Steroid estrogens, conjugated estrogens and estrogenic activity in farm dairy shed effluents |
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Authors: | Jennifer B Gadd Louis A Tremblay |
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Institution: | a Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand b Landcare Research, PO Box 40, Lincoln, 7640, New Zealand c Plant & Food Research, Private Bag 3123, Waikato Mail Centre, Hamilton 3240, New Zealand |
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Abstract: | Agricultural wastes are a source of steroid estrogens and, if present, conjugated estrogens may add to the estrogen load released to soil and aquatic environments. Dairy shed effluent samples were collected from 18 farms for analysis of steroid estrogens by GC-MS, conjugated estrogens by LC-MS-MS, and estrogenic activity by E-screen in vitro bioassay. 17α-estradiol was found at highest concentrations (median 730 ng l−1), followed by estrone (100 ng l−1) and 17β-estradiol (24 ng l−1). Conjugated estrogens (estrone-3-sulfate, 17α-estradiol-3-sulfate and 17β-estradiol-3,17-disulfate) were measured in most samples (12-320 ng l−1). Median estrogenic activity was 46 ng l−1 17β-estradiol equivalents. Conjugated estrogens contributed up to 22% of the total estrogen load from dairy farming, demonstrating their significance. Steroid estrogens dominated overall estrogenic activity measured in the samples. Significantly, 17α-estradiol contributed 25% of overall activity, despite potency 2% that of 17β-estradiol, highlighting the importance in environmental risk assessments of this previously neglected compound. |
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Keywords: | Estrogen Dairy effluent Agricultural wastes Endocrine disruptors |
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