Stormwater's damage to Puget Sound huge, report says

Every year, Puget Sound suffers an oil spill equal to more than half an Exxon Valdez. It just happens drop by drop.

Stormwater from roads, parking lots and elsewhere carries between 6.3 million and 8 million gallons of petroleum into the Sound every year, according to a report issued Friday by the state Department of Ecology. The 1989 Valdez accident in Alaska dumped 11 million gallons.

And the flow into Puget Sound dwarfs the amount of oil that comes from accidental spills, which add up to 270,000 to 340,000 gallons each year.

The findings of the new report underscore a long-standing problem of stormwater pollution as a push to clean up Puget Sound gets under way. It also shows the difficulty of corralling contamination that comes from the region's pavement and storm drains, instead of pipes from a handful of factories.

"Certainly, when you look at the diffuse nature and the complexity of runoff ... yeah, it will make the challenge greater," said Josh Baldi, a special assistant for Puget Sound with the Ecology Department.

Oil is just one in a list of well-known contaminants winding up in the Sound. Others include heavy metals such as lead and mercury, along with pesticides, potentially toxic flame retardants and PCBs, the industrial chemical banned in the 1970s.

While runoff is the biggest single source, toxic chemicals also waft through the air before winding up in the Sound, especially hydrocarbons from car and truck exhaust, and woodstoves, among other sources. And the report may underestimate the amount of toxic chemicals coming from factories and wastewater plants, partly because they don't routinely test for some of the chemicals, Baldi said.

The study comes as the newly created Puget Sound Partnership, a state agency, crafts a plan to clean up the Sound by 2020. The new report is meant to give policymakers ideas about where the biggest problems are and what approaches might work best.

Granted, the steady trickle of oil doesn't have the dramatic impacts of an oil spill such as the Valdez, or the Nov. 7 spill in San Francisco Bay that coated beaches. But scientists have found that even tiny amounts of hydrocarbons in oil can cause long-lasting harm to fish.

After the Valdez spill, researchers discovered that herring and pink salmon that had been exposed as embryos to traces of oil developed curved spines, unusually small jaws and small eyes.

Now, researchers at the federal Northwest Fisheries Science Center, headquartered in Seattle, have found that hydrocarbons can hurt the hearts of developing herring embryos in laboratory experiments, said John Incardona, a research toxicologist there. That can prove fatal. He is now studying whether even lower levels of the chemicals cause problems such as heart defects that affect the fish's ability to thrive.

The Ecology study did not look at other forms of runoff pollution that aren't toxic chemicals, such as bacteria that force closures of shellfish farms and can sicken people, and nutrients that can cause algae blooms.

The latest findings run counter to public perceptions, according to recent polls, that Puget Sound is being sickened chiefly by pollution from industry.

"This study helps reverse that thinking," said Heather Trim, of the environmental group People for Puget Sound. "All of us driving around in our cars and all the things we are doing in our homes and our business are all contributing to this problem."

Warren Cornwall: 206-464-2311 or wcornwall@seattletimes.com