south pole ice core
July 29, 2014

New Report Reveals That Lead Pollution Beat Polar Explorers To The South Pole

redOrbit Staff & Wire Reports - Your Universe Online

Norwegian explorer Roald Amundsen might have been the first person to reach the South Pole, but an international team of scientists has discovered that he was actually beaten to his destination – by industrial air pollution.

In research appearing in Monday’s edition of the Nature journal Scientific Reports, Joe McConnell of Nevada's Desert Research Institute (DRI) and his colleagues explain how data from 16 ice cores collected from locations throughout the Antarctic continent found that “substantial toxic heavy metal lead pollution” had reached the South Pole by 1889.

McConnell, the study’s lead author, as well as the director of the DRI ultra-trace ice core analytical laboratory in Nevada, said the study’s findings demonstrate “the dramatic impact of industrial activities such as smelting, mining, and fossil fuel burning on even the most remote parts of the world.”

The ice core data clearly reveals industrial lead contamination had spread throughout much of the continent by the late 19th century, meaning it arrived in the South Pole some two decades before the first polar explorers, the study authors noted. Furthermore, they said Amundsen’s team traveled over snow contaminated by mining and smelting activities in Australia, and that the lead pollution levels then were nearly as high as they are now.

The research team used DRI’s continuous ice core analytical system to measure the amount of lead and other chemicals in the study. They explained that the combination of low background atmospheric concentrations and distinctive isotopic characteristics of industrial sources provided an excellent way to track this type of pollution.

“Lead is a toxic heavy metal with strong potential to harm ecosystems,” explained co-author Paul Vallelonga of the University of Copenhagen. “While concentrations measured in Antarctic ice cores are very low, the records show that atmospheric concentrations and deposition rates increased approximately six-fold in the late 1880’s, coincident with the start of mining at Broken Hill in southern Australia and smelting at nearby Port Pirie.”

Due to the timing and magnitude of the changes in lead deposition throughout the continent, and the unique isotopic signature of Broken Hill lead, the investigative team believes that this one Australian-based emissions source was solely responsible for the introduction of lead pollution into Antarctica in the 1800s.

Some of the ice cores analyzed by McConnell, Vallelonga and their colleagues had been collected as part of a series of projects funded by the US National Science Foundation (NSF), while others were contributed by various international organizations, including the British Antarctic Survey and the Australian Antarctic Division.

“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,” said co-author Tom Neumann of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

“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,” added Neumann, who is a cryospheric scientist focusing on the development of NASA’s next-generation laser altimeter, ICESat-2, and who participated in a joint US-Norway traverse that collected several of the cores used in this study.

The data from the ice cores indicates that Antarctic lead concentrations peaked in 1900 and remained high until the late 1920's, though there were short-lived declines during the Great Depression and the end of World War II. From that time on, concentrations then increased rapidly until 1975, remaining elevated until the 1990's. Since then it has declined, but the pollution levels remain roughly four times higher than pre-industrialization levels.

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

By Stephen R. Bown - The Last Viking: The Life of Roald Amundsen (A Merloyd Lawrence Book)