Columbia University

Pumping draws arsenic toward a big-city aquifer

Naturally occurring arsenic pollutes wells across the world, especially in south and southeast Asia, where an estimated 100 million people are exposed to levels that can cause heart, liver and kidney problems, ...

Sep 11, 2013
3.8 / 5 (4) 0 | with audio podcast

Tackling an Ice Age mystery

In the northern hemisphere, ice sheets ebb and flow in 100,000-year cycles, driven by varying amounts of sunlight falling on Earth's surface as its orbit and orientation toward the sun changes. But astronomical variations ...

Sep 05, 2013
4.8 / 5 (5) 0

'Highway from hell' fueled Costa Rican volcano

If some volcanoes operate on geologic timescales, Costa Rica's Irazú had something of a short fuse. In a new study in the journal Nature, scientists suggest that the 1960s eruption of Costa Rica's larges ...

Jul 31, 2013
4.7 / 5 (9) 0 | with audio podcast