SAP Addendum Specific to Field Sampling Plan  Remedial Actions under AFCEE ENRAC TO 0019

Section 3 - Sample Collection Procedures

Sampling to be conducted during the environmental studies includes collection of discrete grab soil samples and also composite soil samples.

3.1 - Collecting Discrete Soil Samples

As part of the confirmation soil sampling program, discrete soil samples will be collected from the base and sidewalls of the open excavation after the visibly affected soils and any debris have been removed from the site by the soil excavation subcontractor. If conditions are safe in the open excavation (i.e., depth of excavation is less than five feet), the sampler will step into the excavation to collect the proper number of samples as identified in Section 2.3. If conditions are not safe, then the excavation subcontractor will slope the sidewalls at a slope of 3 feet horizontal to 1 foot vertical, and the soils will be stockpiled for possible later use (as long as a soil sample from the excavated soil pile meets background standards) as backfill into the excavation. The sampler may also collect the necessary samples with the help of the excavation subcontractor. If possible, the trackhoe operator can remove a block of soil surrounding a designated sampling location and bring the block of soil to an area that is safely and easily accessible by the sampler. However, the operator must use great care so as not to disturb the six-inch sampling interval at the designated location as the block of soil is removed and brought to a safer location for the sampler.

Each sample will be collected with a stainless steel hand trowel. The sample depth should extend to a depth of no greater than six inches. In cases where the media to be sampled is bedrock, the sampler will use the hand trowel to chip away an adequate amount of the rock for the sample container. The soil samples will be collected to quantify the concentration of total metals, TCLP metals, and/or other COCs (as presented in Table 2.1) in the soil material after completing excavation and prior to placement of backfill material.

3.2 - Collecting Composite Soil Samples

Composite samples are useful in estimating the overall contamination properties of a specific site; however, composite samples do not provide detailed information of contamination variability as a function of the location. A composite soil sample consists of two or more subsamples from a pre-designated soil volume or land surface area at a specific point in time. Each subsample is collected with a stainless steel trowel and mixed in a stainless steel bowl with the other subsamples. A single average sample is taken from the mixture. Composite samples will be collected for soil piles and designated in-place volumes of soil that must be sampled for waste characterization purposes.

The following specific steps must be followed when compositing soil samples:

1. Determine where composite sample(s) will be obtained from the site.

2. VOCs and, in some cases, SVOCs samples of soils must be collected and contained immediately as stand-alone samples and, therefore, cannot be composited.

3. Collect a minimum of two equal-volume subsamples from the specified sample location with a stainless steel trowel. The volume of each subsample must be at least the amount required for a single sample, and each subsample should be collected from the six-inch depth increment below the surface.

4. Place each subsample in a stainless steel mixing bowl. Thoroughly homogenize the subsamples by mixing with the stainless steel trowel.

5. Transfer the composited sample into the appropriate sample containers. Seal, decontaminate, and label the sample containers.

6. Discard the remaining soil in the mixing bowl and decontaminate sampling equipment.