Corsicana — People shouldn’t eat fish caught in the Trinity River as far north as Fort Worth and as far south as Anderson and Freestone counties, state officials said Wednesday. That stretch of the river includes Ellis and Navarro counties.

All species of fish in that section of the river contain dangerous levels of dioxins and polychlorinated byphenyls, or PCBs.

“This is not new. This is something we’ve been watching for a while,” said Chris Van Deusen spokesman for the Texas Department of State Health Services. “There have been advisories dating back to the 1990s for portions of it. Some of the river along Navarro has been under a similar advisory since 2002. This extends it a bit farther downstream into Freestone County.”

Dioxins are byproducts of combustion and industry, while PCBs are industrial chemicals once used as coolants and lubricants, but which were banned in 1979. Long-term consumption of these chemicals can cause cancer and problems with the liver, immune system and reproductive systems, according to the health department.

Officials with the Texas Commission on Environmental Quality said they couldn’t say where the pollutants were coming from, except that it is coming in during stormwater events.

The state has developed a Total Maximum Daily Load for various chemicals and done a study of how much can be put into the river without affecting fish tissues, explained Ron Stein, TMDL program manager for the TCEQ.

“That document has been developed and early next fall we will take the document to the commissioners to be adopted,” Stein said.

After that, the document will be sent to the U.S. Environmental Protection Agency for approval, then to the North Texas Council of Governments, which will be asked to develop a plan to “improve the loads going into the water body,” Stein explained.

He said he couldn’t say where the PCBs or dioxins are originating, but that PCBs can hang around for a while.

“Those have been banned for quite a long time, but they’re very persistent in the environment. If they’re in the watershed then rainfall will tend to wash them off at a low level. We do see loads from stormwater runoff,” Stein said. “We can tell it’s coming in from stormwater. There may be other sources.”

PCBs are what are referred to as “legacy contamination,” according to Lisa Wheeler, spokeswoman for the TCEQ.

“PCBs were used for over 50 years, up until the EPA banned the use in 1979 — meaning we are not likely to ever find a single source for the elevated PCB levels in the Trinity,” Wheeler said.

Pollution in the Trinity has been a problem since the massive growth of the Dallas-Fort Worth area, according to a paper produced by the U.S. Department of the Interior’s U.S. Geological Survey in 2005.

“In 1925, the Trinity River in the Dallas-Fort Worth area was characterized by the Texas Department of Health as a ‘mythological river of death.’ With a rapid expansion of industry and population and only primary wastewater treatment beginning in the late 1920s and secondary treatment in the mid-1930s, water-quality conditions in the area were poor. They did not substantially improve until State and Federal pollution control laws, like the Federal Clean Water Act of 1972, stimulated efforts to address degraded water-quality conditions. The Upper Trinity River Basin Comprehensive Sewage Plan of 1971 resulted in the construction of large, regional wastewater-treatment plants, elimination of many small, industrial and municipal wastewater-treatment plants, and the upgrading of existing wastewater-treatment plants,” the report states.

The 2010 Trinity River Authority Master Plan echoes the assessment, and points to a number of sources, including wastewater treatment, industry, and farming.

“Toxics – Toxic substances are receiving increased attention in the Trinity Basin, especially in the upper main stem,” the master plan states. “Throughout the Trinity Basin, wastewater discharges, urban runoff, and agricultural runoff have been identified as potential contributors of toxics. Diazinon has been identified as causing biomonitoring compliance problems in wastewater effluents. Measured levels of chlordane in fish tissue have caused fishing bans to be imposed in several urban segments.”

The sources are sometimes measured, and sometimes not measured. In 2009, the environmental advocate group Environment Texas added up the allowed and reported industrial and municipal discharges into state waterways.

“We found 657 pounds of discharges into the Trinity, which made it one of the top third waterways in Texas for toxic pollution,” said Luke Metzger, director of Environment Texas. “Maybe 657 pounds doesn’t seem like a lot, but dioxin is one of the world’s most dangerous poisons and is very harmful at very small levels. Just a few teaspoons can wreak havoc on the environment and human health.”

The state’s environmental agency, TCEQ, doesn’t have a maximum load level for dioxins, Wheeler said.

“This is the first time that dioxins have been mentioned in a health advisory for the Trinity, so we just haven't done any sampling yet,” she said. “We expect to conduct a TMDL for dioxin in the future.”

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Janet Jacobs may be reached via e-mail at jacobs@corsicanadailysun.com. Want to “Soundoff” on this story? E-mail: soundoff@corsicanadailysun.com