Moving from DNA analysis in forensics to studying the impact of pesticides on farm workers may seem unusual – but for Dr Luthando Tiya, it was a natural next step. Driven by a passion for research and protecting vulnerable people, he left the South African Police Service’s Forensic Science Laboratory to follow a new path that could make a real difference for both farm workers and their surrounding communities. This move culminated in a doctorate in pharmacology, awarded to him on Thursday (11 December 2025) at Stellenbosch University’s December graduation.

Tiya’s PhD study investigated pesticide poisonings, farm workers’ exposure to pesticides, and the associated risks to surrounding communities and the environment. The aim was to establish tools to assess the risks of pesticide exposure among farm workers. Tiya says he wanted to generate evidence that could inform public health strategies, regulatory policies, and safer agricultural practices in South Africa.

“Farm workers and nearby rural populations are particularly vulnerable to direct and indirect exposure to pesticides, while the broader public is affected through residues in food products and contamination of water sources. This presents substantial risks to human health, biodiversity, and the health and balance of ecosystems.

“Given that the Western Cape is one of the most agriculturally intensive regions in South Africa, we sought to investigate how such extensive agricultural activity might affect the health of farm workers.”

Tiya notes that there is little direct measurement data from people who regularly handle pesticides. Data is also limited on the breakdown products of pesticides found in human samples, even though evidence suggests these chemicals may be harmful.

He assessed the toxicity of selected pesticides and their breakdown chemicals; developed powerful laboratory techniques to measure these chemicals in the liquid portion of blood; and applied these methods to samples from people in agricultural regions of the Western Cape to gauge real-world exposure and potential health risks.

“My research showed that some people living in farming-intensive areas had herbicides or their breakdown products in their blood, indicating that the wider community was exposed beyond just farm workers,” says Tiya.

“When pesticides break down in the body, the resulting chemicals can be even more harmful than the pesticides themselves. Ongoing, low-level exposure – mainly caused by these chemicals – poses a greater threat than currently recognised.

“These findings raise concerns regarding the potential long-term health consequences for people exposed to pesticides, particularly on or close to farms.”

He adds that his findings underscore the need to develop a set of broader biological signals from the body to capture and assess real-world health risks more accurately.

“For communities affected by pesticide exposure, my research demonstrates that health risks are tangible and quantifiable, and that targeted interventions, ranging from policy reforms to practical protective measures, can substantially mitigate harm.”

Since South Africa reports the highest pesticide use in the Southern African region and regulatory oversight remains fragmented and limited, Tiya calls for immediate action to protect people from the dangers of pesticides.

According to him, existing legislation largely focuses on pesticide registration procedures and application standards but provides limited consideration of cumulative environmental effects and insufficient safeguards for exposure on farms and surrounding communities.

“Implementing stricter occupational safety standards, establishing buffer zones between agricultural areas and residential communities, and enhancing community health surveillance are critical measures. The agricultural sector must implement evidence-based practices that reduce pesticide exposure, safeguard worker health, and maintain sustainable productivity.

“Collectively, these interventions can reduce human exposure, prevent long-term adverse health outcomes, and promote safer and more sustainable agricultural practices for all stakeholders.”

Tiya says his research is not intended to undermine the agricultural sector but rather to promote the safe and responsible use of pesticides, with the aim of protecting agricultural workers, surrounding communities, and the broader ecosystem.

“Ultimately, I hope this research supports evidence-based regulatory frameworks, promotes the responsible use of pesticides, and raises awareness within communities regarding environmental and occupational health risks.”

He emphasises the need for adequate funding, ideally with support and engagement from industry stakeholders, farmers, and government authorities, to continue with this important work.