The report notes excessive health and cancer risks for people who eat fish from the Willamette between Oregon City and Salem

Wednesday, December 6, 2000

If you eat fish from the Newberg Pool, you're boosting your cancer risk.

That's the conclusion state environmental health officials draw from a study of human health risks of fishing the Willamette River between Oregon City and Salem.

The study released Tuesday found that even one monthly meal of any of four nonsalmonid fish species found in the pool poses a long-term cancer risk of more than 1 in a million, which while seemingly low is unacceptable by state health standards. The risk is far greater for subsistence fishermen, and the polluted fish pose dangers to growth and immune systems of children and childbearing women who eat the fish regularly.

Polychlorinated biphenyls, dioxin and now-banned pesticides such as aldrin and DDT-related compounds accounted for most of the cancer risk. PCBs and mercury also pose other noncancer health problems. The study found all of the persistent contaminants at varying levels in 75 carp, smallmouth bass and northern pikeminnow.

Oregon Health Division officials responded to the findings by reissuing their 1997 riverwide consumption advisory. The advisory, based on mercury levels in fish throughout the river, warns children and women of childbearing age to limit their fish intake to as little as a half-serving every seven weeks.

The study, which was overseen by the Oregon Department of Environmental Quality, found recreational anglers who regularly consume Newberg Pool fish most at risk: Their chance of getting cancer from a weekly portion increases to 1 in 100,000. And those who eat the fish 19 times a month, for example, have a greater than 1-in-10,000 cancer risk. Such consumption risks do not take into account many other possible risk factors, such as genetics or smoke exposure.

The study suggests cooking methods do matter. Overall cancer risks run 2 to 11 times greater for individuals who eat the whole fish, as opposed to just fish muscle. Officials recommended that fish be thoroughly cleaned, skinned and filleted before eating. Doing so will help avoid the fatty tissues where the most toxic contaminants accumulate, they say.

The study drew fish from a 45-mile stretch between Oregon City and the Wheatland Ferry north of Salem. But experts say the results have implications for fishermen and landowners along the entire river.

Downriver implications
The study likely means the contaminants lurk elsewhere in the river, particularly in the lower Willamette River, now the focus of a Superfund cleanup, said Eugene Foster, a DEQ toxicologist.

"It's probably, I would suspect, a systemwide concentration," Foster said. "I would expect these concentrations to be similar or higher downstream."

Scientists characterize many of the contaminants found in the study as persistent poisons. Gov. John Kitzhaber has asked state agencies to eliminate them by 2020.

The contaminants lurk for decades and naturally cling to fatty tissues. They also biomagnify, meaning their levels multiply as they pass from fish to birds and humans. That, more than the pool's water chemistry, poses the greatest health risk to humans, said Ken Kauffman, a state environmental health specialist.

"The bioaccumulation phenomenon is really what magnifies these risks," Kauffman said. "If you just look at the water (chemistry), you don't see the risks."

PCBs were widely used to cool electrical transformers. Pesticides likely come from farms, forests and urban runoff.

Dioxins come from trash burning, wood-treating chemicals and historic pulp- and paper-mill bleaching processes. Mercury occurs naturally but also comes from past mining and other human activities.

Scientists also suspect the pool's basalt-lined channel and low gradient allows pollutants that otherwise would be carried downstream to settle out into the river bottom, said Stanley Gregory, an Oregon State University fisheries professor.

Areas for long storage
"The water spends a lot of time there and drops its particles out," Gregory said. "Any of the chemicals that get dumped into the river tend to store there. It's in some ways a fairly simple pipe with deep areas for long storage."

One quarter-mile stretch of the pool near Newberg slinks past a closed landfill and receives wastewater from Newberg's sewage treatment plant, along with discharges form a private pulp and paper mill. But Foster said previous laboratory tests of both wastewater streams found no impacts on northern pikeminnows.

The study was the last and most expensive of a $313,000 series of studies on the Newberg Pool commissioned by the 1997 Legislature. Together, they show that humans have more to fear from fishing than swimming in the Newberg Pool, Foster said.

Among the overall findings:

• Swimmers generally seem safe. A July 1999 study found summertime bacteria levels in the river below human health standards, though windswept waters around Bernet Landing, near the confluence of the Tualatin River, approached unsafe levels of E. coli. The study did not consider the effects of heavy rains, which can generate harmful levels of bacteria. Escherichia coli can cause severe bloody diarrhea, kidney failure, even death.

• The pool's fish show deformities of uncertain origin, and they are plagued with parasites. A 1998 analysis of 1,000 fish found skeletal deformities in 9 percent of northern pikeminnows. That's lower than previous studies. But 26 percent of all chiselmouth turned up deformed. And 50 percent to 75 percent of both species contained parasites.

• In a June 1999 study, scientists grew hundreds of trout eggs in the pool, then hatched them in a lab. One-third developed crooked spines and deformed skulls.

Sources still a question
Still, all four studies fail to answer a decade-old question among conservationists and scientists: What is harming the pool's fish, and who or what is responsible?

"We need to know more, and we need to know as soon as possible everything we can about this," said Travis Williams, executive director of Willamette Riverkeeper. His group recently published a study that found elevated cancer risks from dioxin in the Portland Harbor area. "With what we know about the Newberg Pool area and its fish skeletal deformities, it sadly does not surprise me."

DEQ's Foster said more targeted testing is needed to answer the key questions. Agency officials say they will seek legislative approval next year for additional fish-tissue testing within the pool.