Environmental co-exposure to organophosphate and pyrethroid pesticides and mental health status in rural communities near an industrial pig farming facility

Chronic exposure to pesticide residues from large-scale agro-livestock operations remains poorly characterized, particularly among rural populations living near industrial pig farming facilities. This study examined the association between co-exposure to organophosphate and pyrethroid pesticide residues in soil and well water and mental health outcomes among adults residing near an industrial pig farming facility in rural Chile. A cross-sectional analysis was conducted with a sample of 82 adults. Peridomestic soil and well water samples were analyzed using gas chromatography–tandem mass spectrometry to detect five pesticides: chlorpyrifos, diazinon, pirimiphos-methyl, cypermethrin, and lambda-cyhalothrin. Mental health was assessed using validated instruments measuring depressive symptoms, anxiety, emotional affect, and health-related quality of life. Robust linear regression models were employed, adjusting for age, sex, education level, and body mass index. Chlorpyrifos in water was associated with more depressive symptoms (β = 0.180; 95% CI: 0.016, 0.345) and lower mental quality of life (β = − 0.713; 95% CI: − 1.288, − 0.137). Cypermethrin in water was linked to greater psychological distress (β = 0.913; 95% CI: 0.193, 1.632). Pirimiphos-methyl in soil was associated with higher emotional affect scores (β = 21.29; 95% CI: 1.78, 40.79), while cypermethrin in soil showed an inverse association (β = − 3.66; 95% CI: − 6.99, − 0.33). Lambda-cyhalothrin in soil was linked to lower quality of life (β = − 15.13; 95% CI: − 27.42, − 2.83). Male sex was positively associated with quality of life (β = 14.96; 95% CI: 3.14, 26.79). These findings suggest the presence of measurable associations between environmental pesticide residues and various dimensions of mental health in rural populations living near industrial pig farming operations. Longitudinal studies are needed to follow up on these communities and better understand the potential long-term health implications.