Lower Duwamish Waterway
Source Control Investigation
Spokane St to Ash Grove Cement
River Mile (RM) 0.0-0.1 East
The map shows the River Mile 0.0-0.1 East (Spokane St to Ash Grove Cement)
source control area. Unlike other source control areas on the LDW, River Mile
0.0-0.1 East includes two different upland areas that are separated by a narrow
stretch of the waterway itself. The Harbor Marina Corporate Center is
located on Harbor Island which lies in the middle of the LDW channel. The
Port of Seattle Terminal 104 and the Ash Grove Cement facility are both located
on the east bank of the LDW.
Three facilities of concern are identified for inclusion in this source control
area: Harbor Marina Corporate Center, Port of Seattle Terminal 104, and Ash
Grove Cement. These facilities have confirmed or suspected contamination
of various upland media, or conduct activities that threaten LDW sediments.
Sediments in the portion of the LDW adjacent to the RM 0.0-0.1 East source
control area have been contaminated by various sources and chemicals. The
contaminants first affected upland media including surface water, groundwater,
soil, and air before reaching the LDW sediments.
The following chemicals are considered to be contaminants of concern with regard
to potential sediment recontamination.
||Phthalates (butyl benzyl phthalate)
||Poly Aromatic Hydrocarbons
||Semivolatile Organic Compounds (SVOCs)
Ecology is the lead for source control for the LDW Superfund site. Source
control is the process of finding and then stopping or reducing releases of
pollution to the river. Ecology looks at the source control area drainage basin
to determine what sources need to be controlled (see map). The routes for
contaminants to LDW sediments in 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 for RM
0.0-0.9 East (Spokane St to Ash Grove Cement) which describes what
source control actions are necessary. As part of the Source Control Action
Plan, Ecology hired a contractor to develop a Summary of Existing Information
and Data Gaps report.