River Mile 11 East Update

Learn more about River Mile 11E: http://yosemite.epa.gov/R10/CLEANUP.NSF/sites/11e 

EPA entered into a settlement agreement (April 2013) with several potentially responsible parties to conduct additional investigations along a section of Portland Harbor known as River Mile 11 East (11E). Signatories to the settlement agreement include Glacier Northwest, Inc., Cargill, Inc., PacifiCorp, CBS Corporation, DIL Trust, and the City of Portland. This area is generally located between the Fremont and Broadway Bridges on the east side of the Willamette River.  Previous studies show this area has elevated concentrations of polychlorinated biphenyls (PCBs) and other contaminants.

PCBs are the primary contributor to human health and ecological risk in the River Mile 11E Project Area.  The main way people are exposed to the chemicals in Portland Harbor is by eating fish such as bass, carp, and catfish, which live in the river year round (resident fish).  A graph highlighting the elevated PCB concentrations in fish tissue in River Mile 11E versus other areas of the Portland Harbor Superfund Site is available for review (see link below).  Other contaminants contributing to risk to humans in this section of the river include dioxins/furans, organochlorine pesticides, and arsenic.

The purpose of the supplemental remedial investigations for River Mile 11E is to obtain additional information needed to select and design the cleanup remedy for this section of the Portland Harbor site.  The intent is to begin cleanup of River Mile 11E and other hot spots (areas with elevated contaminant concentrations), such as Arkema and Gasco, before starting cleanup of the rest of the Superfund site.

Supplemental investigations to be conducted are outlined in the Settlement Agreement Statement of Work, which is available for review (see link below).  Activities to be completed include sampling sediment near and under dock structures; sampling upland groundwater; characterizing the riverbank; sampling porewater and collecting sediment information to inform potential sediment cap design; conducting a geotechnical evaluation of the riverbank and sediment; assessing near shore flow patterns and impact of shipping operations on sediment re-suspension and stability; and evaluating storm water.

Learn more - the following are available on EPA’s website below

  • Administrative Settlement Agreement and Order on Consent for Supplemental RI/FS Work, River Mile 11E Project Area within Portland Harbor Superfund Site, Docket No. 10-2013-0087, April 2013
  • Appendix A to Settlement Agreement, Docket No. 10-2013-0087, Statement of Work, River Mile 11 East Project Area
  • Appendix B to Settlement Agreement, Docket No. 10-2013-0087, Figure 1 – River Mile 11E Project Area
  • PCB Concentrations in Smallmouth Bass Tissue, Portland Harbor Superfund Site, March 2013


 Learn more about River Mile 11E: http://yosemite.epa.gov/R10/CLEANUP.NSF/sites/11e 

Portland Harbor:  www.epa.gov/region10/portlandharbor