Mass removal and low-concentration tailing of trichloroethene in freshly-amended, synthetically-aged, and field-contaminated aquifer material

• Published in: Chemosphere (Oxford) Vol. 75; no. 4; pp. 542 - 548
• Main Authors: Johnson, G.R., Norris, D.K., Brusseau, M.L.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2009; Elsevier
• Subjects: Adsorption; Applied sciences; aquifers; Biological and physicochemical properties of pollutants. Interaction in the soil; chlorinated hydrocarbons; Contaminant aging; desorption; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Restoration and Remediation - methods; Exact sciences and technology; Geologic Sediments - analysis; half life; Kerogen; Low organic carbon; Pollution; Pollution, environment geology; sediment contamination; sediments; Soil and sediments pollution; Soil Pollutants - analysis; Time Factors; Trichloroethene; Trichloroethylene - analysis; Low organic carbon; Trichloroethene; Contaminant aging; Kerogen; Pollutant behavior; Ageing; Hydrophobic compound; Desorption; Sediments; Organic chlorine compounds; Long term; Aquifers; Transport process; Sorption; Organic solvent; Pollution; Adsorption; Chlorocarbon; Organic compounds; Ethylene(trichloro)
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2008.12.004

This study investigates the effect of contaminant aging on the sorption/desorption and transport of trichloroethene in a low organic-carbon content aquifer material, comparing mass removal and long-term, low-concentration elution tailing for field-contaminated, synthetically-aged (contact times of approximately four years), and freshly-amended aquifer material. Elution of trichloroethene exhibited extensive low-concentration tailing, despite minimal retention of trichloroethene by the aquifer material. The observed nonideal transport behavior of trichloroethene is attributed primarily to rate-limited sorption/desorption, with a smaller contribution from nonlinear sorption. It is hypothesized that interaction with physically condensed carbonaceous material, comprising 61% of the aquifer material’s organic-carbon content, mediates the retention behavior of trichloroethene. The elution behavior of trichloroethene for the field-contaminated and aged treatments was essentially identical to that observed for the fresh treatments. In addition, the results of three independent mass-balance analyses, total mass eluted, solvent-extraction analysis of residual sorbed mass, and aqueous-phase concentration rebounds following stop-flow experiments, showed equivalent recoveries for the aged and fresh treatments. These results indicate that long-term contaminant aging did not significantly influence the retention and transport of trichloroethene in this low organic-carbon aquifer material.