METABOLIC VARIABLES AFFECTING THE EFFICACY, SAFETY, AND FATE OF AGRICULTURAL CHEMICALS
Location: Animal Metabolism-Agricultural Chemicals Research
Title: Estrogenicity and Nutrient Concentration of Surface Waters Surrounding a Large Confinement Dairy Operation Using Best Management Practices for Land Application of Animal Wastes
Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 9, 2010
Publication Date: April 1, 2010
Citation: Shappell, N.W., Elder, K.H., West, M.S. 2010. Estrogenicity and Nutrient Concentration of Surface Waters Surrounding a Large Confinement Dairy Operation Using Best Management Practices for Land Application of Animal Wastes. Environmental Science and Technology. 44:2365-2371.
Interpretive Summary: Large confinement animal feeding operations (CAFOs) have been suspected of causing harm to the environment, in part through the fouling of surface waters. Such contamination would be possible either directly from the animals themselves, or from the application of CAFO animal waste on land as fertilizer. There have been reports of elevated concentrations of nitrogen and phosphorus in waters in proximity to CAFOs, as well as contamination with natural or synthetic reproductive hormones. Elevations in the chemical nutrients have long been associated with negative environmental impacts (algal blooms, fish kills), hormones have been associated with endocrine disruption and abnormalities in exposed fish. This study sought to evaluate the impact of a large dairy operation (> 2,000 head) on area surface water concentrations of phosphorus; the nitrogen containing compounds nitrate, nitrite, ammonia; and estrogenic activity using a cell culture system. Fifty-four thousand tons of waste was applied to ~2,000 acres from April to July (representing waste of ~1,000 milking head). Tile drain (pipes that run underneath the field to provide drainage) were sampled at two locations. Tile drain samples consisted of water that had percolated through soils onto which waste had been applied. As expected, flow rate from tile drains were very low compared to creek flows. Tile drain samples were the highest of all samples for nutrient and estrogenic activity content. Even peak estrogenic activity was only 25% of the proposed concentration for which there is no biological effect in fish (1ng/L). Creek samples monitored upstream and downstream from both an upstream municipal waste treatment plant and downstream of the dairy facility were no different for estrogenic activity or nitrate, nitrite, ammonia, and phosphorus concentrations and measured nutrients were within regional norms. It appears that use of best management practices for land application of dairy waste results in negligible nutrient and estrogenic contributions to surface waters associated with large dairy operations.
The impact of a confinement dairy operation (> 2,000 head) using best management practices for land application of animal wastes, on estrogenic activity (E-Screen), estrogens, and nutrients of associated surface waters and tile drain runoff were evaluated. Farm tile drain and creek samples were collected from the drainage region: above and below a municipal wastewater treatment plant located upstream from the dairy; and downstream from animal housing, parlor, and fields receiving applied wastes. Fifty-four thousand tons of waste (from ~1,000 milking head) was applied to ~2,000 acres from April to July. Maximum estradiol equivalents (E2Eqs) present in tile drain samples (= 0.257 ng/L) were two fold maximum creek E2Eqs, but only 25% of the proposed no observable effect concentration for E2 (1ng/L). Relative manure slurry estrogen concentrations were estrone > 17a-E2 > 17ß-E2. Creek nutrient concentrations were similar above and below the dairy, with higher concentrations found in tile drain samples: tile ammonia ranged from < 0.05 to 0.70 mg/L, nitrate/ite from 1.2 to 14 mg/L, and total phosphorus from 0.04 to 0.34 mg/L. No differences in estrogenic activity or nitrate/ite, ammonia, and phosphorus concentrations were detected in surface waters downstream of a large confinement dairy facility and measured nutrients were within regional norms.