Study points to chemicals’ health threats

Theo Colburn

A new study that was a focus of the last several years of a late Paonia scientist’s life raises concerns about health threats of four related chemicals that are pervasive in homes and also associated with vehicle emissions and oil and gas development.

A paper published this week and authored by Theo Colborn and two other researchers with The Endocrine Disruption Exchange, or TEDX, found that “exposure to ambient levels of benzene, toluene, ethylbenzene and xylene (known together as BTEX) are linked to hormone-related health conditions in humans,” according to an announcement by the group.

The report was published in the peer-reviewed journal Environmental Science and Technology, and is based on a review of 42 existing studies. It found health effects from exposure levels commonly found indoors and outdoors in the United States, and deemed safe by the U.S. Environmental Protection Agency. The researchers say that due to the danger of even low-level exposure, the government needs to establish more protective air standards. It also should require air monitoring near oil and gas facilities and enforce adequate pollution limits, particularly as such development increasingly occurs in neighborhoods, the researchers say.

TEDX researchers Ashley Bolden and Carol Kwiatkowski joined Colborn in publishing the paper. Colborn died in December at the age of 87. She founded the Paonia-based TEDX, which focuses on possible health and environmental harms of chemicals that interfere with hormones important in the development of people and wildlife. She pioneered research into the issue, and co-authored “Our Stolen Future,” a widely lauded book on the subject.

“We’ve been working on this paper for years. She would say many times, if we could just get the BTEX paper out before she died, she’d be happy. We didn’t exactly pull it off but she knew we were close,” Kwiatkowski said.

The study says health effects from the chemicals, acting individually or in combination, “include sperm abnormalities, reduced fetal growth, low birth weight, cardiovascular disease, respiratory dysfunction, asthma, sensitization to common antigens, and more. Two-thirds of the 42 studies found effects in children, some of whom were exposed prenatally, when effects can be permanent.”

It says such effects might result from disruption of hormones such as estrogens, androgens, insulin and serotonin.

BTEX chemicals are frequently found together, and are a product of oil and gas development. Among their uses are as gasoline additives, and as solvents in consumer and industrial products.

Vehicle exhaust from combustion is a well-known major source of BTEX air pollution, and BTEX has drawn increasing attention recently as a pollutant related to oil and gas development as domestic drilling has boomed.

But Kwiatkowski said a big concern identified by the study is that BTEX levels in the air indoors tend to be much higher than levels outdoors. This is a result of the release of gases from household products. BTEX chemicals can be found in furniture, computers, paint, carpeting, toys and many other consumer products.

TEDX researchers are calling for more research to determine the biggest sources of indoor exposure so they can be reduced or eliminated.

“We don’t know, but definitely something is creating these higher levels,” Kwiatkowski said.

The researchers would like to see the development of safer substitutes for BTEX in household products.

Kwiatkowski said that ordinarily, one solution to reducing high BTEX levels in homes would be to open windows and let in fresh air.

“But if you live near gas wells or in a city with a lot of combustion-related pollution, then that might not be the best recommendation,” she said.

She said one reason TEDX got involved with issues surrounding oil and gas pollution was because of people living near drilling describing some of the same respiratory and other symptoms that are being linked to endocrine-disrupting chemicals.

She said it isn’t really known what level of BTEX emissions occurs from wells, which is why monitoring at pads is important.

An ongoing study led by Colorado State University and funded by Garfield County and energy companies is aimed at helping shed light on such questions. Researchers have been measuring emissions of air pollutants at natural gas development sites in the county and how they disperse up to a few hundred meters away. The researchers also are doing modeling to predict dispersions at greater distances.

Colorado’s Air Quality Control Commission last year passed landmark air emission standards for the oil and gas industry. While the rules made Colorado the first state to specifically target emissions of methane, a potent greenhouse gas, during oil and gas development, they also are expected to significantly reduce the associated emissions of volatile organic compounds including BTEX. The rules address things such as leak detection and repair, and replacement of high-bleed valves with low- or no-bleed valves.

“I think Colorado’s done an incredible job in terms of having really the strongest rules in the country to limit these (oil and gas) emissions,” said Mike Van Dyke, chief of environmental epidemiology for the Colorado Department of Public Health and Environment.

Teresa Coons, a scientist who is executive director of the John McConnell Math & Science Center in Grand Junction and served on the Air Quality Control Commission when the rules were passed, said the focus of those rules was reducing emissions of VOCs as ozone precursors, and methane as a greenhouse gas, and to comply with new national EPA regulations.

“The focus was not on these compounds as endocrine disrupters, but of course, reducing exposure in general should be helpful for any potential health effects. Full implementation of the new … rules should greatly reduce the percentage of VOCs in ambient air that can be attributed to oil and gas operations,” she said.

Cathy Milbourn, an EPA spokeswoman, said the agency will review the TEDX study “and incorporate the findings into our work as appropriate.

“EPA is screening thousands of chemicals for potential risk of endocrine disruption. As potential risk of endocrine disruption is identified, these chemicals are assessed further. In addition, EPA will consult the latest information on health effects assessments in determining remaining risks from sources emitting these pollutants.”

Kathryn St. John, a spokesperson for the American Chemistry Council, said the industry supports the EPA’s Endocrine Disruptor Screening Program and has made recommendations on how to make it sound and science-based.

She added, “Many things can impact the endocrine system — stress, food, exercise, pollution. ACC is engaged with the scientific community and regulatory agencies to enhance the scientific understanding of chemicals that may interact with the endocrine system and to promote sound decisions to effectively manage risks that may exist from exposure to them.”

Van Dyke said endocrine disruption is a concern in the case of BTEX “as well as a lot of other chemicals not related to oil and gas.”

Indeed, TEDX has helped focus attention on endocrine-disruption concerns surrounding BPA, or bisphenol A, in water bottles, toys, consumer electronics and other products. And in a recent paper, Bolden and another TEDX researcher said some substitutes for BPA appear to have the same endocrine-disrupting effects.

Van Dyke said TEDX’s new literature review on BTEX “does a nice job of bringing together a lot of information” and summarizing findings to date, and advancing the science a little “in order to understand these issues better.”

Van Dyke said there hasn’t been enough research on endocrine disruptors, so it’s difficult to set regulations related to them.

“A lot of these things are just not that well understood yet,” he said.

He said the research is challenging in part because it “depends on exposures in short periods of time.”

“The human body’s a complex process, and by disrupting one thing it’s hard to predict what’s going to happen in another,” he said.

“The complexity of endocrine disruption makes it really difficult to study and to make huge advancements. It has to be a step at a time.”

Coons said she’s not an expert in the area of endocrine disruptions, but BTEX has been associated with a number of other human health effects — particularly benzene, which is considered a carcinogen.

“Dose is always the issue with the relationship between exposure to potentially toxic chemicals and health outcomes — thus the EPA’s action levels. It would appear from the research quoted, however, that lower limits for exposure to BTEX chemicals may be warranted,” she said.


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