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Examiner
  • Lynn Youngblood: Chemistry of rivers is changing

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  • This past week I heard two stories on the radio that interested me – both involving rivers.
    The first was reporting on research published in Environmental Science and Technology magazine, showing that two-thirds of 97 rivers studied have become more alkaline – from the Susquehanna to the Mississippi, the largest river in the United States.
    Gwynn Falls, a small urban stream in downtown Baltimore, is where the first signs of alkalinity in a stream were found about six years ago by Sujay Kaushal, a geologist from the University of Maryland. He is a team member of Gene Likens, a scientist who first discovered that air pollution was acidifying rain, killing trees and the ecosystems of streams 50 years ago. Kaushal went to Gwynn Falls after a local water quality official told him he’d been noticing changes in water chemistry.
    “We couldn’t explain it,” Kaushal says. Initially the scientists thought maybe the concrete and cement of pavement, highway overpasses or other structures were to blame.
    “One of the key ingredients of concrete is actually limestone,” he says, and the mix of water and limestone releases bicarbonate – essentially the same stuff that remedies acid indigestion such as Rolaids and Tums.
    However, when Kaushal and Lichens researched outside of urban areas and looked into their rural neighbors, through forests and farmland, they found the same results. Acid rain continues to be the culprit, eating away chunks of rock, especially through limestone – the runoff produces carbonates that flow into the rivers and streams.
    “It’s ending up in our water. It’s like rivers on Rolaids. There’s a natural antacid in these watersheds,” said Kaushal.
    “We’ve changed the chemistry of the Mississippi,” says Peter Raymond, an ecologist at Yale University. “These aren’t small systems.”
    Some of the growing alkalinity of the Mississippi and its tributaries comes from farmers putting lime on fields to counteract the acidity produced by fertilizers, Raymond says. Acid rain likely contributes, too.
    So, now comes radio story number two. After learning all of this, it makes me wonder about hearing all of the recent stories coming out of Colorado and the massive flooding that has been going on. With the rising waters coming from those rivers and streams, due to rain, how will that now affect the soils that have been flooded? Will all of that soil that has been flooded have the chemistry changed in it, as well? Will the pH now be much more alkaline than before? Has anyone thought of this, and will anyone begin testing for this phenomenon? I guess only time will tell.
    Page 2 of 2 - It seems this is yet another example of how we, as people, have negatively impacted this Earth. There are some inherent principles we need to do to carry on with our lives, transportation, building, developing, growing food, etc. I do not debate this. I do not walk around with my head in the clouds, but there are ways we can live more simply and with less impact. It takes forethought and, to some degree, sacrifice. The question is – are you willing to do your part?
    Reach Lynn Youngblood at TheGreenSpace@sbcglobal.net.
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