Flame-retardant chemicals that have been linked to reproductive and neurological problems in animals have seeped into coastal environments even in remote regions and have been found in high concentrations off populated areas such as Chicago and Southern California, a federal study revealed Tuesday.
"This is a wake-up call for Americans concerned about the health of our coastal waters and their personal health," said John H. Dunnigan, assistant administrator of the National Ocean Service, a branch of the National Oceanic and Atmospheric Administration, which released the report.
The study, part of the Mussel Watch Program, was the most comprehensive look at the nationwide presence of chemicals called polybrominated diphenyl ethers, used in a variety of commercial goods since the 1970s as a fire retardant.
High levels of the chemicals were found in sediment and shellfish samples in areas including the Pacific Northwest's Puget Sound; the Tampa-St. Petersburg, Fla., coast; New York's Hudson-Raritan Estuary; Lake Michigan off Milwaukee, Chicago and Gary, Ind.; and off remote shores in Alaska. The highest concentrations were near industrial centers.
The new report builds on a 1996 study that reported levels of the chemicals in limited areas.
The chemicals are credited with saving hundreds of lives each year from the spread of fire, federal scientists said Tuesday in announcing the study's results. But studies on animals have shown that flame retardants can cause thyroid hormone disruption and interfere with developing reproductive and nervous systems.
The chemicals enter the environment through runoff, improper disposal of household and electronic waste, and through sewage sludge. The chemicals also appear to be airborne.
"Action is needed to reduce the threats posed to aquatic resources and human health," Dunnigan said.
Production of the chemicals has been banned in several European and Asian countries. Eleven states in the U.S. have banned certain chemical combinations, and some manufacturers have instituted a voluntary ban. The chemicals are among those targeted in California's green chemistry initiative, which would replace substances thought to pose a health hazard to humans.
Steve Weisberg, executive director of the Southern California Coastal Water Research Project, hailed the federal study for helping to frame the issue of public health and "emerging contaminants."
Weisberg's agency, a joint-powers arrangement among 14 public agencies involved with water issues, has a partnership with the NOAA to study the chemicals' effect on mammals. The concern among scientists is that the chemicals may have reached the food chain in large quantities.
Preliminary studies suggest that pregnant women and their fetuses may be particularly susceptible to damage. The chemicals have been found in breast milk. But federal scientists have yet to determine at what level the chemicals pose a health threat.
Last year, a research team that included scientists from UC Berkeley found that Californians have more of the chemicals in their blood and in their homes than any other group in the country.
Levels in children exceeded those in their mothers, the study found.
High levels have also been found in the eggs of urban peregrine falcons near Los Angeles, Long Beach and San Francisco, according to a study released last year.