text: First, the soil and sediment structures will determine how tightly PCBs are adhered to them and affect the absorption of PCBs into cells. The PCBs’ availability suffers from increasing organic carbon and clay content, for they promote the absorption of PCBs into soil or sediment matrices. Second, the soil contains necessary nutrition for the growth of microbes and anaerobic and aerobic environments. Finally, the local microbial population has significant impacts on the rate of degradation of PCBs, which varies based on the microbial strains and their activities. Then, if there is no history of exposure to PCBs, it may take months for microbes to activates their ability to dechlorinate PCBs and break them down.