It's hard to imagine that the problem can easily be solved in the near term, because there is probably just too much mercury-tainted sediment to feasibly move, Singer said. Perhaps the sediment could be trapped in the event of large floods, or measures could be taken to prevent particularly contaminated sections of sediments from eroding, such as along the Yuba River, he said.
The study suggests that lingering mercury pollution could be a problem in other areas where gold is currently being mined, especially in mountains.
"Unfortunately, gravity is on the side of future contamination," as floods will eventually move mercury-tainted soils downward in California and elsewhere, Singer said.
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