Lab results questioning the effectiveness of the Environmental Protection Agency's controversial conductivity benchmark for protecting streams below mountaintop mines do not tell the full story, according to a Clean Water Act expert.
"There is generally a discrepancy between field and lab when you do things like this," said Margaret Janes, senior policy analyst at the nonprofit Appalachian Mountain Advocates. "But the issue really is that three tests have to be met for a stream to be considered healthy."
According to several years of laboratory data collected by mining companies under order from the EPA, the aquatic organism Ceriodaphnia dubia tolerates levels of conductivity — a measure, essentially, of saltiness — far higher than the restrictive 300 to 500 microSiemens per cubic centimeter the agency used for two years to guide mining permits.
The data were discussed Oct. 31 at the West Virginia Water Resources Conference by Marshall University aquatic ecotoxicologist Mindy Yeager-Armstead.
The EPA's conductivity guidance was thrown out in court in July, not over the science but because the court said the agency had overstepped its authority.
In looking at the science, two other factors need to be considered, Janes said.
Although C. dubia routinely is used in the Whole Effluent Toxicity, or WET, test, it is not found in Appalachian streams, Janes said, and is not characterized by the same sensitivities as the streams' mayflies, stone flies and caddis flies.
The EPA has documented concerns about the appropriateness of C. dubia and, when asked about this, Yeager-Armstead responded that the organism is the agency's "flagship" invertebrate.
"The excerpt that you quote lays out a theory and ‘suggests' they are not good surrogates because they are not as sensitive as the authors think they should be, based on their field observations," she countered in an e-mailed response, noting that the organism is in wide use for such tests. "It is a rationale for why the data do not look as expected. This argument does not appear to consider the alternative, that the ionic constituents may not be ‘toxic.'"
As a second point, Janes noted that, in recognition of the complex interactions between water chemistry and aquatic life, it has been the EPA's approach for more than 20 years to rely not on one test alone in judging the health of a stream and the effect of industrial effluent on it, but on three together.
These are WET testing; water chemistry as embodied in the state's water quality standards; and narrative water quality criteria — which, in West Virginia, typically has meant scoring on the West Virginia Stream Condition Index that looks at stream-bottom bug populations, although that has been called into question as well.
"To deem a stream healthy, each one of those types of tests would have to be done on the stream — and if any one fails, that means the stream is unhealthy," Janes said. "That principle of independent applicability is hard-core EPA policy."
The coal industry, citizens' groups and state and federal regulators have clashed over the complex issues of mountaintop mine effluent, conductivity and implementation of the state's narrative water quality standards for years.
Some at the EPA are seeking more relevant effluent toxicity tests, Janes said.
And the state Department of Environmental Protection currently is working on more sophisticated ways to implement the elusive biologic component of the state's narrative water quality standards, DEP Secretary Randy Huffman has said.
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