THE OCCURRENCE OF 17ß-ESTRADIOL IN SOIL AND SURFACE WATERS IN AN AGRICULTURAL WATERSHED

The estrogen compound 17ß-estradiol (E2) has been identified as an endocrine-disruptor in aquatic organisms, even when present at relatively low concentrations. Its occurrence in surface waters is associated with sewage contamination and animal agriculture. Much of the existing information about E2 refers to its possible adverse health effects and there is limited knowledge regarding its fate and transport in the subsurface, particularly in agricultural watersheds. Soil water was collected from pan lysimeters in November 2003 and in April and June 2004 at a 1.2-km2 subcatchment in central Virginia, to which poultry manure was applied in May of 2003 only. The lysimeters were located at depths of 15, 46 and 91 cm in a cornfield (upgradient in the watershed) and a cattle pasture (downgradient in the watershed). A synoptic survey of 27 sites located in the Delmarva peninsula, northern and central Virginia, and the eastern shore of Virginia was completed in June 2004 in order to understand the magnitude of E2 presence in surface waters of the region. Samples of the synoptic survey were collected from sites directly impacted by agricultural practices or urban development. All samples were analyzed using an enzyme-linked immunosorbent assay (ELISA). The November 2003 concentrations of E2 ranged from 0.03 to 0.45 ng/mL, where the highest levels were in the shallow soil and decreased with depth at both sites. The April 2004 results showed decreased, but persisting E2 levels of 0.08 to 0.14 ng/mL at the cornfield and cattle pasture. The June 2004 results showed E2 at even lower concentrations overall in the soil water, but the highest concentrations were observed at the greatest depth. The soil water results indicate that E2 persists in the subsurface even many months after introduction at the land surface with applied manure and migration to depth in the soil may take place over the course of at least one year. The maximum regional E2 concentrations from the synoptic survey of 27 streams and rivers reached up to 0.03 ng/mL. Regional E2 concentrations were found to be highest in watersheds influenced by urban development.