12 March 2003
chemical found in women's breasts
Bay Area levels higher than Europe, Japan
Kay, Chronicle Environment Writer
Area women have three to 10 times greater amounts of a chemical
flame retardant in their breasts than either European or Japanese
women, says a study by California scientists published Tuesday.
or polybrominated diphenyl ethers, are persistent organic pollutants
that have been increasing worldwide in humans and wildlife over
the last 10 years. The levels found in San Francisco Bay harbor
seals are among the highest in the world.
tissue and blood from 82 women examined at Bay Area hospitals in
two studies in the late 1990s showed that they had levels higher
than those found in Europe and Japan. There were no PBDEs in 420
archived samples collected in the 1960s, according to the study,
which was released online in the Environmental Health Perspectives
journal published by the U.S. Department of Health and Human Services.
are a family of flame retardants used in polyurethane foam, textiles
and plastic electronic casings. Laboratory studies have shown that
the flame retardants mimic hormones and disrupt the endocrine system.
They interfere with the thyroid gland and delay neurological development
in the lab animals.
form used in foam seems to be the one appearing in the breast tissue.
But scientists can't say how people are exposed, said Myrto Petreas,
lead author and a section chief with the Hazardous Materials Lab
in the state Department of Toxic Substances Control.
pesticides, dioxins and PCBs, we believe that more than 90 percent
of the exposure is through the diet," Petreas said. "In
this case, with PBDEs, we speculate that one of the main pathways
is from inhalation in dust from consumer products treated with PBDEs."
study authors are associated with the Public Health Institute in
Berkeley, the state Department of Health Services, UC Davis and
the San Francisco Department of Public Health.
new studies raise questions whether the chemicals are contributing
to higher than expected breast cancer rates in the Bay Area, particularly
don't know," said Dr. Gina Solomon, a physician and senior
scientist at the Natural Resources Defense Council in San Francisco.
"The furthest we can go is to say that these chemicals need
to be looked at carefully to see if they cause cancer in humans.
They haven't even been looked at."
government's National Toxicology Program is expected to release
the results of animal studies within the coming year on cancer effects
PBDEs, Solomon said, are "the new PCBs" -- the banned
chemicals once used as insulators in transformers, capacitors and
hydraulic equipment that persist years later in the environment.
we don't do something now," Solomon said, "these chemicals
will become our grandchildren's nightmare."
week, Solomon and representatives of the WaterKeepers of Northern
California asked the U.S. Environmental Protection Agency offices
in San Francisco to designate the PBDEs as impairing the bay. Such
a designation would trigger stricter regulatory measures.
year, the San Francisco Bay Regional Water Quality Control Board
stopped short of the designation and instead placed PBDEs on a "watch
Taberski, a senior environmental scientist at the regional board,
said the agency was very concerned about the pollutants.
is a big deal because these compounds are similar in structure and,
we believe, toxicity to PCBs and dioxins," Taberski said. "They're
increasing at a very quick rate in the environment. We've also found
some of the highest levels in the world of PBDEs in marine mammals
in the San Francisco Bay."
1989 to 1999, the quantity of PBDEs found in samples from 11 dead
harbor seals stranded along the bay's shoreline increased by nearly
a hundredfold, implying a doubling of concentration every 1.8 years.
The San Francisco regional monitoring program is also finding PBDEs
in white croaker and other fatty fish.
a mystery how they're getting into breast tissue and into marine
mammals," said Taberski. "We're trying to look into the
regional sources and the pathways of exposure."