Determination of 17b-estradiol Concentrations in Runoff from Plots Receiving Dairy Manure

Because of growing concern about estrogenic compounds in animal wastes, theobjective of this research was to measure 17b-estradiol concentrations in runoff from plotsfertilized with liquid dairy waste. Nine plots were established at The University of TennesseeDairy Experiment Station located at Lewisburg, Tennessee, and dairy manure was applied to sixof the nine plots. Three of the plots received manure at a rate sufficient to meet the nitrogen (N)requirement for winter wheat; three received manure at a rate sufficient to meet the phosphorus(P) requirement for winter wheat, and three received no manure. Runoff samples were collectedafter each of the first six runoff events producing natural rainfalls following manure application.Enzyme linked immunosorbant assays were used to determine the concentration of 17b-estradiolin the collected runoff samples. Preliminary results are reported herein, showing that17b-estradiol concentrations in runoff from plots that historically received dairy manure, butwhich had not recently received manure, ranged from below detection threshold to 2.2 ng/L. Incontrast, average 17b-estradiol concentrations in runoff from plots receiving manure at the N-ratewere as high as 41 ng/L; plots receiving manure at the P-rate had average runoff 17b-estradiolconcentrations as high as 29 ng/L. Runoff from both N and P treatments remainedbelow the 100 ng/L level that we have taken to be biologically significant. Runoff concentrationsfrom all plots decreased with time following application of manure.