Last week the Environmental Protection Agency’s (EPA’s) Science Advisory Board (SAB) released its final report reviewing the agency’s draft assessment of the impacts of shale development on drinking water resources. Mainly, the advisers were concerned that the agency did not quantitatively support its statement that it did not find “widespread, systemic impacts on drinking water resources in the United States.” The SAB suggested that EPA discuss the “significant data limitations and uncertainties,” the challenges with accessing various databases, and the rapidly evolving fracking processes that impact its findings. While it seems that that the SAB could have been more charitable in its criticism of EPA’s “no systemic risk” finding, the SAB was correct in suggesting that EPA faces a high burden in asserting that on a national level there are no systemic effects.
To start, EPA must show whether local or statewide effects are systemic. Although there are some well-documented negative impacts of isolated or episodic spill and other events, proving that these issues are systemic is more difficult. Indeed, in North Dakota, Lauer, Harkness, and Vengosh (2016) find evidence of episodic impacts from brine spills due to shale development, which can leave elevated levels of contaminants up to four years at the impacted site. Though the authors do mention that there have been 3,900 brine spills since 2007, further study and a better definition of systemic are required to definitively state that these impacts are both large and consistent enough throughout the state to be considered systemic. EPA’s draft assessment cites a 2013 study by RFF experts of shale gas development impacts on surface water quality in Pennsylvania. We find no statistically significant effect of well pad activities on chloride concentrations (a marker for briny produced water waste from the well) in stream water—supporting EPA’s finding of no systemic effect, at least for spills in Pennsylvania. Nevertheless, our study, as well as EPA’s, does not and cannot rule out the impacts of episodic spill events.
Our study does find a significant, systemic effect on stream quality from shale gas wastewater that is sent to centralized facilities for treatment—that is, that an additional 1.5 facilities treating shale waste results in a 10–11 percent increase in chloride concentrations downstream. Fortunately, Pennsylvania companies voluntarily agreed to stop sending their wastes to the (centralized) municipal treatment plants. But, if these types of shipments are still happening elsewhere, this could be considered a systemic problem.
In any event, extrapolating systemic effects found in various locations or an entire state to systemic effects of national significance is a tall order. Here, the SAB voiced appropriate concern with EPA’s attempts to “draw national-level conclusions regarding the impacts of hydraulic fracturing” when, for drinking water sources, the impacts are by definition local and the literature is skimpy.