Published: July 17, 2010
HARRISBURG - A proposed state rule to limit the concentration in waterways of a salt compound produced by the Marcellus Shale drilling process is under challenge.
The proposal by the Department of Environmental Protection would align the state standard for allowable chloride levels with national criteria used to protect freshwater plant and animal species. The existing state chloride standard was developed mainly to protect water supplies.
Fish and aquatic life can't survive when high levels of chloride are present. Chloride can corrode metals and affect the taste of food products.
The rule is being considered by the Environmental Quality Board as environmentalists warn that increased drilling for natural gas in the Marcellus Shale formation will produce wastewater contributing to high levels of chloride to streams and groundwater.
Chloride occurs naturally in ancient rock formations that once formed seabeds and are reached by the drilling for deep gas pockets.
But chloride can also contaminate waterways through agricultural runoff and discharges from industries and wastewater treatment plants.
The chloride rule is a separate issue from a broader rule to limit pollution in wastewater from natural gas drilling in the final stages of regulatory action. The rule gives drillers several options to treat wastewater.
Under the chloride rule, the DEP would follow toxicity data on the impact of chlorides on plant aquatic life set by the federal Environmental Protection Agency in a 1988 study.
Both environmental and industry groups argue the 1988 data is outdated.
A coalition of environmental groups, including Clean Water Action and the Delaware Riverkeeper Network, note that DEP has the authority to adopt standards more stringent than federal criteria. They want new studies on chloride contamination that focus on aquatic life in Pennsylvania.
The Pennsylvania Coal Association suggests other industries are adversely affected by the focus on Marcellus Shale drilling.
"The proposed regulation does have the potential to again sweep in a wide range of many other Pennsylvania industries, including the mining industry, who to date have not been generally required, to sample for, or treat, chloride in their wastewater discharges," the association said.
This week the state Independent Regulatory Review Commission urged DEP to rewrite the proposal.
"We agree that basing the new criteria on outdated data when more recent data is available is not reasonable," the commissioners said.