Evaluating “Hot Spots” of Soil Contamination (Redux)

Abstract

Every day, thousands of soil samples are collected from properties suspected of being contaminated. The samples are sent to laboratories where the chemical constituents are quantified. Frequently, one or more samples are identified as constituting a “hot spot” of soil contamination. The consequences of such a determination—more sampling, more remediation, more reporting—are often quite expensive. Yet despite the often costly consequences of identifying a “hot spot,” there appears no supportable methodology for objectively deciding which spots are “hot” and which are “not.” This can lead to situations where sampling episodes are required to demonstrate that there is not a problem, even though just exactly what would comprise a “problem” is not particularly clear and sometimes is not stated. The authors provide a review and analysis of common and published information concerning “hot spots.” They then present a different point of view about “hot spots” from those in common practice, a point of view that will challenge many environmental professionals to reconsider how they evaluate sampling results.

Keywords:

• hot spot
• soil contamination
• soil sampling
• risk assessment

Acknowledgements

The authors are grateful to Joanna Kruckenberg and John Muegge, both of the California Department of Toxic Substances Control, for their help with illustrations. The authors also wish to thank Jiayi and Shih-Wen Young whose art was inspirational.

The views and opinions presented herein are solely those of the authors, and do not reflect the policies or positions of the California Department of Toxic Substances Control, the California Environmental Protection Agency, the Wisconsin Department of Commerce, the Interstate Technology & Regulatory Council (ITRC), or any other organization with whom the authors are affiliated.