Levels of some persistent organic pollutants (POPs) regulated by the Stockholm Convention are decreasing in the Arctic, according to new research findings from a team who have been actively monitoring the region for almost 20 years.
Persistent organic pollutants, or POPs, are a diverse group of long-lived chemicals that can travel great distances from their source of manufacture or use. Many POPs were used extensively in industry, consumer products or as pesticides in agriculture, and include chemicals such as DDT and PCBs (polychlorinated biphenyls).
Because they were found to cause health problems for people and wildlife, they were largely banned or phased out of production in many countries, explained a statement, and in 2001, 152 countries signed a United Nations treaty intended to eliminate, restrict or minimize unintentional production of 12 of the most widely used POPs.
Now, more than 33 POP chemicals or groups are covered by what is commonly called the “Stockholm Convention”, which has been recognized by 182 countries.
“This paper shows that following the treaty and earlier phase-outs have largely resulted in a decline of these contaminants in the Arctic,” commented John Kucklick, a biologist from the National Institute of Standards and Technology (NIST), in the statement.
POPs are particularly problematic in the Arctic because the ecosystem there is especially fragile, and pollution can come from both local sources and from thousands of miles away due to air and water currents. They also build up faster in animals and humans than they can be excreted, with this exposure increasing up the food chain.
For almost two decades beginning in 2000, the scientists tracked POPs and monitored air in the Arctic circle for pollution. The biggest decreases were found with a byproduct of the pesticide lindane, a-HCH, with a mean annual decline of nine per cent in Arctic wildlife, according to the statement.
The research team found PCBs had decreased as well – by almost four per cent per year across the Arctic region since being pulled from the market. Only a small number had increased.
Photo credit: Gary Bembridge/ CC BY 2.0