Pharmaceuticals are commonly used to animals and humans for disease control and treatment. Large fractions of administered pharmaceuticals are released into the environment via land application of animal manures and biosolids from sewage sludge of wastewater treatment plants (WWTPs). In this study, we investigated the occurrence and fate of amprolium, carbadox, monensin and tylosin in an agricultural farm. Amprolium and monensin were frequently detected in surface runoff with concentrations at nanograms per liter of water, whereas tylosin or carbadox was rarely found. Soil is a reservoir for these veterinary pharmaceuticals. Accompanied with this study, we developed analytical methods to determine pharmaceuticals in water and biosolids. Among commonly used fifteen pharmaceuticals, fourteen pharmaceuticals were frequently detected in the collected biosolids from WWTPs. This result suggests that pharmaceuticals survive wastewater treatment process and are disseminated into ecosystems via land application. Soil is a major media for retention of pharmaceuticals in the environment, and soil mineral is a major component for sorption of pharmaceuticals. Tetracycline sorption mechanism to clays from aqueous solution was investigated. Cation exchange reaction and metal-tetracycline complexation were identified to be the major processes responsible for tetracycline sorption on minerals. Overall, this study provides useful information to evaluate occurrence and fate of pharmaceuticals in the environment.
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