Estrogenic activity and nutrient losses in surface runoff after winter manure application to small watersheds

Authors: Shappell, Nancy; Billey, Lloyd; Shipitalo, Martin

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2015
Publication Date: 2/1/2016
Publication URL: https://handle.nal.usda.gov/10113/61770
Citation: Shappell, N.W., Billey, L.O., Shipitalo, M.J. 2016. Estrogenic activity and nutrient losses in surface runoff after winter manure application to small watersheds. Science of the Total Environment. 543:570-580.

Interpretive Summary: Confined Animal Feeding Operations generate large amounts of wastes that are land-applied to provide nutrients for crop production and return organic matter to the soil. Production practices and storage limitations often necessitate that these materials be applied to frozen and snow-covered soil. Many studies have investigated nutrients such as nitrogen and phosphorus released from the animal wastes into streams and surface waters. Use of grassed areas at the edge of cropped fields has been shown to decrease pollution of surface waters from field runoff. There has been no study of the hormonal activity of runoff when manure was applied to frozen fields. Therefore, the first year we applied manure (beef) to frozen mature forage plots (a mixture of grasses); and to frozen fields where corn was to be planted (applying turkey litter the first year, and swine manure for 3 years), and measured nutrients and estrogenic activity in runoff. The rate of manure or litter was appropriate for supplying nitrogen needs of corn to be planted. There was no runoff from grassed plots, indicating little risk of environmental impact from nutrient or estrogen loss to surface waters from manure application under these conditions. Estrogenic activity and nutrient concentrations from cropped fields generally peaked in the first runoff event after application. There appears to be little risk from estrogenic activity, as the highest measured activity was less than the concentration for the most potent natural estrogen, estradiol, known to cause an observable effect for aquatic species. Our values for estrogenic activity were well below the runoff concentrations for estrogens measured in other field studies (not on frozen fields) using methods that are known to result in inaccurate results. We were able to find an association between certain mineral concentrations (calcium, magnesium, and potassium) and estrogenic activity. Future monitoring of one of these ions could be done quickly and relatively inexpensively, allowing for more targeted analysis of estrogenic activity, which is time-consuming, labor and facility intensive, and expensive.

Technical Abstract: Confined Animal Feeding Operations generate large amounts of wastes that are land-applied to provide nutrients for crop production and return organic matter to the soil. Production practices and storage limitations often necessitate that wastes be applied to frozen and snow-covered soil. Under these conditions, application setbacks can reduce concerns related to nutrient losses in surface runoff, but their effects on losses of manure components with hormonal activity have not been investigated. Therefore, we measured and sampled surface runoff when manure was applied in the winter at a rate to meet crop N needs and measured estradiol equivalents (E2Eqs) using E-screen technology. In year one, six small (0.55 to 0.79 ha) watersheds (2 no-manure controls, 2 liquid swine manure with 30-m setbacks, 2 turkey litter with 30-m setbacks) used to produce corn were evaluated. In addition, beef manure was applied to six frozen plots (61 X 12 m) plots. For year 2 and 3applications were repeated on the swine manure watersheds and one control watershed. E2Eqs and nutrient concentrations generally peaked in the first runoff event after application. The highest measured E2Eq (5.6 ng L-1) was in the first event after swine manure application and was less than the 8.9 ng L-1 Lowest Observable Effect Concentration (LOEC) for aquatic species and well below the concentrations measured in other studies where methodology subject to cross reactivity was used to measure hormone concentrations. No runoff occurred from plots planted with forage, indicating low risk for environmental impact, and therefore plots were discontinued from study. In year 2 and 3, estrogenic activity never exceeded the Predicted No Effect Concentrations for E2 of 2 ng L-1. When post-application runoff contained high estrogenic activity, strong correlations (R2 0.86 to 0.96) of E2Eq to Ca2+, Mg2+, and K+ concentrations were observed, indicating under some condition these cations might be useful surrogates for E2Eq measurements.