Mercury limits may benefit wildlife, too

New rules limiting the amount of mercury emitted from coal-fired power plants are expected to have a significant impact on human health.

In a report released today, researchers say those rules also could benefit wildlife -- from bats to songbirds.

The study, "Hidden Risk," was by the Biodiversity Research Institute, a Maine nonprofit that focuses on emerging threats to the environment. It was funded, in part, by the Nature Conservancy.

Among its major findings:

  • Mercury amounts found in several songbird species, including the saltmarsh sparrow and rusty blackbird, may reduce their reproductive success.
  • Bats in the northeastern U.S. have mercury levels at which adverse impacts can be expected.

Mercury, a neurotoxin, is released when coal is burned. Once airborne, it can be transported long distances before falling back to earth. Once there, it migrates into waterways, where it is transformed into a more potent and harmful form, methylmercury. The chemical is ingested by organisms and works its way up the food chain. Many waterways in Pennsylvania and New Jersey have "advisories" warning people not to eat the fish because of mercury contamination. 

Anthony DePalma has written a story about the study in today's New York Times.

He notes that "Songbirds with blood mercury levels of just 0.7 parts per million generally showed a 10 percent reduction in the rate at which eggs successfully hatched. As mercury increases, reproduction decreases. At mercury levels of greater than 1.7 parts per million, the ability of eggs to hatch is reduced by more than 30 percent, according to the study."

DePalma quotes Joanna Burger, a behavioral ecologist at Rutgers University who has studied mercury contamination in animals. “It’s incredibly important that someone is following what is happening to these birds,” she said. “The birds not only act as sentinels to what is happening in nature, but the results of these studies propose hypotheses for effects that have not yet been identified for people.”