Lower Duwamish Waterway
Source Control Investigation
KC Lease Parcels
River Mile (RM) 1.0-1.2 East
The KC Lease Parcels Source Control Area is located along the eastern side of
the Lower Duwamish Waterway (LDW) Superfund Site between 1.0-1.2 miles from the
southern end of Harbor Island. The aerial photograph shows the area of
interest which is bordered on the east by East Marginal Way South. King
County owns the property adjacent to the Lower Duwamish
Waterway within this source control area and leases it to several facilities.
From north to south, these facilities are:
- Manson Construction Company (Manson Construction),
- Cadman Seattle Inc. (Cadman) and Lehigh Northwest,
- United Western Supply (UWS), and
- J.A. Jack & Sons (J.A. Jack).
The upland areas in this source control area have been heavily industrialized
for decades. Historical and current commercial and industrial operations
in the area of the KC Lease Parcels include cement and limestone production
facilities, boiler shops and construction services. Seattle Boiler Works
and I.F. Laucks (a paint and glue factory) historically operated in the KC Lease
Sediments in the KC Lease Parcels portion of the LDW have been impacted by
chemical contaminants from various sources. Before reaching the LDW sediments
the contaminants first affected upland media including surface water,
groundwater, soil, and air.
The following chemicals are considered to be contaminants of concern in the KC
Lease Parcels source control area because they could possibly recontaminate
Lower Duwamish Waterway sediments once it has been cleaned up.
||PCBs (polychlorinated biphenyls)
||Polynuclear Aromatic Hydrocarbons (PAHs)
||Bis (2ethylhexyl) phthalate
Ecology is the lead for source control for the LDW Superfund site. Source
control is the process of finding and then stopping or reducing as much as
possible releases of pollution to the river. Ecology looks at the drainage for
the King County Lease Parcels source control area in order to determine what
source control work needs to be done. The KC Lease Parcels drainage basin
outlines the area where sources need to be controlled (see picture). The way
contaminants enter Lower Duwamish Waterway sediments from this source control
area include: direct discharges via piped outfalls, bank erosion from adjacent
properties, surface runoff from adjacent properties, groundwater discharge, air
deposition, and spills directly to the inlet.
Source Control Action Plan
Ecology developed a Source Control Action Plan.
This plan describes the source control actions that are necessary to prevent
sediment recontamination. As part of the Source Control Action Plan, Ecology
hired a contractor to put together a Summary of Existing
Information and Data Gaps report.