Mystery Remains in Donna Reservoir Contamination

By: Duane Craig

The mysterious contamination of the Donna Reservoir and Canal in southern Texas continues to confound since its discovery in 1993. The reservoir system covers 400 acres and serves the local human population and agricultural businesses.

Sediment samplings and samples from fish alerted two Texas agencies to polychlorinated biphenyl, or PCBs, contamination, but after a two-year investigation, no sources could be found. The fish were banned for human consumption and even possessing them was in violation of the ban. Still, people continued to catch and eat the fish. The incidence of that decreased when agencies went door-to-door to warn people of the dangers of eating the contaminated fish. The state also embarked on a large-scale fish-removal program to try to reduce the numbers of tainted water life and reduce the potential environmental issues.

No source for polychlorinated biphenyl or PCBs found

PCBs don’t occur naturally in the environment, and once in water they stay suspended, making them easily consumed by fish. Once inside the fish, the chemicals contaminate the meat. PCBs are generally considered to be a carcinogen, and they accumulate in the body’s tissues where over time they contribute to reproductive problems and behavioral defects in newborns and infants.

The Environmental Protection Agency is preparing a Remedial Investigation and Feasibility Study, or RI/FS, to ultimately decide on a remediation process. A plan is expected to be complete by late 2012, according to the agency’s update.