On a worldwide basis, environmental concern has increasingly focused on the potential impacts of chemical pollutants on the endocrine systems of invertebrates and vertebrates, including humans (Colburn et al. 1996). For example, the discharge of sewage effluents into surface waters has been implicated in the feminization of fish and invertebrates (Jobling et al. 2002). These effects are considered a result of exposure to endocrine disrupting chemicals (EDCs). The endocrine system is a chemical signaling system in animals working in parallel with the nervous system. There is no universal definition of an EDC; however, a common definition is “…any chemical with the potential to alter hormonally mediated signals in plants or animals" (NRC 1999).
King County has been monitoring water quality for many years. The current water quality monitoring program is extensive and includes assessment of streams/rivers, lakes and marine waters; primarily for conventional pollutants. Although some chemicals classified as EDCs have been monitored in the past (e.g., PCBs, DDT), some of the EDCs of most recent concern (e.g., estrogenic hormones) have not been evaluated. A pilot monitoring survey of King County surface waters was initiated for a select group of EDCs of concern. The primary purpose of this effort was to determine if these compounds are present in different types of waters, and if so, at what levels. Initiation of this survey required the King County Environmental Lab (KCEL) to identify and develop expertise conducting chemical analyses for these compounds. To better understand if these chemicals have the potential to cause effects to aquatic life, the data were compared to literature-based effect concentrations associated with laboratory exposures to the EDCs evaluated by this effort. Laboratory based studies have the advantage of isolating the effects of a chemical of concern from confounding chemicals or other environmental and/or site-specific conditions.
This survey examined a number of locations in marine waters, major lakes, rivers, and smaller streams in King County. It was intended to provide sufficient information to determine if future monitoring is warranted, and if so, these data would be used to guide development of future monitoring efforts. The survey was not intended to provide a comprehensive assessment of EDCs in King County waters. This report also provides the results of other concurrent sampling efforts that included analysis of EDCs in stormwater from the SR-520 Evergreen Point floating bridge, and four stormwater discharges to the Sammamish River in the City of Redmond. In addition, data from a number of other surface water sampling efforts that included EDC analysis are presented in this report. These efforts included samples collected from the Sammamish and Snoqualmie Rivers and a variety of other small streams.