DEQ Downtown Willamette River Sediment Investigation Finds Pollutants Don’t Pose Recontamination Threat to Portland Harbor

News Release

For release: Feb. 1, 2012

Contacts:
Marcia Danab, Communications and Outreach, Portland, 503-229-6488
Jennifer Sutter, Cleanup Program, Portland, 503-229-6148

DEQ Downtown Willamette River Sediment Investigation Finds Pollutants Don’t Pose Recontamination Threat to Portland Harbor

Based on a recently completed investigation, the Oregon Department of Environmental Quality has determined that pollutants in the downtown section of the Willamette River do not pose a threat of recontamination to Portland Harbor after the site is cleaned up.

 

            During the investigation, DEQ, the City of Portland and other partners studied sediment quality in the downtown Willamette River reach, from the Steel Bridge to Ross Island. DEQ assessed the potential recontamination threat that contaminants in this portion of the river posed to the Portland Harbor Superfund site located just downstream. DEQ made its determination based on comparisons of the range of pollutant concentrations detected in river sediments.

 

 DEQ conducted the study in two phases, beginning in 2008. Phase I included collection and analysis of 117 sediment samples. Phase II included collection and analysis of an additional 36 samples and analysis of several samples archived during the Phase I study. These studies focused on polychlorinated biphenyls, also known as PCBs, dioxins/furans, pesticides (DDT, chlordane, dieldrin), polycyclic aromatic hydrocarbons (also called PAHs), metals (lead, mercury, arsenic), and tributyl tin. DEQ completed the Phase II data report  in June 2010 and finalized its evaluation of the data in November 2011.

 

Based on the Phase I data collection effort, DEQ identified nine areas where additional sampling was warranted to confirm elevated levels of contamination, estimate the size of the contaminated areas, and help identify potential sources of contamination. Follow-up sampling for two of the nine areas, located adjacent to current or historical Portland General Electric facilities, was conducted by PGE.  Other cleanup sites in the downtown reach include Zidell, PGE Station L, Portland Gas Manufacturing, Ross Island, Crescent Site and Central District Greenway. Cleanup has been completed at the Zidell, Station L and Ross Island sites. Remedial investigation is in progress at the remaining sites. 

 

            In general, the Phase II data showed lower levels of contamination than what was detected in Phase I and suggested that contaminated areas are limited in extent. The data collected is helping to focus and prioritize future efforts to identify potential continuing sources of contamination. Additional work on the west side of the river will be considered pending completion of the Portland Gas Manufacturing and Central District Greenway investigations. Additional work on the east side of the river will be considered pending completion of the Crescent Site investigation and considering the results of PGE’s investigations. PGE is currently finalizing a remedial investigation report for two locations just up and downstream of OMSI on the east side of the river.

 

For more information, contact DEQ Project Manager Jennifer Sutter at 503-229-6148, Portland.

 

            DEQ’s evaluation and data reports on this project as well as a fact sheet are available at the DEQ website http://www.deq.state.or.us/lq/cu/nwr/willametteriver.htm .