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Site Assessment and Sampling
Determining the amount of contamination present on a site is a large part of the cleanup process. Presented here are a few guidelines for examining the site. This investigation stage requires three parts: determining the physical makeup of the site, evaluating the contaminants onsite, and reporting the findings.
Physical Site Assessment- First, the party responsible for evaluating the site should determine the physical makeup of the site. They should establish:
- Groundwater direction
- Composition of the soil
- Depth to the water table and bedrock
- Distance to the nearest surface water
- Presence of aquifers
- Physical land features (elevations)
- Vegetation and Drainage
Understanding the composition of the site and its physical makeup is
necessary to determine how contaminants will travel across the site.
If this is not understood, it is difficult to create an adequate remedial
action plan.
Sampling Technique
After the site has been physically examined, it should be sampled for
contaminants. Since there is no standard for the distance between samples,
it is difficult to determine the adequacy of a sampling plan. Initially,
enough samples should be taken to get an idea of the overall contamination
of the site. This includes testing air, groundwater, and soils for
contamination.
Once the initial sampling is completed, further samples should be taken in
areas of concern. Part of a site might be considered an area of concern if:
-
Contamination is visible
- Initial sampling shows contamination
- Historical use suggests contamination
- Underground storage tanks are nearby
- Area is discolored or smells
The contaminants found should also influence the sampling done. If soluble or leachable chemicals are found in the soils, then both the ground and surface water should also be tested. If volatile contaminants are found, then the air should be tested on the site, as well as air in soil pores.
Reporting in the Remedial Action Plan (RAP)
Any complete Remedial Action Plan (RAP) should contain a complete table
of sample results as well as a site map. It is important that the sample
locations have unique sample numbers, as should each samples. With an
accurately numbered table of results and site map, contaminants can be
easily tracked across the site.
The table should include:
- L ists of all samples and their unique sample numbers
- Results of all samples
- Relevant criteria
- Test methods used
- Test method detection limits
The site map should clearly show:
- Site boundaries
- Locations of all buildings
- Locations of any removed buildings, storage tanks, pipelines, etc.
- Locations of all samples and monitoring wells (numbered)
- Groundwater direction
- Any areas of concern
Web Pages Created by Aaron Hula
The Midwest Hazardous Substance Research Center, Michigan
State University.
Please contact us if you have any
comments or questions.