Mercury contamination in California to last 10,000 years

Mercury contamination in California to last 10,000 years

Toxic remnants of gold rush will seep into San Francisco area waterways for millennia

By Jessica Shugart, 11:43 AM October 28, 2013

California’s gold rush ended more than a century ago, but the contamination it caused will last thousands of years, a new analysis shows.

Some hydraulic gold mining processes use the toxic metal mercury to separate gold from gravel. In the mid-1800s, gold mining released more than a cubic kilometer of mercury-laden sediments into Northern California’s Sierra Nevada foothills. The sediments fanned out and inundated rivers that flow into the San Francisco Bay. Researchers estimate that 90 percen...

Source URL: https://www.sciencenews.org/article/mercury-contamination-california-last-10000-years?mode=topic&context=60