SOIL MANAGEMENT
specific action levels to determine if additional sampling is required or if final decisions can be made from the current data.
How Much Time Can It Take?
As stated earlier, a Phase I ESA typically requires three to four weeks to complete. The sampling and analysis plan can take a week or more to develop, depending on the size and complexity of the project. If the plan needs regulatory approval, it will take another month, and often longer. The need for review by other interested parties will also require additional time.
2a
Following approval of the SAP, scheduling of the drilling or excavation contractor (depending on the sampling approach) may require several weeks. The duration of field work is depen- dent on the size and complexity of the project. A reasonable range for most average-sized commercial construction projects is one to four weeks of field work. Sample shipping, processing, and standard analytical turnaround can require two to three weeks (and even longer for dioxin analysis).
Even if paying 100% markup for 24-hour results, that 24-hours doesn’t start until the soil is in the lab, dried, and appropriately prepped. That’s three to five business days to get the fastest possible result. It’s also important to factor in lab capacity, as the laboratory cannot always accommodate such a fast turn-around time due to staffing and equipment requirements. Furthermore, some analyses simply can’t be performed in 24 hours (e.g., dioxins). If the timeline allows for standard turnaround time results can be expected within two to three weeks from the date of sampling.
2b
Data evaluation and preparation of a technical report may require an additional two to four weeks once analytical results are available (again, depending on the complexity of the project). Assuming sampling and analysis is complete, and an additional iteration isn’t necessary to delineate the extent of contamination, meet regulatory requirements, or fulfil project objectives, the next step would be to prepare a Soil Management Plan (SMP) to address contamination dis- covered at the property. An SMP typically requires another week or two. Prior to initiating site activities, the SMP must be distributed and well understood by all stakeholders, including the owner, general contractor, civil contractor, on-site environ- mental professional, and the regulatory agency.
Are there Strategies for Cost Savings?
There are planning and scheduling techniques that can be employed to achieve cost savings on some projects. These tech- niques require more field time up front but can be implemented to possibly avoid multiple re-mobilization events.
2c
Figure 2a. Single DU with increment locations and single analytical result.
Figure 2b. Example of inter-sample variability of contaminant concentrations in soil samples collected within a few feet of one another.
Figure 2c. Example of intra-sample variability of contaminant con- centrations in subsamples within a single discrete soil sample.
necessary based on statistical analysis of replicate data, and finally compares it to both the most conservative and project-
32 TPG •
Oct.Nov.Dec 2022
One such strategy is to utilize contingent analyses. If the project is set up to include DUs from multiple depths or lateral areas to determine how far contamination extends (horizon- tally and vertically; perimeter DUs), analysis of the perimeter samples may be delayed pending results of samples from the more suspect DUs (spill DUs; Figure 3). If contaminants are detected in samples from the spill DU at concentrations that require additional investigation, the perimeter samples can then be analyzed for only the constituents of concern previ- ously detected. This results in savings for both analytical and remobilization costs. If contaminants are not detected in samples from the spill DU at concentrations exceeding
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