Postnatal pesticide exposure and behavioural outcomes in children and adolescents: findings from South Africa.

INTRODUCTION

Postnatal pesticide exposure and its association with child and adolescent behavioural outcomes remain underexplored in rural agricultural settings, particularly in Africa. This study examined behavioural outcomes in relation to urinary pesticide biomarkers and contextual exposure proxies in participants from the Child health Agricultural Pesticide (CapSA) cohort, South Africa.

METHODS

Data from 434 children (mean age at endline: 13.10, SD: 1.36; 55.53 % male) were analysed. Behavioural functioning was assessed using the Strengths and Difficulties Questionnaire (SDQ), focusing on total difficulties, internalising, and externalising scores. Thirteen urinary pesticide biomarkers-including insecticides (organophosphates, pyrethroids), herbicides, and fungicides-were quantified from spot urine samples collected in 2017 and 2019. Biomarkers were averaged across waves, adjusted for specific gravity, and log₁₀-transformed. Multiple linear regression models assessed associations between SDQ outcomes and two predictor sets: urinary biomarker levels and contextual exposure proxies (agricultural area and farm residence). Models were adjusted for child, maternal, and household factors.

RESULTS

Most biomarkers were detected in >50 % of samples; TCPy, OH-TEB, ETU, and 2,4-D were nearly ubiquitous. No significant associations were observed between urinary biomarkers and SDQ outcomes. In contrast, contextual exposure proxies were significant predictors: children living in Hex River and non-farm residents showed lower SDQ difficulties scores. Behavioural difficulties were higher among participants whose mothers had less education and who were exposed to alcohol or pesticides during gestation.

CONCLUSIONS

While urinary pesticide biomarkers were not associated with SDQ outcomes, farm residence, agricultural area, and socio-demographic factors were. Findings underscore the need for longitudinal, context-sensitive research integrating social and environmental exposures.