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Cancer Causing & Hormone Disrupting Chemicals Found in Most U.S.Homes

ENDOCRINE DISRUPTERS FOUND EVERYWHERE IN HOMES

By Kellyn Betts, Environmental Science & Technology, Sept. 22, 2003

The air and dust inside U.S. homes are likely to contain a wide
variety of chemicals and pesticides that have been identified as
endocrine-disrupting compounds, according to research posted to ES&T's
Research ASAP website this week.The most comprehensive analysis
conducted to date, it reveals that many people may be continually
exposed to dangerous levels of toxic substances, including chemicals
like DDT and PCBs, which have been banned for decades.

This study, together with other data, shows that U.S. families may
have "very widespread exposures" to chemicals that could affect the
health of everyone from infants to senior citizens, warns Mary Wolff,
of Mount Sinai School of Medicine in New York City. Currently, the
U.S. EPA has no regulatory authority over indoor air or endocrine-
disrupting chemicals.

The study was led by Ruthann Rudel of the Silent Spring Institute, a
nonprofit organization based in Boston, Mass., as part of its ongoing
Cape Cod Breast Cancer and Environment Study. The group measured
concentrations of 89 suspected endocrine disrupters in air and dust
samples taken from 120 homes on Massachusetts' Cape Cod peninsula,
where the state's Bureau of Environmental Health Assessment has
documented elevated incidences of breast, colorectal, lung, and
prostate cancers.

The researchers found bis(2-ethylhexyl) phthalate (DEHP), which is
"reasonably anticipated to be a human carcinogen", according to the
National Institutes of Health, in the dust of every home tested, at
concentrations ranging from 16.7 to 7700 micrograms per gram
(micrograms/g). DEHP is used in a wide variety of flexible poly(vinyl
chloride) products, including children's toys, shower curtains,
raincoats, shoes, and floor tiles. The concentrations of DEHP in the
dust of most of the tested homes exceeded EPA's risk-based safety
guidelines of 35 micrograms/g for residential soil, which are based on
the compound's carcinogenicity. There is scientific debate over
whether DEHP is a human carcinogen, but the levels in some households
also exceeded EPA's guidelines of 1240 micrograms/g to protect against
reproductive toxicity, Rudel says.

The study also contains the first reports of residential
concentrations for 30 of the measured compounds, including 4-
nonylphenol, an alkylphenol that can act like female estrogen
hormones, and its ethyoxylates. Nonylphenol or nonylphenol ethoxylates
are found in some laundry detergents, disinfecting cleaners, all-
purpose cleaners, spot removers, hair-coloring and other hair-care
products, and spermicides. The researchers found 4-nonylphenol to be
one of the most abundant chemicals in the air of the sampled homes. It
was discovered in every tested home at concentrations ranging from 21
to 420 nanograms per cubic meter of air (ng/m3).

The European Union (EU) Parliament has approved a directive that
would restrict the use of 4-nonylphenol, but no EPA safety guidelines
have been set for human exposure for it or any chemicals based on
their endocrine activity.

"Finding the alkylphenols in air was a bit of a surprise because EPA
and some documents from the manufacturers had suggested that you
wouldn't expect it to volatilize at all," Rudel says. She adds that
this is just one example raised by the study showing that reliance on
using manufacturers' claims by EPA and the U.S. Food and Drug
Administration can be problematic. Wolff points out that "air
pollutants don't have to be volatile" because they can be adsorbed
onto particles.

People have a limited exposure to nonylphenols through the use of
products, and the daily intake is thought to be very low, according to
the Alkylphenols and Ethoxylates Research Council, an industry group.
Rudel says that the findings show that the compound's potential for
inhalation toxicity merits further investigation.

The researchers also documented the presence of some long-banned
substances in the tested samples, including PCBs and the pesticides
dieldrin, chlordane, and DDT, at levels that exceed federal risk-based
safety guidelines.

4-4' DDT was one of the most abundant pesticides in the tested
household dust. The scientists detected it in 65% of the homes at
concentrations of up to 9.61 micrograms/g. Although they also detected
some of DDT's breakdown products, most of the chemical was in the form
of DDT. "Since [DDT] really hasn't been used in 30 years, it means
it's really not breaking down indoors," Rudel says.

The results could help explain why the Centers for Disease Control
(CDC) has reported that DDT's breakdown product, DDE, is present in
the bodies of youth aged 12-19 who were born after the United States
banned the pesticide.

Another chemical measured for the first time in the study is 2,3-
dibromo-1-propanol, a mutagenic and carcinogenic chemical that was
found as an impurity in the TRIS flame retardant, which was banned in
the late 1970s. Rudel is currently trying to solve the mystery of why
the research team detected the chemical in the air of 9% and in the
dust of 6% of the tested homes.

Other banned pesticides frequently detected in the homes included
heptachlor (found in the air of 44% of the tested homes),
pentachlorophenol (detected in the dust of 86% and the air of 58% of
the homes), methoxychlor (in the dust of 54% of the homes), -chlordane
(detected in 51% of the tested air in the homes), -chlordane (found in
the air of 53% of the tested homes), and chlorpyrifos (found in the
air of 38% and the dust of 18% of the homes). All of these banned
pesticides were detected in some of the homes at levels that exceed
EPA's risk-based safety guidelines.

The Silent Spring team's finding of high levels of the recently
banned chlorpyrifos in some homes could also provide explanatory
fodder for why CDC found that levels of this pesticide are higher in
children aged 6-11 than in the rest of the population.

Although the presence of these compounds in the tested homes should
set off alarm bells, Rudel stresses that the risk presented by
exposure to the compounds could be much higher. EPA has developed
toxicity guidelines for only 12 of the tested compounds, and the
agency does not yet consider the impacts of exposure to mixtures of
chemicals, she says. The agency does not regulate indoor air.

On average, the dust in the tested homes contained 26 different
compounds and the air contained 19 different compounds. In a high
proportion of the homes, the concentrations of at least one of
compounds exceeded risk-based guidelines for safety developed by EPA,
Rudel says.

Although the researchers took samples from the homes of breast cancer
survivors and healthy women, they cannot make associations between
cancer incidence and the levels of chemicals in the homes they studied
because the sample size is too small and the samples were collected
many years after the women were diagnosed. On the basis of values
recorded in other U.S. studies, the researchers say that the levels
they measured in Cape Cod are not significantly higher than elsewhere
in the country.

Home contaminants are important contributors to people's overall
exposure and health effects because studies show that people in the
United States spend 65% of their time in their residences, according
to John Spengler of the Harvard School of Public Health, a paper
coauthor. This figure holds true for most other industrialized
countries, he says.

The Silent Spring researchers focused their efforts on looking for
chemicals that are produced in high volumes in the United States and
have been identified as endocrine disrupters in either whole-animal or
cell-based tests. The pesticides measured in the study are regulated
by the federal government, as are some of the toxic compounds, while
others are candidates.

The study contains what Rudel believes to be the first report of the
levels of the polybrominated diphenyl ether (PBDE) flame retardants in
U.S. household dust. It shows that the levels of PBDEs in household
dust are 10% higher than the levels in Europe and higher than the
levels of PCBs in dust in U.S. homes. "We know that levels of PCBs are
going down, and the PBDE flame retardants are still being made and
their levels of usage are increasing," Rudel says.

Linda Birnbaum, director of the Experimental Toxicology Division of
EPA's National Health and Environmental Effects Research Laboratory,
agrees that this finding is important. Three new animal studies show
that BDE-99 - the PBDE congener found in most abundance in household
dust, according to the study - can have neurotoxic effects and that
embryonic exposures can impair sexual development in addition to
causing thyroid toxicity, Birnbaum adds.

The presence of contaminants like PBDEs and phthalates in household
dust has significant health implications, Spengler says. Many studies

of dust have focused on what crawling babies and children are exposed
to, but he argues that everyone comes into contact with household
dust. "Carpets are very effective at re-suspending materials," he
explains.

Spengler's lab has conducted tracer measurement studies showing that
approximately 10 micrograms/m3 of dust is suspended back in air, on
average, from the dust that has settled. In this manner, dust can be
continually redistributed throughout a home, he says. Vacuuming also
re-suspends contaminants, says Rob Hale of the Virginia Institute of
Marine Science.

The movement of household dust takes on added significance given that
some of the toxic compounds measured in the study - particularly the
phthalates and alkylphenols, which were found in the air or dust of
every tested home - are present in high concentrations.

The Silent Spring findings also imply that people who buy used homes
can be unwittingly exposed to the pesticides and chemicals used by the
prior owners, Spengler says. "The real concern is, How does an
individual get informed about the concentrations in their own home?
It's not easy for an individual consumer to get these measurements
made - the laboratories that can make these measurements are few and
far between, and they're expensive measurements to make," he explains.

In addition to measuring the carcinogenic and teratogenic DEHP, the
Silent Spring researchers detected seven other phthalates, which are
suspected of harming male reproductive systems by interfering with
androgen function, in the homes they tested. As was the case with
previous studies, the phthalate levels were very high - orders of
magnitude higher than the levels of other contaminants (Environ. Sci.
Technol. 2001, 35, 235A). For example, the researchers found a median
value of 340 micrograms/g of DEHP in the dust they tested, while the
median values for all of the other measured chemicals were less than
10 micrograms/g, if they were above the detection limits.

The new phthalate data also raise some new questions. In the past,
most researchers doubted that inhalation was an important route of
exposure for phthalates, but the new measurements suggest that
inhalation may indeed be important, Rudel says. The phthalates that
the researchers found in most abundance in the air of the tested homes
- diethyl phthalate (DEP), which was present at a median level of 590
ng/m3, and di-n-butyl phthalate (DBP), which was present at levels
ranging from 52 to 1100 ng/m3 - are the same ones determined to be
most abundant in human urine by CDC for a cross-section of U.S.
adults.

When CDC's results were first published, they were a surprise because
they were not the phthalates that the National Toxicology Program had
predicted that people would be most exposed to, Rudel explains.
However, although DEP and DBP are not the phthalates used in greatest
quantities, they are used in many personal care products like perfume
and nail polish, she says. DBP is of particular concern because it is
known to be a reproductive toxin. Although the risk-based safety
guideline for DBP in air of 370 micrograms/m3 is significantly higher
than the values the Silent Spring researchers recorded, Rudel says
that the number is not based on the newest research.

"The phthalates and phenols are so widely used in commerce now that
we've got to be concerned about this component of the body burden,"
Spengler says, noting that other studies have shown that food and
water are also sources. Phthalates and alkylphenols are the chemicals
most urgently in need of further toxicity testing, agree Rudel and
Julie Brody, executive director of the Silent Spring Institute and a
paper co-author.

The study also points out the importance of considering the mixtures
of chemicals to which people are exposed in their homes, say Rudel,
Spengler, and Brody. The science of evaluating mixture toxicity is in
its infancy, but European studies have shown that endocrine-disrupting
chemicals can be evaluated as mixtures. Compounds that target the
estrogen receptor site share similar mechanisms of action, and
experiments show that the activity of mixtures of such compounds is
indeed additive, Wiebke Meyer of the University of Bremen in Germany
told attendees at a Society of Environmental Toxicology and Chemistry
meeting in his native country this past May.

However, Meyer's experiments, which are being conducted as part of
the European Commission's ACE project charged with "analyzing
combination effects of mixtures of estrogenic chemicals in marine and
freshwater organisms," are based on evaluations of aquatic toxicity.

"The need to assess mixture toxicity is recognized by most
environmental toxicologists, but the tools to do this, especially for
complex mixtures, are lacking or poorly developed," adds Paul Sibley,
an assistant professor at Canada's University of Guelph who is
interested in aquatic mixture toxicology.

The mixtures of endocrine-disrupting chemicals to which people are
exposed is likely to be more complex than what the Silent Spring study
indicates, the researchers stress. "We just happened to look for 89 of
these chemicals...but most chemicals that are actually in use haven't
been screened yet, so probably the true number of endocrine-active
chemicals that people are exposed to is much, much higher than the
number we came up with," Rudel says.

The finding that a few homes had significantly higher levels of each
chemical has significant implications for risk policy, Rudel says. For
example, a few homes had concentrations of DBP and DEHP, which both
have reproductive toxicity, that were far higher than in the other
tested homes. "We typically go chemical by chemical and say we're
protecting the 95th percentile person, and if you actually look at
these kinds of exposure data, there are a lot of people in the top 1-
2% of the concentration distribution that you're really not
protecting," Rudel says.

Rudel and Brody will consider themselves successful if their work
provides impetus for rethinking such policies and conducting more
toxicity tests. Although the reports on endocrine disruption by such
influential organizations as EPA, the Endocrine Disruptor Screening
and Testing Advisory Committee, and the National Academies, have
identified the need for exposure information to help prioritize which
substances should most urgently be evaluated, there are as yet very
little exposure data, Rudel explains. This new data, says Birnbaum,
give scientists a place to start.

Moreover, Brody adds, "Breast cancer research has really been
hindered by lack of adequate measurements of the pollutants that women
are exposed to that might be relevant to breast cancer, so this is
really a necessary first step."

The researchers are currently analyzing the relationships between the
levels of phthalates and pesticides in the air and dust of different
homes, and the amount of phthalates in the urine of the women living
in those homes. They are also trying to track down the sources of some
of the compounds measured in the study.

* * *

Copyright 2003 American Chemical Society

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