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Impact of Oxidant Residuals on Ground Water Samples at ISCO Sites: Recommended Guidelines for Sample Preservation
Citation:
Ko, S. AND S. Huling. Impact of Oxidant Residuals on Ground Water Samples at ISCO Sites: Recommended Guidelines for Sample Preservation. Presented at 8th International Conference on Remediation of Chlorinated and Recalcitrant Compounds, May 21 - 24, 2012.
Impact/Purpose:
Presentation for the 8th International Conference on Remediation of Chlorinated and Recalcitrant Compounds, May 21-24, 2012, Monterey, CA.
Description:
In-situ chemical oxidation (ISCO) involves the introduction of a chemical oxidant into the subsurface for the purpose of transforming ground water contaminants into less toxic or harmless byproducts. Due to oxidant persistence, ground water samples collected at hazardous waste sites may contain both the contaminant(s) and the oxidant in a “binary mixture”. The commingling of organic contaminants and oxidant residuals in ground water samples is mainly the result of heterogeneities in aquifer materials, and consequently, the heterogeneous distribution of oxidants and contaminants. Ground water solutes can enter a monitoring well screen from different lithologic zones, containing different concentrations of oxidants and contaminants. The effects of binary mixtures also extend to bench-scale studies where residual oxidants occur in laboratory reactors and aqueous samples are collected and analyzed for VOCs. Assuming an oxidant is present in either ground water or bench-scale aqueous samples, and the binary sample is not appropriately detected and preserved, the quality of the sample is likely to be compromised.