The Donna Canal and Reservoir System is a 400-acre area located southwest of the City of Donna, Texas in southeast Hidalgo County within the Arroyo Colorado watershed. The water from the system is used by the City of Donna as a drinking water supply and for crop irrigation.
The site was identified in 1993 by the Texas Department of State Health Services (DSHS) and the Texas Commission on Environmental Quality (TCEQ). Both agencies began a two-year joint investigation with numerous fish and sediment samplings, water assessments, as well as searches for contamination sources. To date, no sources of contamination have been found.
Several reports in 1993 and 1994 by DSHS indicate that high levels of polychlorinated biphenyls (PCBs) have been found in fish at the Donna Canal and Reservoir. As a result, a fish possession ban was placed on the canals and reservoir. Even though this ban has been in effect since 1994, people continue to catch and consume the contaminated fish.
The EPA, working in cooperation with the City of Donna, Donna Irrigation District, TCEQ, DSHS, Texas Parks and Wildlife, US Fish and Wildlife Service, and the Agency for Toxic Substances and Disease Registry will conduct a removal action for the depopulation of contaminated fish in the Donna Canal. The larger, edible sized fish in Donna canal are contaminated with PCBs above US Food and Drug Administration (FDA) allowable consumption limits.
On August 11, 2008 the EPA along with the USFWS began the removal of contaminated fish from the Donna canal. The removal involves a combination of electro-shocking and netting in small manageable segments within the canal. The fish removal is accomplished with boats that are equipped with electrical nodes that send a current of electricity through the water, which stuns the fish for easy capture and removal. The USFWS typically uses this type of specialized equipment for aquatic research and monitoring studies. The captured fish are then counted, weighed, and measured prior to disposal.
EPA is conducting two types of fish analysis; whole body and fillet. These analyses will be used to determine the level of PCB contamination in the fish and verify the reduction of risk resulting from the removal action. Representative edible species of fish will be sent to a laboratory for PCBs as Arochlors chemical analysis.
On August 13, 2008, 9 fish samples including 1 Catfish (wholebody), 2 Smallmouth Buffalo (fillet and whole body), 2 Largemouth Bass(fillet and whole body), and 4 Common Carp (2 fillet and 2 whole body) were shipped to the laboratory for analysis. In addition, 2 water samples including 1 equipment rinseate and 1 surface water from Donna canal Segment 1 were shipped to the laboratory for analysis.
To date the USFWS have identified a total of 14 different species of fish that include Common Carp, Largemouth Bass, Gizzard Shad, Bluegill, Channel Catfish, Smallmouth Buffalo, and a South Texas Siren that is listed by the State of Texas as a threatened species. As of August 13, 2008 there have been a total of 496 fish or 1-55 gallon drum of fish removed from the canal.
Along with collecting fish, the EPA plans to install a number of fish barriers that will act as engineering controls along various points in the canal. The barriers will serve to limit new fish that may be potentially contaminated from re-populating the canal and reservoir.
On August 12, 2008 the EPA held a community meeting at the Donna public library to discuss removal action activities at the Site. The meeting began with a quick introduction by Mayor Simmons of the City of Donna along with representatives from the Donna Irrigation District. The main message given during the meeting was that the fish from the Donna Canal should not be consumed because of health concerns and the EPA has listed the site on the National Priorities List (NPL) for remediation. The NPL process will enable the EPA to look for the source and determine a permanent solution to the problem.
Continue working on the removal of fish from the 3 predetetermined segments of the Donna canal.
Installing fish barriers at strategic locations in the canal.
Characteristic sampling of fish and surface water.
Waste disposal profiling of fish.
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