This Day On The Street
Continue to site
ADVERTISEMENT
This account is pending registration confirmation. Please click on the link within the confirmation email previously sent you to complete registration.
Need a new registration confirmation email? Click here

Gold Rush-era Mercury Flows Downstream In Calif.

FRESNO, Calif. (AP) a¿¿ California's gold rush may long be over, but mercury-contaminated soil from mining activities in the foothills of the Sierra Nevada continues to flow downstream, impacting fish and the environment, a new study suggests.

The heavy metal tends to be loosened during major floods that occur about once a decade and likely will continue unless something is done to prevent mercury-laden sediment from eroding and ending up in the state's agricultural heartland, according to the study published online Monday in the Proceedings of the National Academy of Sciences.

"The problem is very serious indeed," said lead author Michael Singer of the University of St. Andrews in Scotland.

During the 19th century gold rush, miners used mercury to process gold throughout the West. An estimated 26 million pounds of mercury was used for gold recovery in the Sierra Nevada and Klamath-Trinity Mountains.

Scientists have long known that mercury contamination from long-ago mining ends up in sediments and in stream channels. The metal sometimes converts into a more potent form that can be consumed by fish, amphibians and waterfowl. Numerous waterways in Northern California downstream of mining activities post warnings about fish consumption.

In the latest study, a group of U.K. and U.S. researchers studied soil from a Sierra Nevada mining deposit and points downstream. Levels of mercury in the sediment were up to hundreds of times higher than background levels.

Then the team analyzed topographic maps, streamflow data and satellite images, and used computer modeling to show that the mercury in the Sacramento-San Joaquin River Delta and San Francisco Bay came from historic gold mining that was released during episodic floods.

Charles Alpers, a research chemist at the U.S. Geological Survey's Sacramento office, said the findings show how important floods are in transporting mercury.

"This problem isn't going to go away anytime soon," said Alpers, who had no role in the study.

Copyright 2011 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Check Out Our Best Services for Investors

Action Alerts PLUS

Portfolio Manager Jim Cramer and Director of Research Jack Mohr reveal their investment tactics while giving advanced notice before every trade.

Product Features:
  • $2.5+ million portfolio
  • Large-cap and dividend focus
  • Intraday trade alerts from Cramer
Quant Ratings

Access the tool that DOMINATES the Russell 2000 and the S&P 500.

Product Features:
  • Buy, hold, or sell recommendations for over 4,300 stocks
  • Unlimited research reports on your favorite stocks
  • A custom stock screener
Stocks Under $10

David Peltier uncovers low dollar stocks with serious upside potential that are flying under Wall Street's radar.

Product Features:
  • Model portfolio
  • Stocks trading below $10
  • Intraday trade alerts
14-Days Free
Only $9.95
14-Days Free
Dividend Stock Advisor

David Peltier identifies the best of breed dividend stocks that will pay a reliable AND significant income stream.

Product Features:
  • Diversified model portfolio of dividend stocks
  • Updates with exact steps to take - BUY, HOLD, SELL
Trifecta Stocks

Every recommendation goes through 3 layers of intense scrutiny—quantitative, fundamental and technical analysis—to maximize profit potential and minimize risk.

Product Features:
  • Model Portfolio
  • Intra Day Trade alerts
  • Access to Quant Ratings
Options Profits

Our options trading pros provide over 100 monthly option trading ideas and strategies to help you become a well-seasoned trader.

Product Features:
  • Actionable options commentary and news
  • Real-time trading community
SYM TRADE IT LAST %CHG

Markets

Chart of I:DJI
DOW 16,374.76 +23.38 0.14%
S&P 500 1,951.13 +2.27 0.12%
NASDAQ 4,733.4970 -16.4820 -0.35%

Free Reports

Top Rated Stocks Top Rated Funds Top Rated ETFs