by Journal of Environmental Science and Technology

Paper documents use of polyethylene sheets for detecting pollutants in water

NARRAGANSETT, R.I. – March 11, 2008 – A paper published in 2007 by a University of Rhode Island researcher and colleagues at the Massachusetts Institute of Technology has been recognized by editors of Environmental Science and Technology as one of the “best of the best” papers published that year.

The paper, “Polyethylene Devices: Passive Samplers for Measuring Dissolved Hydrophobic Organic Compounds in Aquatic Environments,” by Rachel Adams of MIT and Assistant Professor Rainer Lohmann at the URI Graduate School of Oceanography, was judged the year’s second best in the environmental technology category. Only 10 of 1,200 papers were recognized.

A summary of the winning papers will be published in the journal’s April 1 edition.

The paper outlines how the researchers demonstrated the use of a polyethylene sheet — sold at most hardware stores for $1 as a painter’s drop cloth – to detect contaminants like PCBs, dioxin, and oil components in water.

“These compounds – called hydrophobic organic compounds – prefer to stay out of the water,” explained Lohmann, who lives in North Kingstown. “If they had a choice between getting dissolved in water or becoming absorbed into plastic, they’ll choose the plastic every time.”

So Lohmann and his fellow researchers placed 3-by-10-inch sheets of polyethylene in several locations around Boston Harbor for two weeks. When the sheets were retrieved, they were analyzed in great depth to determine their absorption rates under varying conditions for a wide range of contaminants.

According to Lohmann, this type of sampling device has been used before to detect pollutants, but never before had it been investigated in such detail using controlled laboratory experiments.

“One of the beauties of this type of contaminant detection is that it makes the quantification of trace compounds in water easier and more precise than ever before,” he said. “And because it’s inexpensive, you can look for contaminant sources at smaller scales than before. The novelty of our paper is that we validated that it works anywhere with almost any kind of hydrophobic organic compound.”

The traditional system for detecting contaminants required that a large volume of water be filtered and solvents extracted, which is a laborious, time-consuming and expensive process.

Subsequent to their use in the Boston Harbor tests, Lohmann has continued to use the polyethylene sheets to detect contaminants in Narragansett Bay, New Bedford Harbor, the Hudson River and at a Superfund site along the coast of Los Angeles. He is also consulting with other researchers using them in studies of pollutants in the Arctic.