Can blood tests show the impacts of gas and oil drilling? That’s a question one Colorado doctor hopes to answer. Dr. John Hughes, of Aspen Integrative Medicine recently tested the blood of several Carbondale residents, according to a recent article in the Aspen Daily News. He tested ten people for a range of volatile organic compounds (VOCs) including benzene, toluene, ethylbenzene, and xylene – compounds found in air samples in many drilling areas. His preliminary results found low levels of xylene but, as reporter Nelson Harvey puts it, “no VOC concentrations above federal health thresholds”.
Hughes is looking at this as a baseline, as two gas companies intend to develop 18 gas leases in the area. He’s trying to generate some health data prior to drilling.
Hughes compared the Carbondale samples with blood samples from ten residents in Erie, where close to 17,000 gas wells have already been drilled. He found high levels of ethylbenzene – around 118 parts per billion (ppb) – in the blood of nine Erie test subjects. All of those residents lived between 300 and 1,800 feet from gas wells, and the highest levels ethylbenzene that Hughes detected was found in people living closest to wells.
By contrast, none of the samples from Carbondale residents showed high levels of ethylbenzene.
The Material Safety Data Sheet (MSDS) for ethylbenzene notes that the chemical; “may cause adverse reproductive effects and birth defects … (and) may cause cancer…” That data is based on animal testing.
According to the Centers for Disease Control &Prevention (CDC) National Biomonitoring Program, the median ethylbenzene level in adult’s blood was 0.060 ppb, although residents in high density urban areas may have ethylbenzene levels twice that high. “Workers in the petroleum industry and those with solvent exposure can have blood ethylbenzene levels that are several hundred times higher than those in the general population,” notes the report.
At this time, finding “measurable” levels of ethylbenzene in the blood doesn’t automatically mean the chemical is causing adverse health effects. That data hasn’t been gathered yet. But biomonitoring studies are important, as they can provide health officials with reference values when determining whether people have been exposed to higher levels of ethylbenzene than are found in the general population.
And that is exactly what Hughes is doing: using biomonitoring to establish a baseline for Carbondale residents and, if he can continue, study the environmental exposures associated with drilling.