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New Study Finds Toxic Soup In Household Air & Dust
(Beyond Pesticides, October 16, 2003) In a comprehensive study of indoor toxins found in people's homes, researchers find varying and alarming levels of some of the most commonly used organic chemicals and pesticides containing endocrine-disruptor compounds - some of which have been banned for more than ten years.

On average, 26 different chemicals were found in the dust and 19 found in the air of sampled homes. In a majority of homes, at least one chemical was found to exceed EPA risk-based exposure guidelines, according to an article by Kellyn Betts, the Associate Editor of Environmental Science & Technology.

Of the pesticides found in high dust concentrations in more than 50% of the sampled homes were pentachlorophenol (penta) (86%), DDT (65%), permethrin (45-53%), 2,4-D (63%) and piperonyl butoxide (66%). Penta was also found in high air concentrations in 58% of the samples along with chlordane (51-53%), and o-phenylphenol (67-73%). According to Ms. Betts of Environmental Science & Technology, the high levels of chlorpyrifos found in homes (38% air, 18% dust) may explain the Center for Disease Control's findings that children aged 6-11 have higher exposure levels to the pesticide than the rest of the population.

The study, published in the September 2003 issue of Environmental Science & Technology, was conducted by a team of scientists led by Ruthann Rudel, a senior scientist in environmental toxicology at the Silent Spring Institute, on behalf of the Institute's breast cancer research funded by the Massachusetts Department of Public Health. The team analyzed 89 organic chemicals and pesticides in samples it collected from 120 Cape Cod homes where the Bureau of Environmental Health has reported elevated incidence of breast, colorectal, lung, and prostate cancers.

One of the most widely detected chemicals, diethyl hexyl phthalate (DEHP), was found in the dust of 100% of houses sampled at concentrations ranging from 16.7 to 7770 micrograms per gram (micrograms/g). The presence of DEHP was not surprising since it is used in common household vinyl plastics like linoleum floors, pipes, children's toys, raincoats and shower curtains. Yet, of these samples, says Ms. Betts, many exceeded the EPA's safety measure of 35 micrograms/g to protect against potential cancer risks, and 1240 micrograms/g to protect against reproductive problems.

"Chemicals identified as endocrine-disrupting compounds (EDCs) have widespread consumer uses," said the report. "Yet little is known about indoor exposure." The EPA does not monitor or collect data on indoor air. However, the recent findings do support similar studies done in the early 1990s that tested many of the same chemicals and resulted in similar findings. A 1990 peer-reviewed EPA study found that indoor concentrations were generally higher than outdoors and that high concentrations of the chemicals used in termiticides like chlordane were still detected long after the products had been banned. A 1991 EPA indoor pesticide study on children exposure showed that for newer and older homes alike, "residues of many pesticides are found in and around the home even when there has been no known use of them on the premises."

Chemicals and pesticides that contain endocrine disruptor compounds (EDCs) are highly toxic with potentially serious consequences of human exposure. EDCs are believed to block, mimic or generally confuse the normal activity of hormones that are essential for the healthy development and function of cells and tissues. EDCs have been associated with neurological, developmental and reproductive health problems including cancer, birth defects and immune disorders in both humans and animals. Although the EPA has extensive endocrine-related pesticide data and is slowly supposed to be "screening" chemicals (see Daily News), the agency claims that there "is not enough scientific data on most of the estimated 87,000 chemicals in commerce" to do a real evaluation of all the potential endocrine-related risks.

When asked why the report was finding many pesticides, like DDT, in homes even though they have been banned from residential use, research leader Rudel told Ms. Betts, "'Since [DDT] really hasn't been used in 30 years, it means it's really not breaking down indoors." Also likely, is that the chemicals in the environment that are mandated for non-residential use may simply drift through the window (if airborne), or be tracked into the house by the soles of shoes.

Researchers say that the levels of chemicals and pesticides detected in the Cape Cod homes are similar to levels reported throughout the country - especially for air concentrations, regardless of the high rates of cancer in the area.

The report concluded with a discussion that underscored the need for further studies. Indoor toxicity studies are seriously lacking, even though according to the report, "People spend a large fraction of their time indoors, and indoor sources of chemicals, coupled with limited ventilation and slow chemical degradation processes, cause increased pollutant concentrations." Toxicity levels and risk evaluations pertaining to the endocrine system are also limited, particularly since EPA guidelines do not consider endocrine-effects, and scientific and analytical data of all sorts is missing to determine the risk of exposure to combinations or mixtures of various toxic chemicals (which the report found in nearly every household sampled).

For these reasons, the study notes its somewhat limited usefulness right now in making overall connections between chemical exposure levels and cancer or other health problem rates, but notes its usefulness as a groundbreaking beginning.

The report can be purchased from Environmental Science & Technology

For more information on endocrine-distruptors and their effects, see Arsenic is an Endocrine Disruptor, Chemicals Found to Affect Male Reproductive System in New Way, Breast Cancer and Pesticide Link, and Photostory: Recycled Utility Poles and Railroad Ties