Managing Petroleum Contaminated Soil: Department of Transportation Perspective

Federal and state policies governing contaminated site investigations and remediation strategies have evolved over the past several years. Advances in treatment technologies, especially in situ methods of remediation, are largely responsible for this evolution. However, public opinion has also influenced environmental regulators and helped to shape policy. In dealing with issues of contamination, especially in conjunction with on-going construction projects, making appropriate choices on how to handle petroleum-contaminated soil requires more than comparing costs of treatment methods and weighing the advantages and disadvantages of various cleanup options. Selection of a remediation technique to clean up a site must take into account the community in which the site is located. Local governmental agencies and public opinion can play a strong role in determining what remediation actions are allowable, especially regarding highly visible ex situ treatments. The ability to choose among methods of soil treatment may be quite limited for some responsible parties, depending on whether construction activities are taking place through the zone of contamination and what the current regulatory climate is. It is crucial, especially for state agencies like transportation departments who serve the public, to involve communities early on in cleanup efforts. How a remediation project is implemented and received by the public can have great influence on its acceptance in the future. The objective of this paper is to describe the Minnesota Department of Transportation's experience in dealing with petroleum-contaminated soil and how changing philosophies from environmental regulators and local politics have influenced the process. Descriptions of treatment methods used by the Minnesota Department of Transportation are provided. The paper concludes with a discussion of an emerging issue that may have a significant impact on remediation projects in the future throughout the nation. Paramount to making sound cleanup decisions is the availability of meaningful site contamination data and a scientifically defensible framework for interpreting the data. State and national work groups have already instituted, or are currently evaluating, a unique approach to quantify and interpret total petroleum hydrocarbon analyses that can be used to determine if a site should be remediated and the appropriate cleanup thresholds. This technique can assist in making scientifically defensible remediation decisions that are based on risk determinations to human health and ecological endpoints