DESPITE the decline of acid rain, its legacy still taints the rivers of the eastern US, but in an unexpected way. Following stringent air pollution controls, the acid rain that devastated forests, ponds and small streams in the eastern US has been diminishing since its peak in the 1970s.
鈥淭he legacy of acid rain still taints the rivers of the eastern US, but in an unexpected way鈥�
Now the opposite problem, excessive alkalinity, has emerged in the same area. New research has found that 62 of 97 large rivers, from New Hampshire to Florida, have become increasingly alkaline since the mid 20th century. 鈥淎lkalinity is typically thought of as a good thing,鈥� says Sujay Kaushal at the University of Maryland in College Park, but it can stimulate the overgrowth of algae and wreak havoc with public water supplies ().
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It looks like alkaline by-products of acid-neutralising processes had built up in the rocks and soil, and are now leaching into the rivers.
This article appeared in print under the headline 鈥淎cid still reigns鈥�
