A sequential checklist for the assessment of natural attenuation of dissolved petroleum contaminant plumes from leaking underground storage tanks

Estimates of the number of leaking underground storage tanks (UST) are measured in the hundreds of thousands in the United States alone. The discussion in this article largely pertains to the lighter motor fuels which contain aromatic petroleum hydrocarbons. These include benzene, toluene, ethylbenzene and xylenes (BTEX). The occurrence of dissolved BTEX groundwater contaminant plumes is most commonly associated with leaking gasoline USTs. However, their association with other petroleum products is not uncommon. this article and checklist provide guidance for completing UST assessments, which can support the decision-making process presented in the ASTM Emergency Standard Guide. Following the checklist will measure that the initial site assessment results in an accurate and functional characterization of the details and subtleties of the UST Source Impact Zone. This includes evaluating the UST area to identify release pathways for residual contamination in soil and groundwater. Based on the results obtained from the Source Impact Zone Evaluation, natural attenuation can be assessed for its applicability and performance