Great Lakes or great sink? Pollutants produced abroad and still circulating at home threaten water quality

By Matthew Cimitile, cimitile@msu.edu
Great Lakes Echo 4/22/09

Indian cement plants, Russian incinerators and Chinese farms send large amounts of persistent pollutants to the Great Lakes.

The continued expulsion of these toxins pose serious environmental and health problems for all countries, including those who have long since banned these chemicals, according to the U.S. Environmental Protection Agency. Climate change may further complicate the issue.

As countries like China develop, they are not only becoming the largest emitters of carbon dioxide but of persistent organic pollutants or POPs, according to the International POPs Elimination Network. These chemicals drift into the atmosphere or fall to the surface to evaporate. And they accumulate in animals and humans. Many have been linked to cancer, diabetes and other illnesses.

Persistent chemical compounds travel long distances and eventually concentrate in colder environments to condense and fall back down, said Staci Simonich, a chemistry professor at Oregon State University.

The Great Lakes are a magnet for such pollutants. During the U.S. industrial heyday of DDT and PCB use, large concentrations of the pollutants were found in the lakes, poisoning wildlife and human diet.

Though now banned for decades, POPs from American soil continue to harm the lakes.

“ A great deal of the POPs circulating in the U.S. is from past agriculture pesticide use in the southeast,” said Simonich, whose research focuses on the global atmospheric transportation of POPs. “The same properties that made them effective pesticides, flame retardants and useful to consumers and farmers is also the reason why they persist so long in the environment,” Simonich said.

The new releases from around the globe, say scientists, will only add to the onslaught and ensure the longer persistence of these chemicals in the Great Lakes environment.

In response to growing concerns over airborne persistent chemicals, the Stockholm Convention on Persistent Organic Pollutants was adopted in 2001.

Entered into law in 2004, the international treaty sets out to eliminate and reduce the releases of POPs. It currently focuses on 12 persistent pollutants — known as the dirty dozen — which includes dioxins, DDT, chlordane and others. Next month the convention is planning to list nine more, said Bjorn Beeler, international coordinator for the International POPs Elimination Network.

“There are still a lot of chemicals in wide use that appear harmful,” Beeler said. “For example the U.S. produces a lot of brominated flame retardants.” These flame retardants cause neurological and developmental defects in lab animals, studies have shown.

Though the U.S. has banned the production and use of most of the chemicals on the list and signed the treaty, it has not ratified it.

“The U.S. chemical laws are quite dated and to ratify the convention you would have to seriously overhaul laws that were setup mainly in the late 1970s,” Beeler said.

As the international community works to eliminate the further releases of these harmful chemicals, climate change could impede the effort to eliminate POPs from the environment.

“With climate change, as circulation patterns and ice cover change and bodies of water warm up, POPs that have been deposited into sediment can warm up and move to some place else,” Simonich said.

Thursday: Toxaphene – a persistent pollutant