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Poison in our food, agrochemicals and fertilisers – the realities

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The origin of poison in our food, drink and air we breathe is a topic that has assumed relevance and importance, in view of the ban on chemical fertiliser and pesticides due to their possible involvement in the causation of non-communicable diseases. This brief note attempts to critically look at some of the aspects of this complex problem. The problem obviously has to be viewed from the point of view of the need to feed the growing population, the dwindling of arable land, and associated impact on environment and climate.

Life span of human beings on planet Earth has improved from about 50 years in the 1920s, to more than 75 years in these twenties. This was no doubt made possible by the advancement of science and technology, which helped in the understanding of factors that affect life, and development of measures to maximize beneficial factors and minimise adverse effects. Methods to increase farm yields and discovery of vaccines are two such measures developed by science and technology. At the same time, growth of science and technology itself may have produced injurious factors, which may have adverse effects on life. Pesticides would perhaps be one such factor, though they have their benefits. Noxious gases emitted by industry and motor vehicles would be another. Having said that, there is nothing 100% beneficial or harmful.

Now let us look at the food requirements of the increasing world population and its implications. The Food and Agriculture Organization of the UN estimates that by the year 2050 the world population would increase to 9.7 billion, which is a 30% rise. Food has to be produced to feed these extra mouths. Eighty percent of the extra food that must be produced for this purpose will have to come from methods that increase yield, and crops that could be grown a number of times on the same land. Only 20% could come from expansion of farming land, anything beyond this would endanger life due to denuding of forest cover and climate change, which are already upon us.

This would be the biggest challenge that human beings would face in the next three decades. How could farms yield more with less, less land, fertiliser, water, and other agro-chemicals. Obviously, science and technology will have to take up this challenge. Scientists will have to develop crops that yield more with less inputs. Bio-engineers will have to develop crop varieties that yield more, take up less water and land, and methods that enable use of land for increased number of times of planting per year.

Would such methods increase the amounts of “poison” that we take with our food. Already there is a popular demand for banning of agro-chemicals, which the experts say were one of the main reasons for the high yields and less starvation. Improved crop varieties is the other reason for increased harvest. All this science is looked at with suspicion, and some are agitating and calling for age-old methods of farming with organic fertilizer, natural pest control and varieties of crop used in early times. If the whole world adopts these methods, would there be less cancers, heart disease, diabetes and other illnesses? Perhaps there would be less chemicals in the food and the environment, but there would also be less food. And perhaps less people if the policy is strictly adhered for a length of time!

It is true that the incidence of non-communicable diseases is rising. But whether this is due to agrochemicals and chemical fertilisers has not been proved. Cancer and heart disease have risen mainly due to the type of food and drink people consume. For instance, colonic cancer is associated with red meat consumption. Polycyclic Aromatic Hydrocarbons may be released when these meats are roasted or grilled. These chemicals could cause cancer in the colon, breast, prostate and kidney. Lung disease and certain types of cancers may be associated with the pollutants in the air we breathe. Vehicle fumes are found to be etiological causes of asthma, chronic bronchitis, ischemic heart disease and stroke.

Other foods that may cause disease include vegetable oils produced from seeds such as corn, sunflower, soya. etc., which are rich in polyunsaturated Omega-6 oils and lack the beneficial Omega-3 oils. These oils have no nutrients but ’empty calories’. Further they have linoleic acid, which can cause inflammation of the endothelium in arteries which may result in heart disease and stroke. High consumption of trans fats (eg. margarine), which are produced by pumping hydrogen into unsaturated oils to make them solid, could also cause injury to the lining of blood vessels, which could result in heart disease. Increased consumption of sugar is associated with Type 2 diabetes, heart disease and also colon cancer.

It has been found that chemicals found in pesticides, if ingested in excess of the safety levels, could cause cancer and affect reproductive health. There are about 1000 pesticides in the market and some of them are harmful. However, none of the pesticides authorized by the WHO when used within safety levels is genotoxic, and therefore may not cause cancer or developmental defects. The WHO has two objectives in dealing with pesticides, one is to ban those that are toxic and remain longest in soil, and two to protect people by monitoring the residue levels in food and water. These activities are carried out by the Joint FAO/WHO Meeting on Pesticide Residue (JMPR) and their advice and recommendations are based on data obtained from peer reviewed journals.

As for fertilisers, experts say both inorganic and organic varieties have their advantages and disadvantages. Inorganic fertilisers attempt to supply the essential nutrients like nitrogen, phosphorus, potassium in amounts required by each variety of crop, and therefore small quantities would give good results. However, any excess of it could contaminate groundwater and could be harmful to soil and aquatic life. Organic fertiliser has these nutrients in small amounts and therefore large quantities of it has to be used, and yet they may not supply the amounts needed by high yielding fast growing varieties. However, organic fertiliser would support soil life, which is essential for conversion of organic matter into forms that could be absorbed by plants. They also retain moisture and would be useful in dry lands. Therefore, a judicious mix of inorganic and organic fertiliser would be advisable, instead of reliance on one type alone.

As mentioned earlier, everything has its advantages and disadvantages, and some of these things are essential for life to go on in its present state, which of course is a mad rush. And pesticides and chemical fertilisers may be essential for this mad rush, which includes consumption and reproduction at a rate unbearable to mother earth.

N.A.de S. AMARATUNGA

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