Mars Imitates Earth

The study, published in Science, used data from two instruments aboard the Mars Express spacecraft. They showed the presence of both accelerated electrons and ions in the atmosphere in nightside regions of the planet. What’s more, the areas where the particles were observed corresponded well to known areas of crustal magnetism. The researchers say more Martian auroras can be expected to be seen, 30 to 50 miles high in the atmosphere.

Arsenic and Old LandMany pesticides now in use were formulated to break down over time to reduce their toxicity. That hasn’t always been the case, though. A study by Carl E. Renshaw and colleagues at Dartmouth shows that one old pesticide, lead arsenate, can linger for years, eventually winding up in streams. The researchers looked at the soil in two apple orchards where lead arsenate was applied a century ago. They found significant levels of lead and arsenic in the top 10 inches of soil. What’s more, the metals had bound with mineral and organic particles in the soil. Retilling and replanting of the land had led to erosion. As a result, the metals were found in sediment in a nearby stream as well. The study was published in The Journal of Environmental Quality.

The study suggests that when old agricultural land is converted to other uses—when orchards become subdivisions, for example—old toxic metals may be stirred up. Extra care needs to be taken to control erosion in such areas.

(New York Times)