Just 27 soil samples from a 100-acre site met the owner’s criteria for economic feasibility and satisfied the federal and state environmental regulators
Also see: Investigate the correct contaminant
A 100-acre site had received fill material for nearly 25 years–since the late 1960s. The majority of the fill came from large operators who had total deposits of 10,000 to 200,000 yards. The materials were trucked to the site in loads of 10 to 20 cubic yards each and deposited at different places at different times. The source of the fill material in any given area of the site was not known.
Because it was a well-known land mass and had received a large quantity of fill, the site was investigated by the Technical Assistant Team of the EPA.
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- The investigation resulted in the discovery of zones of waste oil contaminated soil in the fill material deposited at the site.
The owner was directed to conduct an environmental site assessment to determine the presence of hazardous waste. The EPA suspected that hazardous oil refinery waste was included in the fill material.
The owner was understandably concerned about the cost of complying with the environmental regulatory agencies’ request.
- For economy, he needed a site sampling and analysis plan that would utilize the minimum number of samples possible and yet still meet the close scrutiny of the federal and state regulatory agencies.
Harris & Lee Environmental Sciences, LLC developed a cost-effective plan that satisfied the criteria of the environmental regulatory agencies. The plan was designed to collect the minimum number of samples adequate to allow accurate and precise measurement of the chemical properties of the fill material. If the measurements were accurate (free of error) and precise (repeatable), they would meet regulators’ requirements for statistically reliable estimates of conditions at the site.
- Data supplied by the regulatory agencies was used to calculate and estimate the characteristics of a typical “hot spot.”
- Next, statistical analysis was performed to estimate “consumer’s risk” and to establish the mathematical probability of not finding the typical “hot spot.”
- Additional analysis estimated the probability of a “hot spot” existing even if none were found through sampling and the mathematical probability of finding an existing “hot spot.”
- Together with the application of standard statistical methods, these analyses allowed determination of the adequate and reasonable number of samples.
The plan ultimately proposed by Harris & Lee Environmental Sciences called for collection of just 27 samples from the 100-acre site.
- The plan met the owner’s need for economic feasibility and satisfied the federal and state regulatory agencies’ criteria for the environmental assessment of the site.
