Is your watermelon safe? The chemicals you didn’t know you were consuming
While these chemicals ensure watermelons look perfect and remain viable for sale, concerns have been raised about their impact on health and the environment.
As the sun intensely heats and temperatures soar, there is nothing more refreshing than a cold, juicy slice of watermelon.
Watermelons are a staple at Kenyan gatherings, from village celebrations to roadside stalls in Nairobi. They are the go-to fruit for mothers looking for a healthy treat for their weaning babies or toddlers.
But what if we told you that the watermelon you are enjoying could be hiding more than just sweetness?
During a recent TikTok Live session, renowned nutritionist Angela Muthoni highlighted growing concerns about the chemicals sprayed on watermelons.
"People love watermelons for their hydration and health benefits, but we need to be more aware of what goes into growing these fruits," Muthoni said, emphasising the need for consumers to make more informed choices.
One farmer, who preferred to remain anonymous but will be referred to as "Zadok," joined the live session and shared insights into the reality of watermelon farming in Kenya.
Zadok, who grows watermelons in the Central Kenya region, revealed that pesticides and other chemicals are a necessary part of modern farming, particularly given Kenya’s harsh and unpredictable climate.
Zadok noted that watermelons take 70 to 100 days to mature, depending on the region and seed type. However, some farmers may use hormonal sprays, nitrogen-rich fertilisers, or Plant Growth Regulators (PGRs) to speed up the process.
“We must fight pests like aphids, fruit flies, and diseases such as powdery mildew. Without these chemicals, we risk losing entire crops. The demand for perfect fruit means using these sprays is almost a must,” said Zadok, reflecting the struggle many Kenyan farmers face in balancing production with safety.
He added that, at the end of the day, no farmer wants to incur losses—they are in business like any other Kenyan.
Watermelon farming in Kenya, particularly in areas such as Murang’a, Nyeri, and parts of Eastern Kenya like Ukambani, Embu, and Marigat, involves the use of various chemicals to ensure a successful harvest.
These include pesticides to ward off pests like aphids and beetles, herbicides to control weeds competing for nutrients, and fungicides to protect against fungal diseases in humid conditions.
Insect Growth Regulators (IGRs) are applied to prevent pests from maturing and multiplying, while Plant Growth Regulators (PGRs) help ensure optimal growth and the right fruit size.
Post-harvest chemicals are also used to slow down ripening, ensuring the watermelon reaches the market in good condition. Additionally, antifungal sprays help prevent mould growth, particularly in humid regions such as parts of Eastern Kenya and the Rift Valley.
While these chemicals ensure watermelons look perfect and remain viable for sale, concerns have been raised about their impact on health and the environment.
Farmers like Zadok face pressure to meet the high standards demanded by local and international markets, often leading to the excessive use of these chemicals.
The Health Impact
Nutritionist Muthoni warned of the potential health risks of consuming watermelons treated with these chemicals.
"I do not mean to put anyone out of business, but pesticide residues on fruits can be harmful in the long term, especially with frequent consumption. We are talking about hormone disruptions, allergies, and even an increased risk of cancer," she cautioned.
“Washing and peeling the watermelon may help, but it does not guarantee the removal of all chemicals. Some residues seep into the fruit from the early stages of growth until harvest.”
Research supports these concerns, showing that prolonged exposure to pesticides can lead to neurological disorders, reproductive issues, and various cancers.
A 2024 study published in ScienceDirect, titled "Pesticides' Impact on Human Health and the Environment with Their Mechanisms of Action and Possible Countermeasures", found that pesticides sprayed on crops contribute to rising health issues. These include acute poisoning and chronic diseases such as brain, breast, prostate, bladder, and colon cancers, Alzheimer's, Parkinson's, neurotoxicity, infertility, leukaemia, and diabetes.
Another study published by Firenze University Press found that watermelons tested positive for seven different pesticide residues—Dimethoate, Profenophos, Dicofol, Cypermethrin, Lambda-cyhalothrin, Permethrin, and Deltamethrin—many of which exceeded Maximum Residue Limits (MRLs). MRLs refer to the highest amount of pesticide residue legally permitted in food products, as set by regulatory authorities to ensure consumer safety.
According to research, long-term exposure to pesticides like Cypermethrin and Lambda-cyhalothrin can disrupt hormones, leading to reproductive issues and developmental delays. Dimethoate and Profenophos affect the nervous system, increasing the risk of Alzheimer's and Parkinson’s. Chronic exposure to Cypermethrin and Permethrin has also been linked to diabetes and weakened immunity.
Additionally, spraying these chemicals during irrigation can lead to runoff into nearby water sources, contaminating rivers and streams. This is a growing environmental concern in agricultural regions such as Central Kenya, potentially contributing to the rising cases of chronic diseases like diabetes, hypertension, and arthritis.
A study published in August 2023 by Kenyatta University researcher Dr Oyaro Bikwendo examined pesticide use and its effects on aquatic ecosystems and human health in Kwanza Sub-County, Trans Nzoia County.
The study found that:
46.4% of farmers strongly agreed on the necessity of understanding pesticide labels.
61.9% strongly disagreed on the importance of applying pesticides to plants.
49.5% strongly agreed that pesticides are harmful to health.
55.7% strongly agreed that handling pesticides in close proximity exposes them to risks.
46.4% strongly disagreed with applying pesticides regularly.
39.3% strongly agreed, and 46.1% agreed, on the importance of attending pesticide management training.
The findings highlight the urgent need for better education and training to reduce health risks and improve pesticide handling practices.
Zadok acknowledges these risks but insists that farmers are caught between a rock and a hard place.
"We know about the dangers, but these chemicals are necessary to meet market demands. If we don’t use them, we can’t have a good harvest, and we will lose out to other farmers," he admitted.
Muthoni encourages consumers to consider organic options, which are free from synthetic pesticides and fertilisers.
"Organic watermelons are not only healthier but also promote more sustainable farming practices that benefit both the environment and the farmers," she said.
However, switching from conventional to organic farming is no easy task, especially in a competitive market.
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