RUNOFF OF ESTROGEN HORMONE 17-BETA-ESTRADIOL FROM POULTRY LITTER APPLIED TO PASTURE

Environmental loading of hormones contained in poultry litter may caus e or contribute to disruptions in the health and reproductin of animal s. A runoff study was conducted to evaluate the hypothesis that poultr y litter applied to pasture contributes the estrogen hormone 17 beta-e stradiol to runoff. The objectives were to determine the effects of (i ) rate of litter application, (ii) amending litter with alum [aluminum sulfate (Al-2(SO4)(3).14H(2)O)], and (iii) multiple storms on runoff concentrations and losses of 17 beta-estradiol from poultry litter app lied to fescue (Festuca arundinacea Schreber) plots. Normal litter and litter treated in production houses with 1.2 kg alum m(-2) were appli ed 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 therea fter 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 s ingle flow-weighted composite was obtained from the six discrete sampl es. The 17 beta-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 mu g L-1 and 198. 8 mg ha(-1) from the highest application rate of normal litter. Amendi ng the litter with alum reduced mean 17 beta-estradiol concentrations by 42% and losses by 46% in first-strom runoff. Overall, second-storm runoff concentrations and losses were 66 and 69% less than from the fi rst storm. This research indicates that field-applied poultry litter c an contribute 17 beta-estradiol to runoff, that this hormone can persi st for at least 7 d under field conditions, and amending poultry litte r with alum can significantly reduce transport in runoff.