Overall, they include drugs that have long been abused, such as marijuana and cocaine, and drugs whose abuse is a more recent development. Some are stimulants, some depressants, and some hallucinogens-while most exhibit multiple pharmacological properties.
Studies of PCBs in humans have found increased rates of melanomas, liver cancer, gall bladder cancer, biliary tract cancer, gastrointestinal tract cancer, and brain cancer, [1] and may be linked to breast cancer. PCBs are known to cause a variety of types of cancer in rats, mice, and other study animals. [2].
Since people are never exposed to only one of these groups, people exposed to PCBs are at risk of all diseases caused by dioxin, as well as those caused by non-dioxin-like PCB congeners. Everyone living in developed countries has PCBs in their bodies; sources of exposure include food and air (Carpenter 2006).