The Arctic holds a telltale record of how humans have used chemicals globally during the past several decades. These cold corners of the earth act as a sink of sorts chemicals used in industry and agriculture worldwide slowly migrate to and settle there in sizeable quantities in water, snow, ice, soil and vegetation.
In a new study, researchers found that the pollutant breakdown process depends largely on the type of dissolved organic matter residing in a body of water, as well as the presence of sunlight. They reported their findings on September 11 at the meeting of the American Chemical Society in New York City.
"Once pollutants enter the water column, their behavior is poorly understood particularly the processes that govern their lifetime and concentrations," said Amanda Grannas, a postdoctoral researcher in chemistry at Ohio State University. "Such pollutants are now being found in wildlife, from fish to seals to whales, and even in people living in the Arctic."
She and her colleagues analyzed the behavior of two pesticides lindane and hexachlorobenzene (HCB). Both are prominent in Arctic waters, and both are part of a group of chemicals known as persistent organic pollutants. HCB was banned from use in the United States in 1984, but is still used as a pesticide in many developing countries. Farmers in the United States use lindane to treat seeds prior to planting.
In this study, HCB rapidly broke down into at least two detectable compounds, while lindane remained nonreactive. Aside from their ubiquity, the researchers chose these substances because of their water solubility lindane's solubility in water is higher than that of HCB.
"A pollutant's water solubility may play a role in its interaction with dissolved organic matter," Grannas sai
Contact: Amanda Grannas
Ohio State University