Tainted Chinook Found in Wildby Lisa Stiffler
Fish testing shows wide spread of chemicals used as fire retardant
The king of fish -- wild chinook salmon -- is turning up tainted with industrial-strength fire-retardant chemicals in the Pacific Northwest, showing just how far the compounds have spread in the environment.
Wild chinook tested in Oregon and British Columbia had levels of the chemicals -- polybrominated diphenyl ethers, or PBDEs -- that were as high or higher than farmed salmon, according to a global study released today.
The research was the latest blow to the good-for-your-body reputation of salmon, which is packed with heart-healthy omega-3 fatty acids. A prior study by the same researchers recently found troubling levels of PCBs, a known carcinogen, in farm-raised salmon.
Although PCBs, or polychlorinated biphenyls, have been banned for decades, their chemical cousin, PBDEs, are still in production around the world. Bans in Europe, California and Maine will kick in over the next few years, and U.S. manufacturers voluntarily are stopping production of some forms of the fire retardant.
For now, though, PBDEs are still being added to a long list of common household and workplace items -- from computers and other electronic gear to foam seat cushions and synthetic fabrics.
And evidence is mounting that the chemicals in the products are being released into the environment at an alarming rate.
The toxicity of PBDEs isn't fully understood, but the fish-contamination study concerns health officials and environmentalists.
"The bottom line here is pointing out ... we have a problem with PBDEs," said Rob Duff, director of the Washington Health Department's Office of Environmental Health Assessment. "They're rising in the environment. The levels are getting up there."
PBDEs can harm neurological development and function in babies and young children -- just like mercury and PCBs, Duff said.
Besides chinook, other locally caught wild salmon -- coho, chum, sockeye and pink -- generally had lower levels of the fire retardant than their farmed counterparts, according to the study.
Among the farm-raised salmon tested, Washington fish were the least contaminated, with concentrations of the chemicals at slightly more than 1 part per billion. That's lower than the same fish tested in Europe, Canada, the East Coast and Chile. The highest levels were in Scotland, where the fish tested at almost 4 ppb.
On average, wild fish were less contaminated, with two exceptions: chinook from Oregon and British Columbia, which tested at more than 2 ppb and 4 ppb, respectively.
It's unclear exactly how the PBDEs leach out of products, but they've have been turning up in everything from household dust to women's breast milk.
"Add this study to the mounting evidence that shows the PBDEs are in the environment and moving up the food chain," said Ivy Sager-Rosenthal of People for Puget Sound, an environmental group.
The results being published today in the Environmental Science and Technology journal come from a continued analysis of the 2 tons of fish examined in the PCB study.
In both studies, the scientists generally found that farmed fish were more contaminated than wild fish. But the fact that the local chinook were as contaminated with PBDEs as the farmed variety "was a real surprise to us," said the study's lead author, Ronald Hites, a professor at Indiana University.
Studies of Puget Sound chinook and coho also have shown levels of PCBs on par with farmed fish.
Besides Hites, the study involved researchers from Cornell University, the University at Albany, the Midwest Center for Environmental Science and Public Policy and AXYS Analytical Services.
The source of PBDE contamination is likely the salmon's food. Farmed fish eat a fish meal made from ground-up smaller fish, and chinook also eat smaller fish. The other salmon species generally eat lower on the food chain, feeding on jellyfish and plankton. Pollutants such as PBDEs, PCBs and mercury tend to build up in animals, concentrating in organisms higher on the food chain, such as orcas and people.
Unlike other pollutants, there are no dietary recommendations restricting how much PBDE is safe for people to eat.
Health authorities and scientists urged people to continue eating fish, which is a good source of protein and Omega-3 fatty acids.
PBDEs and PCBs concentrate in the fatty tissue of the fish, so removing the skin and using cooking methods that allow fat to drip off can reduce exposure.
People can follow state and federal dietary recommendations based on mercury and PCB contamination in fish and generally will be protected from the harmful effects of fire-retardant chemicals, Duff said.
European countries already have banned two of the main forms of PBDEs, and U.S. manufacturers have promised to take them off the market by the end of this year. That leaves one form -- deca PBDE -- still in production.
The forms of fire retardants most frequently found in salmon were the ones slated for phase-out, said Peter O'Toole, spokesman for the Bromine Science and Environmental Forum, an organization representing chemical manufacturers.
"The logical projection is the levels will decrease over time."
Research on laboratory animals has shown that PBDEs can disrupt thyroid hormones, which can affect the developing brain and have other harmful effects. Newborn mice exposed to PBDEs have learning and motor-skill problems. At least one form of the chemical is known to be carcinogenic.
It appears that the flame retardants naturally and gradually leave the human body over time.
Next month, the state Ecology Department plans to release a draft version of a plan to reduce PBDEs. Public comment will be accepted for 30 days after that.
"These things shouldn't be out in the environment when we don't know what their effects are," Sager-Rosenthal said.
Problem Fire Retardant
Widely used fire-retardant chemicals known as polybrominated diphenyl ethers, or PBDEs, have been found in the breast milk of American women, raising health concerns.
Uses -- PBDEs are used in furniture cushions, car seats, fabrics, computers, stereos and other products.
Human exposure -- Scientists are still figuring this out, but the most likely exposure is through dust from the products or by consuming contaminated food.
Health effects -- High levels of PBDEs have been shown to cause cognitive impairment, memory loss and even brain damage in lab animals.
Phaseouts -- Some American manufacturers are voluntarily phasing out use of the two most dangerous types of PBDEs -- penta and octa -- by 2005; European Union ban takes effect this year, California's in 2008.
Source: Extension Toxicology Network
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