News and Activities
Endocrine Disruptor Study Initiated at the Sonny Bono Salton Sea NWR
Date Posted: September 14, 2001
The Sonny Bono Salton Sea National Wildlife Refuge has a variety of freshwater ponds managed for wildlife that are supplied with Colorado River water. This water carries municipal and industrial discharges and agricultural runoff from upstream sources. Earlier studies indicate that p,p’DDE (a breakdown product of DDT) is widespread in the wildlife and plants of the Imperial Valley, probably from historic applications of DDT to the Valley’s agricultural fields. Various studies have linked DDT, its breakdown products, and sewage effluent with endocrine (hormone) disruption in aquatic species. However, no studies have measured the endocrine effects of these contaminants on aquatic species in the Imperial Valley. Endocrine disruption has the potential to compromise proper development in organisms, leading to reproductive, behavioral, immune system and neurological problems, as well as the development of cancer. Effects often do not show up until later in life. The Carlsbad Field Office has initiated a study on fish and amphibians in these agricultural drainage ponds. The objective of this study is to determine if aquatic species are exhibiting some form of endocrine disruption by evaluating: (1) their exposure to synthetic organic compounds;(2) sperm viability in male fish; and (3) oocyte (egg) development in female fish. The study will also identify the range of contaminants that may be responsible for any observed abnormalities by collecting and analyzing the sediment. Surveys will be conducted for amphibians, and any malformations will be noted.
U.S. Fish and Wildlife Service, Division of Environmental Quality. DDT and Wildlife