On a global average, the amount of mercury falling out of the sky has tripled since the Industrial Revolution, primarily because of the burning of fossil fuels. Although this atmospheric deposition has long been considered the key vector for the widespread contamination of freshwater and coastal ecosystems, some scientists are focusing on another potential source: subterranean flows of terrestrial groundwater.

"A long-awaited vote on the Waxman-Markey climate bill, expected this week or early next month, has environmentalists teetering at the edge of existential crisis. Some believe the bill is so deeply flawed it might actually make matters worse; disillusionment with the bill is causing fierce recriminations within the environmental movement and has led to a knockdown, drag-out fight within the Sierra Club."

"A group of chemicals called hydrofluorocarbons, long hailed as a substitute for gases that can destroy the ozone layer, are now seen as a growing greenhouse threat given their outsize ability to warm the atmosphere."

The Army has finally agreed to an enforceable timetable for cleaning up Superfund sites at Fort Meade in Maryland.

Tesla Motors' chief executive, whose company has been mired in legal actions, predicted in a blog post that the company would become profitable next month.

An inert ingredient in the popular weedkiller Roundup has been found to kill human cells.

Two brothers are busting levees to return the Ouachita National Wildlife Refuge to its primeval condition.

"The Gulf of Mexico Fishery Management Council ... left in place a moratorium on longline fishing to aid a federally protected sea turtle species."

"The Pentagon and the defense industry is lobbying the White House to prevent U.S. EPA from tightening a health advisory for a rocket-fuel chemical."