Occurrence of Hormones in Leachate and Shallow Groundwater Under a Concentrated Swine Feeding Operation.

Between 2003 and 2007, the reproductive hormones 17-β estradiol (E2) and testosterone (T) have been monitored in the shallow groundwater and leachate within and around a swine feeding operation in North Dakota. The soil at the site is a fine sandy loam over fine sand and the water table is within 1 m of the surface at times. Monitoring wells were installed between hoop barns, near a manure storage pond, adjacent to an uncovered manure/bedding pile, and at other locations within the farm site. Leachate was collected via passive capillary wick lysimeters and fluxmeters in small plots, which received annual applications of either raw manure, manure/bedding from the pile, liquid manure from the storage pond, or no manure. Concentrations were quite temporally and spatially variable in the groundwater for E2 (0-104 ng L^-1; mean, 7 ng L^-1) and T (0-77 ng L^-1; mean, 7 ng L^-1). However, the 4-yr mean concentrations between groundwater locations were not significantly different at α=0.05. Leachate concentrations in the small plots were more variable than groundwater concentrations for E2 (0-541 ng L^-1; mean, 9 ng L^-1) and T (0-104 ng L^-1; mean, 6 ng L^-1). Similarly, the 4-yr mean concentrations between plots were not significantly different, except that T was significantly higher in the leachate measured near the manure/bedding pile (19 ng L^-1). Hormone concentrations from the control plot lysimeters and an existing well outside of the farm site were not significantly different from lysimeters in plots receiving manure applications and in wells near manure sources. That indicated that the hormone levels were probably naturally occurring and that sorption and transformation processes may be taking place within the unsaturated/saturated zone. Also, at times both control and non-control hormone concentrations exceeded lowest observed effective concentrations for sensitive organisms.