ABSTRACT
Chlorinated organic compounds are toxic and hazardous, and they may persist in the environment. Aquatic sediments are thought to be repositories of a wide variety of organic and inorganic pollutants, which may be either accumulated in the sediments or be subject to further transformation into less or more toxic substances. Unlike inorganic pollutants, organic pollutants are prone to biological degradation process that may sometimes result in complete mineralization of the compounds. Chlorinated organic compounds are recalcitrant and accumulate in the sediments; their toxicity and persistence depend on the number of chlorine molecules and their position. However, the inherent anaerobic conditions of aquatic sediments in both freshwater and marine habitats can support the degradation of a variety of chlorinated organic compounds as these habitats are abundant in natural organic carbon that would provide sufficient electron donors. While most of the chlorinated organic compounds can persist during aerobic degradation in the sediments, in anaerobic conditions, they are effectively degraded using reductive dehalogenation and ether bond cleavage pathways. Sulfate reducing and methanogenic conditions are favorable for degrading a variety of chlorinated organic compounds in the natural conditions like aquatic sediments.
