The food containing residues of pesticides is one of the top three risk factors of cancer. The commonly used pesticides are Carbaryl, Chlordane, Diazinon, Dichlorvos, Dichloro-diphenyl-trichloroethane (DDT), Lindane, Malathion and Toxaphene. Most of these chemicals used as pesticides have strong carcinogenic effects. The residues of pesticides enter into food articles such as fruits & vegetables. When such food containing residues of pesticides is consumed, the body gets exposed to these highly carcinogenic chemicals, which can cause cancer by damaging the cellular DNA. Studies have shown that the farmers and agricultural workers, who are directly exposed to pesticides, have much higher risk of developing cancer, particularly the non-Hodgkin’s lymphoma. Conventionally grown coffee beans contain high content of DDT residues, which can cause cancer by suppressing the activity of immune cells of the body.
About 15,000 chemical compounds and 35,000 formulations have been used as pesticides since the last 50 years. The global use of pesticides has increased tenfold since 1950. It has been observed that the agricultural produce of Southeast Asia contains much higher levels of residues of carcinogenic pesticides, because pesticides are used aggressively in this part of the world. Southeast Asia has 1.4 per cent of the world’s available land for agriculture, but uses 3.6 per cent of the total consumed quantity of pesticides in the world.
Consumption of fruits & vegetables containing the residues of agricultural pesticides has shown six fold higher risk of cancer in children. About 50 per cent of the insecticides are used for non-agricultural purposes (such as fumigation of homes), which can cause cancer after entering the human body. Herbicides used to control weeds are another major source of chemical carcinogens, which can cause various cancers including leukaemia & brain tumours.
Our single meal might contain residues of a dozen of chemical carcinogens from various pesticides, insecticides and herbicides. After entering the body, these carcinogenic chemicals get accumulated in the breast, prostate, brain and fat tissue. This process is called bioaccumulation. These chemical carcinogens are seldom discharged from the body except in the breast milk of nursing mothers. The bioaccumulation of chemical carcinogens damages the DNA causing mutations in the genes, thus causing cancer.
A study conducted by the department of Occupational Health at Hebrew University Hadassah Medical School in Jerusalem has revealed that there are higher levels of Polybrominated biphenyls (PBBs), Dichloro-diphenyl-trichloroethane (DDT) and certain other pesticides in the breast tissue samples of those women who have the breast cancer as compared to those women who have benign tumour of the breast. Similarly, the men having prostate cancer were found to have much higher levels of pesticides in their tissue samples, as compared to those men who have benign prostate hypertrophy (BPH). Studies have revealed that there is fourfold higher risk of breast cancer in those women, who have higher levels of DDE (a major metabolite of DDT) in their blood.
In 1978, Israel banned Dichloro-diphenyl-trichloroethane (DDT) and Polychlorinated biphenyls (PCBs), which are directly linked to breast cancer. Over the next 10 years, after the ban of these chemicals, the rate of breast cancer declined sharply in Israel. A Swedish study has revealed that exposure to pesticides can cause many cancers including Hodgkin’s disease, testicular cancer, cancer of the endocrine glands and malignant tumours of the brain.
Organic agricultural products are gaining popularity among the discernible section of society, who prefer to grow cereals, vegetables and fruits in the organic way for their own consumption. There is a big challenge ahead for our plant pathologists, genetic engineers and other agricultural scientists to provide sufficient poison free and non-carcinogenic food to the huge population.