Washington ? Concentrations of a flame retardant banned by many European countries have been found in Lake Michigan and are increasing, adding to concerns over previous findings that the chemicals were showing up in supermarket foods and women’s breast milk.

In the latest study, sponsored by the National Oceanic and Atmospheric Administration, University of Wisconsin scientists found PBDEs, or polybrominated diphenyl ethers, in sediment hundreds of feet down in Lake Michigan.

Fish and other animals absorb chemicals and pollutants through the environment, storing them in fat that people then eat. Studies in rats and mice suggest high levels can cause liver and thyroid damage, NOAA said.

“They’re really showing up all over the world,” Bill Sonzogni, a University of Wisconsin professor, said Wednesday. “And the Great Lakes — because of the food chain for bioconcentrating contaminants — has sometimes served as a sentinel for other parts of the world.”

The three-year study found PBDEs of up to one part per billion in the lake sediment — the equivalent of one drop of water in a 10,000 gallon swimming pool. By dating the samples of PBDEs, Sonzogni and scientist Jon Manchester also found that the concentrations were increasing, and that they mirror levels of PBDEs and other flame retardants used since the 1970s.

How the PBDEs and other chemicals get into Lake Michigan is still not entirely clear, but the air appears the mostly likely way.

PBDEs are added to plastics used in computers, televisions, furniture and carpets. Some computer makers stopped using PBDEs in 2002, but a flame retardant related to PBDEs is still used in some circuit boards.

No direct correlation has been shown between PBDEs and specific diseases or developmental impairment, and the government has not set any level of use that is considered safe in food.

Starting in 2008, California will become the first state to ban two forms of the PBDEs because they accumulate in the blood of mothers and nursing babies. The ban was approved last year but delayed to give manufacturers time to find alternatives.

The European Union moved to restrict the chemicals’ use in February 2003. In the United States, the Bush administration has expressed concern that traces of the chemicals, part of a broader class known as brominated flame retardants, have been showing up in people and wildlife.