Alcoa Petitions to Dredge PCB-polluted Sediment
by Erik Robinson
The Columbian, February 17, 2008
Alcoa will dredge 36,000 cubic yards of PCB-tainted sediment from a heavily polluted stretch of Columbia River shoreline in Vancouver, according to an application filed last week with the Army Corps of Engineers.
The document alluded to difficulties Alcoa has had corralling pollution at the site of its now-defunct aluminum smelter.
The Pittsburgh-based company applied to begin dredging the sediment along a 2,300-foot-long section of shoreline beginning in November. The tainted sediment - the equivalent of roughly 3,600 dump truck loads - will be hauled away by trucks for permanent disposal.
State environmental regulators had been aware that the shoreline was polluted with polychlorinated biphenyls, but had yet to force a cleanup of the suspected carcinogen. After researchers last year revealed alarmingly high levels of PCBs in clams in the area, Gov. Chris Gregoire ordered the state Department of Ecology to accelerate the cleanup.
The application is a routine aspect of the cleanup, but it does provide insight about the origin of pollution.
It reiterates Alcoa's contention that Clark Public Utilities unloosed the pollution when it built an outfall pipe from a new power plant in 1997.
"The investigation confirmed that the disturbance of shoreline soils during construction of the outfall was the source of PCBs detected in Columbia River sediments and that 95 percent of the PCB mass was concentrated in a 'hot spot' near the outfall location," according to Alcoa's dredging application.
At the same time, Alcoa acknowledged its own problems keeping PCBs out of the river.
The company, in a 2003 agreement with the state Department of Ecology, tried to stabilize a landfill containing decades of industrial waste from the aluminum smelter. The company lined 800 feet of the landfill next to the shoreline with articulated concrete block, or ACB.
"However, within several months of installation of the ACB, several areas of erosion occurred at the toe of the ACB slope adjacent to the water's edge," according to the document.
Alcoa repaired the embankment by installing a rock buttress at the toe of the slope, along with large logs every 50 feet. The Port of Vancouver is negotiating to buy the old Alcoa property for redevelopment, inviting a heightened level of public scrutiny to ensure the repair stays intact.
"At the time of this permit application, the buttress continues to provide adequate protection against erosion where supplemental rock was placed in 2006," according to the document signed Wednesday by Mark Stiffler, Alcoa's director of asset management.
Alcoa brought the smelter online in 1940, making it the first aluminum smelter in the Pacific Northwest.
Alcoa will dig up and dispose of all clams on the site, to minimize the chance of anyone harvesting them directly - or allowing them to be consumed by other aquatic life. PCBs tend to concentrate in long-lived creatures at the top of the food chain, such as sturgeon.
The substance, historically used as an electrical lubricant, has been banned from production in the U.S. since the 1970s because of negative health effects.
Research shows long-term exposure to PCBs causes cancer and other health problems. The longer and greater the exposure, the greater the risk.
Toxicologists say health problems can crop up with exposure to PCBs through the food web, such as by eating sturgeon, which devour the clams, shell and all.
Federal health researchers have also raised concern about the pollutant slowing behavioral and neurological development in babies born to women eating PCB-contaminated fish.
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