State environmental regulators have found high levels of dioxins in sediment in the Willamette Slough in Salem, and warn that eating fish caught in the area could be unsafe.
The city of Salem, which owns the parks bordering the slough, posted signs Tuesday warning against eating fish caught there.
The contamination may have come from the former Boise Cascade pulp and paper mill, which operated between 1962 and 1982 and used a chlorine bleaching process, the Oregon Department of Environmental Quality said Tuesday.
The “screening level” for dioxins in sediment is 0.001 parts per trillion, said Mike Kucinski, DEQ Western Region cleanup manager.
Samples from the slough came in between 5.5 and 67.9 parts per trillion.
“That does point to it being potentially problematic for people eating fish out there,” said Travis Williams, executive director of Willamette Riverkeeper. “I haven’t seen a lot of this contamination definitively described in the Willamette River above the Portland Harbor.”
It also could pose problems for wildlife, including a heron rookery close by, he said.
DEQ has been working with the company to clean up the site for more than a decade.
The dioxin testing was funded by a U.S. Environmental Protection Agency State and Tribal Response Grant. It began in April, and the final report was completed June 29.
DEQ will work with Boise Cascade over the next few months to complete further sediment and fish tissue studies, Kucinski said. If unsafe levels of dioxin are found in fish tissue, the Oregon Health Authority may issue a consumption advisory.