Two monitoring wells specifically installed to test water supplies deep within an aquifer near natural gas drilling locations in Pavillion, WY, found high levels of benzene and other chemicals, including petroleum-related compounds, according to the U.S. Environmental Protection Agency (EPA) Region 8 office.
The latest sampling results were presented at a meeting attended by about half of Pavillion’s 126 residents (population 126) last week. According to EPA, a total of 42 private drinking water and four stock wells were sampled. Benzene, a carcinogen, measured as high as 50 times the EPA limit in, the testing found. Elevated levels of diesel- and gasoline-grade organic compounds also were detected. High levels of methane were found in 10 of the sampled wells and elevated levels of 2-butoxyethanol phosphate were measured in nine wells.
“Our scientists are continuing to complete their analysis of those data and we are working hard to complete a report interpreting the findings in the near future,” EPA spokesman Matthew Allen said Thursday. A final report on the latest EPA findings is scheduled to be issued later this month, he said.
The U.S. arm of Calgary-based Encana Corp. owns the natural gas field at the center of the controversy, but the company is in the process of selling it to Legacy Reserves, based in Midland, TX. Legacy had no comment.
According to EPA, the Pavillion area has about 80 domestic wells. Pavillion provides municipal water to residents through eight groundwater wells. Private water wells just outside the town are used for drinking water, irrigation and stock watering, and are completed at depths from 50- 750 feet or more. Pavillion is within the Wind River Indian Reservation west of Boysen State Park.
EPA was approached by Pavillion residents in 2008 with concerns about adverse changes to the area drinking water. After meeting with the Wyoming Department of Environmental Quality (DEQ), EPA began sampling drinking water wells in 2009; a second sampling took place last year (see NGI, Sept. 5, 2010; Aug. 31, 2009). Based on the results, EPA installed two monitoring wells to assess conditions deeper in the aquifer. EPA then sampled the monitoring wells and selected drinking water wells in October 2010 and again in April.
Among other things the EPA well tests found:
Officials recommended that residents with the affected wells use alternate water to cook and for drinking. In homes homes with high levels of methane, bathroom ventilation also was recommended. Since last August Encana has been voluntarily funding alternate water for residents with organic contaminants in their wells, EPA said.
As to what’s next, EPA said a work group continues to voluntarily clean up legacy pits in the field and the agency continues to assess wellbore integrity. Alternatives for permanent alternative sources of water also are being investigated.
“The data has already gone through a rigorous quality assurance review process that was recently completed,” the federal agency said. “EPA is sharing the data and background information with the work groups and the public to provide an opportunity for input prior to releasing our findings.”
Once the final report is issued later this month, officials said the peer review process may take “several months.” The peer review panel is to accept comments from all of the stakeholders and the public. Once that process is completed an EPA’s findings are finalized, “we will release a final report in the early spring.”
Many have speculated that the contamination in the water wells resulted from hydraulic fracturing (fracking) when gas drilling was stepped up in the area in the late 19990s through 2006, but EPA said it does not yet have an answer.
DEQ spokesman Keith Guille said the state needs more time to review EPA’s findings before making any decisions. “Certainly we know the EPA has worked very hard on this,” he said. A challenge in making definite conclusions is that no testing was done years ago to document the history of chemicals in the Pavillion area groundwater. “It does make it difficult to track down what’s actually been the issue here.”
The Wyoming Outdoor Council, a conservation group, would not specifically condemn the drilling stimulation process.
“Whether it’s going along natural fractures or those fractures have been expanded or facilitated by the drilling and hydraulic fracturing out there, we don’t really know,” said Steve Jones. The presence of 2-butoxyethanol phosphate may indicate a link to fracking because frack fluid may contain that chemical.
The Pavillion Area Concerned Citizens group also is awaiting EPA’s report, said spokesman John Fenton. While EPA didn’t make any conclusions, Fenton noted that the federal experts said “this is a plume and they need to find out where it’s coming from.”
The groundwater investigation is being conducted by EPA’s regional office in Denver in collaboration with scientists from its Office of Research and Development.
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