Author
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Hakk, Heldur |
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Millner, Patricia |
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Larsen, Gerald |
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Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/13/2004 Publication Date: 1/1/2005 Citation: Hakk, Heldur, Millner, Patricia, Larsen, Gerald. 2005. Decrease in water-soluble 17beta-estradiol and testosterone in composted poultry manure with time. Journal of Environmental Quality 34:943-950. Interpretive Summary: Mammals naturally produce and excrete potent hormones. Among the most common are 17 -estradiol and testosterone. These hormones are more potent than man-made environmental contaminants of concern that also interact with the estrogen or androgen receptors. The purpose of this study was to measure the concentrations of estradiol and testosterone in a poultry manure composting operation in order to assess the effectiveness of composting in reducing or eliminating these hormones. Poultry layer manure was obtained from a commercial producer. Commercial kits were utilized to measure concentrations of both hormones. Both hormones were degraded by aerobic composting as typically practiced in the field. Estradiol concentrations began at an average of 92 ng/g (on a dry weight basis), and were degraded over the 175-day study at half the rate of testosterone. Initial testosterone concentrations were greater than estradiol, i.e. 212 ng/g. Neither hormone was completely degraded to negligible, background levels by the conclusion of the study. The addition of clay, a common texturing agent, to the compost did not significantly affect the rate of decay of either hormone. The results of the study demonstrated that composting of poultry manure was an effective means of reducing, but not eliminating, the introduction of the potent hormones, estradiol and testosterone, into the environment. Technical Abstract: The purpose of this study was measure the concentrations of the potent hormones, estradiol and testosterone, in a poultry manure composting operation in order to access the effectiveness of composting in reducing or eliminating these hormones. Poultry layer manure was obtained from a commercial producer and amended with hay, straw, leaves, and starter compost. Commercial enzyme immunoassay kits were utilized to measure concentrations of both hormones. During the first 21 days of the study thermophilic conditions were maintained (>60 C), while mesophilic conditions (35-55 C) were maintained for the last 154 days. Both hormones were degraded by the heated, aerobic processes occurring in compost, and could be modeled by a first order with time degradation rate constant. Estradiol concentrations began at an average of 92 ng/g, and were more slowly degraded than testosterone. Estradiol in poultry manure compost had a degradation rate constant of -0.0108/day. Testosterone was degraded at a rate approximately two times faster than estradiol, i.e. -0.0233/day. Initial testosterone concentrations were 212 ng/g. Neither hormone was degraded to completely to background levels by the conclusion of the study. The addition of Christiana clay to the compost did not affect the rate of decay of either hormone significantly, i.e. degradation rate constants were -0.0140/day and -0.0214/day for estradiol and testosterone, respectively. The results of the study demonstrated that composting of poultry manure was an effective means of reducing, but not eliminating, the introduction of the potent hormones, estradiol and testosterone, into the environment. |
