Fate and Transport of Steroid Hormones and Veterinary Antibiotics Derived from Cattle Farms

Concentrated animal feeding operations (CAFOs) have been identified as one of the most important sources for the release of animal hormones and veterinary antibiotics into the aquatic environment. Funded by a USDA research grant, Dr. Wei Zheng set out to identify and quantify the environmental fate and transport of several commonly-occurring steroid hormones, veterinary antibiotics, and their metabolites.

The researchers examined levels of 17α-estradiol, 17β-estradiol and estrone in water, manure-contaminated wastewater and soil. They also conducted laboratory experiments to investigate aerobic and anaerobic degradation of six steroid hormones and two antibiotics. The results indicated that anaerobic conditions prevented or slowed the breakdown of hormone contaminants.

Therefore, Dr. Zheng and his team concluded that increasing the residence time of wastewater in CAFO lagoons or using aerobic tanks may be economical and efficient methods to degrade hormone and antibiotic contaminants and thus reduce their loads to the environment.

Batch soil experiments in the laboratory found that the antibiotic ceftiofur showed a relatively higher sorption capacity than florfenicol in soils amended with animal manure. The sorption capacities of florfenicol in manure-amended soils were less than those in non-amended soils, indicating manure-borne colloids can facilitate leaching of this contaminant to groundwater through soil.

Field monitoring of bodies of water surrounding agricultural fields receiving CAFO waste found that hormone contaminants were seldom detected in well water samples, but they were observed in some subsurface tile-drained water samples, especially during effluent irrigation and storm events.

cows standing in a feeding lot, the ground is muddy and waterly