| California Acts to Control Chromium in Drinking Water In a long-awaited move designed to protect people from cancer, California on Thursday proposed a new health goal for chromium 6 in drinking water that is thousands of times lower than the amount contaminating some water supplies.The recommendation culminates a decade of debate among scientists trying to decide what concentration is safe to drink. The controversial water contaminant was made famous by Erin Brockovich and a small Mojave Desert town that won the largest tort injury settlement in U.S. history. [More] rss.sciam.com |
Novel Analysis Confirms Climate "Hockey Stick" Graph The “hockey stick” graph has been both a linchpin and target in the climate change debate. As a plot of average Northern Hemisphere temperature from two millennia ago to the present, it stays relatively flat until the 20th century, when it rises up sharply, like the blade of an upturned hockey stick. Warming skeptics have long decried how the temperatures were inferred, but a new reconstruction of the past 600 years, using an entirely different method, finds similar results and may help remove lingering doubts.The hockey stick came to life in 1998 thanks to the work of Michael Mann, now at Pennsylvania State University, and his colleagues (and many other climate scientists who subsequently refined the graph). Reconstructing historical temperatures is difficult: investigators must combine information from tree rings, coral drilling, pinecones, ice cores and other natural records and then convert them to temperatures at specific times and places in the past. Such proxies for temperature can be sparse or incomplete, both geographically and through time. Mann’s method used the overlap, where it exists, of recent proxy data and instrument data (such as from thermometers) to estimate relations between them. It calculates earlier temperatures using a mathematical extrapolation technique [see “ Behind the Hockey Stick ,” by David Appell, Insights; Scientific American, March 2005]. [More] rss.sciam.com |
Mountaintop removal mining: EPA says yes, scientists say no On the heels of the U.S. Environmental Protection Agency announcement that it would allow a proposed coal mine involving mountaintop removal to go forward, 12 environmental scientists have published a review of the practice that condemns it in no uncertain terms. "Mining permits are being issued despite the preponderance of scientific evidence that impacts are pervasive and irreversible and that mitigation cannot compensate for losses," the scientists wrote in the January 8 issue of Science . "Regulators should no longer ignore rigorous science." [More] rss.sciam.com |
BPA a "chemical of concern"--EPA makes it official First Environmental Protection Agency administrator Lisa Jackson warned in September 2009 that reform of chemical regulations was coming and that bisphenol A, or BPA--a building block of many plastics--was among those that might be due for enhanced scrutiny. Then the U.S. Food and Drug Administration announced it had concerns about BPA and would conduct further testing of its safety in January. Now the EPA has made it official by designating BPA as a "chemical of concern" for its human health and environmental impacts. [More] rss.sciam.com |
Spare Times: For Children A selected guide to events for and by children and teens in the New York area. nytimes.com |