Global, regional, and national statistics
Cancer is a group of diseases that affect body cells in a manner that causes abnormal, uncontrollable cell division and growth. Its impact on human health and the financial burden associated with treatment has made it a significant public health challenge. It is the second-highest cause of death globally in 2018, with about 9.6 million of all deaths that occurred being the result of cancer (WHO, 2018). Further, there were about 18 million cases of cancer globally, with 9.5 million being men, and 8.5 million being women (Bray et al., 2018). According to WHO (2018), 70% of the deaths associated with cancer happen in middle and low-income countries. The number of 5-year prevalent cases of cancer in Africa was 1,930,912 in 2018, and 693, 487 deaths as a result of cancer. In Kenya, there were 47,887 new cases of cancer, and 32,987 deaths as a result of different types of cancer (Bray et al., 2018). Moreover, cases have risen by 30% in the past 8 years, and cancer is the third highest cause of mortality, behind infectious and cardiovascular diseases.
Pesticide Residues in Food
It is quite unfortunate that of all the means through which people get exposed to carcinogenic compounds, food is one of them. Food puts people at risk of cancer directly through certain toxic compounds that are a byproduct of processing (certain additives), contaminants (such as heavy metals), or through conventional food production and pesticide use. While global nutrition guidelines recommend increased consumption of fruits and vegetables, these foods when grown conventionally might not be safe and might contain a mixture of pesticide residues. This situation is particularly worse in African countries such as Kenya, where pesticide use is largely unregulated, the use of pesticides that are well-known to cause cancer are still available for food production and consumer awareness is relatively low.
While global nutrition guidelines recommend increased consumption of fruits and vegetables, these foods when grown conventionally end up with pesticide residues.
Carcinogenicity Tests: Are They Reliable?
The categorization of pesticides as carcinogens is not merely the result of theory or assumptions; it is a result of numerous, critical scientific tests. Usually, carcinogenic tests are done on animals, mostly mice and rats, which are surrogates used to predict the extent to which exposure to the active ingredients would cause cancer in humans. The mice are given different dosages of the pesticide under study. A control group is not exposed to the active ingredients. Afterward, tests are done to see changes, such as tumors, as a result of the exposure. These tests are then extrapolated to the context of humans.
A pesticide is allowed for manufacturing by various international or national institutions for use for a certain period, after which the institution decides to allow further extension or not. In Europe extension for the manufacture of a pesticide can be withheld when the pesticide has been linked to cancer. However, the procedures through which the carcinogenic properties of pesticides are assessed have been questioned recently. An example is the reauthorization of the herbicide Roundup with the active ingredient glyphosate; that is probably the most used herbicide in the world. This authorization in 2017 came at a time when the International Agency for Research on Cancer (IARC), the World Health Organization’s cancer agency, had already classified glyphosate as ‘probably carcinogenic to humans (Kogevinus, 2019). It also happened in the midst of intense public outcry by European citizens, who wanted the ban of glyphosate (Clausing, 2019). At the same time, a regular user of Round-Up in the US ended with non-Hodgkin’s Lymphoma, a type of cancer, although he used this herbicide with protective clothing. Studies show quite well a relationship between glyphosate pesticides and non-Hodgkin’s Lymphoma (Zhang, Rana, Taioli, Shaffer, & Sheppard, 2019). It is for this reason that this man won the case against Monsanto, the main distributor of Round-Up.
The Pesticide Action Network (PAN) Germany and the Health and Environment Alliance (HEAL) commissioned for a review of the European carcinogenic hazard assessment of 10 active ingredients. In the report, 7 out of the 10 active ingredients were erroneous in their categorization, as the appropriate assessment protocols were not properly followed as outlined in the OECD, European Chemicals Agency (ECHA), and EU guidelines. In this report, the active ingredients folpet, pirimicarb and thiacloprid should have been classified as “presumed to have carcinogenic potential for humans”, and not just “suspected human carcinogen.” Active ingredients are categorized as “presumed to have carcinogenic potential for humans” when sufficient laboratory studies show carcinogenicity in mice/rats following exposure, hence “presumed” to act similarly in humans. For those categorized as “suspected human carcinogen”, there are limited studies on carcinogenicity and no convincing evidence that would place them under the former category. In addition, the PAN/HEAL study could not achieve a concrete decision as to the categorization of captan, chlorpropham, phosmet and dimoxystrobin due to insufficient data (Clausing, 2019). The manner with which pesticide assessments are conducted as shown in this report shows that the interests of the industry precede the health of consumers.
Folpet, pirimicarb and thiacloprid should be classified as “presumed to have carcinogenic potential for humans”, and not just “suspected human carcinogen.
Carcinogenic Pesticides in Kenya
In Kenya, there are a number of pesticides commonly used for horticultural purposes that are either categorized as carcinogenic or potentially carcinogenic. Examples of carcinogenic active ingredients such as clodinafop, fenchlorazole, oxyfluorfen, permethrin, and pymetrozine, found in 24 products are widely used. Out of these, fenchlorazole, permethrin, and pymetrozine are not approved for agricultural use in Europe. Moreover, there are hundreds of products whose active ingredients are in the category of “possibly carcinogenic.” It is within the mandate of the Pest Control Products Board (PCPB) to ensure that those pesticides are withdrawn from the Kenyan market, especially because proper protection of farmworkers and consumers can’t be assured, but there seems not to be efforts yet.
There are six active ingredients in Kenya, found in 24 products, which are categorized as carcinogenic. Three of these active ingredients are not approved in Europe.
By failing to establish regular monitoring of foods for pesticides, and withholding information on levels of pesticide residues in common local foods, PCPB and KEPHIS are not only going against the Pest Control Products Act but also international codes of conduct. The Biodiversity and Biosafety Association of Kenya (BIBA-K), Kenya Organic Agriculture Network (KOAN), Resources Oriented Development Initiatives (RODI Kenya) and Route to Food Initiative (RTFI) highlighted these issues (Oruko, 2019). A petition was presented by Gladys Boss Shollei in parliament and is still under due processes, and hopefully, it will be acted upon promptly.
Replacing Conventional Agriculture with Agroecology
There is a need for more support for sustainable agricultural techniques, such as agroecology, to be popularized in order for some progress to be made. Agroecological agriculture is superior to conventional agriculture for long-term efforts to reduce the global incidences of cancer, as it advocates for integrated pest management instead of toxic, chemical pesticides. Moreover, as some studies show, foods grown with agroecological principles have significantly higher levels of phosphorous, mega-3 fatty acids (Dangour, Dodhia, Hayter, Allen, Lock, & Uauy, 2009), iron and magnesium (Lairon, 2010). They also have very high levels of phytonutrients, which help the body to fight free radicals that trigger cancer. Plants produce phytonutrients to keep off pests since they hardly come in contact with pesticides.
We need to obtain yields but not at the expense of the health of populations, and a deteriorating environment. It is too expensive to treat cancer worldwide, especially in developing countries like Kenya. Therefore, the principle of “prevention is better than cure” should be the greatest concern for the government as at now.
Bray, F., Ferlay, J., Soerjomataram, I., Siegel, R. L., Torre, L. A., & Jemal, A. (2018). Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA: a cancer journal for clinicians, 68(6), 394-424.
Clausing, P. (2019). Chronically underrated? A review of the European carcinogenic hazard assessment of 10 pesticides. Retrieved from Pesticide Action Network (PAN) Germany and the Health and Environment Alliance (HEAL) website: https://www.env-health.org/wp-content/uploads/2019/10/2019_09_Summary_06_en-web.pdf
Dangour, A. D., Dodhia, S. K., Hayter, A., Allen, E., Lock, K., & Uauy, R. (2009). Nutritional quality of organic foods: a systematic review. The American journal of clinical nutrition, 90(3), 680-685.
Kogevinas, M. (2019). Probable carcinogenicity of glyphosate.
Lairon, D. (2010). Nutritional quality and safety of organic food. A review. Agronomy for sustainable development, 30(1), 33-41.
Oruko, I. (2019, September 12). Mp wants harmful pesticide banned from the market. Daily Nation [Nairobi]. Retrieved from https://www.nation.co.ke/news/MP-wants-harmful-pesticide-banned-from-the-market/1056-5270876-o9kaoez/index.html
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Zhang, L., Rana, I., Taioli, E., Shaffer, R. M., & Sheppard, L. (2019). Exposure to glyphosate-based herbicides and risk for non-Hodgkin lymphoma: a meta-analysis and supporting evidence. Mutation Research/Reviews in Mutation Research.