ATLANTA, GA — New guidelines raising the level of mercury contamination considered a threat to human health were issued April 19 by the U.S. Agency for Toxic Substances and Disease Registry (ATSDR), an arm of the federal Department of Health and Human Services.

Humans are often exposed to mercury when they consume fish caught in mercury-contaminated waters. The ATSDR's new minimal risk level (MRL) for ingestion of mercury is 0.3 micrograms per kilograms of body weight (g/kg) daily, three times the previous MRL. The new MRL is also three times the U.S. Environmental Protection Agency's (EPA) reference dose of 0.1 g/kg, a fact that has led to complaints from clean-water advocates.

ATSDR spokeswoman Kathy Skipper said protesters have misunderstood the purpose of the MRL, a non-regulatory tool intended for health officials evaluating incidents of toxic exposure.

The ATSDR revised its mercury MRL based largely on recent studies in the Seychelles and Faroe islands, where residents have been subjected to long-term, low-dose mercury exposure.

"Questions of water quality and pollution levels are probably going to be addressed by the EPA," said Skipper.
"But since this [MRL] reflects the latest science, I'm sure they're going to be looking at how we interpreted this research."

As much as 2.5 billion gallons of waver are produced annually by the wellheads, about 55 percent of Edmond's water supply.

Bacteria found in underground water

Feb. 2 — Widespread pollution has been discovered in a major Southern Indiana cave system, raising concern about the region's drinking water supply, according to the Courier-Journal.