Evaluating and controlling pharmaceutical emissions from dairy farms: a critical first step in developing a preventative management approach

Concern that pharmaceuticals may be escaping into the environment where the potency and persistence of certain compounds at trace concentrations could be chronically affecting biota is growing. Hitherto the main focus has been on human medications, personal care products and industrial endocrine disrupting chemicals. These generally enter sewerage systems where there is at least the prospect of partial removal by treatment plants before they enter waterways. By contrast, the agricultural sector, a significant user of veterinary pharmaceuticals, has no such treatment – compounds are deposited straight to ground in dung and urine or washed from hides in the case of topical applications.This study investigates the fate of a number of antibiotic compounds (as well as the insect repellent, DEET, via a pilot assessment) used in herd health programs on dairy farms in the cow-rich Macalister Irrigation District in Victoria, Australia. Results from samples taken from irrigation drainage channels and streams demonstrate that these compounds are foot printing into an aquatic environment that extends to the Ramsar-designated Gippsland Lakes and associated wetland system. Conclusions are drawn as to how this problem might be lessened by a targeted water quality monitoring program and some rather straightforward changes to farm management practices.