Cross-sectional analysis of odor exposure, household pesticides, and chlorpyrifos residues in flies in Chilean rural communities

Background The expansion of agricultural and livestock production in Chile has increased environmental and health concerns for rural communities living near these activities. The primary aim of this study was to investigate the perception of odour emissions, health conditions, and exposure to household pesticides in rural communities situated near a pig farm in the Maule Region, Chile. Methods An cross-sectional study was conducted with 82 adults residing within approximately 10 km of the “El Arbolillo” area between San Javier and Cauquenes, Maule Region, Chile. Structured questionnaires assessed odor perception, health conditions, and domestic pesticide use. Flies were collected in 17 households, and chlorpyrifos residues were analyzed using gas chromatography–tandem mass spectrometry. Results Most participants (83%) perceived odors as strong or extremely strong. Odor-related discomfort was associated with household pesticide use (69%) (p = 0.006), which was more frequent in homes located ≤ 4,319 m from the pig facility (p = 0.001). Chlorpyrifos residues were detected in flies from 68% of sampled households, with a mean concentration of 0.118 ng mg⁻¹ per insect (range: 0.025–2.449). Higher odor discomfort was associated with hypertension (OR = 3.28; 95% CI: 1.46–9.39), reflux/gastritis (OR = 3.34; 95% CI: 1.23–9.08), shortness of breath at rest (OR = 2.72; 95% CI: 1.05–7.05), and loss of appetite (OR = 2.91; 95% CI: 1.08–7.81). Household pesticide use was associated with migraine (OR = 5.06; 95% CI: 1.40–18.3), gastritis/ulcer (OR = 6.09; 95% CI: 1.53–24.3), and allergic contact eczema (OR = 5.31; 95% CI: 1.22–23.1). Conclusions The findings describe an environmental health problem affecting rural communities near the pig facility. Intense odor perception, frequent domestic pesticide use, and the presence of chlorpyrifos residues in flies indicate simultaneous exposure routes. These results highlight the need for mitigation measures, enhanced health surveillance, and strengthened environmental regulation to protect rural populations in the Maule Region. Trial registration: Not applicable.