Assessing the Potential of Hormones from Agricultural Waste to Contaminate Groundwater

Concern has recently emerged about a group of trace organic compounds identified in the aquatic environment which might affect reproduction and development of wildlife species and humans due to endocrine disruption (Colborn et al., 1996; Roefer et al., 2000). Studies in recent years have documented a high occurrence of these endocrine disrupting compounds (EDCs) in aquatic ecosystems (e.g. Kolpin et al., 2002), although the impact of EDCs in groundwater is not well understood. An important source of EDCs which may potentially impact groundwater 1s manure from animal feeding operations (Schiffer et al., 2001; Lange et al., 2002). Animal feeding operations generate more than 500 million tons of manure annually (USEPA, 2003) which can enter the environment in a variety of ways including runoff into surface waters after field applications or leaching from holding tanks and composting facilities. Livestock excretions can contain a mixture of natural and/or synthetic steroid hormones (Lange et al., 2002) which have the potential to act as EDCs. Some of these hormones, such as the synthetic steroid hormones used in the cattle industry, have been found to be persistent in the soil (Schiffer et al., 2001) increasing the chance for movement into groundwater.