20090716105324.pdfSubject: LI;TTERREPQRT
SOIL SAMPLING
Former H mOAg Oil UST
21522 96" Avenue West
Edmonds, Washington,
Dear Mr. Tokarz:
HWA GeoScieiices :Inc. (RWA) was coi tracted by you to provide underground storage tank. (UST)
environmental consulting; services at your property :at 21522 96th Avenue West, Edmonds,
Washington.. This report describes soil sampling conducted aiter removal. of:a residential heating. oil
UST (by others). Figure I shows: the project location. We understand that you are redeveloping
the residential property; :anal. require -an: assessment of soil conditions at the former UST location.
BACKGROUND
We understand that. a 300-gallon`heating oil UST was:removed from the property in: June,. 2009.
The UST was not used after the residence was reportedly converted to natural gas !heat between
five and ten years ago. At the time .of the UST removal, petroleum -affected soil was reportedly
encountered adjacent to tilel fill port of the UST. Hales and corrosion were reportedly observed
.in the USTand soils i.mmediately surrounding the UST were observed: to be petroleum -affected.
Approximately four- tons of soils were reproved fivm the excavation surrounding the VST
location for off-site treatment and. disposal.
SCOPIC OF WORK
HWA performed the.fo low ng tasks:
N
0
Collected four soil samples from the base and s dewalls of the' excavation..
,Submitted the soil samples to a Washington State Department of Ecology (Ecology)
accredited. analytical laboratory for analysis for:.heating oil rangepetroleum hydrocarbons by
Washington Method NWTPH=Dx.:
Prepared this report..
June 22, 2009
HWA project No. 2009-078-22
SOIL SAMPLING & ANALYSIS
HWA preformed soil sampling at the UST excavation on June 15, 2009. The excavation was
already open at the time of our site visit; the UST had been previously excavated and removed
by others prior to our visit. The excavation was approximately six feet long by three feet wide
and six feet in depth. Soils in the excavation sidewalls consisted of approximately three feet of
brown silty sand topsoil and fill overlying very dense gray silty sands with gravels. The
underlying soils were interpreted to be glacial till, a compact, unsorted soil deposited by glacial
ice. Glacial till is locally known as "hardpan" and is typically very dense and of limited
permeability. We did not observe any petroleum -affected soils (based on odor or staining)within
the excavation, nor any ground water.
HWA collected soil samples along the excavation sidewalls and base (Figure 2) in general
accordance with UST site assessment guidance (Ecology, 2003). Photographs of the excavation
and sampling locations are included as Attachment A.
ALS Laboratory Group of Everett, Washington, an Ecology -accredited analytical laboratory,
analyzed samples for total petroleum hydrocarbons (TPH) as Diesel and Oil by Washington
method NWTPH-Dx. Table 1 presents the analytical results. Attachment B presents copies of
the laboratory report.
TABLE 1
UST EXCAVATION SOIL ANALYTICAL RESULTS
(all results in milligrams per kilogram (mg/kg))
Notes:
ft bgs — feet below ground surface
Bold — Analyte detected
< — Not detected at given reporting limits
MTCA Method A— Ecology Chapter 173-340 WAC MTCA Method A soil cleanup levels (Ecology, 2001)
Laboratory results did not indicate the presence of diesel or oil range petroleum hydrocarbons in
the soils adjacent to the UST location, with the exception of a low concentration of diesel -range
petroleum detected in the composite sample collected from the north and cast sidewalls. This
concentration is well below the Ecology Model Toxics Control Act (MTCA) Cleanup Regulation
Tokarz UST letter report062309 2 HWA GEOSCIENCES INC.
Sample,
UST B B"
UST B 7
UST -SW 3
UST -NE 3
Method A ,?
Cteanup
Level
One foot
' Comp°site
Composite
i3ase of
„
below base
sample,
south and
— . ...le
n°rth and
Location •
excavation
of
fest
under UST
excavation,
sidewalls
„east
sidewalls
under UST
;
ad',ito USf
ad'ao,U$T.;
Sample de th, It b s
ii
7
3
3
Petroleum
Dlesel Range
<25
<25
<25
30
2,000
Hydrocarbons
Loil Range
<50
<50
<50
<50
2,000
Notes:
ft bgs — feet below ground surface
Bold — Analyte detected
< — Not detected at given reporting limits
MTCA Method A— Ecology Chapter 173-340 WAC MTCA Method A soil cleanup levels (Ecology, 2001)
Laboratory results did not indicate the presence of diesel or oil range petroleum hydrocarbons in
the soils adjacent to the UST location, with the exception of a low concentration of diesel -range
petroleum detected in the composite sample collected from the north and cast sidewalls. This
concentration is well below the Ecology Model Toxics Control Act (MTCA) Cleanup Regulation
Tokarz UST letter report062309 2 HWA GEOSCIENCES INC.
June 22; 2009
FIWA Project No. 2009-078-22
Method.. A soil cleanup level ,of 2 (?0:0 T glkg. Method A -cleanup levels ax'.e- employed i.n.routine.
cleanups of UST sites.
CONCLUSIONS & RECOMMENDATIONS
Because petro:leurn concentrations did not exceed the Method A cleanup levels, and significant
T.csidual: petroleum was not detected in the soil. samples,. subsequent:soil excavation is not
recommended,
Residential heating oil USTs are generally exempt from Washington Department of Ecology
closure and assessinent requirements undei the Underground Storage Tank :Regulations, Chapter
173-350 WAC. However, releases and cleanups from; residential USTs are regulated under the
Model Toxics Control. Act (MT -CA) Qlea. nip Regulation, Chapter 173340 WAC..:
This site is, not likely subject io repot ting requ rentents under MTCA, because the petroleum
release was minor (e.g., only aMeted soils adi,acent to the UST) and petroletunl af'f'ected soils
were removed from the site for proper. treatment.and disposal: We recommend you retain this
report, along with documentation recording the removal of the UST and soils, for purposes of
disclosure to futum lenders or purchasers .of the property or if subsurface work occurs at the UST
location in the future,
RF,FERF,NC'ES
Washington .State Department of Ecology, 2001, Model Toxics Confr ol.Act Clmnup Regulation,.
Chq]. ter 173-340 WAC, Publication No. 94-06,.dated.February 12.
Washington Department of Ecology, 2003, Guidance for Site Checks and Site Assessments of
Underground. Storage Tanks, dated Apel.
0 # 0
We appreciate.the opportunity of providing these services. ShQuid you have anyquestions
regarding this report, or require additional services, please contact us at your convenience.,
Sincerely,
HWA GEoSoENas INc.
(',A,, I _,, L� — Q_
Arnie Sug • L ., LI_G 'Vance Atkins, LG; LHG
President;, nvi .onm.ental Geologist Senior Hydrogeologist
Enclosures: Figure l Site Location Map
Figure 2— Sample Location Map
Attachment A -- Site: Photographs
Attachment B — Laboratory Analytical Results
Tokazz UST tetter rep.Oa002309 3 HSV A G�OSCIENCE-s INC.