Precision Castparts is investigating whether PCBs it dumped into Johnson Creek during six decades of operations in Southeast Portland pose significant risks to human health and the environment, according to the Oregon Department of Environmental Quality, which is monitoring the study.
DEQ said Polychlorinated biphenyls — a class of manmade chemicals known as PCBs — in Johnson Creek came from a Precision Castparts metal fabrication plant at 4600 S.E. Harney St., where the company initially set up operations in 1956. The creek runs just south of the plant near the Clackamas-Multnomah county line.
In 2016, when the Portland Tribune first reported PCBs in the waterway, DEQ said it could not "definitively" identify the source of the toxins. But last week, DEQ spokeswoman Laura Gleim said her agency no longer has any doubt that the PCBs spilled from a storm sewer running from the Precision plant property to the creek.
She said DEQ also is keeping an eye on underground contamination from the plant that is polluting an aquifer running toward the city of Milwaukie.
Precision Castparts, which produces a variety of products for the aerospace industry, has been treating its stormwater runoff since 2016 to prevent further contamination at the site from reaching the creek, she said.
"It's important to note that contamination is no longer migrating from the site into Johnson Creek, and the groundwater doesn't pose a current health risk to people," Gleim said. "We're still gathering data to develop a full characterization for the site, which will take some time."
Precision Castpart's portion of the investigation is expected to wrap up later this year, according to company spokesman David Dugan.
Travis Williams of Willamette Riverkeeper noted that DEQ first learned of PCB contamination in Johnson Creek more than 14 years ago. "It seems a bit absurd that a plan has not been finalized to clean this up," he said.
PCBs are a group of carcinogenic chemicals used in electrical equipment. The manufacturing of PCBs has been illegal in the United States since 1979. PCBs are the main contaminant of concern in the Portland Harbor Superfund site, which is located in the Willamette River several miles downstream from Milwaukie.
As the Tribune reported in 2016, three studies conducted from 2005 to 2014 found steadily increasing levels of PCB contamination in the urban section of Johnson Creek, downstream from the storm sewer's outfall.
The 2005 study discovered the presence of PCBs throughout the entire two miles between the plant and the creek's mouth in Milwaukie. The highest concentrations of PCBs in Johnson Creek were detected in 2014 at a location about 150 feet from the outfall.
One 2014 measurement at a hot spot on the south side of the creek showed PCB levels of 480 parts per billion, or more than twice a standard the agency calls a "risk-based concentration," a level of contamination that is projected to cause at least one cancer diagnosis in 1 million people.
It's not known whether PCB levels at that hot spot are any different today. A new study released in February showed DEQ chose not to resample PCBs there. Instead, the nearest samples were taken on the other side of the creek, where PCB levels were measured to be about 80% lower.
A 2014 investigation of PCBs in soils on the Precision Castparts property found high levels of PCBs at 21 different locations.
Gleim said DEQ will wait until Precision Castparts completes its study before determining "if there is a risk to human health or the environment."
Although Precision Castparts is responsible for conducting the risk assessment, Gleim said the state agency will oversee the study, review it and approve it only if it meets the state's standards.
Such risk assessments are "a standard part of DEQ's cleanup process to evaluate whether contamination is above levels that would require cleanup," she said, noting that DEQ has sole authority over any mitigation.
"The assessment will be used only to guide cleanup decisions made by the DEQ," she said.
In addition to PCBs, the state agency is concerned about Precision Castpart's discharges of volatile organic compounds (VOCs) such as tetrachloroethylene, trichloroethylene and acetone, Gleim said, as well as toxic metals including nickel and chromium. Both metals have been linked to cancer.
Some of these chemicals leached into the groundwater under the plant and drifted south in an aquifer toward the city of Milwaukie, which operates several nearby wells used for drinking water. However, Gleim said the chemicals are not likely to get anywhere near the city's drinking water supplies.
DEQ takes samples of the groundwater in the area four times per year. No PCBs have been reported in the groundwater.
Every year, a handful of coho and Chinook salmon are spotted in the creek, according to the Johnson Creek Watershed Council. In 2018, the city of Portland removed some contaminated soils from the creek near the plant to improve fish habitat and to reduce erosion. The city is expected to release a report on this work this summer.
"These soil actions have improved site conditions," Gleim said, "but are not the final selected remedy,"
Portland freelance writer Paul Koberstein is editor of Cascadia Times.
Find out more
Read more about the Portland Tribune's investigation into Precision Castparts' environmental record:
Precision Castparts hunkers down amid concerns over air emissions
Company also has a water pollution problem, in Johnson Creek
Seattle law firm files class action lawsuit against company
Studies show state knew of problems at Precision Castparts years ago
Precision Castparts responds to neighbors' complaints
State says Precision Castparts' air emissions pose no health threat
Neighbors continue to push for legal remedy against 'Precision Plume'
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