BUSTING A CAP AND TRADE: California Sen. Barbara Boxer announced today that she and fellow Democrats will draft a cap-and-trade bill to regulate greenhouse gas emissions within "weeks, not months," then added the less aggressive promise that "it will be before the end of the year." Democrats' goal is to get the carbon-regulating wheels in motion before this December's climate summit in Copenhagen, and although a similar cap-and-trade bill failed in the Senate last year, Boxer is optimistic, saying, "We know that we have to act, and we intend to act." (Source: New York Times)

NORTHERN EXPOSURE: The mercury is rising in Canada's North, but not in thermometers. Caribou are showing increasing levels of the toxic heavy metal, which is emitted by coal-fired power plants around the world and drifts toward the Arctic. High mercury levels in predators such as bald eagles can indicate widespread contamination throughout the local ecosystem, since it accumulates up the food chain; while caribou are herbivores, researchers are still testing their food sources — including lichen, cotton grass and willows — to see where the mercury is coming from. (Sources: CBC, NY Times)

LOOK WHOSE TOXIN: Two recent, unrelated public-health scares have turned out to be the result of inept chemical dumping. Most recently, residents of Bellaire, Ohio, had to abstain from their drinking water for several hours on Monday after workers at a chemical-treatment plant accidentally added 40 pounds of hydrochloric acid to the city's water supply. And on Jan. 19, L.A. authorities feared a terrorist attack after several people at a Metro station were overcome by a cloud of noxious gas and began vomiting. But it turned out maintenance workers at a nearby hotel dumped most of two 50-gallon drums containing muriatic acid and chlorine into a drain that emptied near the station. (Sources: Associated Press, Los Angeles Times)

"NO EXPLOSIONS": The 813 earthquakes that "swarmed" below Yellowstone in 11 days are nothing to worry about, scientists say. Although the swarm was the most intense since 1985, it subsided Jan. 5, and the park normally has 1,000 to 3,000 in a year. Since it's above an ancient supervolcano, though, concern is understandable. So a guy with the reassuring title "scientist-in-charge" tells us simply, "No explosions." (Sources: NY Times, Discovery.com)

NOT A DROP TO DRINK: The BBC reports on the worldwide state of water, which isn't exactly sparkling. People generally need at least five gallons a day for the basics — drinking, cooking and washing enough to avoid spreading disease. But while the average American or Japanese citizen uses nearly 100 gallons a day, the average Cambodian gets by with about 10, and during the 2005-'06 East African drought, many lived on less than two. With 2.5 billion more humans expected by 2050, pressure will only grow in places where water is scarce, and major sources such as the Yellow River and Lake Chad are already running dry. In addition to growing demand for water to drink, more hungry stomachs will need more food, and agriculture already accounts for 70 percent of water used around the world. (Source: BBC)

DOWNWARD-FACING DOLPHIN: Atlanta's Georgia Aquarium, billed as the world's largest, will begin hosting yoga classes this Sunday. A spokesman for the aquarium says it "probably had 100 independent requests for yoga." Classes will be held throughout the building, including in front of its Ocean Voyager tank, which includes whale sharks, grouper and sting rays. (Source: Atlanta Journal-Constitution)

Russell McLendon