| Air deposition |
Contamination entering a site by being carried on the wind as dust. |
| AOPC |
Area of Potential Concern - where remediation efforts will occur within a Superfund cleanup. |
| ARAR |
“Legally applicable or relevant and appropriate standard, requirement, criteria or limitation” promulgated under federal or state environmental laws. |
| Background |
The contamination level at a site that cannot be removed due to its continuing existence in the environment. Waterways and sediments in urban areas have higher background contamination levels, called “urban background” than do undeveloped areas. Undeveloped areas have lower levels of contamination referred to as “natural background”. |
| “C” Alternatives |
Alternatives within the Lower Duwamish Feasibility Study that focus on “Containment” of contamination through capping. “C” alternatives increase the seafood consumption risk, have longer construction periods and higher impacts for the community than do “C” alternatives. |
| Capping |
Physically and/or chemically containing sediments in place. Achieved by placing clean sand, gravel or rock above contaminated sediments. |
| COC |
Chemical of Concern – the chemical contaminants that trigger a cleanup and are monitored to evaluate the effectiveness of a cleanup |
| CSL |
Cleanup Screening Level (MTCA term; only minor adverse effects from sediment remain when achieved) |
| Dredging |
The physical removal of contaminated sediments from a waterway. Dredging projects increase and prolong the risk to human health from seafood consumption by stirring up contaminated sediments that are left behind during the dredging process and then consumed by fish. |
| EAA |
Early Action Area – specific sites within the Lower Duwamish Waterway cleanup area that the LDWG partners (King County, City of Seattle, Port of Seattle, The Boeing Company) agreed to clean up prior to the Superfund listing. These projects serve as the basis for every cleanup alternative proposed in the Feasibility Study. |
| ENR |
Enhanced Natural Recovery- encouraging natural processes that reduce health risks from contamination, typically by placing thin layers of clean materials on top of contaminated areas. |
| ICs |
Institutional Controls – nonengineered methods for reducing the risk from a Superfund site’s contamination, such as seafood consumption advisories or beach closures. |
| MNR |
Monitored Natural Recovery – tracking natural processes’ reduction of health risks from contamination |
| PRP |
Potentially Responsible Party – those entities the U.S. EPA believes to be responsible for the contamination at a Superfund site. There are more than 100 PRPs associated with the Lower Duwamish cleanup, including King County. |
| PRG |
Preliminary Remediation Goal – The level of chemicals of concern necessary to attain to achieve the cleanup’s risk reduction goals |
| “R” Alternatives |
Alternatives within the Lower Duwamish Feasibility Study that focus on “Removal” of contamination by dredging. “R” alternatives increase the seafood consumption risk, have longer construction periods and higher impacts for the community than do “C” alternatives. |
| RAL |
Remedial Action Level - The chemical of concern level triggering remediation at a Superfund site. |
| RAO |
Remedial Action Objectives – The cleanup’s risk reduction goals |
| ROD |
Record of Decision – The U.S. EPA’s formal announcement of its decision on how to clean up a Superfund site. |
| SMA |
Sediment Management Area – The area likely to be cleaned up during a Superfund. |
| SMS |
Sediment Management Standards – The cleanup’s criteria including Sediment Quality Standards and Cleanup Screening Levels |
| SQS |
Sediment Quality Standards - more stringent than a CSL. All risk to biological resources or humans from sediment are removed at this level |
| SWAC |
Surface Weighted Average Concentration- Post-cleanup sediment concentrations, in this case describe the average PCB sediment concentration in the Lower Duwamish cleanup site. |
| VM |
Verification Monitoring |
