24-100334-DOE Findings-01.31.24
Muhammad Saad Mohyuddin
saadmohi@googlemail.com
11/29/2023
Re: Environmental Soil Sampling – SAAD 295th Short Plat
Thank you for the opportunity to provide comments on proposed project at 1013 South 295th Place, in Federal
Way, Washington. The project site includes one 0.55-acre King County Tax Parcel, No. 5151800035. This project
is located in an area predicted to have arsenic and lead in the soil because of the air emissions from the old
Asarco Smelter in Ruston, Washington (Figure 1).
This proposed project includes a 2-lot short plat. The existing
residence will remain, and a new residence will be constructed on a
currently undeveloped portion of the property. Ecology recommended
soil sampling to evaluate the levels of arsenic and lead in the soil prior
to project commencement. Ecology also recommended enrollment in
the Voluntary Cleanup Program (VCP) if lead or arsenic are found at
concentrations above the Model Toxics Control Act (MTCA) Method A
cleanup levels.
On behalf of Muhammad Saad Mohyuddin, Cobalt Geosciences, LLC
(Cobalt) conducted soil sampling on the Property on October 10, 2023
(Figure 2). Cobalt followed the recommended guidance in the
Department of Ecology’s Tacoma Smelter Plume Model Remedies
Guidance.
In October 2023, a total of 16
discrete soil samples were collected
from 12 locations throughout the
Property. Twelve samples were
collected from 0 to 6 inches below ground surface (bgs), and four samples
were also collected from 6 to 12 inches bgs. One composite duff sample
was collected from the site.
Cobalt submitted the soil samples to OnSite Environmental Inc, in Redmond, Washington for analysis of arsenic
and lead using Environmental Protection Agency (EPA) Method 6010D. On behalf of Cobalt, DMP Inc, submitted a
Figure 1. Vicinity Map
Project
report with the results of soil sampling to Ecology1. Ecology reviewed the report and concluded that the average
soil concentrations were below the cleanup level of 20 milligrams per kilogram (mg/kg) for arsenic and 250 mg/kg
for lead (Figure 1). Similarly, no samples exceeded the maximum allowable concentration for a single soil sample
of 40 mg/kg for arsenic or 500 mg/kg for lead.
Sample Depth
(inches)
Arsenic mg/kg (EPA 6010D) Lead mg/kg (EPA 6010D)
Minimum Maximum Minimum Maximum
0-6 soil <11.0 <17.0 <5.4 44
6-12 soil <11.0 <13.0 <5.3 78
Duff (one sample) ND 10
MTCA Levels 40 500
Ecology does not recommend this property enter the
Voluntary Cleanup Program. No soil remediation for the
contamination associated with the Tacoma Smelter Plume is
needed for this property.
Please note, this is not a “No Further Action” determination for
the property since the property was not enrolled into the VCP
with Ecology.
Diana Ison
Technical Assistance Coordinator
Toxics Cleanup Program
Southwest Region Office
Washington State Department of Ecology
diana.ison@ecy.wa.gov
Phone: 360-999-9593
1 Cobalt Geosciences. Environmental Soil Sampling. November 28, 2023.
Figure 2. Locations of Soil Sampling
Figure 1. Summary of Soil Sampling