In its latest round of water tests in Dimock, Pa., the EPA found one residential well with high methane concentrations, but no need for further action in others.
The EPA report issued this morning considered analytical data from 12 wells in the area where shale gas development has been linked to water pollution. The agency reported the results of the well with a high concentration of methane to the resident, the Pennsylvania Department of Environmental Protection and the Susquehanna County Emergency Management Agency, said EPA spokesman Roy Seneca. The other results did not show levels of contaminants that gave agency officials reason to take further action.
The quality of the water in Dimock has been the matter of scientific study and public scrutiny since Norma Fiorentino’s well exploded on January 1, 2009. The Pennsylvania DEP traced the problem to methane migrating from nearby Marcellus Shale gas wells into the aquifer that supplies homes along Carter Road.
Including the test results released today, the EPA has completed analysis of 61 wells in the area. It began the tests earlier this year after data provided to the agency by the state DEP and by Cabot Oil & Gas showed levels of contaminants in four wells that posed a health concern. Those wells have been taken offline and the EPA is providing water to those households. Since then, the agency’s tests have shown the water to be potable in most wells. But some wells showed traces of sodium, methane, arsenic, chromium, and lithium and other elements at or near “action levels,” which are flags for more analysis.
The federal agency will resample the four wells with a history of contamination, Seneca said, although the agency’s initial tests of those wells found no need for action. The agency is also following-up with three homeowners who expressed interest in initial sampling but have not yet scheduled a time, he said.
Comprehensively analyzing the impact of drilling on ground water is tricky, because problems can come and go in certain places over time, owing to the complexity and dynamics of the water table, and the transient nature of drilling operations.
When the sampling is complete, Senaca said, the agency will “conduct a comprehensive review to determine if there are any trends or patterns in the data as it relates to home well water quality.”