DEQ: Landfill 'poses no threat' to Johnson Creek
An abandoned landfill near Johnson Creek in north Clackamas County does not pose a threat to the nearby creek, according to a new review of Oregon Department of Environmental Quality files.
The report appears to resolve questions about the landfill raised by a September 2016 news article in THE BEE's sister newspaper, the Portland Tribune. That report was based on many of the same documents, which the paper obtained through a public records request.
The Tribune's report was on written statements that DEQ officials made in 1980, which seemed to indicate that they were concerned that chemicals leaching from the landfill might contaminate Johnson Creek. But the new report reveals that the DEQ failed to release all of the documents that it had on hand that concerned the landfill.
Despite the Tribune's multiple requests seeking access to all documents related to the landfill, the DEQ failed to provide a solid waste disposal permit from 1971, as well as memos and correspondence related to the development, issuance, and implementation of the permit. It also withheld requests to allow the disposal of used tires at the landfill, various neighborhood complaints, and correspondence.
The old landfill, which has not been used since the 1970s, is now found to be "very unlikely to be causing any impacts to Johnson Creek, or surrounding areas," reported Keith Johnson, an environmental cleanup manager with the agency.
The DEQ based its determination on a fresh review of its old documents, produced in the 1990s and earlier. It has not conducted any new studies on the landfill since the late 1990s.
In the statement, Johnson said that the DEQ no longer sees any reason for concern, other than for methane produced by decomposing material in the landfill. Johnson said that the amount of methane vented by the landfill has decreased over the years, but "still can present real hazards." He called for an investigation of the landfill's methane control system.
The DEQ's review corrected several statements contained in the old files that had been reported by the Tribune. For example, the review found that Precision Castparts Corp., operator of the nearby titanium plant, has not sent any waste to the dump since it closed in 1973, despite a ledger showing it sent waste there in 1979 and 1980. Another DEQ document from 1980 said the unlined landfill was built on a floodplain some 750 feet from Johnson Creek. But the new statement, the DEQ said the landfill is actually located between 1,000 to 1,300 feet from the creek.
The old documents also said that 24 toxic chemicals had leached out of the landfill and had reached the groundwater some 30 feet below the surface. But the new review clarified that the groundwater contained only "low levels" of these contaminants, and does not threaten to contaminate the creek. It recommended no action be taken to address this contamination.
As reasons for its "no action" recommendation, the DEQ cited the "relatively low mobility for metals in groundwater", and the 19 years "of attenuation and degradation" that have occurred since the most recent data was collected. It also said a majority of the landfill is now paved over with asphalt, reducing the amount of rainwater soaking through the ground and leaching chemicals out of the dump.
Meanwhile, the DEQ — in a response to a separate public records request filed by the Tribune — released the Johnson Creek Toxics Evaluation Project, a 2005 study that examined toxic contamination throughout the 24-mile-long creek.
The 2005 study found dozens of toxic chemicals at low levels in Johnson Creek, including seven of the twenty-four chemicals found in the landfill's leachate. At various points in the creek just downstream of the landfill, it found peaks of acenapthene, barium, benzo(a)pyrene, chromium, polyaromatic hydrocarbons, lead, and nickel.
If these substances were not from the landfill, it is not clear where they came from. The study found similar peaks for these and many other chemicals near the Precision Castparts plant located more than a mile farther downstream from the landfill.
The study also revealed that the creek contains quite low levels of substances that could possibly have originated from the Precision Castparts plant, such as PCBs; and several others that most likely did not, such as DDT and Aldrin — pesticides that are no longer in use in the United States, but still persist in the environment decades after they were banned.
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