Children in farming communities who are regularly exposed to agricultural chemicals may experience impaired ability to think, learn, remember and solve problems.

By Amelia Genis, senior journalist at African Farming and Landbouweekblad

Researchers at the University of Cape Town’s Centre for Environmental and Occupational Health Research and the Swiss Tropical and Public Health Institute at the University of Basel made these findings drawing on data collected in the Western Cape between 2017 and 2019, according to an article published on the website Juta Medical Brief.

The teams assessed 445 learners aged 9 to 16 from seven schools in the Hex River Valley, Grabouw and Piketberg to determine how pesticide exposure affected their brain health.

They tested for 13 pesticides, and detected 12 of them in the children. Nearly all the children tested positive for the pesticides chlorpyrifos (L10929, Act 36 of 1947), pyrethroids, mancozeb (L4754, Act 36 of 1947), 2,4-D (L4505, Act 36 of 1947), and hydroxy-tebuconazole (not a pesticide itself but the main metabolite of the active ingredient tebuconazole).

The study formed part of the doctoral research of Paola Viglietti, lead author of the article “Postnatal pesticide exposure and executive function in children and adolescents: Findings from South Africa”, published in the journal Environmental Research.

Also read: Farmworkers demand national ban on ‘poisonous’ pesticide

Pesticide Exposure Affects Developing Brains

The research supports similar studies elsewhere in the world showing that chronic exposure to low doses of pesticides during childhood and adolescence – periods of intense brain development – can disrupt healthy brain growth. This means the cognitive functions that help children plan, concentrate, solve problems and regulate their behaviour may not develop properly.

Viglietti says children are naturally more vulnerable to toxins in the environment because their organs are still developing; they have more skin contact through hand-to-mouth activity; they inhale relatively larger volumes of air; and they often play in higher-risk zones. All these factors increase exposure.

“For children living in agricultural communities, pesticide exposure continues long after birth through household dust, pesticide drift and contaminated food and water,” she says.

Because this exposure hampers brain development needed for academic performance and long-term wellbeing, it may prevent children from reaching their full potential, the authors note.
They add that pesticide exposure is a significant – but modifiable – environmental risk factor for children’s brain development, and that the risk is worsened by poor enforcement of regulations, limited protective infrastructure and social vulnerability.

South Africa applies more pesticides than any other country in sub-Saharan Africa. More than 3 000 formulations are registered.
In research conducted in 2017, stone fruit, grape and wheat farms were found to use up to 96 different active ingredients.

The authors argue that their findings strengthen the case for stricter control over the registration, sale, storage and handling of pesticides, as well as measures to reduce children’s exposure.

Training and Protective Clothing

Dr Gerhard Verdoorn, operations and stewardship manager at CropLife South Africa, says that since the research was conducted, the organisation has done extensive work to promote more responsible pesticide use.

“From our side, we have trained 2 800 workers in the Western Cape in the responsible use of pesticides.”

He says what concerns him about research of this nature is that lifestyle factors are often not considered. “I do not deny that pesticides are a problem, but we are doing a great deal of work to raise awareness, especially about the importance of protective clothing for farm workers.”

The use of chlorpyrifos has been banned in South Africa since February 2025, Verdoorn says. He adds that banning pesticides alone does not solve the issue, and emphasises the importance of using them correctly.