The carbon footprint of Brazilian beef, plus the health effects of pollution and electrification in this week's news

Heart attacks: pollution a common trigger

Compared to using cocaine, eating a heavy meal or undertaking a physically exerting task, air pollution is not a particularly potent trigger for heart attacks, a Belgian-Swiss research team finds. Owing to pollution’s ubiquity, however, readily inhaled fine  particles under 10 micrometers in diameter appear to underlie as many nonfatal heart attacks as far more potent triggers. The researchers report their results, which are based on 36 previously published studies, in the Feb. 26 Lancet.  Janet Raloff

Health impacts of global electrification

Rapidly developing countries like India and China have undertaken wholesale urban electrification. But pollution associated with the coal plants on which these nations rely can pose health tradeoffs, explains an international team of scientists. Working with data for 41 countries on projected development trajectories, health demographics and coal emissions, the researchers project that rising electricity consumption will improve health only where pre-electrification infant mortality is beow 1 in 10 live births. In an upcoming issue of Environmental Health Perspectives, the researchers describe why increased electricity use will “not lead to greater health benefits.” —Janet Raloff

Ice down below

Antarctica’s massive ice sheet stays thick partly because water freezes at its base, a new study shows. Researchers had known that ice sheets thicken as snow falls on top and compacts. Now, scientists led by Robin Bell of the Lamont-Doherty Earth Observatory in Palisades, N.Y., have used radar to probe the base of East Antarctica’s ice sheet. They find that water freezing from the bedrock below can account, in places, for up to half the ice thickness. The finding, reported online March 3 in Science, could help inform the quest to drill into the world’s oldest ice. — Alexandra Witze

Rainforest’s carbon hoof prints

As farmers clear tropical rain forest in Brazil to make room for cattle ranching, carbon that had been stored in the felled trees will be released into the atmosphere, a trend that can foster global warming. The likely carbon footprint attributable to this land-use change during the first two decades following deforestation can exceed 700 kilograms of carbon dioxide per kilogram of beef carcass, a team of researchers in Sweden and England calculate. That value is “orders of magnitude larger than the figure for beef production on established pasture on non-deforested land,” they explain in the March 1 Environmental Science & Technology.  Janet Raloff

Some plants could be Typhoid Marys
A British research team has identified strains of Salmonella capable of making leafy greens sick. The scientists infected the weed Arabidopsis thaliana, the lab rat of plants, with Salmonella enterica, germs that ordinarily cause gut-wrenching disease in people. Some strains caused plants to wilt and turn sickly yellow, the scientists reported online February 23 in Environmental Microbiology. Other strains elicited no visible disease despite surviving for up to eight days inside the leaves. This suggests that some germs that evolved to grow in the mammalian gut may hitchhike to their next host embedded deep inside salad leaves — where they can’t be rinsed off. — Janet Raloff

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