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Slip 6 RM 3.7-3.9 East
Lower Duwamish Waterway
Source Control Investigation
Slip 6 RM 3.9-4.4 East
Site Background
The former Slip 6 Source Control Area is located along the eastern side of
the LDW Superfund Site. It sits 3.9 to 4.4 miles from the southern end of
Harbor Island. The map shows the areas of interest which include: the
former Paccar site, the former Rhone-Poulenc site, the Museum of Flight, a
portion of the Boeing Developmental Center, and a portion of the King County
International Airport.
The upland areas next to Slip 6 have been heavily industrialized for decades.
Historical and current commercial and industrial operations in the area of Slip
6 include cargo handling and storage, auto storage lots, truck manufacturing,
chemical processing, aviation operations, and airplane parts manufacturing.
The nearest residential area is about one-half mile to the southwest across the
LDW.
Contamination
Sediments in the Slip 6 portion of the LDW 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.
| Metals |
Organics |
| Mercury |
PCBs |
| Copper |
Dibenz(a,h)anthracene |
| Lead |
Phthalates (butyl benzyl phthalate) |
| Tin |
Volatile Organic Compounds (VOCs) |
| Arsenic |
Semivolatile Organic Compounds (SVOCs) |
| Chromium |
Petroleum Hydrocarbons |
| Nickel |
|
| Zinc |
| |
8801 East Marginal Way South Site (a.k.a. Kenworth Truck Co. Site)
This site
is located at 8801 East Marginal Way South, in Tukwila, Washington on the east
bank of the Lower Duwamish Waterway. This site is bordered to the north by
property owned by The Boeing Company, to the south by property owned by
Container Properties, LLC (formerly the Rhone-Poulenc site) and the Museum of
Flight Foundation, to the east by East Marginal Way South and to the west by the
Lower Duwamish Waterway.
Ecology negotiated an Agreed Order to address the
upland area of the site with PACCAR Inc and Merrill Creek Holdings LLC, the
potentially liable parties (PLPs). Under this Agreed Order, the PLPs will
update and implement an Interim Action Work Plan for the upland portion of the
site.
Click here for more information on the 8801 East Marginal Way South
site.
Source Control
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 Slip 6 drainage basin to determine
what sources need to be controlled (see map). The routes for contaminants to
Slip 6 sediments 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 Slip 6 which describes what source control actions are necessary. As part of
the Source Control Action Plan, Ecology hired a contractor to put together a
Summary of Existing Information and
Data Gaps report.
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