FORT WORTH -- The Trinity River in Tarrant, Dallas and six other counties is so contaminated with chemicals that eating any species of fish from it over the long term could lead to serious health problems, the state health department warned Tuesday.
Although the state did not ban fishing from those stretches of the Trinity, it advised people not to eat anything they catch. Tests indicate that fish in the river have elevated levels of dioxins and polychlorinated biphenyls, or PCBs.
"It's very likely that the advisory will be in effect for years," said Chris Van Deusen, a spokesman for the Texas Department of State Health Services, on Wednesday. "Dioxins and PCBs degrade very slowly."
Consumption of fish contaminated by the chemicals may eventually cause cancer and liver, immune system and reproductive problems, among other health concerns, the agency warned.
However, the high levels of PCBs and dioxins do not pose a health risk for swimmers or those taking part in recreation, the advisory warning stated.
The advisory includes the Clear Fork of the Trinity River from the Benbrook Reservoir dam to where it joins the West Fork on the north end of downtown Fort Worth, and the West Fork from the Lake Worth dam to the U.S. 287 bridge on the Freestone-Anderson county line in East Texas. That area covers Tarrant, Dallas, Ellis, Kaufman, Henderson, Navarro, Freestone and Anderson counties.
The agency issued an advisory in 2002 for portions of the river, but the new one on Wednesday expanded it, officials said.
For the testing, officials took 34 fish samples from three locations in Tarrant County in 2008: near West Rosedale Street, at the Purchey drain and near Beach Street. The fish included channel catfish, largemouth bass and carp.
PCBs are industrial chemicals that were commonly used in caulk, cooling and insulating fluids for transformers and capacitors, flame retardants, and floor finish and paint from the 1930s through 1977. The federal Environmental Protection Agency banned PCBs in 1979, but items containing it did not have to be replaced. The chemicals, which are odorless and tasteless, persist in the environment because they are very difficult to destroy and degrade slowly.
PCB levels in fish of about 0.047 milligrams per kilogram (mg/kg) or higher may pose a risk to human health, according to state standards. The levels in fish from the Trinity River averaged more than three times that much, at 0.185 mg/kg, though some ranged as high as 1.301 mg/kg, state officials said.
Dioxins are highly toxic chemicals that are mainly byproducts of combustion and manufacturing and may be released into the environment because of inadequate waste incineration, according to the World Health Organization. They accumulate in the food chain, and once in the body endure a long time.
Levels of dioxins for the Trinity River fish tested averaged 2.64 picograms per gram (pg/g). The state standard is 2.33 pg/g. A picogram is one-trillionth of a gram.
The state health department is not in charge of determining where the dioxins and PCBs came from, Deusen said.
The Texas Commission on Environmental Quality is scheduled in a few months to present a plan to the EPA on how it will clean up a 150-mile stretch of the river from Benbrook and Lake Worth to Cedar Creek Reservoir south of Corsicana.
At a February meeting in Arlington, commission staff members said the idea is be to prevent more PCBs from getting into the river and allowing the PCBs already in the sediment to break down over time.
"We must establish a plan to improve the quality of the water," said Ron Stein of the commission's Maximum Daily Load Program. "But it's a long process."
Also Wednesday, state officials lifted two orders that prohibited people from possessing fish from a smaller section of the Trinity River because of high levels of the pesticide chlordane, which was banned by the EPA in 1988.
The ban had applied to a one-mile stretch in the Clear Fork of the Trinity near West Seventh Street, and the West Fork of the Trinity below Lake Worth, according to a March report by the commission.
Chlordane levels are no longer a health concern., the advisory said.
The new fish consumption advisory, however, applies to those stretches.
DOMINGO RAMIREZ JR., 817-390-7763