Attempts to demonstrate reductive dechlorination of chlorobenzenes by anaerobic microorganisms

Chlorobenzenes are a source of environmental pollution throughout the world. Investigations of the potential biodegradability of these compounds have been conducted employing different media under various conditions. In this study, the biodegradability of hexachlorobenzene (HCB), pentachlorobenzene (QCB), and 1,2,3,4-tetrachlorobenzene (1,2,3,4-TetCB) at a concentration of 70 uM (20 ppm), 80 uM (20 ppm), and 93 uM (20 ppm), respectively, was investigated. The source of inoculum was fresh anaerobic digester sewage sludge. Compound and sludge were combined in a serum bottle incubation system under anaerobic conditions and allowed to incubate at 30°C for several weeks. An extraction method utilizing hexane and acetone was developed. Analysis after 8 weeks for HCB and QCB, and 10 weeks for 1,2,3,4-TetCB revealed no biodegradation of the compounds. In addition, it was also discovered via extraction of the butyl rubber stoppers in a mixture of hexane.and acetone that the compounds absorb into the stoppers used to close the serum bottles