Every day, Kenyans in different homes around the country prepare meals that include “healthy” vegetables. For urban dwellers, the vegetables are often purchased from the market.
“I look for succulent sukuma wiki (kale); well-defined onions; or round, big, unblemished tomatoes,” says Leah Wafula, a mother of two.
Day in and day out, health nutritionists advise that vegetables are healthy. “At least half of your plate should be vegetables,” they say.
And so, every night, people like Leah retire to bed with the satisfaction that they and their families have been well nourished. But are they?
Going by local research and surveys, the era when vegetables would be given the blanket term ‘healthy’ is long gone. Some vegetables contain pesticide residues that could potentially cause ill health.
A baseline study on pesticide residues on tomatoes, sukuma wiki and onions – conducted in Kajiado, Nakuru and Nyandarua counties – shows that some of our vegetables are making it to our kitchens with unhealthy levels of pesticides.
“Farmers use pesticides to protect crops from pests,” says Dr Esther Kimani, the CEO of the Pest Control Products Board (PCPB).
Pesticides are a range of chemicals that kill insects, fungi, microorganisms, animals and plants either destroying crops or hindering their growth.
Before the advent of pesticides, history has it that crop failure was common; sometimes causing famine and upending socio-economic aspects of human life. The development of pesticides sounded a death knell to pests: making it possible for farmers to realize bumper harvests, and therefore profits.
In the aftermath, the pesticide solution has increasingly become problematic for human health. Study upon study links pesticides to a myriad of illnesses in humans such as Alzheimer’s, Parkinson’s, asthma, bronchitis, infertility, birth defects, autism, cancers, diabetes, obesity, respiratory diseases, organ diseases and system failures.
“We use pesticides because they are toxic to the target,” says Dr Kimani. “Hence they are also toxic when they come into contact with or enter the human body.”
Indeed, pesticide products come with instructions on their packaging – directing usage and handling.
At the time of harvesting a crop, says Kimani, the harmful effects of the pesticide should have cleared or reduced to levels that wouldn’t draw concern.
The internationally accepted standard on healthy pesticide residue levels in food is the Codex Alimentarius standard (Codex).
Kenya subscribes to Codex maximum residue levels (MRLs): the highest level of pesticide residue that is legally tolerated in or on food.
MRLs, says Dr Kimani, offer reasonable certainty that no harm will result from exposure to the pesticide residue.
The National Pesticide Residue Monitoring Programme, undertaken by Kenya Plant Health Inspectorate Services (KEPHIS) between 2013 and 2018, analysed 1139 samples. Out of these 46.5 per cent had pesticide detections and 10.8 per cent had exceeded the set European Union (EU) MRLs.
From the samples collected kales, peas and capsicum had the most pesticide residue detections at 94.4 per cent, 75.8 per cent and 59.2 per cent respectively.
In the Kajiado, Nakuru and Nyandarua baseline study (conducted by Bureau Veritas Kenya Limited for Agrochemical Association of Kenya) out of the 20 Kale samples, 22 tomato samples, 21 onion samples, 98.4 per cent, 95 per cent and 100 per cent respectively complied with Codex.
One kale sample had high levels of Acetamiprid (0.78 mg/kg) above Codex safe MRL of 0.04 mg/kg. When graded against the European Union (EU) MRL standards – which is stricter than Codex – 8 per cent of the samples failed the safety test.
Three samples of kale had high levels of Acetamiprid compared to the EU MRLs limit of 0.01 mg/kg.
One kale sample had high levels of Fenhexamid (0.04 mg/kg) compared to the EU MRLs limit of 0.01mg/kg.
One tomato sample had high levels of Acephate (0.02 mg/kg) compared to the EU MRLs limit of 0.01 mg/kg.
A relatively smaller study by Kenya Organic Agriculture Network (KOAN), done in Kirinyaga and Murang’a counties, on kale and tomatoes, had grimmer results.
In the study, three samples – tomatoes and kale – from three markets, were collected and sent to the Netherlands for analysis.
Pesticide residues were found in all the tomato samples; from all three markets. Notably, acephate exceeded EU MRL guidelines.
As for kale, only one market had kale with pesticide residue below MRL recommendations. Kale from the second and third markets had elevated levels of acephate, methamidophos and acetamiprid.
In most of the studies, the number of samples showing higher than prescribed MRL levels is not alarmingly high.
According to a 2021 report on pesticide usage in Kenya, prepared by Route to Food Initiative (RTFI), a civil society organisation, acephate metabolises into methamidophos: an enzyme inhibitor and neurotoxin. The report describes acetamiprid as an endocrine disruptor.
A 2022 study published online in the Journal of Health Sciences showed that fenhexamide, a fungicide, is an endocrine disruptor; promoting the formation of larger and denser tumours.