Due to the high toxicity

potential of biological accumulation

recalcitrance to degradation and the known carcinogenic/teratogenic/mutagenic effects

the chlorinated organic compounds have been listed as priority controlled pollutants by the United States Environmental Protection Agency (EPA). In view of chlorinated pollutants contaminated sites

the traditional physical

chemical and biological remediation methods often impose relatively high costs and considerable impacts on the surrounding environment. The monitored natural attenuation (MNA) is an effective technology for site remediation and management and has been widely used internationally

which gradually attracts more and more attentions in China in recent years. It relies on the intrinsic potential of the pollutants to degrade naturally to meet the remediation requirements

and thereby would reduce treatment costs and lower on-site project risks. This paper focuses on the introduction of MNA technology

as well as the characteristics of chlorinated organic compounds such as the biodegradation pathways and mechanisms during the process of natural attenuation

the main degradation microbial communities and the key biodegradation enzymes. A preliminary discussion on the suitability of implementing MNA remediation on chlorinated organic compounds contaminated sites is provided.