Estrogenicity of agricultural runoff: A rainfall simulation study of worst-case scenarios using fresh layer and roaster litter, and farrowing swine manure

Authors: SHAPPELL, NANCY - Retired ARS Employee; SHIPITALO, MARTIN - Retired ARS Employee; Billey, Lloyd

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2020
Publication Date: 8/3/2020
Citation: Shappell, N., Shipitalo, M., Billey, L.O. 2020. Estrogenicity of agricultural runoff: A rainfall simulation study of worst-case scenarios using fresh layer and roaster litter, and farrowing swine manure. Science of the Total Environment. 750:141188. https://doi.org/10.1016/j.scitotenv.2020.141188.
DOI: https://doi.org/10.1016/j.scitotenv.2020.141188

Interpretive Summary: Scientists have hypothesized that use of animal wastes on agricultural soils increases hormone contents of surface water (runoff) sufficiently to have negative effects on fish. Controlled experiments were conducted to determine the effects of animal waste applications on hormone (estrogens) concentrations in runoff after simulated rainfall events. Experiments were also conducted to determine whether calcium ions might serve as an easily measured 'sentinel' marker for estrogens, which are difficult and expensive to measure. During three years of study, concentrations of estrogens in runoff never exceeded concentrations reported to affect fish, even when manure was applied to soils at very high rates. Calcium concentrations in runoff were not related to estrogen content, proving that this simply measured ion was not a useful marker for estrogen. The study indicates that with the use of best management practices, application of animal wastes for use as fertilizers has little potential to elevate estrogen in runoff waters to levels of concern.

Technical Abstract: Scientists have correlated land application of animal wastes as fertilizer with the feminization of fish. Two questions were asked. 1) Under a worst case scenario when animal waste (layer and roaster litter, or farrowing swine slurry) is applied and tilled in 24 h prior to a surface-runoff producing rainfall, will estrogenic equivalents exceed the Lowest Observable Effect Concentration (LOEC) for fish (10 ng/L)? 2) Can calcium concentrations in runoff, measured using a rapid meter-based method, be used as a sentinel of elevated estrogenic activity? In a 3-yr study wastes were surface-applied and incorporated and 24 h later, 1.5 by 3 m plots were subjected to simulated rainfall and again 1 wk and 3 wk later. Nutrients in runoff were also measured, and in year 1 total coliforms and E.coli were assessed. Except for an initial preliminary test run, runoff from all plots and years never exceeded 10 ng/L E2Eq equivalent. Calcium concentrations in runoff were not related to estrogenicity, negating its use as a sentinel marker. Specific estrogens in animal waste and runoff were identified by mass spectrometry with concentrations in runoff dependant on manure source and timing of rainfall. As expected, total coliform and E.coli concentrations in runoff were increased by the application of layer litter. Concentrations of nutrients in runoff would not be expected to result in surface water concentrations higher than guidelines for protection of aquatic species. Animal wastes applied in quantities appropriate for crop nutrient requirements, tilled into the soil surface, in observance of regulations avoiding application within 24 h of a predicted rain event, should not result in estrogen levels of environmental concern.