EPA adds to NC's polluted-water list

The Environmental Protection Agency has added to North Carolina's list of polluted waterways, saying the state should have included 52 more bodies of water than it did.

States have to update the so-called 303(d) list of impaired waters every two years. But EPA objected to new methodology the state Environmental Management Commission adopted to update this year's list.

EPA added back to the state's list 52 river and stream segments that are impaired by metals, which can be toxic to fish and humans. The additions include Mecklenburg County's Irwin Creek, where the water contains lead and zinc.

EPA spokeswoman Dawn Harris-Young said adding to a state list is "not common, but it is not an unusual occurrence." EPA added one segment to North Carolina's 2012 list, state officials say.

The state environment commission last year raised the bar for proving that waterways are impaired.

Under the old standard, more than 10 percent of water samples had to show elevated levels of contaminants to be deemed impaired. The commission added a requirement that sample results be shown to be accurate at a 90 percent confidence level.

Establishing that confidence level meant analyzing more water samples. The N.C. Division of Water Resources moved some water bodies, for which it lacked the additional data, from "impaired" to "inconclusive."

The EPA objected, adding those waterways back to the list. It will take public comment on the additions through Sept. 12 -- email hopkins.marion@epa.gov.

EPA approved the state's listing of nearly 1,200 water bodies as impaired, and the removal of 227.