Consumption of the food containing residues of pesticides is one of the three major causes of cancer. Our single meal may contain a dozen of chemical carcinogens as residues of pesticides, insecticides and herbicides. After entering the body, these carcinogenic chemicals get accumulated in different tissues of the body such as the breast, prostate, brain and the fat tissue, known as bioaccumulation. Thereafter these carcinogens are seldom discharged from the body except in the breast milk of nursing mothers. The bioaccumulation of these chemical carcinogens in various tissues of the body may cause cancer by damaging the cellular DNA. The farmers and agricultural workers, who are directly exposed to pesticides, have much higher risk of cancer, particularly the non-Hodgkin’s lymphoma. About 50 per cent insecticides are used for non-agricultural purposes such as fumigation of homes, factories, cinema halls and aeroplanes that may lead to cancer after entering the human body.
The global use of pesticides has increased ten times since 1950. About 15,000 chemical compounds and more than 35,000 formulations have been used as pesticides throughout the world during the last 50 years. The agricultural produce of Southeast Asia contains much higher levels of the residues of pesticides because these are used aggressively in this part of the world. It is worth mentioning that the Southeast Asia has 1.4 per cent of the world’s available land for agriculture, but consumes 3.6 per cent of the total quantity of pesticides used in the world.
The commonly used pesticides are Carbaryl, Chlordane, Diazinon, Dichlorvos, Dichloro-diphenyl-trichloroethane (DDT), Lindane, Malathion and Toxaphene, most of which possess strong carcinogenic activity. Residues of pesticides enter the food articles such as fruits, vegetables and cereals. When such a food is consumed, the body gets exposed to these highly carcinogenic chemicals that may cause cancer by damaging the DNA. The conventionally grown coffee beans are found to contain higher contents of DDT residue that may cause cancer by suppressing immune system of the body. The consumption of fruits and vegetables containing residues of agricultural pesticides has led to a much higher incidence of cancer in the children.
A study conducted by the department of Occupational Health at Hebrew University Hadassah Medical School in Jerusalem has found much higher concentration of DDT, Polybrominated biphenyls (PBBs) and other pesticides in the breast tissue samples taken from those women, who were suffering from the breast cancer as compared to those who were having benign breast tumours. Similarly, the men suffering from the prostate cancer were found to have much higher concentration of pesticides in their tissue samples as compared to those who have benign prostate hypertrophy. Studies have revealed four times higher incidence of the breast cancer in those women, who have higher levels of DDE, a major metabolite of DDT, in blood.
In 1978, Israel banned the use of DDT and Polychlorinated biphenyls (PCBs). 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 may cause the brain tumours, Hodgkin’s disease and cancers of the testes & the endocrine glands.
Organic agricultural products are gaining popularity among the discernible section of society, who prefer to grow cereals, vegetables and fruits in the organic way. There is a big challenge ahead for our plant pathologists, genetic engineers and other agricultural scientists to provide sufficient non-carcinogenic food to the huge population.
The tap water supplied by municipalities for drinking purposes may get contaminated by certain carcinogens including chlorine by-products, toxic industrial wastes, heavy metals and residues of pesticides, insecticides & herbicides that may lead to genesis of cancer. Waste products of dye industries, lead smelting units and electroplating industries include acids, cyanide & heavy metals that may contaminate the ground water. The ground water may also get contaminated by alpha particles released from natural radionuclides (such as uranium, radium and radon) and man-made radionuclides that have carcinogenic effect. There are about 800 man-made radionuclides from the nuclear power industry, out of which 200 are believed to contaminate the ground water.
Chlorine is commonly used to kill bacteria such as Shigella, Salmonella and Vibrio cholera in the drinking water. The chlorination of drinking water may lead to formation of various carcinogenic compounds in the water. For example, when chlorine reacts with the organic matter found in water, certain carcinogenic compounds known as trihalomethanes are produced, which include trichloroethylene and chloroform. Chloroform, earlier used as an anaesthetic agent, has already been banned since 1976 due to its carcinogenic effect. Chlorine may interact with the humus, formed by decaying plants found in water, producing two chlorinated acids, known as MX and DCA, both of which promote growth of cancer and also possess mutagenic activity. DCA is known to cause the liver cancer.
The prolonged use of chlorinated water may lead to cancers of the rectum and the bladder. A Norwegian study, published in 1992 in the International Journal of Epidemiology, revealed that incidence of the colorectal cancer has been increased by 30 per cent due to the chlorinated water.
It has been observed that about 70 per cent carcinogens found in water, enter the body through skin while taking a bath or shower. Studies have revealed that inhalation of chlorine is more dangerous than drinking of the chlorinated water. According to a report published in the International Health News, the amount of chloroform inhaled or absorbed through the skin during a shower is 6 times higher than that consumed by drinking the chlorinated water in a day.
Fluoride is another carcinogenic compound that has been added to the public drinking water and toothpastes since the 1950s with the aim to protect teeth from caries (that lead to formation of cavities in teeth). Fluoride becomes more concentrated when the water is boiled. Studies have revealed that fluoride has carcinogenic effect in concentrations as low as 1ppm. The fluoridated water may cause cancers of the bone and the skin. Fluorine, a component of fluoride, is known to suppress the natural DNA repair mechanism, thereby enhancing the risk of cancer. A study conducted by the National Cancer Institute by compiling 14 years data has revealed that incidence of the oral and the pharyngeal cancers has increased by 50 per cent due to consumption of fluoride.
Dr. S.P. Kaushal
Sino Vedic Cancer Clinic