Dear Ms. Ayesha, that’s an interesting query; the Source-water contaminants of concern include arsenic, asbestos, radon, agricultural chemicals, and hazardous waste. Of these, the strongest evidence for a cancer risk involves arsenic, which is linked to cancers of the liver, lung, bladder, and kidney. The use of chlorine for water treatment to reduce the risk of infectious disease may account for a substantial portion of the cancer risk associated with drinking water. Chemical substances are intentionally added to foods to modify flavor, color, stability, texture, or cost. Chemical substances are used in such a way that they may unintentionally enter the food supply. These substances include components of food-packaging materials, processing aids, pesticide residues, and drugs given to animals. An unknown number of naturally occurring chemical contaminants also find their way into food. For a food or drink to be considered a carcinogen, strong evidence must link its consumption to an increased cancer risk and show how cancer may develop as a result. The World Health Organization’s International Agency for Research on Cancer (IARC) classifies carcinogens by determining how likely they are to cause cancer. Hopefully, the information given is sufficient for you.