Environmental groups are petitioning the Environmental Protection Agency to change the way it measures water quality in six Appalachian states, including Kentucky. The groups—which include the Sierra Club, Earthjustice, the Kentucky Waterways Alliance and Kentuckians for the Commonwealth—say stricter protections are necessary to safeguard streams from mountaintop removal coal mining.

In the petition, environmental groups ask the EPA to issue a testable numeric water quality standard for Appalachian streams, to protect against damage from coal mining. This would set a water quality standard based on a measurable test for conductivity—or the amount of dissolved solids in the water.

Right now, Kentucky uses a narrative water quality standard, which evaluates water based on descriptions of what a healthy waterway should look like. Earthjustice attorney Emma Cheuse says that standard doesn’t adequately protect communities, and a hard limit is needed.

“So that everybody knows how to protect waters and it’s very clear for the state permitting agencies to be able to make sure that they don’t allow any project that will cause harm above that limit,” she said.

Kentucky Department for Environmental Protection Commissioner Bruce Scott says it’s premature for him to say whether the state would oppose a numeric water quality standard.

“I think we would argue, at least currently, that the approach we’re using, the biological in-stream sampling, that it does the same thing, that it accomplishes the same goal that a potential numeric number would otherwise accomplish,” he said.

In a guidance for mountaintop removal mining finalized in 2011, the EPA required mine permits to be judged with a conductivity benchmark—that guidance has since been vacated by a federal court, and is now under appeal. But Scott says Kentucky has always argued that if the EPA was going to require that benchmark, it should be done with a water quality standard. That’s what the environmental groups are proposing now…but it’ll be up to the EPA whether the agency decides to accept the petition and begin the rule-making process, or deny the request. The environmental groups are asking the EPA to respond within six months.