Hormones and Pharmaceuticals Generated by Concentrated Animal Feeding Operations
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loginSteroidal hormones have existed nearly as long as early multi-cellular life forms first emerged. This means that nature has long developed methods for removing them from the environment but it also means that many life forms as simple as corals and snails use the steroid hormones in their reproductive cycles. What is of concern is that the concentrations of steroid hormones released from CAFOs has resulted in concentrations of hormones not previously seen in nature and has the
potential to disrupt ecology of the exposed areas. For example, a dairy barn of 100 cows produces about 2 kg of estrogen/year while the estrogens can affect fish and plants at the 10 ng/L level.
Measuring the transport of steroids in the environment has the advantage in that the kg amounts of steroids produced per year by just a small CAFO can be easily traced as they move through the environment. Each of the major steroids produced has different mobility (mobile, partially mobile, and immobile) in the environment and these differences in mobility can be used to characterize the movement of the veterinary pharmaceuticals released from the same source. This is of import as
neither the pharmaceuticals nor the steroids follow the physiochemical models that work for pesticides and herbicides. Furthermore, it is difficult to evaluate potential EDCs until we have some understanding of the role of the physiologically active steroids constantly secreted into the environment.
The plethora of pharmaceuticals used in animal husbandry makes it difficult to determine what the most likely compounds to cause risk are. Most of the compounds are released in concentrations several orders lower than their lowest observable effect. However, even very small amount of sulphonamides and tetracycline reaching the soil induce antibiotic resistant genes (ARGs) in soil bacteria, thus the study of ARGs is a new way of evaluating the affects of antibiotics in the environment
