Polychlorinated biphenyls (PCBs) are toxic, carcinogenic, and bioaccumulative compounds that are often found in lake and river soils and sediments. PCBs in soils and sediments represent a human health risk, especially if natural processes promote PCB volatilization and subsequent exposure to humans. Biodegradation of PCBs would reduce the risk of adverse human health effects, but this process is poorly understood in sediments. The objective of this research is to test the hypothesis that aerobic, PCB-degrading bacteria are present and active in PCB-contaminated sediments from Indiana Harbor. Preliminary studies revealed aerobic PCB biodegradation potential, but additional experiments are needed to determine if PCB-degraders are active in these sediments. An array of experimental approaches, some of which are innovative, involving reverse-transcription (RT)-PCR, real-time RT-PCR, proteomics, and metabolite analysis are proposed.