Incorporation of toxicity testing in site assessment and remediation

Site remediation for contaminated sites may be conducted following chemical analyses of soil and groundwater for specified chemical parameters. These parameters are defined by regulatory agencies and include analyses for metals, mono-, polyaromatic-, and chlorinated hydrocarbons, phenolic and miscellaneous organic and inorganic compounds. Following analyses, data are scored and regulatory exceedances noted. A site remediation plan may be developed using regulatory guideline criteria (chemical-specific endpoints) or a risk assessment. From an environmental protection point of view, such an approach raises a number of concerns. A limitation of criteria-based approaches revolves around the fact that the number of pollutants identified by the regulatory agencies is minuscule compared to the number of known chemicals. Therefore cleanup to chemical-specific endpoints raises questions as to the presence of toxic chemicals that may not be listed by the regulatory agencies and which should be included in a site remediation plan. An alternative to the regulatory chemical-specific approach is to use a toxicity-based approach. In addition to collecting regulatory agency chemical-specific data for contaminated groundwater samples from a contaminated site, toxicity identification evaluations were performed. Chemicals of concern identified using the chemical-specific approach were monoaromatic hydrocarbons, whereas the toxicity based approach revealed that the major contributormore » to toxicity was t-butylphenol. Follow up investigations, revealed that the t-butylphenol was part of an operation that had been missed during the Phase 1 audit of the site.« less