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Nature

Lead Pollution Got To The South Pole Before We Did

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Lisa Winter

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clockJul 29 2014, 19:41 UTC
1633 Lead Pollution Got To The South Pole Before We Did
Stein Tronstad/Norwegian Polar Institute

Roald Amundsen led the first expedition to reach the South Pole back in 1911. Unfortunately, a recent study has revealed that lead pollution from Australian mining beat him to the punch by over 20 years. The research was led by Joe McConnell of the Desert Research Institute and the findings were published in the journal Scientific Reports

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McConnell’s team analyzed 16 ice core samples from around Australia, including one sample from the South Pole. This core analysis provided insight of environmental conditions around the continent from 1600-2010. The levels of lead during this 410 year timespan were averaged out and it revealed that 22 years before Amundsen reached the bottom of the globe, lead levels were already six times higher than average.

“Our new record shows the dramatic impact of industrial activities such as smelting, mining and fossil fuel burning on even the most remote parts of the world," McConnell said in a press release.

In addition to the core samples obtained by McConnell’s team, British, German, and Australian collaborators also provided samples. The ice provides information about the atmospheric conditions, and particular isotopes reveal industrial sources of lead. This helps track the full range of industrial pollution.

The lead originated from the Broken Hill mining site in southern Australia that has been excavating silver, zinc, and iron ore since 1885. Lead is a toxic heavy metal that can have longterm effects on animals, microorganisms, plants, and soil in an ecosystem.

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"The ice cores obtained through international collaborations were critical to the success of this study in that they allowed us to develop records from parts of Antarctica not often visited by U.S.-based scientists," co-author Tom Neumann added. "This included the Law Dome region of East Antarctica and a big section of East Antarctica visited by the Norwegian-United States Scientific Traverse of East Antarctica.”

The core samples indicated that after the lead spiked due to Australian industrialization, levels remained high through the earliest part of the century, bottoming out during World War II. Lead levels skyrocketed until the mid-1970s, though it has been declining over the last 20 years due to environmental regulation concerning bans on leaded gasoline and other industrial uses. The most recent samples from 2010 are still four times higher than before the industrial age, but the downward trend is encouraging.

"Our measurements indicate that approximately 660 tonnes [1.5 million pounds] of industrial lead have been deposited on the snow-covered surface of Antarctic during the past 130 years," McConnell concluded. "While recent contamination levels are lower, clearly detectable industrial contamination of the Antarctic continent persists today, so we still have a ways to go."


Nature
  • antarctica,

  • lead,

  • South Pole

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