PCBs are very durable in soil and water, with no known decomposition processes other than the slow degradation of microorganisms. They stick to the soil or evaporate, so they are usually not submerged in the groundwater. PCB contaminated deposits in lakes or rivers can slowly release the PCB back into the water and eventually evaporate.
In water, a small amount of PCB may still dissolve, but most adhere to organic particles and bottom deposits. PCBs are absorbed in water by small organisms and fish. They are also consumed as food by other animals that eat these aquatic animals. PCBs accumulate in fish and marine mammals, reaching levels that can be thousands of times higher. Farmed salmon contain higher levels of PCBs than wild salmon. This reflects the fact that farmed salmon may be submerged in small fish contaminated by contaminated marine waters.
The short-term health effects of short-term exposure to MCL are acne-like eruptions and skin pigmentation; auditory and visual problems; spasms. Long-term health effects Exposure to a lifetime above MCL levels includes exposures similar to acute poisoning, irritation of the nose, changes in the throat and gastrointestinal tract, changes in liver function, and cancer.