Pesticides could be to blame for upsurge in cancer cases, deaths

Pesticides could just turn out to be one big category of substances seriously affecting our health. Not all, but many of them. [iStockphoto]

According to the Kenya Cancer Policy 2019 - 2030, new cases of cancer in the country rose from 37,000 to 47,884 between 2012 and 2018. In the same period, cancer deaths rose from 28,500 to 32,987 - almost four deaths per hour - making cancer the third leading cause of death in Kenya after infectious and cardiovascular diseases.

The projections are not rosy either; these deaths could rise by up to 120 per cent in the subsequent two decades.

As a doctor, I did not need these statistics to tell me that cancer is rising. I see it every day. We do know that cancer is multi-factorial. There is a genetic component, and there is an even bigger environmental component. What has been baffling is that many of the cases are not in the patients we would expect. Young people, those who exercise and are fit, those who neither drink nor smoke, watch what they eat and have no family history of anything other than a common cold, are getting cancer.

But why so?

Recently, I quipped that had all 40 instances of clotting being investigated following the Covid-19 vaccination happened in Kenya, nobody would have noticed the association. The thing is, our surveillance systems are yet to mature if they are in place at all. Obvious linkages will be missed. This is how we end up with media reports of potentially harmful substances being stocked in the food sections of supermarkets, or unmonitored poisons in the water in our taps or the greens from the supermarket. The fact that we are just now strengthening our surveillance systems means that we are vulnerable to numerous risks.

The thing with the environmental factors that cause cancer is that one has to be exposed to them consistently for prolonged periods. This gives us an idea that these harmful agents are things in close proximity to us, things we would not even suspect to be harmful. We the Swahili say kikulacho kinguoni mwako.

Pesticides could just turn out to be one big category of substances seriously affecting our health. Not all, but many of them. Widespread use of very toxic, but inexpensive products, as well as small-scale farmers in Kenya not being able to mitigate risks, could have led to the above statistics.

Recently, I was invited to a task force that was asked to review scientific evidence on a number of pesticides molecules that the Pest Control Products Board (PCPB) is considering removing from the Kenyan market. This is how I got an insight into the secret world of pesticides. What I found was nothing short of astonishing.

Pesticides could be contributing in a big way to the rising incidence of cancers and many other non-communicable diseases. Farmers have understood that to get good yields, they must embrace some form of pest control measures. A good number of these chemicals leave residues on or in the farm produce that we consume. While the quantities we consume may be small, the fact that we eat every day means that the harmful effects accumulate over time. As I looked at study after study, I could not understand why some of these molecules are allowed at all in Kenya, given that there are alternatives.

The US Environmental Protection Agency classifies Bifenthrin as a possible human carcinogen. It has been shown to cause a rise in the incidence of urinary bladder tumours, adenoma and adenocarcinoma of the liver, and bronchoalveolar adenomas and adenocarcinomas of the lung in mice. It is very much on our shelves today. Some of the chemicals still in use here have been banned in Europe too.

In ideal settings, there are clear guidelines on how pesticides should be applied. These are meant to protect farmers and consumers from unplanned exposures. However, competing interests, limitation in resources and inadequate information mean that shortcuts are taken and safety concerns relegated. It is not clear that the recommended methods of application are adhered to. The staff that work on these farms are themselves not always fully protected.

The reason why manufacturers are able to get away with deviations is that regulations and enforcement of set rules in this part of the world are still weak. Often we have to trust what the manufacturers say. This is not a fool-proof method. Given the risks involved, we can and ought to adopt a higher standard for what we accept, especially when we have reasonable alternatives. By outlawing “notorious” molecules, it is less likely that farmers will have access to them and even less likely that they will legally find their way into our food.

Farmers should be supported to implement integrated pest management approaches, where synthetic pesticides – the least toxic of them – are the last step in a more holistic approach at farm agro-biodiversity, water recycling and soil health. Biopesticides are one of the tools in our toolbox that we have not adequately invested in despite the availability of natural resources such as neem and pyrethrum.

Agrochemical producers have identified Africa as the next big market. Revenue from the sale of pesticides is projected to be as high as six billion dollars per year in the early stages alone. Is Africa the next big frontier for toxic pesticides?

We have to start being concerned about what we do. When all is said and done, we will find that the chemicals in food and the contaminants that find their way into farms contribute to the many new health challenges, including cancers. It is my duty, and your duty too, to keep ourselves and our people safe.