Pure Earth POLLUTION BLOG

Chronic mercury exposure in the U.S. has risen dramatically, not only in numbers of people affected but also in amounts.

A study by Professor Dan Laks found that mercury was detected in only 2% of the blood samples collected over a seven-year period between 1999-2006, but it was present in 30% of samples taken in the one year between 2005-2006.  Furthermore, mercury levels of blood rose from 0.33 µg/L to 0.39 µg/L over the seven-year period, and seemed to increase with age, offering strong evidence of mercury accumulation in the blood.

Another study from Mahaffey et al. estimates that 300,000-600,000 American children born in 1999-2000 had elevated risks of neruo-developmental disorders with blood organic mercury levels of >5.8 µg/L based on the number of births and adult female blood organic mercury levels.

The Price of Gold

But why the huge increase?

The answer may lie in the rising price of gold.

Small scale gold mining is the biggest source of mercury emissions. The Mercury Watch database estimates that mercury releases from small scale gold mining have increased roughly 30% to 1320 tonnes per year in 2011 due to increased gold mining driven by the high price of gold and high poverty rates in countries where it is practiced (70 countries – see map)

Mercury:  A Global Pollutant

And the thing with mercury is that it is a truly global pollutant because it travels so well. 40% of mercury released by artisanal gold mining goes directly into the atmosphere and circulates around the globe before landing in oceans and rivers, contaminating fisheries worldwide. The remainder (about 600 tonne) goes into local waterways and soils but much of this may later also escape to the atmosphere.  So not only are miners and their families (including some 600,000 child gold miners!) at risk from mercury, but also children and pregnant women half a world away. [Read our earlier post, All That Glitters, for a solution]

Thanks to Blacksmith Technical Advisory Board member Dr. Kelvin Telmer, the executive director of the Artisanal Gold Council, who shared this information with us, and the video below: