How are PCB transported in the environment?

How are PCB transported in the environment? In surface waters, PCBs are present in substantial quantities in sediments. Indeed, PCBs tend to attach to the surface of organic matter, clay, and micro-particles that are still suspended in the water or have already settled down. They can remain buried in sediments for a long time and be slowly released into the water and evaporate into air. Releases through water into air occur especially when it is warm and when PCB concentrations in sediment are high as this keeps the PCB levels in water elevated. Credit: http://www.greenfacts.org