Cleanup starts on highly polluted Arkema site in Northwest Portland
May 01, 2012 (Menafn - The Oregonian - McClatchy-Tribune Information Services via COMTEX) --After a two-year delay, work is set to begin this week on one of the Portland Harbor's toughest cleanup jobs: Stopping pollution from a former northwest Portland chemical plant that produced DDT and rocket fuel from getting into the Willamette River.
The work -- including a 9.8 million, 1,800-foot-long wall designed to contain contaminated groundwater from the Arkema site -- is crucial to federal Superfund cleanup of the harbor, first listed as a Superfund site in 2000.
Oregon's Department of Environmental Quality originally hoped the work would start in spring 2010. But figuring out details, including a new stormwater collection and treatment system, delayed the launch, said Matt McClincy, a DEQ project manager.
Work on the stormwater system begins this week. Work on the wall, about 30 feet from the riverbank and stretching to bedrock 50 to 80 feet below ground, will begin this summer and be completed by October, McClincy said. The wall will be made of a grout mixture that includes bentonite clay, much like a clay landfill lining designed to keep toxics out of groundwater.
The entire project, including a groundwater treatment system and temporary caps in a former DDT manufacturing area, should be complete by March 2013, McClincy said. State regulators and the company still have to devise a final cleanup plan.
The 54-acre Arkema site, where industrial toxics were produced from 1941 to 2001, sits on the riverfront east of U.S. 30, across the river from the University of Portland. It's one of the most polluted sites along the 11-mile Superfund stretch.
Plumes of DDT and other toxics are still running into the Willamette from the site. And long-delayed work cleaning up contaminated mud in the river can't begin until the groundwater pollution is contained -- the dirty water would re-contaminate cleaned up sediments.
Arkema, a Philadelphia-based chemical manufacturer, knocked down the plant and other structures in recent years. But over the plant's 60-year history it produced a wide variety of industrial chemicals, including sodium chlorate, an herbicide and bleach for paper pulp; chlorine hydrochloric acid; DDT; ammonia and rocket propellant.
The plant made DDT -- a probable human carcinogen that is highly toxic to aquatic life -- between 1947 and 1954. According to environmental records, workers dumped residue of the long-banned chemical into a floor drain piped to the river. That flow was eventually redirected to a nearby pond and, later, to a 285-foot-long trench, contaminating the land as well.
The U.S. Environmental Protection Agency and Arkema are still haggling over how to clean up contaminated river sediments. The disputes include how large of an area to clean up and whether the contamination has to be dredged out of the river, a more expensive option, or contained on site.
-- Scott Learn
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