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 insufficiently 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 study was conducted with 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 outcomes included depressive symptoms, anxiety, emotional affect, and health-related quality of life, assessed with validated instruments. Robust linear regression models were used, adjusting for age, sex, education level, and body mass index. Higher chlorpyrifos concentrations in water were associated with increased depressive symptom scores (β = 0.180; 95% CI: 0.016, 0.345) and lower mental health-related quality of life (β = −0.713; 95% CI: −1.288, − 0.137). Cypermethrin concentrations in water were associated with higher psychological distress (β = 0.324; 95% CI: 0.124, 0.525). In soil, pirimiphos-methyl was positively associated with depressive symptoms (β = 21.29; 95% CI: 1.78, 40.79), whereas cypermethrin showed an inverse association (β = −3.66; 95% CI: −6.99, − 0.33). Lambda-cyhalothrin concentrations in soil were inversely associated with overall quality of life (β = −15.13; 95% CI: −27.42, − 2.84). Male sex was positively associated with overall quality of life (β = 14.96; 95% CI: 3.14, 26.79). These findings indicate associations between environmental pesticide residues in soil and water and multiple dimensions of mental health among rural populations living near industrial pig farming operations. Longitudinal studies are needed to clarify temporal relationships and potential cumulative effects.