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Guidance Policy: Site Soil Data Acquisition and Analysis (Smear Zone 3-D Delineation/Interpretation)
The acquisition and analysis of site soil data can provide a clearer depiction of the vertical and lateral extent of a suspected continuing source of chemicals of concern (CoC) at fuel release sites. PSTD has required this analysis since the first of the year. This delineation of a continuing source of CoC supply should be completed before a consideration of any remediation plan proposal. Field screening for VOCs in soils should be conducted according to the procedure presented in PSTD's "Soil Data Acquisition and Interpretation" Workshop. Additionally, we now require all soil samplin to be conducted according to the methanol extraction methodology incorporated in EPA Method 5035. An approved analytical method must still be used in the analyses for CoC. Prior to preparation of a Purchase Order Request for this analysis, the Remediation Consultant should always communicate with the appropriate PSTD Hydro to determine a work plan that will be required to complete the scope of work. The extent of the analysis will vary from site to site, but all analyses should include, at a minimum, the following data interpretations:
1) A sufficient number of cross sections to adequately depict the full
extent of the smear zone (continuing source of CoC). A minimum number of
sections will not be required, but the optimum number should be agreed to by
both the PSTD Hydro and the Remediation Consultant. Each boring used in
constructed cross sections should show all OVM readings and appropriate
geologic/stratigraphic information.
2)
A constructed isopach map of the extent of the suspected continuing source
zone. More than one isopach map may be required to adequately present a
site's continuing source zone. If so, the appropriate maps should be agreed
to by the PSTD Hydro and the Remediation Consultant.
3)
A ratio map (total footage containing OVM readings divided by the sum of
footage containing OVM readings exceeding a selected cutoff reading).
4)
All data used in the analysis (OVM data, Ratio data, etc.) should be
reproducible by the PSTD Hydro.
5)
Preparation of simple data table, showing all borings used in analysis and
providing the following information: boring number; depths; OVM readings;
corresponding Benzene and/or TPH lab analysis data.
6)
All maps and cross-sections must be titled and contain an appropriate legend
so the PSTD Hydro can readily determine values used in the continuing
source analysis.
7) OPTIONAL: The following data interpretations may be useful in
determining the full extent of the continuing source of CoC at a site but
are not always required.
a) Structure map constructed on top of the continuing source
zone;
b) Structure map constructed on the base of the continuing
source zone; and,
c) Isopach map of overburden covering the continuing source
zone.
Additional costs caused by the methanol extraction method of soil sampling
is a reimbursable expense. If reasonable costs to complete the scope of
work agreed to by both the PSTD Hydro and the Remediation Consultant are not
fully covered by the reimbursable cost of the "3-D Smear Zone
Interpretation" Unit Cost Worksheet, appropriate supplementary costs can be
recouped by including additional hours on the "Stand Alone Time and
Materials" Unit Cost Worksheet. Talk to your Hydro to receive pre-approval
of all proposed work plans. |