Environmental Litigation Issues in Taiwan and the Forensics Strategies of Chlorinated Hydrocarbon Contaminated Sites

Based on the Soil and Underground Water Pollution Remediation Act of Taiwan, a site has to be enlisted first before a proper pollution control measure can be enforced and liability be imposed. To enlist a site, proof should be provided to demonstrate that the pollution source is well-defined or is located. However, it could be subjective as to what can be the proof. This has been one of the major litigation issues faced by the Taiwan EPA, particularly on the chlorinated hydrocarbon contaminated sites. To learn from these litigation issues, a contaminated site whose enlisting decision just got rescinded in court was presented and the forensics strategy was discussed. According to the court decision, a localized contour of trichloroethylene in the groundwater was not considered as a solid proof of a pollution source because the contaminants could come from elsewhere and accumulate on that site due to hydrogeological heterogeneity. Thus, the proposed strategy was comprised of two aspects. One is to strengthen the arguments presented and to eliminate the scenarios like those brought up by the judges in this case. The other is to provide the direct evidence, such as visual demonstration of the migration pathway or highly contaminated soil which indicates the presence of non-aqueous phase liquids. With the aid of compound-specific isotope analyses, we were able to verify only one source existing on the site and to narrow down the location. An in-situ mapping using membrane interface probing coupled with a detector sensitive to halogenated organic compounds was also attempted to help determine the soil sampling locations. With a combination of multiple lines of evidence, a conclusion shall be drawn based on a clear causation relationship.