Scientists had previously determined that these contaminants, called polycyclic aromatic hydrocarbons, or PAHs, could biodegrade if suspended in water. But it was also believed that once PAHs sank into the silt at the bottom of the harbor, they could not be oxidized or degraded a theory that the new study challenges.
"This is important because it demonstrates that the self-purification capacity of the harbor is much greater than previously recognized," said UMass microbiologist Derek Lovley, a co-author on the paper. "Furthermore, if future spills of contaminants can be eliminated, the harbor may get cleaned up in large part due to natural activity without the requirement for expensive remediation strategies. It does give us hope for the longer term, if practices change."
Marine harbors are frequently polluted with contaminants from fuel spills, industrial waste, shipping activities, runoff, soot, and creosote-treated pilings, Lovley said. Although some chemical portions of these contaminants readily degrade, PAHs tend to accumulate in the sediment. "They're not very soluble in water, and they don't react chemically with many other compounds," said Lovley, "so they collect in the mud at the bottom of the harbor." Previous research has shown that PAHs accumulate in fish and other aquatic animals, and are often associated with cancers in some fish. Some PAHs are highly toxic, and are suspected carcinogens in humans.
The UMass team was prompted to study the issue after earlier research by Lo
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Contact: Elizabeth Luciano
luciano@journ.umass.edu
413-545-0444
University of Massachusetts at Amherst
13-Nov-2002