.CESIUM~137 AND STABLE CESIUM ' IN A HYPEREUTROPHIC LAKE < y Thesis for the Degree ”of Ph. D. ' MICHIGAN STATE UNIVERSITY L. DEAN EYMAN 1972 LIB RA R Y Michigan Ste :73 University This is to certify that the thesis entitled CESIUM-137 AND STABLE CESIUM IN A HYPEREUTROPHIC LAKE presented by L. DEAN EYMAN has been accepted towards fulfillment of the requirements for Ph'D° degree inEifiheriew Wildlife Zia” /Afieezj Morpmfm Datum 0-7639 umbma av "DAG! SIMS" 800K BINDERY INC. uamnv stanzas mammalian ABSTRACT CESIUM-137 AND STABLE CESIUM IN A HYPEREUTROPHIC LAKE BY L. Dean Eyman 137Cs and stable Cs and their The inputs of distribution among the various components of an aquatic ecosystem were studied in a lake exhibiting an advanced stage of eutrophy. Components sampled and analyzed for these two isotopes of cesium included water, sediments, macroPhytes, filamentous algae, zooplankton, and several species of fish. Most of the cesium pool (87%-l37Cs; 98%—stable Cs) was associated with the sediments. Stable Cs enters the lake primarily in an organically bound state as migratory waterfowl excreta and is deposited to the sediments. Cesium-137 enters as a soluble inorganic form and is distributed throughout the system. Specific activity 137Cs/ng stable Cs) of the sediments is lower than (pCi. other components of the system due to the different modes of entry of the two isotopes of cesium. L. Dean Eyman A trend of increased 137Cs concentration at higher trophic levels is demonstrated for those fish that are free-ranging limnetic feeders. No such trend is evident for stable Cs. Forms closely associated with sediments have higher 137Cs concentrations than expected based on their feeding habits. On the dates samples were collected, specific activity in limnetic fishes was constant but was variable in other forms. The degree of association of biotic forms with sediments is reflected in their specific- activity. CESIUM-137 AND STABLE CESIUM IN A HYPEREUTROPHIC LAKE BY 6 LV’Dean Eyman A THESIS Submitted to , Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Fisheries and Wildlife 1972 ACKNOWLEDGMENTS I wish to thank those individuals whose help was eSSential to the completion of my research:‘ Mr. W. J. Johnson of the Kellogg Bird Sanctuary for his coopera- tion and aid in obtaining samples and providing data on waterfowl usage of the lake; fellow graduate students J. Eckenrode, D. Jude, and A. Szluha for help in the field; J. Seelye for discussions and suggestions on analytical methodology; Dr. B. J. Mathis for his review and helpful suggestions in the preparation of the manuscript. I extend gratitude to my graduate committee: Dr. R. C. Ball, Dr. F. M. D'Itri, Dr. J. L. Gill, and particularly to Dr. N. R. Kevern for stimulating dis- cussions on radioecology as well as his advice and guidance during the period of my graduate studies.‘ For her patience and constant encouragement during my graduate study and her complete involvement in pro- viding a secure home for our children in my absences, I affectionately extend my gratitude to my wife, Ginny. To son Jeffrey and daughter Angela, constant sources of strength, thanks for being. ii This research was supported through a Predoctoral Fellowship S-Fl-WP-26,354-03 from the Water Quality Office of the Environmental Protection Agency to whom I am grateful. iii TABLE OF CONTENTS LIST OF TABLES O O O O O O I O O O O . O C O 0 LIST OF FIGURES O O O O O O O O O O O O O O 0 INTRODUCTION 0 O O I I O O O O O O O O O O O 0 STUDY SITE 0 O O O O O O O O O O O O O O O O 0 METHODS O O O O O O O I O O O O O O O I O O 0 Preparation of Samples . . . . . . . . . . . RESULTS 0 O I O O O O O O O O O I O O O O O 0 Inputs of Cesium-137 and Stable Cesium . . . Waterfowl . . . . . . . . . . . -,- . . . Precipitation . . . . . . . Distribution of Cesium-l3? and Stable Cesium in the Lake . . . . . . . . . . . Cesium Levels in Biotic Components . Concentration Factors . . . . . . . . Trophic Level Effect . . . . . . . . Specific Activity . . . . . . . . . DISCUSSION 0 o o o o o o o o o o o o o o o o 0 SUMMARY ' o o o o o o o o o o o o o o o o o o 0 REFERENCES CITED 0 o o o o o o o o o o o o o 0 APPENDIX A. METHODS AND MATERIALS . . . . . . . . On-Site Measurements . . . . . . Field Collections . . . . . . . Sample Preparation and Digestion Controls .'. . . . . . . . . . . Radiocesium Analysis . . . . . . Cesium Analysis . . . . . . . . iv Page vi viii 14 16 17 17 17 23 25 27 29 33 33 37 46 48 APPENDIX Page B O LITEMTURE REVIEW 0 O O O O O O O O O I O O 76 Stable Cesium in Aquatic Environments . . 76 7C5 in the Aquatic Environment . . . . 78 Sources . . . . . . .'. . . . . . . . . 79 Pathways of 137Cs to Aquatic Environ- ments . . . . . . . . . . . . . . . . . 81 Uptake . . . . . . . . . . . . . . . . 82 Metabolism . . . . . . . . . . . . . . 84 Amplification of 137Cs in Aquatichood Chains . . . . . . . . . . . . . . . 85 SpBCifiC ACtiVity o o 0 V o o o o o o o o o 87 C o WINTERGREEN LAKE o o o o o o o o o o o o o 8 9 Table 1. LIST OF TABLES Estimated input of 137Cs and stable Cs by migratory waterfowl during 1970 . . . . . . Deposition rate and accumulation of 137C5 from PreCipitatj-on o ‘0 o o o o o o o o o 0 Estimated distribution of 137Cs and stable Cs in Wintergreen Lake . . . . . . . . . . Concentrations of 137Cs and stable cesium and specific activities in Wintergreen Lake 0 o o o o o o 0'. o o.- o o o o o o o. Stomach contents (% volume) of fishes collected in Wintergreen Lake . . . . . . . Concentration factors of 137Cs and stable Cs in various components of the biological community, Wintergreen Lake . . . . . . . ., Two-way ANOVprith time blocked. Test of- hypothesis: no difference in Cs levels among species . . . . . . . . . . . Two-way ANOVA with time blocked. Test of hypothesis: no difference in specific activity among species . . . . . . . . . . Nitric acid digestion procedure for biological materials . . . . . . . . . . . Preparation of sediment for analysis of Ce . Efficiency of cesium recovery from sediment amples O O O C O Q , O O O O O O O O O O O O - Cs collection and preparation for flame emmission analysis . . . . . . . .g. . . . Preparation of low-cesium AMP (Folsom and Sreekumaran, 1970) . . . . . . . . . . . . vi Page 22 24 26 28 30 32‘ 34 35 65 66- 67 69 70 Table A-6o Reagent blanks and spiked blanks used as controls on methods Efficiency of cesium recovery from biological materials Cesium content in fresh water reported from various studies Cesium content of freshwater fish as reported from various studies . Morphometric parameters for Wintergreen Lake Annual range of chemical parameters at 1.0 m depth . Percent volatile residue of sediments from Wintergreen Lake Estimate of annual nutrient input to Winter- green Lake from Canadian geese (Branta canadensis interior Linn.) Species of fishes reported from Wintergreen Lake 0 vii O Page 72 73 77 77 92 92 94 96 98 Figure l. 2. A-Zo A-3o C-l. LIST OF FIGURES Hydrographic map of Wintergreen Lake ... . Dissolved oxygen and-temperature profiles for September, 1970 . . . . . . . . . . Dissolved oxygen and temperature profiles for May, 1971 I O O O O O O O O I I O 0 Specific conductance profiles for September 1970 and May, 1971 . . . . . . . . ... . Seasonal distribution of precipitation at Wintergreen Lake (1926-1960) . . . . . . Annual pattern of migratory waterfowl usage of Wintergreen Lake . . . . . ._. . . ._ Principal pathways of cesium in an aquatic QCOSYStem o o o o ' o o - o o o o o o o o o Ranking of fishes from Wintergreen Lake on a "Trophic Continuum" . . . . . . . . . Percent recovery of 137Cseon ACFC (Ammonium Hexacyanocobalt (II) Ferrate (II) resin verses flow rate in liters per hour ._. Polystyrene ion exchange column . . . . . Wet oxidation apparatus (3 or 5 liter flask) Hydrographic map of Wintergreen Lake with associated ponds utilized by waterfowl .. viii I O Page 11 13. 19 21 39 44 59 61 64 91 INTRODUCTION The distribution and biogeochemical cycling of cesium in natural ecosystems have received increased attention since the advent of the nuclear era with the concomitant release of isotopes from weapons tests and use. Contributions of cesium isotopes from atmospheric fallout have declined since the nuclear test ban treaty of 1964. However, a new and potentially more significant source is developing in connection with Operation of nuclear powered electric generating facilities. Although nuclear power accounts for only 1% of the present generating capacity, this share is expected to reach 30% by 1980 (Arnold, 1970). Nelkin (1971) estimates cooling water needs will equal 20% of the total annual supply of runoff in the United States by 1985. Release of radioisotopes in cooling water due to fuel cell leakage and activation products will be incorporated into aquatic communities exclusively. Movement of cesium and availability to various components differ significantly between terrestrial and aquatic ecosystems. Terrestrial studies have demonstrated a correlation between nuclide distribution and various parameters, such as type of bedrock, soil types, rainfall and snowfall patterns, and vegetation type (Osburn, 1967). 137Cs levels in biotic Accumulation and magnification of components of terrestrial ecosystems have been related or correlated to moisture content of soil (Stewart, 1961; Stewart and Hungate, 1967); levels of precipitation (Rickard, 1967; Krieger, Kahn, and Cummings, 1967; Low and Edvarson, 1959); latitude (Stewart, Osmund, Crooks, and Fisher, 1957); season (Wellford and Collins, 1960; Parker and Crookall, 1961) and feeding habits (Pendleton gt_gl., 1964). Freshwater ecosystems appear to offer a greater potential for radiocesium buildup in upper trophic level predators. This is due to increased availability to aquatic plants and algae, in addition to the presence of a greater number of intervening predatory levels that result in increased concentrations. Sorption and transfer 137 of Cs by various components of an aquatic community were described by Pendleton (1965). Williams and 137 Pickering (1961) demonstrated the source of Cs in bluegills was food rather than direct absorption from water. Uptake of 137Cs by algae and aquatic plants was studied by Cline (1967), Williams (1960) and Rickard (1969). Levels in aquatic insects were determined by Osburn (1969) and Krumholz (1967). Radiocesium levels in fish have been correlated with season (Pendleton, 1959; Krumholz, 1954, 1956), feeding habits (Kolehmainen gt_al., 1967; Hannerz, 1968) and sediment activity (Gustafson, 1969). Accumulation and amplification of 137 Cs at higher trophic levels has been demonstrated by Nelson (1967), Pendleton (1965), Gustafson (1967), Hasanen (1963) and Kolehmainen (1966). Nelson (1969) tested the relationship between specific activity of water and fish. He found the relationship to hold constant under conditions of con- tinuous isotope release into the system. From the above discussion it is apparent that a 137 wealth of information is available on Cs in aquatic ecosystems. The present study deals with the distribution 137 133 of Cs and Cs in an aquatic ecosystem. The feasability of using specific activity as a tool for predicting levels of 137 Cs in aquatic plants of potential commercial value as well as fish important in sports fisheries is investigated. STUDY SITE Wintergreen Lake is located in Kalamazoo County, southwestern Michigan. It has been managed as a waterfowl refuge since 1929 and is presently part of the W. K. Kellogg Biological Station, administered by Michigan State University. The lake may be classified as temperate, partially meromictic. It is typical of the many moranic basin and pit lakes located in that region of Michigan. Surface area is 15.9 hectares. Mean depth is 3.5 meters; maximum depth 6.3 meters and the watershed area is 140.8 hectares. There are no permanent feeder streams and only one perma- nent dwelling is located adjacent to the lake. A high degree of eutrophy is quite evident. Approximately three-fourths of the surface is covered by extensive growths of submergent, emergent and floating macrophytes. Volatile residue of sediments range from 15-20%. Inorganic carbon concentration (CaCO3) ranges up to 10%. Productivity is very high (~ 1200 mg C/mZ/day) as evidenced by diel fluctuations in pH. Values of 9.8 were recorded in mid-afternoon on sampling dates. The primary source of nutrient addition to the lake is waterfowl which use it extensively during migration. Each fall an estimated 10,000 Canadian geese use the lake. Approximately 10,000 ducks are also present during migra- tion. A resident population of ducks, geese and swans numbering 300 use the lake year-round. Wintergreen Lake was chosen as a study site because of its unique features. It is surrounded by a small watershed without permanent feeder streams and is inaccessible to the public. Data on waterfowl usage and various limnological parameters were available. Temperature, dissolved oxygen, and specific conductance profiles for the lake are shown in Figures 1, 2, 3, and 4. Figure 1. Hydrographic map of Wintergreen Lake. WINTERGREEN LAKE KALAMAZOO COUNTY, MICHIGAN I . 9W., TJN. Soc. 0 Contour intorvols Elovotlon 271m ln motors. Aron 15.0 In 9 5° "2° 25° METERS Figure 1 Figure 2. Dissolved oxygen ( ----- ) and temperature ( ) profiles for september, 1970. Depth (m) Dissolved Oxygen (mg/liter) 5 IO ‘15 28 25 0" ‘1 2+ / / / / / 31 / ’ / / / / / I 4" / I Y 5-4 6 I U I T l 5 IO IS 20 25 Temperature (C) Figure 2 10 Figure 3. Dissolved oxygen ( ----- ) and temperature ( ) profiles for May, 1971. Depth (m) 11 Dissolved Oxygen (mg/ liter) a If) I? 29 2f O~ / \ \ I l H I . 1 ,/ I / l 2* / / / ,./é'- #- " ’ I 3% / / / 4. 5~y 6 / I r ~-:—- — --—1 r IO IS 20 25 Temperature (C) Figure 3 12 Figure 4. Specific conductance profiles for September, 1970 ( ) and May, 1971 (—---é). Depth (m) 13 0-4 200 360 400 500 600 Specific Conductance (u mho) Figure 4 METHODS Specific conductance, alkalinity, hardness, pH, dissolved oxygen, and temperature profiles of the lake were determined on each collecting date (American Public Health Association, 1971). Several methods were employed in obtaining fish. Experimental gill nets (32 m in length, 4 mesh sizes ranged from 1.0 to 5.0 cm) were set perpendicular to the shoreline as well as parallel at a depth of 1.5-2.0 meters. Forms not susceptable to capture with gill nets were taken with hook and line. Young of the year were captured by seining. - Macrophytes and algae were collected at random over the lake. Samples of emergent forms included stems and leaves only. MacroPhytes analyzed include Ceratophyllum sp. and Nuphar sp. Dense growths of the filamentous alga Mougeotia sp. were entrapped among macrophytic growth which facilitated the collection of large samples. Zooplankton samples were taken with light traps and plankton net tows. Samples were collected at night. 14 15 Sediment samples were collected on a transect along the depth gradient. An Ekman dredge was used, with each sample made up of two grabs. Droppings from waterfowl were collected from resting areas along the shoreline. Two replicates were obtained for each species tested. All samples were kept frozen until analyzed. Preconcentration of at least 400 liters of lake water was required to obtain a statistically accurate count of radioactive cesium during a reasonable counting time. This was accomplished with the on—site use of a fast-flow (10 liters/hour) ion exchange apparatus composed of-a submersible pump from which water passed through a check valve to a volume recording flow meter. Water then passed through two in-line filters and into a 76 liter. reservoir. A float mechanism attached to a microswitch served to maintain a constant pressure head on the ion exchange column. The apparatus was constructed entirely of polyethylene materials to avoid adsorptive losses (Seelye, 1971). Polystyrene vials (2.5 cm by 7.0 cm) packed with 5 g of ammonium hexacyanocobalt (II) ferrate (II) (ACFC) served as columns. Two complete systems were used in the field to obtain duplicate samples. 16 Preparation of Samples Biological samples were wet-ashed with concen- trated nitric acid. Cesium was removed from the resultant solution with ammonium molybdophosphate (AMP) resin (Feldman and Rains, 1964; Folsom, Young, and Sreekumaran, 1969; Yamagata, 1965). AMP residues were solubilized in sodium hydroxide and extracted with sodium tetraphenylboron (TPB) solution. Extraction of cesium from sediments was accom- plished by leaching with 6 N hydrochloric acid. Samples were then filtered and the filtrate was treated using procedures outlined for digested biological materials (Table A—4, p. 69). AMP and ACFC resins were counted for 137Cs activity with a single channel gamma scintillation spectrometer coupled with a three inch sodium iodide crystal and photomultiplier. Counting times were calculated to provide minimal counting error (P < 0.05) (Overman and Clark, 1960). Total cesium was determined on TPB extracts by flame emission spectrophotometry. A Jarrell-Ash model 82-800 instrument with a detection limit for cesium of ~ 0.05 mg/l was used. RESULTS Inputs of Cesium—137 and Stable Cesium Cesium enters the lake from two principal sources: atmospheric fallout (rainfall and snowfall), and excreta from migratory and resident waterfowl. Both sources exhibit a seasonal pattern with precipitation at a maximum- in April while waterfowl usage peaks in November (Figures 5 and 6). Waterfowl Utilization of the lake by waterfowl is extensive. Johnson (1972) estimates a total of 100,000 duck use days and 140,000 goose use days annually. These values are. adjusted to time actually spent on the lake or along the shoreline. Kear (1962) estimates excreta produced per day 137Cs and as 3.2% of body weight. Total deposition of stable Cs by waterfowl excreta during 1970 was calculated to be 2.65 mCi and 356 g respectively (Table 1). Most of the 137 Cs and stable cesium entering the lake as waterfowl excreta is probably organically bound and is deposited to the sediments. 17 18 Figure 5. Seasonal distribution of precipitation at Wintergreen Lake (1926—1960). 19 -' l— 0' he :3 F~—4 +l I-—-t I---I ._...— t——+—-t H. .——4 F 4. |-——————4 .4 t—-———t $3: 6§5é&6$$;g N N N - — — — ll’IOIIBj IBI'IUUV JO “IOOJOd Month Figure 5 20 Figure 6. Annual pattern of migratory waterfowl usage of Wintergreen Lake.a aData compiled by W. J. Johnson, Kellogg Bird Sanctuary. 21 .‘W IIIIIIWIIIII ’C'I'M';’#J.g..m" ouHIIIIHA—‘LULIJWIIJ'91" -- ._ _ -- - l - u I '. . O . Q I - .v. Q -- ..Q h I I I I I I I I I I I “I I. I. I. I. I I ' I... hv'vfifi’i‘Vrvv-I 0"."OO '- ._. I I I I I I I I I I I I I I I I I I I I I I I I I I o I 0'. I 0"...I...I.I.I.O..'..O.I.0-.-. I :‘l-I..-I.flfi‘ 'T' g m. Vfi-o-oqo' .W I I I I I I I ”I I ”I I I I I I I I I I 0' I . , . . . . . . . . . . . I I I I I I I ”I I I I I I .TO .- I I I I I “I I I I I I I I I I I I I. 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III I I III I I I I I I I III I I I :zII IIO.II I I 0....OOIOOI I I II IIIIIIIIIII I I IIIII IMOOCIIII 0......OOOICOO ALA AAAA‘AAAAALLAAAAAAIIA’I}...IIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIII.:IIIIIIIII I IIIIIIII IIIIII IIIIIII .IIIIIIIU IIIIIII Figure 6 IIIOII.IIIIIII IIIIIIIIIIIIIIIIIIII Ducks Goose v 'fi'm'v‘ . v o v a o n N N N u "' 30-4 281 new I41 84 61 4 2 5': 3'2 efiesn |enuuv JO wowed Month 22 Table 1. Estimated input of 137Cs and stable Cs by migratory waterfowl during 1970. Geese Ducks Bird use days/year 1.43 x 105 1.00 x 105 Excreta/bird/day(g dry wt) 142a 32a Excreta/year (metric tons) 20.3 3.2 1”Ca (pCi/g) 0.113 0.113b Stable cesium (ng/g) 15.2 15.2b 137Cs added to lake in 1970 (uCi) 2.29 0.36 Cs added to lake in 1970 (g) 307 49 aFrom Kear (1962). bEstimated values. 23 Precipitation 137Cs deposition for the period 1954-1969 Rates of are presented in Table 2 along with total accumulation (Radiological Health Data and Reports, Environmental Protection Agency). Corrected for radioactive decay, the 137Cs from precipitation on the lake total accumulation of surface is 21.84 mCi. This value assumes no significant export and no addition due to runoff from the watershed. The watershed is predominately sandy loam which has a large exchange capacity for cesium (Squires and Middleton, 1966). Peak deposition rates prior to the atmospheric test ban treaty are quite apparent. Input of 137Cs to Wintergreen Lake from precipitation in 1970 was ~ 300 uCi. The cesium entering the lake as precipitation is in an inorganic soluble state and is generally distributed in the system. Although data are lacking on addition of 137Cs to the lake from waterfowl for years prior to 1970, it is assumed to follow the general trend exhibited for precipi- 137 tation (Table 2). Total Cs addition in 1970 attributable to waterfowl was approximately 2.5 uCi which accounted for 0.85% of the total. If the assumption of~ 137 parallel trends is valid, addition of Cs to the lake‘ by waterfowl over the period 1953-1970 is insignificant. 24 Table 2. Deposition rate and accumulation of 137Csfrom precipitation. Deposition Rate Total Depositiona mCi/sz/year mCi/Km2 1954 1.53 1.04 1955 5.78 5.05 1956 6.12 9.40 1957 5.44 13.36 1958 8.50 19.68 1959 11.90 28.77 1960 2.89 31.01 1961 5.61 35.48 1962 34.51 63.70 1963 52.02 107.14 1964 26.52 129.77 1965 8.50 137.18 1966 3.40 140.22 1967 2.04 142.09 1968 1.70 143.67 1969 2.04 145.63 aCorrected to 1970 for decay. 25 Distribution of Cesium-137 and Stable Cesium in the Lake 137 The distribution of Cs and stable cesium is partitioned into four compartments: fish, plants, water, and sediments. Although this is only an estimate, 137Cs and stable Cs is associated with the apparently most sediments (Table 3). Sediments were sampled to a depth of approximately 10 centimeters. Fish and macrOphytes are the only biologic components considered since they account for most of the standing crop. Estimates of the fraction of the total 137 Cs and stable Cs pool in fish and plants are high since biomass estimates of one kg/m2 was used for plants (comparable to sewage lagoon standing crops) and population estimates of fish are based on Fetterolf's (1952) results. Since the carrying capacity of the lake is relatively constant for fish populations and there has been no exploitation, the standing crop is probably comparable to Fetterolf's estimates. Doubling these estimates would not significantly change the percentage of the cesium pool incorporated in fish (Table 3). In spite 137Cs and of the overestimates, approximately 87% of the 98% of the stable Cs pool is incorporated in sediments in the organic fraction or physically associated with the inorganic fraction. No attempt is made to differentiate these two fractions of the sediments. 26 Table 3. Estimated distribution of 137 in Wintergreen Lake. Cs and stable Cs +4 Cesium-137 Stable Cesium Compartment mCi % grams ' % Fish 1.03 x 10'3 < 0.01 3.45 x 10"2 < 0.01 Plants 2.23 x10"1 1.8 31.29 0.6 Water 1.39 11.2 47.0 0.8 3 98.6 Sediment 10.82 87.0 5.5 x 10 27 Cesium Levels in Biotic Components 137 A pattern of increased Cs concentration at higher tr0phic levels is demonstrated for chubsuckers+ hybrid sunfish+perch+bass (Table 4). No such trophic effect is evident for stable cesium. Previous studies (Nelson, 1969; Kolehmainen and Nelson, 1969) have also failed to demonstrate a trophic effect for stable cesium. Those forms which are more intimately associated with sediments have higher levels of stable cesium relative to radiocesium as reflected in their specific activity (activity/unit mass of element). Since sediments serve as a "sink" for cesium, the lake is, in effect, a two- compartment system. Those forms which are predatory limnetic feeders, limited to the epilimnion due to hypolimnetic anoxic conditions, would have a specific activity which reflects 137Cs or stable cesium their food source. A buildup of along a trophic scheme is partially explained by several factors: (1) larger animals having a longer biological half-life, (2) differential assimilative efficiencies, and (3) feeding rates. Forms which feed more exclusively on benthic fauna would all tend to reflect the specific activity of the 137 sediments. Since 87% of the Cs and 98% of the stable Cs pool is associated with sediments, forms feeding only 2E3 m m oN.o Nm.o m.Hw « o.hmw v.5m « H.Nom nod. H oam.a omN.o H hoa.N uuGQEHvom m nu w~.o nu ~.m « «.mh nu ooo.o « vow.o nn .mn mmmmmm o nn mm.o nu v.0 « v.oa un voo.o « hao.o un .mm adaaxcmoumumu c nn vm.o nn w.H « m.oa nn moo.o « awo.o un couxcnanoumnm c v om.a mm.o o.H « o.~ o.h « m.mm oao.o « vvo.o ~vo.o H mHN.o couxsaHQOON nn m nu h«.v nn H.~ u ~.m nn «no.0 H -~.o amazon m nn am.a nu m.v w h.m nn vmo.o « mma.o uu occnaasm saoum ON nu No.v nu «.H « n.m nu ovo.o « mvN.c nn vnonaasm onHo» m o om.~ mH.v H.~ u n.h o.H « m.m vvo.o « hma.o mno.o « cmn.o uoxosansno axon ma «a m~.m hm.a m.o « m.m ~.N « o.h «Ho.o « m~H.o «no.0 « and.o nnwucsm pawn»: ma ma mm.d mo.o w.~a “ v.m~ ~.ma « «.mv vno.o « vvn.o vno.o « vhn.o nouom soaao» mm ma m>.v mm.~ v.~ « 5.x v.~ « «.ma vno.o « muv.o ~mo.o « mnv.o anon nanosomuuq .suz ..uao Hbmfi .aoz chmH ..»mom Hbaa .sum onaa ..umom anon lawn. A a a “Ho oma «v Asm\mcc 1H0 «ma “v Asu\fiomv no umnssz aud>suo¢ usuaoomm asauou magnum unanandaoo .oxna soouououcas cu nowufi>wuoo cauaoomn can adauco manna. can no uo occauouusoosoo .v wanna hnH 29 partially on benthos would have the specific activity of other food sources "masked." Specific activity values in Table 4 demonstrate this point. Fish forms feeding on benthos have a specific activity of 2.0 x 10'2 pCi/ng or less. Yellow perch, however, may appear to be an excep- tion. Stomach content analysis revealed they were feeding extensively on larvae of the phantom midge, Chaoborus sp. (Table 5). Aquatic macrophytes also show a difference in. specific activity. Ceratophyllum demersum had a specific activity of 0.93 x 10-2 pCi/ng, while for Nuphar sp. it was 0.26 x 10-2 pCi/ng or about one-third of the former. This latter value was similar to sediments (0.29-0.32 x 10-2 pCi/ng). Since Nuphar sp. is a rooted form, one might expect its specific activity to be similar to the sediment in which it is rooted. Concentration Factors Concentration Factor (C.F.) is obtained as follows: concentration of element per unit weight of organiqm C‘F' a concentration25?%element per unit weight of water For 137Cs in fish it varied by a factor of three ranging from 1,671 in largemouth bass collected in September, 1970 to 476 in hybrid sunfish collected in the spring of .mommmE mmm omHMHusmowcs mo mucsoem mmumqo .couxGMHmooN mo wuomwuco accowuocsm on» .:H omomHm ma DH .uommcfl cm mm was» smsonuad .mm msuonomsu maucmcwfioomnmn .mmfloomm nomw How omaoom mucousoo nomfioumw 3O o o o.ooa o o mumxosmnano oo.mm o o.hm o o cmmgaasm,soaamm o o o.v 0.6H o.om ommnaflsm csoum o.m o.m o.~a o.~m o smflmcsm chunsm o.m o nm.om m.na o scams sedan» o o o o.~H o.mm mmmm nusosmmumq mnomsmaamomwz coaumummm> couxcmamooN mvoomcH swam musmpcou noofioum m.mxmq smoumumucwz a“ omuomaaoo mwsmam mo AmEsHo> av mucousoo nomfioum .m manna 31 1971 (Table 6). The C.F. for bass is approximately 50% higher than reported by Kolehmainen (1969). The large C.F. present for zooplankton in September is probably due to the presence of large numbers of Chaoborus sp. in the sample which show the influence of their association with the sediments or the sediment-water interface. Concentration factors for stable Cs in fish are generally lower than for 137Cs. This appears to be due to differential availability of stable Cs. Perch showed a C.F. of 2,009 and 1,209 for stable Cs in the fall and spring respectively. These high C.F.‘s reflect their feeding habits (selection for Chaoborus sp.). ZOOp1ankton samples collected in September had a high C.F. for stable Cs as well as 137Cs. Nuphar sp. exhibited the highest C.F. for stable Cs of any form tested. This, again, is due to the closer interaction with sediments. Concentration factors for stable Cs in perch, fall zooplankton samples, and Nuphar sp. are somewhat misleading since they are based on concentrations in water. They should be compared to available stable Cs levels in sediments. However, since destructive analyses were carried out, that fraction of stable Cs in the sediments available for uptake cannot be estimated. 32 Table 6. Concentration factors of 137Cs and stable Cs in various components-of the biological community, Wintergreen Lake. September, 1970 May, 1971 Form 137Cs Stable Cs, 137Cs Stable Cs Largemouth Bass 1,671 723 1,580 413 Yellow Perch 1,043 2,009 1,271 1,209 Hybrid Sunfish 525 333 476 181 Lake Chubsucker 875 262 712 348 Yellow Bullhead -- -— 932 252 Brown.Bullhead -- -- 587 319 Bowfin 845 248 -- -— Zooplankton 833 1,595 167 133 Phytoplankton -- -- 334 498 Ceratophyllum sp. -- -- 368 493 Nuphar sp. -- -- 774 3,790 33 Trophic Level Effect Data from largemouth bass, yellow perch, hybrid sunfish, and lake chubsuckers, representative of four 137Cs, and specific trophic levels were analyzed for activity using a two—way analysis of variance (ANOVA). Data on stable Cs for those species were not analyzed since a trend for trophic amplification was not in evidence (Table 4). Cesium-137 activities among species (Table 7) were significantly different (P < 0.005) while time-species interaction was not significant (P > 0.05) (Table 7). Since the data show variance heterogeneity, comparisons of means was completed using Scheffé's (1953) multiple comparison test. All means were significantly different (P < 0.05) except those for lake chubsuckers and hybrid sunfish (Table 7). It may be noted that lake chubsuckers were higher in activity than hybrid sunfish. This, again, is attributable to the closer association of the former with the sediments. Specific-Activity Both specific activity among species tested and, time-species interaction were not significant (P > 0.05) (Table 8). Although values for the specific activities of these species appears to be different (Table 4) the lack of significant differences among species remains. This is probably due to large variances around the individual 34 Table 7. Two-way ANOVA with time blocked. Test of hypothesis: no difference in 137C3 levels among species. Source SS df MS F FO.95 Time 0.0005 1 0.0005 0.098 3.93 Species 1.6037 3 0.5346 98.67***~ 2.69 Interaction 0.0415 3 0.0138 2.55 2.69 Error 0.6481 110 0.0059 TOTAL 2.2939 117 zab 1 3 4 0.131 0.208 0.309 0.427 aAny two means not underlined by the same line are significantly different (P < .05).~ b1. Chubsuckers: 2. Hybrid Sunfish; 3. Yellow Perch; 4. Largemouth Bass. Table 8. Two-way ANOVA with time blocked. hypothesis: 35 activity among species. Test of no difference in specific Source SS df MS F F0.95 Time 0.0108 1 0.0108 2.07 3.93 Species . 0.0373 3 0.0125 2.38 2.69 Interaction 0.0218 3 0.0073 1.39 2.69 Error 0.6113 110 0.0056 TOTAL 0.6813 117 36 means. The degrees of freedom were approximated in computing F-critical values for trophic effect and specific activity (Sokal and Rohlf, 1969). This was necessary due to heterogeneous variance. Since this is an approximate test and the calculated and F-critical values are very close for species (Table 4), the null hypothesis of no difference among species in specific activity is acceptable, but questionable. DISCUSSION Cesium-137 and stable Cs concentration in aquatic flora and fauna in a lake are influenced by several factors. These include the mode by which isotopes enter the system, degree of eutrophy in the system, behavior and cycling of the isotopes, biological half-life, and assimilative efficiencies. 137Cs and stable Cs to Two sources contributed Wintergreen Lake. Precipitation, which is the primary source, adds these isotopes to the lake water where they are initially distributed uniformly in the upper strata. The second source, waterfowl excreta, introduces cesium in both a water-soluble and insoluble fraction (Figure 7). The soluble portion, as with precipitation, is generally distributed. The organically bound insoluble fraction is, however, deposited to the sediments, where, due to hyper- eutrophy of the lake with accompanying anaerobic condi- tions, it accumulates. This portion is available only to those forms feeding in the sediments and in turn the forms which feed on them. An important route of isotopes from sediments to higher forms is by way of food chains with bacteria as a base (Figure 7). Culver and Brunskill (1969) 37 38 Figure 7. Principal pathways of cesium in an aquatic ecosystem. 39 Phytoplankton Waterfowl Excreta Sediment Figure 7 Precipita— tuon Benthic Invertebrate Macrophytes 40 found zooplankton with their gut tubes filled with sulfur bacteria in'a meromictic lake where phytoplankton produc- tivity was low. If bacteria dominate the biomass (under conditions of prolonged anaerobic conditions) Likens (1972) concluded they may provide a very concentrated and impor- tant source of food for zooplankton. These observations may explain the high C.F.‘s for zooplankton collected in September (Table 6). However, specific data on bacterial populations in the lake are lacking. The soluble fraction of isotopes from waterfowl and precipitation are ultimately added to both the sedi- ments and the insoluble fraction. Adsorption to suspended particulate matter in the water column with subsequent settling is one mechanism of removal from water. A second mechanism postulated by Manny (1970) for removal of ions from the water column is through marl (CaCO3) formation and deposition. Algal cells, during photosynthesis, remove CO2 from water in sufficient quantities to exceed the solubility product of CaCO3 in adjacent water resulting in deposition of marl on the cell surface. When sufficient accumulation occurs to exceed a cell's buoyant capacity, it settles to the bottom. As-a result, cesium incorporated into algal cells is delivered to the sediments. Theoretically CaCO3 should resolubilize due to aggressive CO2 in the lower water strata (Ruttner, 1953). 41 This apparently does not occur in Wintergreen Lake.‘ Manny (1970) suggests the marl-covered algal cells are coated with a layer of organic nitrogen in the form of large amorphous molecules which prevents attack by C02. This prevents dissolution of the CaCOB. Biological half-life and assimilative efficiency are important factors in determining the concentration of cesium at higher trophic levels. Biological half—life is positively correlated with size of an animal. Since metabolic rates per unit weight necessary for maintenance decrease in larger animals, the turnover rates decrease resulting in a longer biological half-life. Predatory fish change their feeding habits as they grow., Younger age classes of a population of predatory fish consume zooPlankton and bottom organisms. With an increase in size they become predators, consuming small fish. With this change in feeding habits, they are passing from a lower to a higher trophic level. Kolehmainen 32431. (1968) found large perch to have twice the concentration of 137Cssas small perch in the same lake. The difference was attributed to a change in feeding habits from bottom organisms to small fish. They suggested the assimilative efficiency of perch may be higher for small fish than for bottom organisms. The increase may also be partially attributed to growth. Growing fish would utilize a 42 significant percentage of food intake in the deposition of new tissue in growth. Since the small fish that predators. 137Cs than bottom organisms and zooplankton, a higher concentration of 137Cs consume have higher concentrations of is present in the food for the predator. This would result 137Cs in the predator. Con— in higher concentrations of sidering the factors discussed above, one would expect an increase in cesium concentration at higher trophic levels. The expected relative concentrations of 137 Cs along a "trophic continuum" is illustrated in Figure 8. Various. fish forms analyzed from Wintergreen Lake are ranked (0-10) based on feeding habits presented in the literature (Harlan and Speaker, 1956). A second ranking on the 137 continuum is based on Cs concentrations determined for the various species. Largemouth bass were placed at 9.0 on the scale and the mean 137Cs concentrations for bass- was divided into mean concentrations of other forms to determine rank on the second scale. Mean 137Cs concentra- tions for those forms associated with sediments were higher than expected (Figure 8) (i.e., brown.and yellow bullhead'and lake Chubsucker). Cesium-137 content in bowfin was much lower than expected. No conclusions.can be drawn due to small sample size (3 fish) and large variance about the mean concentration. 43 Figure 8. Ranking of fishes from Wintergreen Lake on a "Trophic Continuum." A. Expected ranking B. Ranking based on 137C8 concentration (pCi/g wet weight). 44 A. Traphic ranklng based on feeding hablts tronn literature. 10.0-- 9.0‘ 7.0:: 5.0 4.0- LO- t Bowfin LLargemouth Base L - Yellow Perch t ~Hybrld Sunflsh P n-LBKO Chubsucker -Yellow Bullhead :Brown Bullhead 0.0‘ Figure 8 8. Relative ranking based on Cealum137 content (pCi/g wet welght). 1 no.0« 9.01» Largemouth Bass 8.0+ 7.0d r ~Yellow Perch 6.0"- smcvellow Bullhead bBowfln #Lake Chubsucker 4.0» 3-°i=unybnud Sunfish ~Brown Bullhead 1.0-(f 004l- 45 137 Trophic level effect on Cs concentrations (lake chubsuckers+hybrid sunfish+yellow perch+1argemouth bass) is largely explained by common availability of the isotope 137Cs in these forms are to these forms. If levels of compared to levels determined for forms more closely associated with sediments (Table 4) the trophic level r5 137Cs concentration is not as apparent. effect on Gustafson (1967) found a similar situation in his work with fishes of Red Lake, Minnesota. The explanation of these data involves several V '~ gm, factors. The lake can be thought of as a two-compartment 137Cs exchange between them. system (water-sediment) with Sediments ultimately serve as an autochthanous source of cesium to the water as well as directly to the biological community. Within the trophic structure of a lake commu- nity, both compartments are included. Trophic structure, however, does not imply interaction. Several distinct food chains may exist within a given trophic structure. Significant differences in degree of bioamplification between food chains within a trophic scheme may be present. If this situation exists as in Wintergreen Lake where more than 90% of the total cesium pool is in the sediments, it is meaningless to look at trophic effect on cesium concentration without regard to degree of interaction of species tested. SUMMARY 1. Usage of Wintergreen Lake by waterfowl is extensive. They contribute in excess of 20 metric tons of excreta (dry weight) per year to the lake. The amount 137 of the total annual Cs input attributable to them is less than 1%. 2. Of the total cesium pool ~ 87% of the 137Cs and ~ 98% of the stable Cs is incorporated in sediments. 3. It appears that stable Cs enters the system as organically bound (waterfowl excreta) and is deposited to the sediments whereas 137 Cs enters in soluble inorganic form and is distributed throughout the system. Conse- quently specific activity of sediment is lower than any other_component of the ecosystem. 4. The intimacy of association of biotic forms with sediments is reflected in lowered specific activity. 5. Concentration factors for 137 Cs are higher than for stable Cs except in forms closely associated with sediments. 137 6. A trend for bioamplification of Cs resulting in greater activity at higher trophic levels is 46 47 demonstrated. This trend is not in evidence for stable Cs. 7. No significant differences were found in specific activities among forms that are limnetic and predatory. 8. Forms closely associated with sediments have 137 higher Cs content than would be expected based on their feeding habits. REFERENCES CITED REFERENCES CITED American Public Health Association, et a1. 1971. Standard methods for the examination of water and waste water. 13th ed. New York, 873 p. Arnold, D. E. 1969. Thermal pollution, nuclear power, and the great lakes. Limnos. 2(2):4-ll. Barth, D. S. 1967. Public health aspects of nuclear explosives (Plowshare) program. Conf. 671029-1, SWRHL. Beattie, J. R., and P. M. Bryant. 1970. Assessment of environmental hazards from reactor fission product‘ releases, AHSB(S) R 135, UKAEA Health and Safety Branch. Bortoli, M. de, P. Gaglione, and A. Malvicini. 1967. Environmental radioactivity, Ispra 1966. Joint Nuclear Research Center Ispra Establishment, Italy. European Atomic Energy Community--Euratom. Report EUR-3554-E. 70 p. Cline, J. F.' 1969. The effects of substrate conditions on the uptake rate of Cs-137 by plants, p. 547- 552. In D. J. Nelson and F. C. Evans, (ed.), Symposium on Radioecology, AEC DOC. CONF 670503. Culver, D. A., and G. J. Brunskill. 1969. Fayetteville Green Lake. V. Studies of primary production and zooplankton in a meromictic marl lake. Limnol. Oceanogr. 14:862-873. Davis, J. J. 1963. Cesium and its relationship to potassium in ecology, p. 539-556. In_V. Schultz and A. W. Klement, Jr., (ed.), Radioecology. Reinhold Publ. Corp., New York. 48 in” 0: . .t F- I'. K A) .u—r-sv" I'l 49 Davis, J. J., W. C. Hanson, and D. G. Watson. 1963. Some effects of environmental factors upon accumu- lation of worldwide fallout in natural populations, p. 35-38. £2.V' Schultz and A. W. Klement, Jr., (ed.), Radioecology. Reinhold Publ. Corp., New York. Feldman, C., and T. C. Rains. 1964. The collection and flame photometric determination of cesium. Anal. Chem. 36:405-409. Fetterolf, C. 1952. A population study of the fishes of Wintergreen Lake, Kalamazoo County, Michigan: With notes on movement and effect of netting on condition. M.S. thesis. Michigan State University. 127 p. Finston, H. L., and M. T. Kingsley. 1961.- The radio- chemistry of cesium. Nat. Acad. Sci., Nuclear Sci. Ser. NAS-NS-3035. Office of Technical Services, Dep. of Commerce, Washington, D.C. Folsom, T. R., and C. Sreekumaran. 1970. Some reference methods for determining radioactive and natural cesium for marine studies. Reference Methods for Marine Radioactive Studies, Annex IV, I.A.E.A., Vienna, Austria. Folsom, T. R., D. R. Young, and C. Sreekumaran. 1969. An estimate of the response rate of Albacore to cesium, p. 337-345. In D. J. Nelson and F. C. Evans, (ed.), Symposium 53 Radioecology, AEC DOC. CONF 670503. Garner, R. J.' 1971. Transfer of radioactive materials from the terrestrial environment to animals and man. CRC Critical Reviews in Environmental Control. 2(3):337-385. Gallegos, A. F., and F. W. Whicker. 1968. Radiocesium Kinetics in a montane lake ecosystem. Ann. Prog. Report, UeSeAeEeCe636-52e Gustafson, P. F. 1967. Comments on radionucliggs in aquatic ecosystems, p. 853-858. In B. erg and F. P. Hungate, (ed.), RadioecologiEal Concentra- tion ProCesses, Permagon Press, New York. 50 Hannerz, L. 1966. Fallout 137Cs in fish and plankton from Lake Malar and the Baltic. Acta. Radiol. Suppl. 256:22-28. Hannerz, L. 1968. The role of feeding habits in the accumulation of fallout Cs-137 in fish. Rep. of Inst. Freshw. Res., Drottningholm. 48:112-119. Harlan, J. R., and E. B. Speaker. 1956. Iowa fish and fishing. State of Iowa, Des Moines. 377 p. Hasanen, E., and J. K. Miettinen. 1963. Caesium - 137 content of freshwater fish in Finland. Nature. 200(4910):1008-1020. Hough, J. L. 1958. Geology of the Great Lakes. Univ. Illinois Press. Urbana, Ill. Johnson, W. J. 1972. Personal communication. Kahn, B., D. K. Smith, and C. P. Straub. 1957. Determina- tion of low concentrations of radioactive cesium in water. Anal. Chem. 29:1210-1214. Kear, J. 1962. The agricultural importance of wild goose droppings, p. 72-77. In H. Boyd, (ed.), The Wild- fowl Trust, l4th AnnuaI—Report, 1961-62. F. Bailey and Son, LTD., Dursley, Gloucestershire. Kevern, N. R. 1966. Feeding rate of carp estimated by a radioisotopic method. Trans. Am. Fish. Soc. 95(4):363-37l. Kevern, N. R., and N. A. Griffith. 1966. Effect of trophic level on radionuclide accumulation by fish, p. 88. In_Health Physics Division annual progress report for period ending 31 July, 1966. ORNL-4007 (Oak Ridge National Laboratory. Tenn.). King, 8. F. 1964. Uptake and transfer of cesium-137 by Chlamydomonas, Daphnia, and bluegill fingerlings. Ecology 45:852-858. Kolehmainen, S., E. Hasanen, and J. K. Miettinen. 1966. 7Cs levels in fish of different linmological types in Finland during 1963. Health Physics 12:917—922. 51 Kolehmainen, S., E. Hasanen, and J. K. Miettinen. 1967. Cs in fish, plankton and plants in Finnish lakes during 1964—5, p. 913-919. In B. Aberg and F. P. Hungate, (ed.), Radioecologiaal Concentra- tion Processes, Permagon Press, New York. Kolehmaingg, 8., E. Hasanen, and J. K. Miettinen. 1968. l Cs in the plants, plankton, and fish of Finnish lakes and factors affecting its accumulation, p. 407-415. In W. S. Snyder, (ed.), Proceedings of the first congress of radiation protection, Rome, Sept. 1966. Vol. 1. Permagon Press, London. Kolehmaifieg, S., and D. J. Nelson. 1969. The balances of 3 Cs stable cesium, and the feeding rates of bluegill (Lepomis machrochirus Raf.) in White Oak Lake, USAEC Report ORNL-4445. Krieger, H. L., B. Kahn, and S. Cummings. 1967. Deposi- tion and uptake of Sr-90 and Cs-l37 in an: established pasture, p. 59-72. In B. Aberg and F. P. Hungate, (ed.), RadioecologIcal Concentra— tion Processes, Permagon Press, New York. Krumholz, L. A. 1954. A summary of findings of the ecological survey of White Oak Creek, Roane County, Tennessee. USAEC Doc. No. TID-7632(Book 2):360- 371. Krumholz, L. A. 1956. Observations on the fish popula- tion of-a lake contaminated by radioactive wastes. Bull. Am. Mus. Nat. Hist. 110(4):281-367. Krumholz, L. A. 1967. Accumulation of radioactive fallout materials in the biota of Doe Run, Meade County, Kentucky, 1959-63, p. 791-818. In B. Aberg and F. P. Hungate, (ed.), Radioecological Concentration Processes, Permagon Press, New York. Kudo, A., and E._F. Gloyna. 1971. Transport of 137Cs-II interaction with bed sediments. Water Research 5:71-79. Langham, W., and E. C. Anderson. 1959. Cesium-137 biospheric contamination from nuclear weapons tests. Health Physics 2(1):30-48. Leentvaar, P. 1967. Observations in guanotrophic environments. Hydrobiologia 29:441-489. 52 Likens, G. E. 1972. Eutrophication and aquatic ecosystems, p. 3-13. In G. E. Likens, (ed.), Nutrients and eutrOphiEEtion: the limiting- nutrient controversy. Amer. Soc. Limnol. Oceanogr., Inc. Special Symp. Vol. 1. Low, K., and K. Edvarson. 1959. Cesium-137 in Swedish Machta, milk and soil. Nature 187(4739):736-738. L., and J. H. Harley. 1969. Predictions of radioactive fallout and fallout dose estimates, In A. M. F. Duhamel, (ed.), Progress in nuclear energy, series XII, Health Physics 2:610. Permagon Press, Oxford. Manny, B. A. 1971. Interactions of dissolved and particulate nitrogen in lake metabolism. Ph.D. thesis. Michigan State University. 189 p. Merlini, M. 1967. The freshwater clam as a biological Nelkin, Nelson, Nelson, Nelson, Osburn, indicator of radiomanganese, p. 977-982. In B. Aberg and F. P. Hungate, (ed.), RadioecoIogical Concentration Processes, Permagon Press, New York. D. 1971. Nuclear power and its critics: the Cayuga Lake controversy. Cornell University Press, Ithaca. 128 p. D. J. 1967. The prediction of 90 fish using data on specific activities and biological half lives, p. 843-851. In B. Aberg and F. P. Hungate, (ed.), Radioecological Concentration Processes, Permagon Press, New York. Sr uptake in D. J. 1969. Cesium, cesium-137, and potassium concentrations in white crappie and other Clinch River fish, p. 258-265. In D. J. Nelson and F. C. Evans, (ed.), Symposium on Radioecology, AEC.DOC. CONF 670503. D. J., and S. V. Kaye. 1971. The specific activityconcept applied to aquatic ecosystems, p. 735-746. In Nuclear Techniques in Environ- mental PollutiSn. I.A.E.A. Vienna, Austria. W._S.‘ 1967. Ecological concentration of nuclear fallout in a Colorado mountain watershed, p. 675- 710. In B. Aberg and F. P. Hungate, (ed.), RadierElogical Concentration Processes, Permagon Press, New York. ' 53 Overman, R. T., and H. M. Clark. 1960. Radioisotope Techniques. McGraw-Hill, New York. 476 p. Pantard, G. E. 1960. Calcification in unicellular' organisms, p. 1—14. Ian. F. Sognnaes, (ed.), Calcification in Biological Systems. Amer. Assoc. Advan. Sci. Publ. 64, Washington, D.C. 511 p. Parker, R. P., and J. O. Crookall. 1961. Seasonal variation and age of radioactive fall-out. Nature 190(4776):574-576. Pendleton, R. C. 1959. Effects of some environmental factors on bioaccumulation of cesium-137 in an aquatic community, p. 42-46. In Hanford biology research annual report for 19587 HW-59500, Hanford Laboratories, Richland, Wash. Pendleton, R. C., R. D. Lloyd, C. W. Mays, and B. W. Church. 1964. Trophic level effect on the accumulation of cesium-137 in cougars feeding on mule deer. Nature 204(4959):708-709. Pendleton, R. C. 1965. Accumulation of cesium-137 through the aquatic food web, p. 355-363. In C. M. Tarzwell, (ed.), Biological Problems in Water Pollution, third seminar, Aug. 1962. U.S. Dept. Health Educ. Welf. Publ. No. 999-WP-25. Petrow, H. G., and H. Levine. 1967. Ammonium hexocyanocobalt ferrate as an improved inorganic exchange material for determination of cesium-137. Anal. Chem. 39(3):360-362. Poluektov, N. W., and V. T. Mishchenko. 1962. The present state of the analytical chemistry of lithium, rubidium, and cesium, p. 34-55. In A. P. Vinogradov and D. I. Ryabchikov, (ed.), DeEECtion and Analysis of Rare Elements. (Translated by Isreal Program for Scientific Translations, Jerusalem). Preston, A., D. F. Jefferies, and J. W. R. Dutton. 1967. The concentrations of cesium-137 and strontium-90 in the flesh of brown trout taken from rivers and lakes in the British Isles between 1961 and 1966: the variables determining the concentrations and their use in radiological assessments. Water Research 1:475-496. 54 Radiological Health Data and Reports. Environmental Protection Agency, Office of Radiation Programs.’ Rickard, W. H.~ 1967. Accumulation of Cs-l37 in litter and understory plants of forest stands from various climatic zones of Washington, p. 527-532. IB_B. Aberg and F. P. Hungate, (ed.), Radio- ecological Concentration Processes, Permagon Press, New York. Rickard, W. H. 1969. Cesium—137 in Cascade Mountain vegetation-—l966, p. 556—570. In D. J. Nelson and F. C. Evans, (ed.), Symposififi on Radio- ecology, AEC DOC. CONF 670503. Ruttner, F. 1953. Fundamentals of Limnology. University of Toronto Press. 295 p. Scheffé, H. 1953. A method for judging all contrasts in the analysis of variance. Biometrika 40:87. Schreibner, R. A. 1958. A survey of the insect bottom ‘ fauna of a limited area of Wintergreen Lake, Kalamazoo County, Michigan. M.S. thesis. Michigan State University. 51 p. Seelye, J. G.’ 1971. A measurement of low level cesium isotope concentrations in a fresh water lake. M.S. thesis. Michigan State University. 71 p. Sloey, W. E. 1970. The limnology of hypereutrophic Lake Butte Des Morts, Wisconsin. Proc. 13th Conf. Great Lakes Res. 1970:951-968. Smit, T. van R. 1958. Ammonium salts of heteropoly acids ’ as cation exchangers. Nature 18:1530-1531. Sokal, R. R., and F. J. Rohlf. 1969. Biometry. W. H. Freeman and Company. 776 p. Squire, H3 M., and L. T. Middleton. 1966. Behavior of 1 7C3 in soils and pastures: a long term experi- ment. Radiat. Bot. 6:413-416. Sreekumaran, C., K. C. Pillae, and T. R. Folsom. 1968. The concentration of lithium, potassium, rubidium, and cesium in some western American rivers and marine sediments. Geochimica et. Cosmochimica 55 Stewart, H. F., G. M. Ward, and J. E. Johnson. 1965. Availability of fallout C3137 to dairy cattle from different types of feed. J. Dairy Sci. 48:709-713. Stewart, J. D. 1961. Effect of soil moisture on uptake and translocation of-cesium-l37 and potassium in bean plants, p. 92-96. In Hanford Biology Research--annua1 report fBr 1960. Hanford Atomic Products Operation, General Electric Co., USAEC report HASL--42. Stewart, J. D., and F. P. Hungate. 1967. Effect of soil moisture on uptake and translocation of 137Cs Potassium, 45Ca and 85$r, p. 409-414. In B. erg and F. P. Hungate, (ed.), RadioecologicaI'Concen- tration Processes, Permagon Press, New York. Stewart, N. G., R. G. D. Osmond, R. N. Crooks, and E. M. Fisher.. 1957. The world-wide deposition of long lived fission products from nuclear test ex- plosions. United Kingdom Atom. Energ. Auth., Research Estab., Harwell, report AERE-HP/R-2354. Tamura, T., and D. G. Jacobs. 1960.- Structural implica- tions in cesium sorption. Health Physics 2:391-398. Welford, G. A., and W. R. Collins, Jr. 1960. Fallout in New York City during 1958. Science l3l(3415):l7ll- 1715. Wetzel, R. G. 1966. Variations in productivity of Goose and hypereutrophic Sylvan Lakes, Indiana. Invest. Indiana Lakes, and Streams 7:147-184. Williams, L. G. 1960. Uptake of cesium-137 by cells and detritus of Eu lena and Chlorella. Limnol.-and Oceanogr. 5:301-311. Williams, L. G., and H. D. Swanson. 1958. Concentration of cesium-137 by algae. Science 127:187—188. Williams, L. G., and Q. Pickering. 1961. Direct and food- chain uptake of cesium-137 and strontium-90 in bluegill fingerlings. Ecology 42:205-206. Yamagata, N. 1965. Review on the analytical methods for the stable and radioactive cesium. Dept. of- Radiological Health. The Institute of Public Health, Tokyo UDC. 543.036:546.36., APPENDICES APPENDIX A METHODS AND MATERIALS APPENDIX A METHODS AND MATERIALS On-Site Measurements The following parameters were measured on each sampling date: (1) pH (Beckman Model-N portable pH meter); (2) alkalinity and hardness (American Public Health Association, 1971); (3) temperature and specific con- ductance (portable conductivity meter and thermistor); and (4) dissolved oxygen (Precision Scientific oxygen analyzer). Due to low levels of Cs, lake water was passed through ion exchange columns in situ in order to pre- concentrate the element in quantities sufficient.for analysis. An ACFC (ammonium hexacyanocobalt (II) ferrate (II)) resin was used (Petrow and Levine, 1967). This form of resin was chosen to avoid the presence of 40K 137Cs was done with a single channel since counting of analyzer. ACFC is a stable resin which does not lose the integrity of its crystalline structure producing "fines" which reduce flow rates resulting in variable efficiency (Folsom and Sreekumaran, 1970). A curve of uptake 56 57 efficiency for 137Cs on the ACFC resin is shown in Figure A-l. Apparatus developed by Seelye (1971) for on- site preconcentration of cesium was used in this study. Four replicates for determination of cesium content of water-were obtained on each sampling date. Polystyrene vials were used as ion exchange columns. The bottoms of the vials were cut out and caps removed when they were in use. Prior to use, vials were stored with caps in place and filled with distilled water in order to have the resin activated thus avoiding efficiency changes associated with resin swelling in the field. The ion exchange column is shown in Figure A-2. Column dimensions were such that they could be placed in the detector and counted directly. Field Collections Fish were collected using experimental gill nets (1&5 cm mesh) and hook and line. Young of the year were collected by seining in shallow areas of the lake. Macrophytes and algae were collected randomly over the surface of the lake. Zooplankton were obtained at night using light traps and net tows. Sediment samples were taken along a-depth gradient using an Ekman dredge. All samples were kept frozen until analyzed. 58 Figure A-l. Percent recovery of 137Cs on ACFC (Ammonium Hexacyanocobalt (II) Ferrate (II)) resin verses flow rate in liters per hour.‘ Percent Recovery of Cesium 137 59 100- 85-1 80* 75? q a {2 {a . 2'0 2'4 Flow Rate (liter/ hr) Figure A-l 60 Figure A-2. Polystyrene ion exchange column. 61 L_ 30mm . ' fl Snap-on T L --------- J polyethylene cop 70mm Polyethylene disc (pore size :90“) ACFC resin (59) j ////////// Polyethylene disc (pore size =90uul P 28mm r A. Figure A-2 62 Sample Preparation and Digestion All biological material was wet oxidized using concentrated HNO3 at 130 C. Digestion was carried out in 3 or 5 liter round bottom two-necked boiling flasks. The flasks were connected to reflux condensers and fitted with electric heating mantles. Each mantle was connected to a rheostat for temperature control. Methods for sample preparation and digestion are outlined in Table A-1. The digestion apparatus is shown in Figure A-3.. When possible, fish were digested and analyzed individually. However in the case of smaller forms (perch and hybrids) it was necessary to pair the fish for analysis in order to have sufficient Cs present to be quantifiable. Sediment samples were extracted with hot 6 N HCl using methods as outlined in Table A-2. Replicate samples from each depth were analyzed. Filter residue from each sample was counted in order to determine the extraction efficiency. The overall percent efficiency of cesium extraction was 99.2 i 0.44 (a .05) (Table A-3). Cesium was removed from the acid solution using a batch method with ammonium molybdophosphate (AMP) as an inorganic exchanger (Smit, 1958: Kahn et;al,, 1957). The batch method was used since the microcrystalline structure of AMP makes its use in a column impractical due to reduced flow rates. The method used was adopted from 63 Figure A-3. Wet oxidation apparatus (3 or 5 liter flask). 64 l Stopcock for distilling on excess acid and water llllllfllllllllll‘ /W ./ // Q? v Thermometer 45/50 opening to introduce sample Figure A—3 65 Table A—1. Nitric acid digestion procedure for biological materials. 10. Divide sample into portions which pass through neck of boiling flask. Determine wet weight of sample. Place sample in boiling flask. Add approximately 5.0 ml of concentrated HNO3 per gram of sample. Allow digestion to proceed 3-4 hours at room temperature. Reflux until nitrous oxide fumes are no longer apparent. Open stopcock and distill off excess water and acid until approximately 2 ml of acid are left per gram of fish. (Do not distill further since precipitates will form which may result in severe bumping.) Add additional concentrated HNO3 to bring back to original volume (step 4). Reflux with st0pcock closed until no oil can be seen floating on the surface (6-10 hours). Additional acid may be required if oil droplets are present at the end of this time. Allow digestant to cool and remove from flask. Pass sample through glass wool filtering material and rinse flask thoroughly with distilled water. Rinse into polyprOpylene beaker of at least twice the volume of the sample. Allow to cool to room temperature and proceed with AMP collection of Cs. 66 Table A-2. Preparation of sediment for analysis of Cs. ===fi ‘ Dry-sample-at 70 C (48-72 hours). Powder sample (mortar and pestle or Wiley mill) and weigh out aliquot (100 g). Place aliquot in Pyrex beaker (1 liter) and add 6 N HCl (5 ml/g). CAUTION: If sediment is high in organic content or contains significant amounts of marl (CaCO3) extensive foaming may result. Addition of an antifoaming agent (silicone solution) may be necessary. Allow reaction to proceed at room temperature for 2-3 hours. Stir sample periodically. Place watch glass over beaker and apply heat. Main- tain a temperature just below the boiling point. Allow leaching to continue with heat for 15-20 hours. Allow sample to cool and pass through Whatman no. 41 filter paper. Treat fitrate as outlined in Table A-4. 67 Table A-3. Efficiency of cesium recovery from sediment samples. Efficiency of Extraction Depth _iyAMP-l __ AMP-2 Filter Residue (meters) DPM/g % DPMig % DPM/g % 1.5 A 208 88.3 26 ll.l~ 1.6 0.6 1.5 B. 202 86.3 31 13.3 1.0 0.4 3.0 A 208 - 66.1 106 33.6 1.0 0.3 3.0 B 279 90.0 25 8.2 2.9 0.9 4.0 A 151 69.8 62 28.6 3.5 1.6 4.0 B 166 66.9 80 32.2 2.3 0.9 4.5 A 311 87.4 43 12.2 1.7 0.4 4.5 B 325 90.5 33 9.3 1.0 0.2 5.0 148 71.4 56 27.2 3.1 1.4 6.0 A 127 65.4 67 34.6 0 0 6.0 B 120 88.3 13 9.6 2.9 2.1 Percent recovery using: 1. Single addition of AMP = 80.1 i 7.4a 2. Two successive additions OfAMP= OOOOOOOOIOOO. 99.2 H- o e 3b .5 aMean i 95% C.I._ 68 Feldman and Rains (1964) with modifications as suggested by Folsom and Sreekumaran (1970) and as outlined in Table A-4. Two successive additions of AMP to the acid solution were necessary since a single addition produced highly variable recoveries. With two additions the percent recovery of cesium was 97 t .74 (a .05) (Table A-7). Subsequent cleanup steps eliminated potassium from the sample, thus eliminating interference in counting due to 40K. Commercially available sources of AMP have been found to contain 0.2 to 1.0 mg Cs/g which renders them unsuitable for use in trace analysis of cesium (Folsom and Sreekumaran, 1970). Therefore AMP was prepared in the laboratory using a procedure which purges it of cesium. The prepared AMP was counted with no detection of 137C3. Procedures for preparation of cesium-free AMP are outlined in Table A-5. Initially, polyethylene or polypopylene labware was used in all analytical procedures to avoid adsorption losses of Cs.w PolyprOpylene was later used exclusively due to its superior resistance to acid. The final NaOH solution containing cesium was extracted with 0.1 N sodium tetraphenylboron solution (TPB) (3/1 hexone:cyclohexane). The solution was less concen- trated than suggested by Feldman and Rains (1964). However, it gave more favorable resolution (signal-to- background ratio) necessary for analyzing trace amounts 69 Table A-4. Cs collection and preparation for flame 12. 13. emmission analysis. 3 To acid solution of biological material add 4 mg AMP/g wet wt. Stir solution for 30 minutes and allow sample to settle overnight. Decant supernatant and collect AMP in 50 m1 graduated polypropylene centrifuge tube. Repeat steps 1—3. Centrifu e collected AMP (5 min at 1800 rpm) and count 13 Cs. - . Dissolve AMP in 1.0 N NaOH (~ 15 ml per gram). Adjust pH to 3.5 with powdered tartaric acid. Add 0.8 mg AMP/g wet weight and stir for 30 minutes. Repeat step 3 and 5. Solubilize AMP in 1.0 N NaOH (~ 10 m1). Place 10 ml NaOH Cs solution in separatory funnel with 10 ml 0.1 N TPB and shake vigorously for 2 minutes. Allow layers to separate overnight. Retain organic layer for flame emission analysis. (Keep samples refrigerated) 70 Table A-5. Preparation of low-cesium AMP (Folsom and Sreekumaran, 1970). Solutions used: 1.--81 g NH4NO3 + 81 g citric acid + 102 g (NH4)6Mo7O24 + 2140 ml H20 2.-—391 ml 70% HNO3 + 455 ml H20 3.--Add sol. 1 slowly into sol. 2 stirring without heat 4.—-100 g (NH HPO + 2000 m1 H 0 4’2 4 2 Place solution 3 in a 4 liter Pyrex beaker and add 2 ml of solution 4. Heat to a boil while stirring. Cool solution in water bath and allow yellow ppt. (AMP) to settle. Decant mother liquor (60-80 C) into another 4 liter Pyrex beaker and discard AMP that was made in step 1. The mother liquor has now been purged of cesium.‘ To mother liquor add 100 ml of solution 4 and bring to boil while stirring. Allow to cool and decant supernatant. Wash the ppt. (AMP) with l N NH4NO3. Collect on Whatman No. 41 filter paper. 'Dry at 70 C overnight and store in dry place. The yield will be ~ 71 9 AMP. 71 of Cs. The organic layer was retained for analysis of total Cs by flame emission (8521 A). Controls Reagent blanks were run routinely to check for contamination. Periodically, sample blanks were spiked to check on the efficiency of recovery of cesium (Table A-6). The spiked blank, however, cannot be considered as a true test of methodology since interferences present in acid digests of biological materials would not be present in reagents. In order to test for interferences, successive treatment of the sample with AMP was counted separately. In all cases it was found that all of the activity was. removed from the sample with three additions of AMP. The total activity found in the three aliquots was divided into the activity of each to determine the percent Cs recovered in each addition (Table A-7). Radiocesium Analysis Cesium-137 activity of water, biological and sediment samples was analyzed gamma-spectrometrically with a single channel solid scintillation counter (0.662 Mev.). A three inch NaI(Tl) crystal with a 1.25 inch by 2 inch well was coupled with a Nuclear Chicago spectrometer and scaler. Counting vials were all one inch in diameter insuring uniform sample geometry. 72 .uu nn o o o o oomm h nu o.ooH om m mo em oomN o o un o o o o ooma m nn «.mm mmm mm now own ooma m o nn o o o o oomm v un m.hm omm mm Hon mmm oomm m o nn o o o o ooma m un h.mo How on Hum ohm ooma a San: mnm>oomm flag. Dug Hug :38 :5 .02 no unmoucm Azmov cuum>oomm mo poops moon.H mozm mamaum .mcocume co mHouucoo up can: mxcman coxfimm can mxcman vcmmcum .ou¢ manna 73 Table A-7. Efficiency of cesium recovery from biological materials. Sample AMP-l AMP-2 NO . DPM % DPM % DPM % W06-C 178.2 79.5 34.3 15.3 11.5 5.1 W06—E 116.2 88.6 11.0 8.4 4.0 3.0 W06-H 76.1 71.4 26.3 24.7 4.2 3.9 W03-A 107.0 75.8 29.1 20.6 5.0 3.6 W03-C 103.0 75.0 29.7 21.6 4.6 3.4 W03-E 177.5 90.5 15.1 7.7 3.6 1.8 W03-F 111.5 90.0 9.3 7.5 3.2 2.5 W05—A 81.0 80.7 13.3 13.3 6.1 6.0 W05-D 372.0 89.0 40.4 9.7 5.7 1.3 W05-G 896.0 89.8 86.8 8.7 14.5 1.5 W07-A 605.0 82.6 108.8 14.9 18.4 2.5 W07-B 535.0 86.6 71.7 11.6 11.4 1.8 W08-D 578.0 84.2 83.5 12.2 24.8 3.6 W08-F 513.0 80.0 108.0 16.8 20.5 3.2 W09-C 709.0 85.4 104.0 12.5 17.4 2.1 Percent recovery using: Single addition of AMP 83.3 i 3.35a Two successive additions of AMP = ............. 97.0 i 0.74 aMean i 95% C.I. 74 Standards were counted daily to determine efficiency which averaged 13.5%. Counting times were calculated to provide deter- mination of 137 Cs activity at 95% level of significance according to the following formulae (Overman and Clark, 1960): Rs-l-b + / (Rb) (Rs+b) *3 ll 5 (82) (Rs?) Where: TS = Sample time (min) S = Sample rate (cpm) Rb = Background rate (cpm) Rs+b = Total rate (cpm) G = percent error (0.05) /R Tb=Ts/ £2 R b Where: T = Background time (min) Cesium Analysis Cesium analysis was accomplished by flame emission spectroscopy. The instrument used was a Jarrell-Ash model 82-800 with an infrared grating and red-sensitive 75 photomultiplier (R446). An air—H2 flame was used.’ The detection limit for-cesium in hexone—TPB was approximately 0.05 mg/liter. The principle emission line of cesium (8521A) was used. Cesium standards (CsCl) were prepared in NaOH and extracted with equal volumes of 0.1 N TPB in 3/1 hexone:cyclohexane. APPENDIX B LITERATURE REVIEW APPENDIX B LITERATURE REVIEW Cesium, although widely distributed in the earth's crust, is a rare element seldom occurring in significant quantities. Typical of the alkali metals, cesium forms' strong bases and its salts are generally water soluble. It is the most electro-positive of all metals and is readily oxidized. The chemistry, radiochemistry and analytical methods for analysis are reviewed by several authors (Finston and Kinsley, 1961; Poluektov and Mishchenko, 1962, Yamagata, 1965). Stable Cesium in Aquatic Environments Cesium content in marine forms has been investi- gated much more extensively than freshwater counterparts. Fish are the only freshwater forms for which data are available on natural cesium levels. Most fresh water studies have dealt with isotopes of cesium occurring-in 7 134Cs). Levels of cesium greatest abundance (13 Cs and reported for fresh water and freshwater fish are summarized in Tables B-1 and B-2 respectively. 76 77 Table B-1. Cesium content in fresh water reported from, various studies. Location Cs(ng/l) Reference Lakes in Northern Italyv 0.043-0.087 Kolehmainen 1969 Clinch River, Tennessee 0.025 Nelson 1969 Lake Mead 0.057 Sreekumaran et al. 1968 Colorado River 0.023 Sreekumaran et a1. 1968 Table B-2. Cesium content of freshwater fish from various studies. as reported Species Cs(ng/g) Location Reference White Crappie 12.9 Clinch River Nelson 1969 Freshwater Drum 8.7 " " n n White Bass 16.0 " n n n Channel Catfish 4.1 " " n u Bluegill 3.4 " n u n Mixed Group 9.8-57.0 Northern Italian Lakes Bortoli.as cited by Kolehmainen 1969 78 Kolehmainen gt_§1. (1968) found that cesium is removed from water to a much greater degree in eutrophic and turbid lakes than in oligotrophic lakes. Removal is probably accomplished by algal bloom uptake in eutrophic lakes (Williams, 1960) and through sorption by suspended in- organic particulate matter in turbid lakes (Tamura and Jacobs, 1960; Kudo and Gloyna, 1971). 137Cs in the Aquatic Environment Cesium has 21 isotopes ranging in atomic weight from 123-144. The stable isotope is 133Cs. The most 137Cswhich has a abundant radionuclide of cesium is physical half~life of 30.23 years. A major component of fallout from atmospheric testing of nuclear weapons, 137Cs-is formed late in nuclear detonations by the following reactions: 137 19 137' 3.4 137 30.23 137 I SEE Xe HIT: CS- W Ba (stable). Emissions resulting from decay include gamma rays (0.662 mev) and beta particles (0.514, 1.18 mev). A relatively high fission yield (6%), long half-life and 137Cs presents a potential hazard energetic emission of to biotic components of various ecosystems when this isotope is incorporated into them. 79 Sources Large-scale atmospheric testing of nuclear devices 137Cs contamination of the envi- is the primary source of ronment. Total production of this isotope from detonations prior to the nuclear test-ban treaty of 1962 is estimated at 30 MCi (Machta and Harley, 1969). Due to delayed formation of 137 Cs in detonations, it is associated with smaller particles which are injected into the stratosphere (Davis, 1963). Stratopheric residence time is six months to three years. During this period radioactive debris is subject to atmospheric circulation patterns in which air enters the stratosphere primarily at the equator and descends in temperate and polar latitudes during the Spring (Davis, Hanson, and Watson, 1963). Spring peaks in fallout have been observed by several investigators (Parker and Crookall, 1961; Stewart gt_al., 1957). Accidental venting from continued underground testing subsequent to the moratorium has resulted in injection of fission and activation products into the atmosphere. Nuclear detona- tions for the purpose of excavation is an additional potential source of atmospheric 137Cs. The Sedan test (1962) which produced a crater 1,200 ft. wide and 320 ft. deep released an estimated total activity of 2 kCi (Barth, 1967). 80 Radionuclides are released from reactors both as fission and activation products. Contamination is primarily due to neutron activation of elements in the coolant as well as corrosion products in the reactor cooling system. Small quantities of_fission products may enter coolant systems from leakage of fuel elements. Most power reactors recirculate coolant which prevents chronic release of nuclides to the environment. Fission and activation products are removed continuously by purifica- tion systems (ion exchange). Nuclides not readily removed by these systems (tritium, xenon, and krypton) are released to the environment. During operation, however, reactor fuel is replaced periodically. Replaced fuel elements are usually stored in cooling ponds for a period before shipping to a processing plant. During this interval 137Cs) enter activation and fission products (including the cooling pond water and are released to surface or ground waters. A substantial release of nuclides from reactor accidents is a distinct possibility. The Windscale acci— dent of 1957 released 600 c1 of 137 Cs (Garner, 1971). Beattie and Bryant (1970) state it is a realistic assump- tion that in future accidents, escape of "volatiles" (including cesium) is unavoidable. 81 Garner (1971) concludes there are two sets of circumstances through which the biosphere may be exposed to radionuclides: (l) the "normal" introduction through chronic release from atomic energy operations and (2) introduction of large amounts of activity during a short time period from either atmospheric fallout or accidental release. The former circumstance requires a knowledge of the environmental ramifications of long-lived components of release while in the latter situation, short-lived isotopes assume an ephemeral position of great importance followed by persistent long—lived forms. 137 Pathways of Cs to Aquatic Environments Since cesium is water soluble the most significant 137Cs to ecosystems is via the hydrologic cycle. source of Fallout levels have been correlated with seasonal patterns of precipitation. In many soils 137C3 is firmly bound to clay minerals. Sandy soils exhibit an apparent complete fixation three years after contamination (Squires and Middleton, 1966). This high affinity of soils for ionic cesium precludes contribution to aquatic environments due to leaching. Fallout deposition in snow is generally more available to aquatic systems since snowmelt with accompa-s nying runoff occurs before soil surfaces thaw. Contribu- tions due to sheet erosion may be significant in localized 82 137 areas, however, Cs remains in a bound form and is incorporated into sediments of lakes or streams. 137Csto water systems is A second source of precipitation directly on the water surface. Low level wastes may enter water from power and experimental reactors as well as fuel element processing plants. In localized 137 situations, transport of Cs into lakes by migratory waterfowl in the form of excreta may be significant. Uptake 137Cs is subject to Upon entering surface waters physical-chemical-biological mechanisms occurring in the system. It is readily rendered unavailable through sorp- tion phenomena (both adsorption and absorption). Particu- late suspended matter (organic and inorganic) exhibits a strong.affinity for ionic cesium through physical and chemical adsorption. Phytoplankton, zooplankton, and macrophytes also remove ionic cesium from water to a much greater extent than do their terrestrial counterparts (Pendleton, 1962; Rickard, 1967; Williams, 1960). Algal uptake was demonstrated to be almost immediate. Dead algal cells exhibited a high affinity for l37Cs. Williams (1960) determined a concentration factor for dead Euglena cells of 16 and Chlorella of 418. Apparently, structural components persist in dead algal cells which adsorb cesium from: solution. Kolehmainen et a1. (1968) concluded adsorption 83 of 137 Cs to clay particles with subsequent settling out was the main factor removing this isotope in turbid eutrOphic waters. This mechanism along with uptake by algal cells with retention upon death and settling results in significant deposition to the sediments. Whether cesium is an essential trace element for metabolism has not been established. A metabolic function, however, may be inferred by the fact of active uptake by plants. Uptake of 137Cs by other biotic components of aquatic systems is generally thought to be by way of food. ZOOplankton absorbs most of its radiocesium from food sources (King, 1964). Assimilation from food is low (~ 21%) which may partially eXplain the lack of an in- creased concentration of this isotope over levels present in food sources. Data on benthic forms are lacking. They obtain most of their cesium burden from food since they are predominantly detritus feeders. Although large quantities of clay particles are passed through the gut during feeding, the adsorbed isotope may not be available. In cattle feeding experiments Stewart gt_al. (1965) con- cluded 30% of the total 137 Cs, that portion bound to clay particles associated with hay, was completely unavailable to the cow. Major contributions of radiocesium to benthic forms is apparently from both autochthanous and allochthanous organic materials. 84 Uptake by freshwater fish is almost exclusively via food (~ 99%) as opposed to movement across the gills Kolehmainen gt_al., 1967). Assimilative efficiencies range widely (7-80%) depending on food type (Kevern, 1966). Variable efficiencies are very significant in considering movement of 137 Cs through food chains. It may help in explaining the build-up or lack of build-up through trophic levels. Metabolism Metabolically, the behavior of cesium is frequently compared to that of its chemical analogue, potassium. Levels of 137Cs in micro- and macro-aquatic plants is regulated by concentrations of the isotOpe and of potassium in the water surrounding them (Kolehmainen and Nelson, 1969). Stable cesium, at concentrations found in aquatic environments, does not show a carrier effect on 137Cs (King, 1964). At high concentrations (natural levels x 103) stable cesium resulted in decreased concentrations of 137CS in Euglena intermedia. This was interpreted, how- ever, as an isotopic dilution effect (Williams and Swanson, 1958).. An inverse relationship between potassium content 137Cs content in aquatic plants has been in water and demonstrated (Kolehmainen etaal., 1967). Pendleton et a1. (1965) described an increased Cs/K ratio at higher trophic 85 levels implying a differential retention time of the two elements. Nelson (1969), utilizing a double tag (134 42 42 Cs and K) on white crappie, observed no K excre— tion in five days while 26% of the 13703 was excreted in three days. He concluded K was retained more efficiently than Cs under identical diet conditions. Nelson's results imply that increased 137 Cs content at higher trophic levels is probably due to differences in assimilative efficiencies and food habits rather than differential excretion rates for Cs and K as indicated by Pendleton et a1. (1965). 137Cs in Aquatic Food Chains 137 Amplification of Increased Cs content at higher trophic levels. has been demonstrated by numerous investigators (Pendleton, 1962; Gustafson, 1967: Gallegos and Whicker, 1968). Other studies (Kevern, 1966; Kevern and Griffith, 1966; Kolehmainen and Nelson, 1969) are inconsistent with the 137 concept of amplification of Cs content at higher trophic levels. Pendleton (1962) has postulated a concentration factor of'3 per trophic level. Gustafson (1967) found pike 137 (Esox lucius) contained 4.81 times as much Cs as perch (Perca flavescens) while perch were 1.85 times higher than small fish they were eating. He also found, however, con- centrations of radiocesium in Whitefish (Coregonus sp.) 86 and sheepshead (Aplodinotus sp.) to be higher than in perch (P. flavescens) (1.46 x and 2.89 x respectively). Gustafson's results (1967) point to the influence 137Cs accumulation in freshwater of feeding habits on fishes. Hannerz (1968) found 3-4 fold differences in the radiocesium concentration in several whitefish species in the same lake. Those forms which were planktivorous were consistently higher than bottom feeders. Gallegos and 137 Whicker (1968) found levels of Cs in trout to be about twice that found in amphipods they fed on. Kevern (1966) 137 found no significant differences between. Cs levels in carp and food sources. Kevern and Griffith (1966) observed slightly higher 137 Cs activity in bluegill than in gizzard shad or largemouth bass, but the differences were not significant. Kolehmainen and Nelson (1969) found no relationship between 137Cs content and trophic level. Gizzard shad and golden shiners contained similar levels of the isotope (47.03 and 62.61 pCi/g) as largemouth bass (52.75 pCi/g). Their results are partially explained by the time of year samples were collected. It is apparent from the above studies that trophic level increases of 137 Cs in aquatic ecosystems is not a universal principle. The trophic level effect appears to be demonstrable in aquatic environments with relatively 87 low turbidity and those which would be considered oligotrophic. As stated by Kolehmainen and Nelson (1969), body burden for an organism is influenced by four factors: (1) assimilation, (2) feeding rate, (3) concentration of l3.7Cs in food and (4) biological halfvlife. Any of these factors could account for the presence or absence of a trophic level increase in radiocesium content. Levels of 137Cs have been positively correlated with size for various species (Hannerz, 1966; Kolehmainen and Nelson, 1969). This may partially account for apparent trophic level increases since in predatory food chains the size of the organisms is greater at higher trophic levels. Specific Activity Specific activity is defined as the ratio of a radionuclide to the total quantity on that element (Nelson and Kaye, 1971). The underlying assumptions and con- straints governing the use of specific activity in aquatic systems are: (l) radionuclide and stable nuclides of the element are equally available. This implies they are completely mixed and in the same chemical form, (2) the various nuclides of an element are metabolically in- distinguishable by the organisms being considered, (3) organisms are at equilibrium with their environment, and (4) the physical half-life of the radionuclide is 88 significantly longer than the equilibration time for organisms in a given system. The specific activity concept has been used: successfully to predict radionuclide levels in organisms subject to chronic exposure (Preston, 1967; Nelson, 1967, 1969). Other investigators have found specific activity to vary two to four fold in aquatic systems (Bortoli et_al., 1967; Merlini, 1967; Kolehmainen and Nelson, 1969). The need for future research in this_area is very apparent in order to ameliorate information on specific activity in aquatic systems and develop its potential as a predictive tool. APPENDIX C WINTERGREEN LAKE APPENDIX C WINTERGREEN LAKE Wintergreen Lake is located in Kalamazoo County, southwestern Michigan and is one of the many pit lakes in an outwash plain of the Kalamazoo morain (Hough, 1958). The watershed (240.8 ha.) is undulating glacial till covered by well drained sandy loam. Mean annual percipitation is 86.3 cm. Snowfall averages 129.5 cm per year. High rainfall periods are April-June (28.2 cm) and August-October (24.7 cm) (Climatological data-—U.S. Weather Bureau). Morphometric and chemical data are presented in Tables C-1 and C-2 respectively. Inflow to Wintergreen consists of surface runoff and intermittent flow from a stream originating in dairy farm feed lots. During periods of high lake levels, water flows into adjacent Gull Lake through an outlet located on the west side of Wintergreen (Figure C-l). Sediments range from pulpy peat to sapropel (Ruttner, 1953). Extensive marl (CaCO3) deposits are found over the entire lake to a depth of 3.5 meters. 89 90 Figure C-l. Hydrographic map of Wintergreen Lake with associated ponds utilized by waterfowl. 91 HuO unamwm ace. 2: 5 32:3... 32.30 numbwz \ 11 . . as 0.2 ee..( On. a e E KN 32.253 .\ Sushi—n.5,... 240522 .3233 00:25: 3:: 23.5.3sz 92 Table C-l. Morphometric parameters for Wintergreen Lake. Length (m) 544 Width (m) ’ 375 Area (ha) 14.98 Volume (m3) 530,584 Mean Depth (m) 3.5 Maximum Depth (m) 6.3 Shoreline Development 1.15 Table C-2. Annual range of chemical parameters at 1.0 m depth.a N03 (mg/liter) 0.005-l.340 N02 (mg/liter) 0.012-0.040 NH4 (mg/liter) 0.005-2.320 Total dissolved P (mg/liter) 0.02 -0.13 Total dissolved C (mg/liter) 3.0 -9.1 pH 7.3 —9.5 Alkalinity (CaCO3) (mg/liter) 100-180 Specific conductance (umhos) 230-280 Annual mean pelagic productivity. (mg C/m /day) > 1200 aData from Manny, 1971. 93 Percent volatile residue increases with depth to three meters. At depths of three meters or more, volatile residue is relatively uniform (Table C-3). Submergent, emergent and floating aquatic macrophytes cover 70% of the lake to a depth of approxi- mately three meters. Dominant submergent forms include Ceratophyllum demersum L., Myriophyllum exalbescens Fernald, Najas flexilis (Willk.), Potamogeton foliosus Raf., P. pectinatus L. Nuphar advena Aiton, is the principle emergent form. Floating macrOphytes include Lemna minor L., Spirodella polyrhiza, and L. wolfia. Mean annual pelagic productivity is in excess of 1,200 mg C/mz/day-(Manny, 1971). The productivity, macrophytic standing crop, dissolved oxygen regime (pro- longed hypolimnetic anoxia), high organic content of sediments, and pronounced diurnal oscillations of pH in Wintergreen Lake fit the description of other hyper- eutrOphic lakes (Wetzel, 1966; Sloey, 1970). Extensive blooms of the blue-green algal forms, Aphanizomenon flos- aqae and Microcystis aeruginosa occur regularly each spring. The contribution of carbon, nitrogen, and phosphorous (particulate and dissolved) by waterfowl as excreta is the most important nutrient source to the lake. Canadian geese (Branta canadensis interior Linn.) use 94 Table C-3. Percent volatile residue of sediments from Wintergreen Lake.a Depth (m) 9/70 5/71 leS 14.7-15e5 13e0‘13e9 3e0 19e4-1905 ._- 4.0 10.3-10.5 20.0-21.5 5.0 19.3-19.7 19.0-19.8 6.0 -- 19.0-19.7 aAmerican Public Health Association, 1971. 95 Wintergreen Lake as a stopping point on both north and southbound annual migratory flights. The input of excreta per year froeranadian geese is approximately 20 metric tons (dry weight). Table C-4 presents estimate of annual inputs of nitrogen and phosphorous.to the lake from goose droppings. Other migratory waterfowl also use the lake during migra- tion with contributions of nutrients. Based on estimated nutrient input, Wintergreen Lake may be described as "guanotrophic" (Leentvaar, 1967). Zooplankton are abundant, occasionally reaching a density great enough " . . . that they present the appear- ance of a false sandy bottom to the eye" (Fetterolf, 1952). Principal forms include Daphnia galeata mendotae, D. pulex, Bosmina longispina, and Chaoborus sp. larvae. The latter exhibit a diurnal pattern in vertical migration resulting in great numbers present in the upper strata at night. A large, diverse benthic community is present in the lake, especially in the littoral area where macrophytic growth provides a very diverse habitat. Studies of the macroinvertebrate populations of the lake are conducted each year by limnology classes taught at the W. K. Kellogg Biological Station. Schreibner (1958) has also studied the benthic community of the lake._ 96 Table C-4. Estimate of annual nutrient input to Wintergreen Lake from Canadian geese (Branta canadensis interior Linn.) Adjusted goose days 143.000a Excreta/goose/day (g dry wt) 142b % N 1.42b % P 0.37b Input of excreta (kg/ha/yr) 1,269 Nitrogen input (kg/ha/yr) 18 Phosphorous input (kg/ha/yr) 4.7 aAdjusted to time actually spent on lake--compi1ed by W. J. Johnson. bData from Kear (1962). 97 Previous studies of the populations were conducted by Fetterolf (1952). A summary of fish species reported for Wintergreen Lake is presented in Table C-5. Although several species of shiners and bluntnose minnows are reported from earlier studies, none were collected during the present study. The more advanced stage of eutrophy exhibited in the lake may explain their absence. . (Is! ‘3. l.- ' 'F‘g.’ 98 Lake. Species of fishes reported from Wintergreen Micropterus salmoides (Lacepede). Lepomis cyanellus Rafinesque. Lepomis macrochirus macrochirus Rafinesque. Lepomis gibbosus (Linnaeus). L. cyanellus x L. macrochirus. L. gibbosus x L. macroshirus Amia calva Linnaeus. Erimyzon oblongus (Mitchill). Notropis heterodon (Cope). Notropis heterolgpis heterolopis Eigenmann and Eigenmann. Notropis cornutus chrysocephalus (Rafinesque). Notemigonus crysoleucas auratus (Rafinesque)., Pimephales notatus (Rafinesque). Ictalurus natalis (LeSueur). Ictalurus nebulosus (LeSueur). Esox americanus vermiculatus LeSueur. Perca Flavescens (Mitchill). Ambloplites rupestris (Rafinesque),Rock Bass Largemouth Bass Green Sunfish Common Bluegill Pumpkinseed Greensunfish x Bluegill Pumpkinseed x Bluegill Bowfin Creek Chubsucker Blackchin Shinera Northern Blacknose Shinera Central Common Shinera Western Golden Shinera Bluntnose Minnowa Yellow Bullhead Brown Bullhead Mud Pickerela Yellow Perch b aReported from earlier surveys but not collected by author. bSingle specimen collected. "lllllnllllillililillull“