds their book to the pile and passes both books to
the next person.

This progression continues until the person who has beenpassed the
“collective books” can no longer hold onto them without dropping them —
just like bioaccumulation of contaminants that build in an environment until
they can no longer be tolerated and ultimately cause the break down of
the system! This number will differ according to the number of books and
the muscle ability of the person who is holding the books - a good model
for a contaminant being benign in one environment and toxic in anotheril
The “environment” can be altered by moving the students around the
circle according to size (smallest student to largest student or vice versa).
In this case the model shows that smaller organisms (e.g. fresh water
crustaceans) struggle with less toxic concentrations, just as larger
organisms (e.g. wildlife/humans) struggle with larger concentrations of
contaminants. In this step of the demonstration it is important to point out
that the larger organisms are carrying a larger contaminant load — an
indicator of tolerance.

110

Class Discussion

This demonstration gives a physical model of an event that occurs
in nature all of the time. The books represented a substance (zinc, for
instance) that in small amounts is necessary for life, but when put into an
environment where the substance builds, can be‘ devastating. As the
books (toxins) were passed from one student (organism) to another, the
effect that they had on the bearer (student holding the book/toxin) became
greater and greater, until eventually the organism couldn’t tolerate the
load.

Bioaccumulation occurs in the same manner. What starts out as a
tolerated substance can potentially become a lethal toxin. As the
substance moves from one area to another — copper sulfate (for instance)
from a home septic system to a river, the contaminant is exposed to
changing environmental conditions which can alter the chemical structure.
This in turn can cause the contaminant to be taken up by organisms that
normally wouldn’t be harmed or exposed (due to the change in the
pathway), which pass the contaminant on to other organisms either
through the food web or by the nature of their existence - contaminated
water at a soil interface.

The students will be asked about proactive choices. They should
be able to generate ideas about markers in the environment that indicate
accumulation is occurring. For instance, if there is a ﬁsh kill in the local
stream, it can be an indication of toxicity — and if it is happening to the ﬁsh,
what has happened to the microscopic organisms inhabiting the water, as
well as the plants? Questions the students might come up with are “where
“did the toxin come from, how long will it remain there, how is the toxin
transported from one area to another and where does it go when it settles
to the sediment layer of the river”?

Assessment

Each student will be given 2-3 minutes to think about their answer to the
following question, and responses that reﬂect an understanding of the
accumulative effects of a substance will indicate success of activity.

“Give an example of a situation or event that starts out not harmful, but
through a series of events, “accumulates” into a problem or toxic situation”

111

Appendices M: New You See It, Now You Don’t

M-1: Student Sheet AcidlBase Experiment

Now You See It, Now You Don’tll
Copper Sulfate Precipitate Lab

Purpose: The intent of this lab is to demonstrate that when a metal is
exposed to changing pH ranges, it has the ability to move in and out of
soluble forms.

Material:

20 ml of 0.1 M CuSO..

2 — plastic pipettes

0.1 gm CaC03 - buffer

2 ml 0.1M NaOH (sodium hydroxide)
2ml 0.1 M HN03 or HCI (nitric acid or hydrochloric acid)
2 — 25 ml beakers

1 strip pH paper

2 medium test tube

Goggles

Rubber stopper to ﬁt test tube
Graduated cylinder

Procedure:

Put on safety goggles. Label each beaker — one with NaOH and
the other with HNOa, Using the graduated cylinder measure 2 ml of
NaOH, carefully pouring into proper beaker. Repeat process with HN03
(or HCI).

Trial One

Measure 20 ml of CuSO4 into a clean graduated cylinder. Pour into
the test tube. Place in test tube rack. Record your observations of color
and clearness of copper sulfate in your lab book.

Using a pipette, ﬁll barrel with NaOH (sodium hydroxide).
Counting, add 10 drops of sodium hydroxide to the copper sulfate test
tube, carefully observing the changes. Write down your observations in
your lab book. Using a stopper, invert the tube to mix the base (NaOH)
with the copper.

Once you have recorded your observations, using the other pipette,
ﬁll the barrel with HCI (hydrochloric acid). Counting, add 10 drops of

112

hydrochloric acid to the test tube of copper sulfate/sodium hydroxide,
carefully observing the changes. Record observations in lab book.

Place test tube in rack.

Trial Two

Repeat step 2 using a new test tube, adding 20 ml of copper sulfate
and 0.1 mg of calcium carbonate. Put stopper on tube and invert to mix.
It may take 2-3 minutes for calcium carbonate to dissolve.

Using your memory and written observations, begin adding NaOH
to test tube, count each drop added until you have achieved the same
color/cleamess of the original copper sulfate that you had in trial one.
Record total NaOH drops added, as well as your visual observations.

Repeat the process using HNOa, counting drops and recording your
observations.

When completed, place test tube in rack.

Lab Questions - Place in lab book

. Describe what the copper sulfate looked like when you began to
add the base (NaOH)? .

Describe what happened to the cloudiness when you added the
acid (HNO3)? Give an explanation as to why you think this happened.

In an acidic environment, metals such as copper become more
soluble (which means the copper won’t separate from the solvent when
ﬁltered). How did you know that the copper had been exposed to an acid?
Describe what you saw.

When you added the calcium carbonate to the test tube in trial two,
describe how it affected the number of drops of base and acid that had to
be added to the test tube, to match trial one.

Calcium carbonate is a buffer, which means that it keeps the pH of
a solution or an environment (your yard) from moving too acidic or too
basic. If there was a metal contaminant that you were trying to get to be
taken up by plants, and the pH needed to be below 6 (acidic), how could
you accomplish this?

113

M-2: Teacher Edition New You Se It, Now You Don’t

Now You See It, Now You Don’t
Teachers Edition

This lab is a good quick way to help students gain a greater understanding
of acid/base reactions and the impact of buffers. It isn’t necessary to do
qualitative work, but rather to help the students create a visual model of
metal precipitation due to exposure to a basic solution.

It can be applied to many types of classes because it doesn’t
require a great deal of measurement for the students, but does help them
to improve their ability with simple lab equipment. It is helpful to explain
that an acidic solution will release a hydrogen (proton) and that a basic
solution will accept a proton. In this lab the exchanging of hydrogen
results in a copper precipitate. Applied to a natural environment, the
exchange of a proton and the amount of acid in a solution is also a
measure of pH. Regarding soil, a neutral pH Is in a range of 6.5-7.5,
above that is basic, below 6.5 is considered acidic.

As an environmental model, the manipulation of soil/water pH is
beneﬁcial when dealing with a metal contaminant. Especially in the case
of plant - assisted remediation, the metal must be soluble (available for
uptake) which dictates that the metal be in an acidic environment. This
can sometimes be accomplished by acidifying the soil through the
application of acidic acid.

Moreover, this lab directly shows that when a metal (copper sulfate)
is put in the presence of a ‘basic’ environment the metal will become less
soluble, and in the case of remediation, stick to the soil or sludge,
hindering removal.

Solution “Recipes”
All Solutions Are 0.1 M - Each student pair requires 40 ml

Copper Sulfate

15 grams per 600 ml of distilled H2O - swirl to mix
Each student pair requires 40 ml

This amount gives enough for 15 - paired students

Nitric Acid or Hydrochloric Acid

Nitric Acid

0.06 grams per 100 ml of distilled water
Each student pair requires 2 ml

Hydrochloric Acid

0.16 grams per 100 ml of distilled water
Each student pair requires 2 ml

114

Sodium Hydroxide
0.24 grams per 100 ml of distilled water

115

Appendix N: Soil Percolation Demonstration
BOTTLED WATER — WHAT IS GOING ON WITH THE GROUND?

For this exercise, you will be working in groups of six — 2 people per
team/bottle. You will be using your ﬁne observation skills to determine the
process of water ﬁltering, through a model that you will build in class. So
it’s really important that you work together and stay focused — there's a lot
of learning to do!

Materials:
Per 2 person team
1 - 2 liter bottle
1 — graduated cylinder
1 — 600 ml or 1000 ml beaker
500 ml of sand or potting soil or a mix of both
500 ml of water — placed in an ehrlenmyer ﬂask
1 timer or a good view of a clock

The construction of the bottles is the hardest part of this lab.

 

116

Procedure:

. Place a 2 liter bottle ﬂat on the table and locate the “hip” near the bottom
(the area that starts to round down to the base of the bottle). Using the
point of the scissors, carefully puncture a hole in the bottle so that you can
insert the scissor blade. Cut a straight line around the circumference of the
bottle, removing the base.

. Flip the bottle over so that the cap is on the table. As one team member
measures 100 ml of water in the graduated cylinder, the other team
member locates a permanent marker. Supporting the bottle, pour the 100
ml of water into the opening and make a mark on the outside level with the
water line.

. Repeat the process of adding 100 ml increments of water and marking the
outside of the bottle until you have reached the 1000 ml mark.

. From the group of six, each team of 2 members will be assigned a
different soil type: sand, potting soil or a 50/50 mix of both. Once your
instructor has given your team its soil type, ﬁll your overturned bottle to
the 500 ml mark with that soil.

. Obtain a 600 ml or 1000 ml beaker. Place your inverted bottle into the
beaker. Your bottle cap should not touch the beaker bottom. Fill a ﬂask
with 500 ml of water, measuring the amount with a graduated cylinder if
needed.

. Your team should now have three bottles with three different soil types in
them. On your lab sheet place your “guess” as to which one of the bottles
will move 500 ml of water through it the fastest (question #1 ).

. In the data table you will record the time it takes 100 ml, 200 ml, 300 ml,
400 ml and 500 ml of water to move through your soil column. As one
member of the team watches the clock or sets the timer, the other team
member pours 500 ml of water into the over turned bottle. Begin timing as
soon as the wafer is poured onto the soil, and record the seconds/minutes
per 100 ml.

. Once the 500 ml of water has moved through the soil column, record the
numbers of your other team members in your data table, and discuss your
ﬁndings. What were the differences in time, what factors contributed to
the speed, why has one type of soil held onto the water, etc? Be prepared
to discuss your ﬁndings with the entire class.

117

9. Empty and rinse the beaker that has the collected water in it -— only if your
soil column is still dripping should your leave your bottle on top of the
beaker. Discuss as a class and answer lab questions.

Data Table for Porosity/Penneability Lab

 

Water Time
Amount

 

 

Sand Potting Soil 50/50 Mix

 

 

100 ml H20
200 ml H20
300 ml H20
400 ml H20
500 ml H20

 

 

 

 

 

 

 

 

 

Post Lab Questions

1. Which soil column (which bottle/type of soil) will the water move through
the fastest? ‘

 

 

2. According to the actual experiment, which soil type allowed the water to
move through the fastest? Which soil type was the slowest?

 

 

3. Looking at the soil in the bottle, which type has the largest grain or biggest
pieces? How do you think this affects how fast the water moves through
the column?

 

 

 

 

118

4. Comparing your data to the rest of your classmates, is there a general
statement that can be made about soil types? If so, what could you say?
“ When you compare sand, potting soil or a mix of both, it has been found
that” .........................

 

 

 

Extension Question

5. You learn that there has been a hazardous waste spill at a construction
site. Applying what you know, what type of soil would you hope that the
spill occurred on so that you would have enough time to clean the area
(what kind of soil would you want to be there to “hold” the contaminants so
that they don’t move into the water table)? Explain your answer.

 

 

 

 

 

119

Appendix 0: Remediation Unit Evaluation
REMEDIATION UNIT EVALUATION
Read the following questions and answer them with an honest opinion.
. Did you learn anything about how toxins in the environment can harm
living organisms?

Yes No

. Are there natural systems in the environment that can clean toxins out
of the soil and water?

Yes No
. List three things that you learned from this unit
a.
b.
c.

. Did your opinion of the impact of humans on the environment change
after this unit? If yes, how?

Yes No
. Did you know before the unit that plants have the ability to clean up
contaminants from the environment?

Yes No

. If you had to decide if an area was contaminated, what part of the
environment/habitat would you look at ﬁrst and why?

. What activities that you were involved in helped you learn the most?
Why: Bullfrog Pond

b. Red worm Lab

0. Wetland Tanks

d. Soil Column Demo.

e. Precipitation Lab

f. Research Paper

120

8. What was the best part of this unit and why?
9. What was the worst part of this unit and why?

10. Give one suggestion to make this unit better when it is taught again.

Thanks for your input. Your opinion is valuable and important.

121

Appendices P: Rubrics
P-1: Maintaining a Journal
MAINTAINING A JOURNAL

In science class it is often easy to get lost in the middle of Ieaming, caught
up in the excitement of the lesson. Then your instructor asks you a
question, and you stare blankly at him or her, hoping that no one knows
that you are there. I know this, I have been there.

One of the best things that l have learned is that if I keep a written
record of the steps in a lab, my results, howl felt about a project, etc., it
was a lot easier to hold on to the information. With that, you will be
required to keep a lab journal throughout the unit on contamination and
remediation. You will be rewarded for your hard work by having gained a
greater sense of organization, a deeper base of knowledge, and most
importantly, a substantial grade.

The requirements for the journal are simple: any lab that is done in
class will be recorded (the procedures in your own words) including the
results of the experiment, any observations that are the result of a
demonstration, class notes, and any thoughts or feelings that you hold
about a lesson.

Your journal will be worth 270 points, a documentation of all that
you have learned. Include in your entries: calculations, data, class and
personal observations, outcomes of experiments. Each experiment has
an expected outcome, but your opinion is your own, one-of the things that
' cannot be degraded or criticized.

This journal is an opportunity to say what you mean and mean what
you say!

GUIDELINES FOR EXPERIMENTS AND JOURNAL WRITING

Experiments
Lab reports will be placed in the second half of the book and will be
numbered and titled.
Lab information will be placed on the right side and calculations/personal
observations will be placed on the left.
All entries are written in ink, not pencil. Mistakes are not erased — a line is
drawn through them, and the entry is rewritten.
All lab reports will include the following:

. Name of the lab

- Your name and the members of your group

122

Purpose of the lab — what are we trying to ﬁgure out
Hypothesis

Material used

Procedure (may be written in your own words)

Data and results

Conclusion - what did you learn, how did you feel about it?

Journal Writing

Journal entries placed in the front half of the book

Date of entry — left hand column

State what you are referring to — a lab, an observation, etc.
Questions you need answered

Anything you don’t understand

Suggestions on how the lab/demollesson can be improved

123

P-2: Remediation Unit Grading Rubric
Rubric for Remediation Unit

Journal *Daily entries, all projects, labs included
*Followed guidelines

*Neat, orderly, easy to read

Bull Frog Pond Questions
*Analysis questions

Now you see it Lab (includes observation)
Self Sustaining Mechanisms Handout

1”t data table
Avg. mass table

Graph
Questions

Redworm Lab

Heavy Metal
Wetland tanks

Copper charts
Plant chart
Questions
Question #11

’ Notes *plant/animal micronutrients
* Glaciation

* Phytoremediation

Total Possible

124

50 points
30 points
20 points

10 points
15 points

5 points
10 points

20 points
5 points

15 points
20 points

10 points
5 points
30 points
5 points

5 points
5 points
10 points

270 points

P- 3: Pre and Post Test Grading Rubric
Pre and Post Test Grading Rubric — 20 Total Points

1. What is meant by “heavy metals”? How do they differ from other
metals?

Heavy metals have a higher density and tend to accumulate in the
environment, include living organisms, at a higher rate than other metals.
This question was worth 2 points, partial credit of 1 point given if they
answered part of the question correctly.

2. Deﬁne toxic

“Toxic” refers to any substance that can cause harm or death when it
reaches a critical concentration, a level that is not tolerated by the
organism

This question was worth 1 point if answered correctly, no partial credit
given.

3. Describe how a substance can become toxic.

Any substance can become toxic if it accumulates, either in the
environment or within an organ system, and can not be disposed or
removed from the system.

This question was worth 2 points, partial credit of 1 point given if
students answered only with “the substance accumulates”.

4. Name three different ways that heavy metals are known to enter the
environment?

Heavy metals occur naturally in the environment, where they are generally

tolerated. Other contributing pathways include: industrial waste (liquid,

solid, gaseous), human activity private life (car exhaust, lawn application

of fertilizer, septic chemicals, etc.) break down of natural containment

areas, pollution.

This question was worth 3 points, partial credit of 1 point given per stated

example.

5. Explain why lower organisms, such as plants and invertebrates are the
ﬁrst

living things to be affected by toxic contamination.
Toxicity is dependent on concentration of substance and the organism’s
ability to remove the toxin from its system. Lower organisms are generally
smaller in size, their vascular systems are smallerand they live directly in
(contact) with the source of the contamination. Due to their inability to
move away from the source of toxicity, they are affected ﬁrst and most
often banned in the greatest way, when contamination occurs.

125

This question was worth 2 points, partial credit of 1 point given if student
stated that the organism lived in the soil but could not explain why it would
be poisoned ﬁrst.

6. Describe the difference In soil types and explain why soil composition
affects

the toxicity of a contaminant.
There are three main soil types — sand, peat, loam and a mix of all three.
Depending on the area of the world (geographically), soil types are
different, due to environmental factors such as water exposure, glacial
activity, slat concentration, etc, The larger the particle size, the larger the
air space between particles. This air space also allows for solid/liquid
contaminants to move and be stored in one area. The sandier the soil, the
greater the “holding ability” of the soil.
This question was worth 2 points given for stating soil types and 1 point
given for explanation of compaction.

7. Deﬁne remediation and explain why it is important.

Remediation is the process of containing and cleaning an area that has
been contaminated by a toxic substance. This can be accomplished a
number of ways, and it beneﬁts the environment because it stops the
contamination from spreading to other habitats, and harming other
organisms.

This question was worth 2 points for a full deﬁnition and statement of
importance, partial credit of 1 point given if a deﬁnition or the importance
. was stated, but not both.

8. Deﬁne phytoremediation and explain how plants are able to “take up”
metals

through their roots into the shoots, stems and leaves.
Phytoremediation is the use of plants to contain a toxin in a contaminated
area by sequestering the toxin, in this case, heavy metals, through their
root systems. Once the metal has entered the root system, it is taken up
into the plant through the vascular system and is either contained or
volatilized by the plant.
This question was worth 2 points if the deﬁnition and explanation of
removal of metals was provided, 1 point partial credit was given if only a
deﬁnition was provided.

9. Give an example of a natural remediation site that can be found in
nature.

A wetland is a natural remediation site. Contaminants are removed and/or
contained by the roots/shoots of the plant and the water is cleaned by the
respiration of the plant. Other examples of natural remediators include
poplar trees, weeping willow, cat tails and duckweed.

126

This question was worth 2 points if an example was given and an
explanation of how the site removed toxins, 1 point partial credit given for
only stating the example.

10. Can plants used for phytoremediation be recycled? How?

Plants that contain metals and other contaminants that have been
sequestered can be recycled. Burning the organic material and collecting
the ore is one example. Plants can also be removed from the
contaminated area and buried in a landﬁll, adding to the organic structure
of the soil.

This question was worth 2 points if the student stated that plants could be
recycled and explained how that was accomplished, 1 point partial credit
given if there was no explanation as to how the plant was recycled.

127

Appendix Q: Permission for Use of Copyrighted Song

SLij: Re: lnqulry
Date: 8l18l2004 8:20:31 AM Eastern Standard Time

From: admin@dy_nkeld._co.uk
T0: Ruledbylove@admm
Dear Karen,

You have our permission with great pleasure....it's great to hear of
Dougie's lyrics and music being used in such a way...the 11th graders
are our future!

Good luck with the unit

Kind Regards,

Jennifer

Jennifer MacLean

(Manager for Dougie MacLean

Director of Dunkeld Records Ltd: Partner Limetree Arts and Music
Publishing)

Tel: 01350 724281

Mobile: 07739 414169

www.dougiemaclean.com

On 3 Aug 2004, at 12:24, Ruledbylove@aol.com wrote:

> Mr. Maclean,

> I am an environmental teacher in the United States who will be

> teaching hazardous waste to a group of 11th grade students. I am

> interested in playing your song "Rescue Me" as an introduction to the
> unit. It will not be published or used in an manner for money making
> - it is my intent to raise the awareness of the students, broaden

> their idea that not everyone is ok with poisioning the ground.

> I am not sure to the requirements or your permission to using this

> work in this manner, can you help me out?

> Thanks for the consideration and help.

> Sincerely,

> Karen Gould

128

 

ornce or
RESEARCH
ETHICS AND
STANDARDS

Unlvonlty Committee on
Research Involving
Human Subjects

Michigan State University
202 Olds Hall

East Lansing. MI

48824

517/355-2180

FAX: 517/432-4503

Web: WWW msu edu/usei/ucrihs
E-Mail: ucrihs@msu.edu

MSU is an affirmative-action.
equal-opportunih- ll'lSl'lUilOlI.

Appendix R: UCRIHS Letter of Approval

MICHIGAN STATE

UNIVERSITY

 

July 23. 2004

TO: Merle HEIDEMANN
118 North Kedzie Hall
MSU

RE: IRB# 04-582 CATEGORY: EXEMPT 1

APPROVAL DATE: July 22, 2004
EXPIRATION DATEJuIy 22, 2005

TITLE: A Study of the Removal of Heavy Metals in the Environment through
Phytoremediation

The University Committee on Research Involving Human Subjects' (UCRIHS) review of this

project is complete and I am pleased to advise that the rights and welfare of the human

subjects appear to be adequately protected and methods to obtain informed consent are

appropriate. Therefore, the UCRIHS approved thls project.

RENEWALS: UCRIHS approval is valid until the expiration date listed above. Projects
continuing beyond this date must be renewed with the renewal form. A maximum of four such
expedited renewals are possible. Investigators wishing to continue a project beyond that time
need to submit a 5-year application for a complete review.

REVISIONS: UCRIHS must review any changes in procedures involving human subjects, prior
to initiation of the change. If this is done at the time of renewal, please include a revision form
with the renewal. To revise an approved protocol at any other time during the year, send your
written request with an attached revision cover sheet to the UCRIHS Chair, requesting revised
approval and referencing the project‘s IRB# and title. Include in your request a description of
the change and any revised instruments, consent forms or advertisements that are applicable.
PROBLEMS/CHANGES: Should either of the following arise during the course of the work,
notify UCRIHS promptly: 1) problems (unexpected side effects, complaints, etc.) involving
human subjects or 2) changes in the research environment or new information indicating
greater risk to the human subjects than existed when the protocol was previously reviewed and
approved.

If we can be of further assistance, please contact us at (517) 355-2180 or via email:
UCRIHS@msu.edu. Please note that all UCRIHS forms are located on the web:
http://www.humanresearchmsu.edu

Sincerely,

Peter Vasilenko, Ph.D.

UCRIHS Chair

PV: kj

fCZ Karen Gould

224 E. Court St. #106

129

   

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