Public Health Assessment Donna Reservoir and Canal System Donna, Hidalgo County, Texas. EPA Facility ID: TX0000605363. Final Release

摘要

The Donna Reservoir and Canal System site is located in Donna, Hidalgo County, Texas. On September 19, 2007, the site was proposed to the National Priorities List (NPL), commonly known as Superfund, due to polychlorinated biphenyl (PCB) contamination in fish. In cooperation with the Agency for Toxic Substances and Disease Registry (ATSDR), the Texas Department of State Health Services (DSHS) has evaluated the public health significance of this site and determined that the PCBs found in fish taken from the site pose a public health hazard. The discovery of the PCBs in the fish goes back to 1993 when the United States Environmental Protection Agency (EPA) measured an extremely high PCB concentration in a fish. The fish was reportedly caught in the Donna Canal by a family from Brownsville, Texas. The fish was reportedly taken from the Donna Canal near Donna, Texas. In response to this sample result and the results of analyses from subsequent fish taken from the Donna Reservoir and Canal System, DSHS concluded that the site posed a public health hazard and issued Aquatic Life Order 9 (AL9). This order banned the possession of fish taken from the Donna Irrigation System (aka Donna Reservoir and Canal System). Subsequent sampling events have confirmed the continued presence of PCBs in fish from this site at levels exceeding those used by DSHS to ensure protection of public health from adverse systemic health effects. DSHS placed warning signs along the canal and irrigation system to advise people of the fishing ban. The signs warned that fish caught from the reservoir and canal system may contain harmful chemicals and that keeping the fish may result in a fine of up to $500.00. Upon visiting the site we observed that many of the warning signs either were missing or damaged. Additionally, after talking with local area residents and observing evidence of fishing, it was apparent that there was a high probability that people were still consuming fish from the site. Based on available information we have concluded that as long as there are fish in the Donna Reservoir and Canal System and the warning signs are ignored, the presence of PCBs in fish at this site would continue to pose a hazard to public health. The source of the PCBs is not known; however, PCBs also were detected in suspended sediments. Based on available information and reasonably plausible exposure scenarios we have concluded that the PCBs found in the suspended sediments do not pose a hazard to public health. PCBs were not detected in any other media. As long as people continue to eat contaminated fish from this site, the site will continue to pose a public health hazard. Currently, DSHS, the EPA, and local agencies are working with area residents to inform citizens about the potential health risks associated with consuming the contaminated fish. Additionally, EPA and the United States Fish and Wildlife Service (USFWS) are in the process of removing fish from the canal system. Future exposure to PCBs in the fish, and by inference the public health conclusion category for this site, will depend on the efficiency of the fish removal operation, locating the source(s) of the PCBs, and the effectiveness of improving public awareness.