Desorption of chlorinated organic compounds from a contaminated estuarine sediment

✍ Scribed by Peter Gess; Spyros G. Pavlostathis

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 122 KB
• Volume: 16
• Category: Article
• ISSN: 0730-7268
• DOI: 10.1002/etc.5620160806

✦ Synopsis

Batch kinetic and equilibrium partitioning experiments were performed to determine the desorption rate and extent of chlorobenzenes and hexachlorobutadiene found in a contaminated estuarine sediment. A small fraction (less than 3%) of most sediment contaminants desorbed in a single-step batch test performed over 62 d. When a desorption test was conducted with contaminated sediment and successive replenishment of the supernatant, the desorbed contaminant fraction increased to as high as 17% after 33 successive desorption steps were completed. The 1,2,4-trichlorobenzene isomer attained the highest extent of desorption. The desorbed contaminant fraction strongly correlated to the organic carbon-based partition coefficient (K oc ) of the contaminants. The two-site model was used to describe the desorption of chlorinated organic compounds from the sediment. Partition coefficients were determined both experimentally and by a computer optimization technique based on the batch desorption kinetic data and the two-site model. The first-order rate constant for the desorption of the contaminants from the ''slow'' desorption sites ranged from 1.1 ϫ 10 Ϫ4 to 2.5 ϫ 10 Ϫ2 /d and was negatively correlated with the contaminant hydrophobicity (K oc ).