"The volume of drilling wastes from Pennsylvania’s Marcellus shale is growing and threatening to overwhelm existing waste-handling infrastructure in Ohio and other states, according to a study released Tuesday."

"A landmark report on Portland harbor cleanup alternatives drafted by key harbor property owners last year has 'many deficiencies' and needs 'substantial revision,' the U.S. Environmental Protection Agency says."

"A new federal report finds toxic contamination remains widespread in the Chesapeake Bay, with severe impacts in some places, which health and environmental advocates say lends support to their push in Annapolis for legislative action on pesticides and other hazardous chemicals."

"An antibiotic widely used in soaps and cosmetics that mostly goes down the drain is slowly converting to toxins at the bottom of many of Minnesota's lakes and rivers."

"The largest gathering of scientists and engineers from around the world to discuss the effects of the BP Deepwater Horizon oil spill kicks off in New Orleans on Monday, with more than 800 people from universities, state and federal agencies, non-governmental organizations and industry expected to attend. The three day Gulf of Mexico Oil Spill & Ecosystem Science Conference is aimed at understanding the impacts of pollution resulting from the spill and its effect on natural systems in the Gulf and along the shoreline, and on the people who live and work there."

"In a bid to clean up one of the nation’s dirtiest coal-fired power plants without causing economic harm to the Navajo Nation that surrounds it, the Environmental Protection Agency indicated on Friday that it would give the plant’s owners five extra years, until 2023, to install expensive state-of-the art emissions reduction equipment."

"GENEVA -- A new and legally binding international treaty to reduce harmful emissions of mercury was adopted Saturday by more than 140 nations, capping four years of difficult negotiations but stopping short of some of the tougher measures that proponents had envisioned."

"Crisis-weary developed countries' reluctance to help finance a ground-breaking international treaty to rein in the use of health-hazardous mercury is threatening the accord, UN officials warned Thursday."

"Opponents of the Keystone XL pipeline and the heavy Canadian crude oil that it would carry released two reports on Thursday asserting that the environmental impacts of the project are worse than previously estimated, and urged the Obama administration to veto it."

"The U.S. Environmental Protection Agency said Wednesday that total toxic air releases in 2011 declined 8 percent from 2010. In the mid-Atlantic region, which includes Pennsylvania and Delaware, the agency recorded a decline of 13.8 percent or 32.5 million pounds. Among the hazardous air pollutants showing declines were hydrochloric acid and mercury, which EPA attributed to improved pollution control technologies at coal-fired power plants and a shift to other fuel sources."