Reduction of estrone to 17 β-estradiol in the presence of swine manure colloids.

Land application of animal manure and municipal biosolids to improve soil fertility carries the risk of adding to aquatic ecosystems contaminants that can disrupt the endocrine systems of aquatic organisms. This study explored the fate of two estrogens, 17 β-estradiol (E2) and estrone (E1), in the presence of organic colloids derived from swine manure. Most reports concerning environmental estrogens indicate a degradation/transformation pathway that leads to decreased estrogenicity, that is, E2 is transformed to E1 and potentially to other daughter products. However, in this study we found that within 24 h the reverse reaction was possible (E1 transforming to E2) in a swine manure colloidal suspension closed to the atmosphere. The reaction occurred after approximately the same 24-h period in separate colloidal suspensions of swine manure that had been initially incubated with E2 or with E1. In the experiment with E2, there was an apparent complete reversal of the solution estrogen form, from E2 to E1 and then back to E2. Our observations support the concern that environmentally relevant estrogens have the potential to increase in estrogenicity and/or to persist under reducing conditions.
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