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.
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. "Alkalinity is typically thought of as a good thing," 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 (Environmental Science & Technology, doi.org/nkf).
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 "Acid still reigns"
- Subscribe to New Scientist and you'll get:
- New Scientist magazine delivered every week
- Unlimited access to all New Scientist online content -
a benefit only available to subscribers - Great savings from the normal price
- Subscribe now!
If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.
Have your say
Only subscribers may leave comments on this article. Please log in.
Only personal subscribers may leave comments on this article
All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.
If you are having a technical problem posting a comment, please contact technical support.
