Feasibility Study

After finalizing its Remedial Investigation in August 2011 to determine the scope, sources, and magnitude of contaminants present in the Portland Harbor that pose unacceptable risks to humans and the environment, Lower Willamette Group will complete its draft Feasibility Study (FS) which assesses various cleanup or remedial options.  The FS was due to EPA on November 15, 2011.  EPA has granted an extension until Mar. 30, 2012 for LWG to incorporate a more detailed anaylsis of RALs and alternatives to augment the use of the FS as a tool in designing the Proposed Plan and ROD.

 

The FS will have various sections, outlined below, that are designed to provide EPA with a full range of options on which to base its ultimate cleanup decision in the Record of Decision (ROD).  In the FS, LWG will suggest to EPA what it believes is the best cleanup strategy based on what it learned in the FS process, but EPA will make the final decision in the ROD.

 

The FS is comprised of four primary sections:  Remedial Action Obectives (RAOs), Remedial Goals, Remedial Options, and an Alternatives Analysis.

 

Remedial Action Objectives (RAOs)

 

     RAOs can be broken into three subgroups: human health, ecological health, and site-wide management goals.  The objectives are aimed at reducing risks to humans and wildlife from contaminants whether through ingestion, sediment contact, or surface water, groundwater, and indirect exposures.  To see a full list of RAOs provided by LWG, click here.

 

Remedial Goals

    

Preliminary Remediation Goals (PRGs):  These are concentrations of contaminants in sediments expected to meet RAOs.  These concentrations will help guide EPAs decisionmaking process when deciding final cleanup levels in the ROD.

 

Areas of Potential Concern (AOPCs):  These are areas where concentration levels in a given area of sediment exceed RAOs.  The FS focuses on these areas to determine if they require cleanup.  However, these areas represent risk only and do not take other factors such as implementability into account.

 

Sediment Management Areas (SMAs):  These areas are based on AOPCs and developed to take into account both risk and non-risk factors, allowing greater flexibility in managing areas with individual needs.  For example, SMAs may be developed to take into account the depth necessary to remediate to remove a contaminant risk or such non-risk factors as shoreline or navigational uses.

 

 

Remedial Options

 

Below are some examples of possible remediation options.  This list in not exclusive, however, it gives a good sense of various technologies and options.  Keep in mind that in both the FS and the ROD, a combination of these options will likely be employed for various contaminants and cleanup areas.  Also keep in mind that some of these options may have the potential to remove multiple contaminants that are "co-located."

 

         Dredging

         Capping

         Disposal

         Monitored Natural Recovery

         Treatment

 

 

To read the presentation of CAG's technical advisor, Peter De Fur, on the topic of Remedial Options, click here.

 

Alternatives Analysis (AA)

 

This section of the FS will evaluate the various remedial options in light of the RAOs, the Remedial Goals, as well as other factors such as cost, implementability, and both long and short-term effectiveness.  The AA will set forth various options and scenarios and will make a recommendation to EPA as to what LWG believes are the best combination of cleanup options.  Ultimately, EPA will decide the cleanup required in the ROD, a final agency action subject to judicial review.