Singer
says mercury is currently a big problem in San Francisco Bay and the
Delta. "People know there was gold mining in the Sierra Nevada and they
know that there was mercury mining in the Coast Ranges, but they're not
really sure of the modern-day impact, especially when the contaminant
sources are not directly by the bay," he said. "People want to know what
is causing contamination of the food webs of the Central Valley."
The
PNAS paper begins to answer that by documenting flood-driven fan
erosion, sediment redistribution and a process called progradation, the
growth of a sedimentary deposit farther out into the valley over time,
which, in this case, spread the mercury-laden sediment into parts of the
basin where there is higher risk of it being taken up by food webs
http://www.universityofcalifornia.edu/news/article/30258
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