Scientists have sought explanations for the alkaline nature of many area waterways.
Something surprising is happening to rivers in the eastern part of the United States. Scientists from the Universities of Virginia and Maryland say human activities are changing the basic chemistry of the water.
In a survey of 97 rivers from Florida to New Hampshire over up to six decades, scientists discovered many becoming less acidic — a surprise in light of how much acid rain has fallen in this part of the world.
Michael Pace, a professor of environmental sciences at UVA, thought at first that acid rain was dissolving concrete in U.S. cities, causing alkaline particles to wash into rivers. But he and his colleagues soon realized something more was happening.
"We think what's going on is essentially the watersheds — the landscapes around these rivers — are being weathered, and if they have carbonate rocks, which contain calcium carbonate, it essentially converts to baking soda," Pace says.
It is, he says, like rivers on Rolaids, with the carbonate balancing any acidity. That's good news for aquatic life, and no problem for the Chesapeake Bay. But alkaline rivers mean more work and expense for water treatment plants.
"You get fouling of the pipes and scaling and things like that," Pace says.