August 17, 2005

Study: Car Exhaust Polluting Puget Sound

OLYMPIA, Wash. (AP) -- Mud and sand at the bottom of Puget Sound is increasingly tainted by pollution from vehicle exhaust, not heavy industry, a state Department of Ecology study says.

The research, which compiled 12 years of sediment test results, showed that toxic metals associated with industrial pollution declined while chemicals tied to vehicle exhaust increased.

Margaret Dutch, an Ecology Department scientist who studies marine sediments, said the study is a warning about the changing nature of pollution in the region.

"It's a really important thing to know that the levels of these compounds are increasing, and it's probably associated with people driving," she told the Seattle Post-Intelligencer.

Researchers said pollutants called polycyclic aromatic hydrocarbons, or PAHs, typically fall directly into the water from airborne exhaust or are washed into the sound by rainfall. Those chemicals can cause liver lesions and tumors in fish, and can change the growth rates and behavior of sediment-dwelling invertebrates.

The Ecology Department analyzed test results from 1989 through 2000. Sediments were gathered at 10 sites stretching from Bellingham to the Olympia area.

Puget Sound's sediment has become generally cleaner over the past 50 years, partly because of a crackdown on pollution and the use of cleaner energy sources, said Eric Crecilius of the Battelle Marine Science Lab, a scientist not involved in the state study.

A reverse during the 1990s likely happened because "there's just more of us," Crecilius said.

State officials said the new study points to another reason for Puget Sound-area residents to drive their cars less.

"The kind of pollution that's getting worse, it's probably because of a lot of repetitive activities by people like you and I," Ecology Department Director Jay Manning said.