EMERGING CONTAMINANTS IN A RIVERBANK FILTRATION SYSTEM, PLATTE RIVER, NEBRASKA

The US Geological Survey in Nebraska, in conjunction with the US EPA and the City of Lincoln Water System, has recently completed a project to determine the occurrence, transport, and fate of pharmaceuticals and other organic endocrine disrupting compounds (EDCs) in surface water and ground water under the influence of surface water at a rural well field in eastern Nebraska along the Platte River that is the pre-treatment source of drinking water for a population of 225,000 people. Samples were collected from the Platte River and from wells adjacent to the river. In addition, a small number of samples were also collected and analyzed from potential sources within the watershed, including a cattle feedlot lagoon, a hog confinement lagoon, and the effluent from a wastewater treatment plant that discharges into a tributary of the Platte River. Sources of pharmaceuticals and other organic EDCs were found to exist in the watershed throughout the year. The most prevalent organic EDCs detected at the site were the pesticides atrazine and acetochlor. Low levels of many pharmaceuticals and organic EDCs generally associated with wastewater were also found in the surface water and ground water at the well field site. However, detected concentrations were not high enough to allow us to accurately determine riverbank filtration efficiency of the streambed sediments for these compounds.