(CN) – Hydraulic fracturing of oil and gas wells, or “fracking,” can impact drinking water, a United States Environmental Protection Agency scientific report finds.
Congress requested the assessment to give states and others a scientific foundation to better protect drinking water resources where fracking is occurring or being considered, the EPA said in a statement Tuesday.
In the report, the EPA identifies conditions in which impacts from fracking can be more frequent or severe, and “provides scientific evidence that fracking can impact drinking water resources in the United States under some circumstances,” the EPA specified.
The report is organized by types of water use during fracking and their potential to impact drinking water. The stages include: acquiring water; putting chemicals in the acquired water; injecting the fluids into the production well to create and grow fractures in an area where withdrawal of fuel is expected; collecting the wastewater afterward; and wastewater disposal or reuse.
EPA found cases of impacts on drinking water at every stage, it said.
According to the report, conditions under which impacts from fracking can be more frequent or severe, include:
- Water withdrawals in times or areas of low water availability, particularly in areas with limited or declining groundwater resources;
- Spills that result in large volumes or high concentrations of chemicals reaching groundwater resources;
- Injection of hydraulic fracturing fluids into wells with inadequate mechanical integrity, allowing gases or liquids to move to groundwater resources;
- Injection of hydraulic fracturing fluids directly into groundwater resources;
- Discharge of inadequately treated hydraulic fracturing wastewater to surface water resources; and
- Disposal or storage of wastewater in unlined pits, resulting in contamination of groundwater resources.
Impacts “ranged in severity, from temporary changes in water quality, to contamination that made private drinking water wells unusable,” according to EPA’s statement.
The report also identifies uncertainties and data gaps, which limited EPA’s ability to fully assess local and national impacts, the agency said. “Generally, comprehensive information on the location of the activities involved is lacking, either because it is not collected, not publicly available, or prohibitively difficult to aggregate. In places where we know activities have occurred, data that could be used to characterize fracking chemicals in the environment before, during, and after were scarce. Because of these data gaps and uncertainties, as well as others described in the assessment, it was not possible to fully characterize the severity of impacts, nor was it possible to calculate or estimate the national frequency of impacts on drinking water resources.”
The agency’s conclusions are based on review of over 1,200 cited scientific sources; feedback from an independent peer review conducted by EPA’s Science Advisory Board; input from engaged stakeholders; and new research conducted as part of the study, EPA said.
“The value of high quality science has never been more important in helping to guide decisions around our nation’s fragile water resources. EPA’s assessment provides the scientific foundation for local decision makers, industry, and communities that are looking to protect public health and drinking water resources and make more informed decisions about hydraulic fracturing activities,” said Dr. Thomas A. Burke, EPA’s science adviser and an administrator in EPA’s Office of Research and Development.