OSAKA — High concentrations of a chemical compound widely used as a flame retardant have been detected in mother’s milk and marine life in Japan, according to a study announced this week by Japanese researchers.

The levels of polybrominated diphenyl ethers (PBDE) were far higher than anticipated by the team of scientists at Setsunan University in Hirakata, Osaka Prefecture, according to Soichi Ota, an associate professor and the study’s lead researcher.

The team will report its findings today at a conference in Sapporo.

If burned incompletely, PBDE generates polybrominated dibenzo-p-dioxin, a substance similar to dioxin in structure and toxicity. Dioxin is a known carcinogen and endocrine-disruptor. Studies have shown that levels of the compound are rising in the environment.

Setsunan researchers measured levels of PBDE in the milk of six women, Ota said, and measured levels of the compound in four kinds of fish and shellfish.

The study showed that fish and shellfish found closer to shore contained higher concentrations of PBDE.

Yellowtail and salmon contained 1,190 picograms and 734 picograms of PBDE per gram, respectively, while a yellowfin tuna, which inhabits the deep sea, had 21.5 picograms. One picogram is a trillionth of a gram.

The study also found the average concentration of PBDE was higher in the milk of women who consume a large amount of fish.

Milk from four of the women, who eat fish on more than three days a week, was found to contain between 1,160 picograms and 1,480 picograms of PBDE per gram of fat. Milk from the two other women, who eat less fish, had levels of 766 picograms and 655 picograms each.

Previous studies showed the average concentration of dioxin in fish and shellfish as 1.2 picograms per gram and 33 picograms per gram in mother’s milk.

“There is no regulation on PBDEs, although manufacturers produce 50,000 tons of it a year as flame retardants,” Ota said.