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Bioassay of estrogenicity and chemical analyses of estrogens in streams across the United States associated with livestock operations
Alvarez, D., N. Shappell, L. Billey, D. Bermudez, V. Wilson, D. Kolpin, S. Perkins, N. Evans, W. Foreman, J. Gray, M. Shipitalo, AND M. Meyer. Bioassay of estrogenicity and chemical analyses of estrogens in streams across the United States associated with livestock operations. WATER RESEARCH. Elsevier Science Ltd, New York, NY, 47(10):3347-63, (2013).
According to USDA estimates, livestock operations across the U.S. generate more than 1.1 billion tons of manure annually (USDA 2009) much of which is land-applied as fertilizer. In some instances, however, land application can contribute to degradation of surface water quality. Historically, concerns pertaining to animal manure have dealt primarily with nutrient issues (Jongbloed and Lenis, 1998). More recently, however, concerns have arisen about other constituents present in manure, such as naturally occurring hormones (Hanselman et al., 2003). Animal feedlot/feeding operations (AFO) have limited data on the fate of estrogenic compounds that may be present in runoff emptying into receiving waters (Leet et al., 2011). Therefore, the U.S. Geological Survey (USGS) led a multi-year study to assess the occurrence of a broad range of chemical and microbial contaminants derived from AFOs in streams across the United States. Study sites included small, headwater watersheds (— 1 to 30 km2) chosen to be representative of the major livestock types (swine, poultry, beef, and dairy) located across the nation over a range of geographic and hydrogeologic settings. In addition, a similar set of “rural, background” watersheds that had similar land use (e.g. cropland) but with no livestock operations or manure applications were sampled to establish baseline conditions. Samples consisted of manure, discrete water, time-integrated water (using passive sampling devices), and streambed sediment. All samples were analyzed for a comprehensive set of chemical and microbial constituents, including a number of chemicals that are known to be estrogenic. For this paper, we present data only on estrogens and estrogenic activity in discrete and time-integrated water samples.
Animal manures, used as a nitrogen source for crop production, are often associated with negative impacts on nutrient levels in surface water. The concentration of estrogens in streams from these manures is of concern due to potential endocrine disruption in aquatic species. Streams associated with livestock operations were sampled by grab sample or by time-integrated polar organic chemical integrative samplers (POdS). Samples were analyzed for estrogens by gas chromatography-tandem mass spectrometry (GC-MS2) and estrogenic activity was assessed by three bioassays. Samples were collected from 19 streams within small (—1 to 30 km2) watersheds in 12 US states representing a range of hydrogeologic conditions, dominated by: dairy (3); grazing (3) and feedlot cattle (1); swine (5); poultry (3); and 4 areas where no livestock were raised or manure applied. Discrete (n = 38) and POCIS (n = 19) samples from each watershed were analyzed using Yeast Estrogen Screen (YES), T47D-KBluc Assay, MCF7 Estrogeriicity Screen CE-Screen) and GC-MS2. Water samples were consistently below the proposed Lowest Observable Effect Concentration for estradiol in fish (10 ng/L) in all watersheds, regardless of land use. Estrogenic activity was often higher in samples during runoff conditions following a period of manure application. Estrone was the most commonly detected estrogen (13 of 38 water samples, mean 1.9, max 8.3 ng/L). Because of the T47D-KBluc assay’s sensitivity towards estrone (1.4 times estradiol) it was the most sensitive method for detecting estrogens, followed by the E-Screen, GC-MS2, and YES. POCIS resulted in greater detection of estrogens than discrete water samples across all sites, even with the less sensitive YES bioassay.