More dangerous than thought, and restoring wetlands makes it worse, go figure…
MERCURY'S GOLD RUSH LEGACY MAY BE WORSE THAN THOUGHT
By Hank Shaw
March 05, 2008
Capitol Bureau Chief
SACRAMENTO - Many area residents know that the miners of the Gold Rush unleashed a toxic legacy on the region in the form of millions of pounds of mercury - mercury that has accumulated in soil, plants, fish and birds, many of which we eat.
But a legislative hearing on the mercury problem Tuesday revealed some disturbing new facts about this relic of the Gold Rush, which was used to help extract tiny bits of gold and other metals from rock:
What we know about the extent of the contamination is likely only a slice of how much quicksilver is really out there.
And the common practice of restoring seasonal wetlands - dry in summer and wet in winter - actually makes the mercury problem worse.
"If we do wetland restoration, then we potentially cause more methylation of mercury, which is the toxic form of mercury," said CALFED Director Joe Grindstaff. "That's a big problem for us."
Thousands of normally dry acres in the Delta and the Central Valley are flooded with the winter's rains. Rice farmers use the water to help old rice stubble rot back into the soil, and wildlife groups ranging from the California Waterfowl Association to The Nature Conservancy spend millions to create new wetlands for ducks and other waterbirds.
One of the most polluted areas is the Yolo Bypass, which, when it floods, releases enormous amounts of methylmercury - a substance created by bacteria when mercury-containing muck dries out. Methylmercury can accumulate in the tissues of animals, including humans.
