PBDEs SSC: Catfish Flambé

You don't cook your catfish with a blowtorch, so would you expect it to contain fire retardants? Yet sometimes it can. In the first U.S. market-basket study of fire retardants in foods, published in the September 2004 Environmental Science & Technology, catfish and salmon topped of the list. The chemicals also showed up in duck, hot dogs and other animal products bought from three Dallas supermarket chains. Used in computers, foam cushions, mattresses and electronics, the fire retardants, called polybrominated diphenyl ethers (PBDEs), have been linked to neurological, reproductive and thyroid damage in animals. Although it involved a very small sampling, Dr. Linda Birnbaum, director of the EPA's experimental toxicology division and study coauthor, says the study is a "heads up call" and notes that "the importance of this paper is that it says these chemicals are in foods, they are in foods of animal origin and they are in higher fat foods."

As to how the PBDEs are getting into food, "We really don't know," Dr. Birnbaum says, but she adds that scientists suspect that PBDEs leach into the air from products and factories, then cycle with rain back into rivers, contaminating fish and wildlife. In San Francisco Bay, the fish-eating Forester's tern has the highest PBDE levels measured in any wildlife, 63 parts per million (ppm) compared with about 1 ppm for the most contaminated human breast-milk samples. PBDE levels are increasing in the breast milk of North American women, approaching amounts shown to harm rats and mice.

The news isn't great for fish-loving humans either: One of the three salmon fillets tested had PBDE levels more than twice as high (3,078 parts per trillion [ppt] or .003 ppm) as those in the worst meats: pork sausage and wieners (1,373 and 1,333 ppt). If these numbers seem small, remember that once PBDEs are in your body fat they stay there, adding up over a lifetime. Like dioxins and other so-called bioaccumulative toxins, they adhere to fats, concentrating in humans and animals at the top of the food chain who eat contaminated animals and plants.

Unfortunately, Dr. Arnold Schecter, study author and professor at the University of Texas Health Science Center, says the study was too small—with only three samples of salmon, two of catfish and one each of shrimp, tilapia, shark and rainbow trout—to determine if farmed fish PBDE levels differ from those of wild fish, but he plans to pursue this in further research. However, tilapia, a farmed fish, showed very low PBDE levels (8.5 ppt), less than pork (41 ppt), evaporated milk (29 ppt) and even soy formula (16.9 ppt). This last item was a real surprise to the authors, who suggest factory contamination as the source.

What to do? Rather than worry too much about exposure to PBDEs in food, "The bottom line is, people should eat a healthy heart diet, and if you do you'll reduce your exposure to a lot of unhealthy chemicals," Birnbaum advises.

What You Can Do

* Eat a diet high in vegetables, fruit and whole grains.

* Broil, or cut fats from, meat and fish.

* Eat leaner meats and less high-fat dairy foods like cheese, butter and ice cream.

* Drink skim milk: it's PBDE- and dioxin-free.

* Select PBDE-free foam furniture, available from IKEA, mattresses and futons (see "PBDE Fire Retardants and Health Threats" at www.thegreenguide.com/doc.mhtml?i=97&s=pbde. Among computer manufacturers, Sony does not use PBDEs, and Apple, Panasonic and NEC all have reduced PBDEs.

Resources

Download The Green Guide's PBDE Smart Shoppers wallet card (see sidebar).

"How Can I Get the PBDEs Out of My Sofa?" www.thegreenguide.com/doc.mhtml?i=ask&s=pbdes

"PBDE Fire Retardants and Health Threats," www.thegreenguide.com/doc.mhtml?i=97&s=pbde