SNEAK LEAK 

The Exxon Mobil oil spill that fouled the Yellowstone River last week may extend for miles farther than previously reported, company officials admitted Monday, while its cause and even its exact location remain a mystery. Efforts to clean up the 42,000-gallon spill are also being hampered by the Yellowstone's surging, debris-filled waters, the New York Times reports, since the river is one of many U.S. waterways already swollen by heavy snowmelt in the Rocky Mountains.

"The situation is very challenging," Exxon Mobil Pipeline Co. President Gary Pruessing tells the Times, adding that the river is four times its usual flow for this time of year. "Because the river is outside its banks, it's flowing into areas that don't normally flood. Yesterday, we saw the tops of fence posts in the river, and we just can't wade into there and start working." In fact, response crews have yet to reach the ruptured pipeline or even locate it in the river, the Billings (Mont.) Gazette reports. "They're really trying to figure out how to do it," Exxon Mobil spokesman Alan Jeffers tells the Gazette. "It's not a safe place to be right now." The company has at least traced the leak to its Silvertip pipeline, the main line that moves oil from northern Wyoming to a refinery in Billings. That pipeline has now been shut off, so the flow of oil has likely stopped, but not before it poured large "swirls of red-brown oil" into the river and "gobs of black crude" onto its banks, according to the Gazette's Rob Rogers. An estimated 42,000 gallons leaked before the pipeline was shut off, although Rogers reports that more likely seeped out until the depressurized pipe completely emptied.

Local farmers and other residents are displeased with Exxon Mobil's handling of the spill, arguing the flow of oil has overshadowed the trickle of information. "I need to know what we've been exposed to," goat farmer Mike Scott demanded from Pruessing after a news conference Monday. Scott's partner was diagnosed with acute hydrocarbon exposure after she became dizzy, winded and nauseated, the AP reports; Pruessing told Scott that air and water tests have shown no health risks so far, but that the company will publicly release more information. Meanwhile, Anthony Swift of the Natural Resources Defense Council says the spill highlights the need for more stringent regulations on U.S. oil and gas pipelines. "These are the sort of spills that we shouldn't be tolerating," he says. "We need to incorporate tougher safety standards."

(Sources: Associated Press, New York Times, Billings Gazette, Reuters)

AUTISM AND ENVIRONMENT 

The long-running debate on the origins of autism may have reached a turning point, the Los Angeles Times reports, thanks to a groundbreaking new study that suggests environmental factors are at least as important as genes in causing the condition. The study doesn't single out which environmental factors are involved — nor does it dismiss the role of genetics — but its emphasis on environmental exposure nonetheless marks a paradigm shift that has drawn a range of reactions from the scientific community.

"This is a very significant study because it confirms that genetic factors are involved in the cause of the disorder," says Peter Szatmari, an autism researcher and behavioral neuroscientist at McMaster University in Ontario. "But it shifts the focus to the possibility that environmental factors could also be really important." Not everyone is convinced the focus should be shifted, however. "It's a massive claim," argues Angelica Ronald, a behavioral geneticist at Birkbeck University of London. "It flies in the face of the previous data. I don't see why the results have come out the way they have." The study is the largest of its kind to focus on twins, with researchers examining 192 pairs of identical and fraternal twins in which at least one twin has the classic form of autism. According to their findings, only 38 percent of the cases could be attributed to genetic factors, while environmental factors seem to be involved in 58 percent. "Genetics don't explain it," co-author Neil Risch tells the Times. "They're part of the story, but only part of the story."

As if to underscore how complex that story is, another study published Monday reports a link between antidepressant use in mothers and autism in their children. Led by researchers at Kaiser Permanente, the study looked at 1,800 children in Northern California, finding that among the 300 with autism, 6.7 percent of their mothers had taken selective serotonin reuptake inhibitors, or SSRIs, while pregnant. Among the 1,500 kids without autism, only 3.3 percent of their mothers had taken SSRIs while pregnant. "Our results suggest a possible, albeit small, risk to the unborn child associated with in utero exposure to SSRIs, but this possible risk must be balanced with risk to the mother of untreated mental health disorders," says lead author Lisa Croen, adding that further study is needed to confirm the findings.

(Sources: Los Angeles Times, New York Times, e! Science News)

SULFUR SKIES 

China's rapid growth may have become the largest single contributor to global warming, but Chinese pollution has also helped delay the effects of climate change, according to a new study published in the Proceedings of the National Academy of Sciences. That's because the country's toxic sulfur emissions have had a cooling effect that softens the warming caused by carbon dioxide and other greenhouse gases — at least temporarily.

"What's going on is, human activities do two things: They cool the planet and they warm the planet," lead author Robert Kaufmann of Boston University tells the AP. "People normally just focus on the warming effect of CO2, but during the Chinese economic expansion there was a huge increase in sulfur emissions." Sulfur has a cooling effect in the atmosphere — almost like a reverse greenhouse effect, since it reflects [skipwords]solar[/skipwords] heat away from the Earth's surface — whether it's from volcanic eruptions or from old power plants that haven't installed pollution-eliminating "scrubbers." Such scrubbers are now common in the U.S. and Europe, and as China begins upgrading its own sulfur-belching smokestacks, researchers say the health and environmental benefits may be shadowed by a spike in the greenhouse effect. 

"The researchers are making the important point that the warming due to the CO2 released by Chinese industrialization has been partially masked by cooling due to reflection of [skipwords]solar[/skipwords] radiation by sulfur emissions," Joanna Haigh of Imperial College London tells the Guardian. "On longer timescales, with cleaner emissions, the warming effect will be more marked."

(Sources: AP, Reuters, Guardian)

LAUNCH SPECIAL 

NASA's 30-year space shuttle program is just three days away from its final launch, and the crew of Atlantis has already arrived at Kennedy Space Center in Florida to prepare for the swan song, CNN reports. The four astronauts arrived at Cape Canaveral on Monday, and will spend the coming days training and spending time with their families before liftoff, which is scheduled for 11:26 a.m. on Friday, weather permitting.

"I think I speak for the whole crew in that we are delighted to be here after a very arduous nine-month training flow, and we're thrilled to finally be here in Florida for launch week," shuttle commander Chris Ferguson told reporters Monday. The 12-day mission will mark the 135th and final flight for the space shuttle program, and as the Washington Post reports, it has raised some anxiety about the future of America's "shrinking astronaut corps." NASA plans to send just four to six astronauts to the International Space Station per year — including both foreign and U.S. crew members — and must pay Russia up to $56 million per seat. "A lot of astronauts have to make a decision. Do they want to wait five, six, seven years?" one former astronaut tells the Post. "This is a time of transition, and it's stressful for everyone at NASA," adds another, who recently left the federal agency for SpaceX, a commercial space-flight company.

Atlantis is scheduled to deliver various supplies and spare parts to the ISS during its final mission, and will also carry an experimental rig that will test methods of robotically refueling satellites in space, CNN reports. Its return to Earth will mark the conclusion of the space shuttle program, which began in 1981, and will herald a period of transitional uncertainty while NASA begins to focus more on big-picture missions to Mars and an asteroid.

(Sources: CNN, Washington Post)

THIS DAY IN HISTORY

Record heat wave sweeps North America, U.S. ends secret "Operation Popeye," and more.

Russell McLendon

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Photo (Yellowstone River at Hayden Valley, Wyo.): U.S. National Park Service

Photo (one of two 6-year-old twins with autism in Marietta, Ga.): ZUMA Press

Photo (air pollution over Chongqing, China, in 2009): Feng Li/Getty Images

Photo (space shuttle Atlantis at Cape Canaveral, Fla., in June): ZUMA Press

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