Chlorinated Solvents

Historical storage and disposal practices mean that chlorinated solvents can be present in substantial amounts beneath former manufacturing and tertiary industrial sites. They pose risks to health and the environment due to their partially-soluble and volatile nature and the high toxicity of primary compounds and their breakdown products. Chlorinated solvents form liquids that are denser than water. Such dense non-aqueous phase liquids (DNAPLs) tend to migrate down through soil and groundwater following complex paths and can often be present at considerable depths. Characterising the extents of DNAPL contamination is therefore a technically demanding exercise and determining whether source material remains often implies the use of indirect methods, based on geochemical and hydrogeological information. Effective remediation of chlorinated solvents further depends on careful selection of technical approach to achieve site-specific remedial targets.