Remedial Investigation

A Remedial Investigation (RI) takes an in-depth look at the nature and extent of contamination in a Superfund site, including surface and subsurface sediment, fish and shellfish tissue, surface water, groundwater, and storm water,  It also describes the physical features, current and historical land and harbor uses, and habitat areas of the river and nearby lands. In the Portland Harbor, the initial RI studied a 10 mile stretch of the lower Willamette.


The RI consists of two primary components:  A Human Health Risk Assesment (HHRA) and a Baseline Ecological Risk Assessment.


EPA received the draft Portland Harbor Remedial Investigation (RI) Report from the Lower Willamette Group in September, 2009.  Here is a link to the Executive Summary.


One key finding of the draft report is that the most significant and widespread risks are from exposure to four chemical groups – Polychlorinated biphenyls, (PCBs), dioxins and furans. DDT, and polycyclic aromatic hydrocarbons (PAHs). Ingestion of resident fish poses the greatest risk of adverse health effects for humans. However, there are many other contaminants that pose some risk.

The draft RI report is the outcome of a thorough eight-year undertaking to study the Portland Harbor Superfund Site and it provides the base of knowledge needed to complete the remaining steps of the cleanup planning process, including a Feasibility Study to develop and evaluate viable cleanup options, a Proposed Plan for public comment and then issue a Record of Decision to document EPA's cleanup decision.

Key sections of the report are posted on the EPA Portland Harbor website.  A paper copy of the RI report is located at the St. Johns Branch of the Multnomah County Library.  You can also get a DVD copy of the report by sending an e-mail request that contains your mailing address.


EPA reviewed the RI for accuracy and completeness and submitted initial comments to LWG regarding the HHRA and BERA in Dec. 2009.  For a full copy of the comments sent by EPA to LWG, click here.


The CAG sent comments to EPA as well, echoing many of these concerns.  To read the letter sent to EPA by the CAG, click here.  To read Environmental Stewardship Council's summary of concerns, click here


To summarize, the CAG's primary concerns over the HHRA are:


1.  Uncertainties identified in the assessment are resolved in favor of lowering the risk estimate, which results in underestimating risk. 

2.  Inappropriate decisions made by LWG in the BERA resulted in removal of chemicals from consideration prematurely.

3.  Both risk assessments fail to consider the combined or synergistic effects of chemicals, which results in an underestimate of the true risk of each chemical.

4.  The BERA does not adequately consider the impacts on the threatened and endangered Peregrine Falcon which is known to nest and hunt in the study area.

5.  All of these concerns will result in a level of clean up that is not protective of human health and the environment as required by CERCLA.


LWG received extensions from EPA to address the agency's concerns in its revised HHRA.  The deadline for the revised HHRA is May 2, 2011.


LWG presented to the CAG on May 11, 2011 about revisions to the HHRA.  The presentation can be found by clicking here.

The Revised Baseline Ecological Risk Assessment is due to EPA in July.


The Final Remedial Investigation is due to EPA on August 28th.  LWG will then submit its Feasibility Study on November 15th.