Toxics persist in Washington rivers, lakes and fish

Toxic chemicals banned decades ago continue to linger in the environment and concentrate in the food chain, threatening people and the environment, according to three recent studies by the Washington state Department of Ecology. In one of the studies, state government scientists found unacceptable levels of toxic substances in 93 samples of freshwater fish collected from 45 sites. The toxic substances included polychlorinated biphenyls, PCBs; dioxins; two chlorinated pesticides, DDE and dieldrin; and brominated flame retardants known as poly-brominated diphenyl ethers, PBDEs. PCBs are a family of manufactured, chlorinated chemical compounds that were once used in products such as coolants and lubricants in transformers, capacitors, electrical equipment, old fluorescent lighting fixtures, and hydraulic oils. Commercial production of PCBs was stopped in 1977 because of concerns about toxicity and persistence in the environment. Earlier this year Washington became the first state in the nation to target all forms of PBDE flame retardants for elimination from the many common household products in which they are used. In 2004, a study of 40 mothers from Oregon, Washington, British Columbia, and Montana found PBDEs in the breast milk of every woman tested. Studies in animals show that PBDEs can affect the developing brain, altering behavior and learning after birth and into adulthood. Levels of PBDEs are rising in people worldwide, but are highest in North America. Children are at the most risk from these chemicals.