Gold Rush's Poisonous Legacy: Mercury Will Linger for 10,000 Years

[xchrom]

http://www.livescience.com/40794-gold-rush-mercury-pollution.html

Even though the California Gold Rush took place more than a century ago, it left a toxic legacy of mercury pollution that will continue to be a problem for some time, scientists say.

New research shows that gold mining in the Sierra Nevada mountains between 1848 and 1884 left tons and tons of mercury-contaminated sediments in river valleys downstream, such as the Yuba River valley. About once a decade, large floods lose enough of this sediment to create a spike in mercury concentrations downriver and in the San Francisco Bay, said Michael Singer, a geologist and hydrologist with joint appointments at Scotland's University of St. Andrews and the University of California, Santa Barbara.

"This is a big deal because at the moment, there's quite a bit of mercury contamination that's in the ecosystems of the [San Francisco] Bay and Sacramento Delta," Singer told LiveScience.

Going up the food chain

It was previously thought that most of the mercury from this mining, much of which took place more than 150 years ago, had already exited the river system, Singer said. But a study by Singer and colleagues published this week in the journal Proceedings of the National Academy of Sciences showed this isn't the case. Instead, the study found that there is enough mercury-contaminated sediment to significantly add to levels of the heavy metal downriver and in the San Francisco Bay for the next 10,000 years. The sediment is washed away by large floods but also by the meandering of the river, which curves back and forth within its valley and exposes long-buried, polluted dirt, he added.

[Uben]

1. Kinda like the fracking going on today...

...do you know whats in fracking fluid? Yeah, I know, no one does! It contains all the poisons and heavy metals the oil refineries need to get rid of. So, we inject them into wells to force oil and gas into areas they can be recovered. But hey, isn't that where our water supply is? Oops! Shhhhh! We can't let this get out.

To dispose of the materials properly would cost the oil companies billions of dollars. But, in the interest of cheap fuel, we let them shove this stuff back into the ground around our water supply. At least we'll have cheap gas to get to all the funerals!

[Nihil]

2. Good job that it's merely toxic for thousands of years rather than measurably radioactive ...

... or people might start to get concerned ...