Burning Coal Has Increased Arctic Toxicity

Posted on Aug 27, 2008 in Heavy Metals

From RedOrbit – The burning of coal in North America and western Europe has been a prime contributor to heavy metal pollution in the Arctic, according to a new study.

Scientists from the Desert Research Institute measured levels of cadmium, lead and thallium in a Greenland ice core and found them to be linked other chemicals that point to coal as the origin.

These chemicals accumulate in the bodies of plants and animals that live in the region.  Some Arctic caribou, whales, polar bears and even humans carry high levels of the heavy metals in their bodies.  These metals can cause a number of medical conditions.

Although clean air legislation has reduced the amount of heavy metals in recent years, increased coal burning in Asia may now be causing levels of the metals to increase, researchers say.

The researchers conducted their study by examining a Greenland ice core that provided a continuous record of atmospheric pollutants from as far back as 1772. They then took monthly measurements of heavy metal levels.

Graphs of all three metals showed that levels soared between 1850 and 1900 as the industrial age took off, with early 20th Century inputs 10 times higher than in pre-industrial times.

The 1930s Great Depression saw levels recede as economies contracted, followed by increases once the global economy recovered.

However, all three of metals decreased in abundance by the 1970s, coincident with the establishment of clean air legislation in North America and Europe, the main source regions for most of the input to the Greenland ice.

“In North America and western Europe, there was a big effort to clean up the air,” lead researcher Joseph McConnell told BBC News.

“Part of that was a shift from coal to oil and gas, and part was a move to burn coal at higher temperatures and burn it in a better way,” he said.

The fluctuations correlate well with variations in the amount of sulfur and black carbon, both coal burning products, captured in the ice.   Scientists said this indicates that coal was the primary source of these emissions.

Heavy metals bio-accumulate, passing into animals where they remain immune to digestion and the body’s waste removal functions.

When that animal is consumed by another higher up on the food chain, the predator, typically takes on a substantial part of the toxic material.

Most previous studies on Arctic populations have focused on mercury, another heavy metal produced by coal burning and other industries.  These studies have suggested that mercury may have contributed to neurological impairments in some communities.

Some Arctic populations have been found to have cadmium levels in excess of the recommended safe limits. Previous studies suggested the cadmium load was highest during the 1960s and 1970s, but the new research found the peak input actually occurred decades earlier. The metal’s most prominent heath impact is kidney damage.

“There’s been very little study of thallium in the Arctic, though,” Dr. McConnell said.

Thallium, once used to make rat poison, is a potent toxin. It was initially suspected in the death of former KGB agent Alexander Litvinenko in London two years ago.   Its use is how highly restricted,

The new study will assist investigators studying the health of Arctic peoples by providing a detailed record of the history of heavy metal input to the environment.

As the global population rises, economies develop and natural gas supplies peak, the International Energy Agency predicts coal usage will also increase around the world.  This is particularly true of areas such as China and India, they say, who will likely be responsible for most of the increase.

Dr McConnell believes his research suggests the increase in coal burning is leading to an upturn in heavy metal input in the Arctic.  He is proposing to drill in other parts of the Arctic, including areas north of Russia and east Asia, to establish the global trends.