"GRASSY NARROWS FIRST NATION—For more than 40 years the mercury has percolated through river sediment, the food chain and generations of residents."

"HUGO, Colo. — Officials told residents of a small Colorado town not to shower or drink tap water Thursday because wells have been contaminated with marijuana's intoxicating chemical."

"Canadian oil transport giant Enbridge has reached a $177-million settlement with the U.S. Justice Department and Environmental Protection Agency over 2010 oil spills in Marshall and Romeoville, Ill."

"Exposure to more intense shale gas development correlates with a higher risk of asthma attacks among asthma patients, according to a new study of Pennsylvania's Marcellus Shale, one of the nation's largest and most active fracking regions."

"The enormous algae outbreak that has coated swaths of Florida's St. Lucie River with guacamole-like sludge is a man-made affliction, arising from political and economic decisions made over the past 140 years."

"The Tennessee Valley Authority's Colbert and Widows Creek power plants have already burned their last piece of coal to generate electricity, but some environmentalists are worried that the tons of coal ash left behind in watery ponds could cause environmental problems long after the burners were turned off."

"Three attorneys general on Tuesday directly challenged Volkswagen’s defense over its emissions deception, calling the decision to thwart pollution tests an orchestrated fraud that lasted more than a decade, involved dozens of engineers and managers and reached deep into the company’s boardroom."

The U.S. EPA is facing off with Minnesota's Pollution Control Agency over exempting taconite mining operations from clean-water rules meant to protect wild rice.

"The [Canadian] federal government has quietly approved the use of a highly controversial chemical for dispersing ocean oil spills, despite growing scientific evidence it doesn’t always work as claimed and even intensifies the toxicity of oil."