Multi-scale risk factors for unsafe agrochemical handling and environmental exposure in Guinea

In Sub-Saharan Africa, the availability of highly hazardous pesticides on local markets and their extended use by non-trained farmers pose severe threats to human and environmental health. The study aimed to identify and analyze the interconnection between individual, community and systemic factors influencing the use, unsafe handling and environmental impact of agrochemicals in N’Zérékoré area of Guinea. A cross-sectional field study was conducted, combining questionnaires and comics (pictograms) with 141 farmers and 24 agrochemical sellers. A composite knowledge score (0–4) was generated for each respondent, and multivariate logistic regression was performed to identify predictors of safe disposal practices among the farmers. The results revealed a notable prevalence of highly and moderately hazardous pesticides (WHO Class Ib and II). In total, 65% of farmers reported using at least one WHO Class Ib pesticide (cyfluthrin 52% and abamectin 13%). A significant ( p < 0.05) knowledge-practice gap was noted; while only 42% of farmers (versus 41% of sellers) had received formal training, this training was the strongest predictor of higher knowledge scores (3.51 vs. 1.42 and 3.36 vs. 1.75, p < 0.001), but it did not guarantee safer disposal ( p = 0.164 and p = 0.200, respectively). Multivariate analysis confirmed that older farmers was associated with decreased odds of safe disposal (OR = 0.89 per year, p = 0.004), whereas reliance on sellers for information was associated with approximately 19-fold higher odds of safe disposal (OR = 19.16, p < 0.001). The synthesis of the results suggests a linked pathway from systemic (sale of highly and moderately hazardous pesticides, lack of useful knowledge from sellers) to community (economic pressure) and individual (middle-aged farmers, inadequate knowledge) risk factors. Systemic approaches adhering to One Health principles that simultaneously target sellers, policymakers and farmers are needed to mitigate threats from unsafe agrochemical use and promote sustainable and health-conscious agriculture.