Runoff of Estrogen Hormone 17β-Estradiol from Poultry Litter Applied to Pasture

Environmental loading of hormones contained in poultry litter may cause or contribute to disruptions in the health and reproduction of animals. A runoff study was conducted to evaluate the hypothesis that poultry litter applied to pasture contributes the estrogen hormone 17β-estradiol to runoff. The objectives were to determine the effects of (i) rate of litter application, (ii) amending litter with alum [aluminum sulfate (Al₂(SO₄)₃ · 14H₂O)], and (iii) multiple storms on runoff concentrations and losses of 17β-estradiol from poultry litter applied to fescue (Festuca arundinacea Schreber) plots. Normal litter and litter treated in production houses with 1.2 kg alum m⁻² were applied to four replicated plots 1.52-m wide by 3.05-m long on Captina silt loam (fine-silty, siliceous, mesic Typic Fragiudult) at 1.76, 3.52, 5.28, and 7.05 Mg ha⁻¹. Simulated rain was applied immediately thereafter and 7 d later at 50 mm h⁻¹. Runoff samples were collected at 5-min intervals for 30 min beginning 2.5 min after runoff began, and a single flow-weighted composite was obtained from the six discrete samples. The 17β-estradiol content of the composites was determined by enzyme-linked immunoassay. First-storm runoff concentrations and mass losses increased with application rate and were 1.28 µg L⁻¹ and 198.8 mg ha⁻¹ from the highest application rate of normal litter. Amending the litter with alum reduced mean 17β-estradiol concentrations by 42% and losses by 46% in first-storm runoff. Overall, second-storm runoff concentrations and losses were 66 and 69% less than from the first storm. This research indicates that field-applied poultry litter can contribute 17β-estradiol to runoff, that this hormone can persist for at least 7 d under field conditions, and amending poultry litter with alum can significantly reduce transport in runoff.