VOC Ground-Water Sampling Decontamination Procedures: A Case Study

Abstract

A case study is presented where acetone was detected in ground water at a site even though acetone was neither used by the current or previous facility operators nor during ground-water sampling for volatile organic compounds. Sampling and decontamination procedures followed recommended U.S. Environmental Protection Agency (USEPA) decontamination procedures. The only organic solvent used during field decontamination procedures was pesticide grade isopropanol. Acetone was detected in the pesticide grade isopropanol used during the field activities. Investigation of the chemistry of isopropanol and acetone indicated that isopropanol can be oxidized to acetone. The results of a controlled test showed that isopropanol and acetone can be introduced into a ground-water monitoring well via decontaminated sampling equipment even after residual decontamination reagent is allowed to air dry in accordance with USEPA procedures. It is concluded that standard decontamination procedures can introduce regulated substances into the ground water. Decontamination procedures should be continuously reviewed and updated, designed for specific sites, and evaluated by skilled professionals based on analytical results obtained for a site. The use of pesticide grade isopropanol for decontamination at sites where acetone is a constituent of concern should be avoided altogether.