Decreased Lung Function in 7-year-old Children Living in Proximity to Agricultural Applications of Elemental Sulfur

Background: Elemental sulfur, ‘the oldest of all pesticides’, is the most heavily used agricultural pesticide in California and Europe. Sulfur is considered relatively safe and is used in both conventional and organic farming systems. Adverse respiratory effects have been reported in applicators and animals, but the effect on residential populations, and especially on children living in proximity to fields treated with elemental sulfur is not known. We evaluated the associations between residential proximity to elemental sulfur use and respiratory symptoms and spirometry of children living in an agricultural community. Methods: Participants were 279 children enrolled in the CHAMACOS longitudinal birth cohort. Data from the California Pesticide Use Reporting System were used to estimate the amount of elemental sulfur applied within 0.5-, 1- and 3-km of a child’s residence during the week, month and 12 months prior to pulmonary evaluation. Spirometry was performed and questionnaire data on symptoms were collected at age 7. Results: Adverse associations with spirometry, asthma medication use and symptoms were found for applications within 0.5- and 1-km radii. Specifically, FEV1 decreased (ß=-0.143, 95% CI=-0.248, -0.039, p=0.008) and asthma medication usage and reported respiratory symptoms increased (OR=4.28, 95% CI=1.71-10.76, p=0.002; 2.20, 95% CI=1.30-3.71, p=0.003, respectively) per 10-fold increase in the estimated amount of sulfur used within 1km of child residence during the year prior to pulmonary evaluation. Conclusions: This study suggests that elemental sulfur use, allowed in both organic and conventional farming, in close proximity to residential areas may affect children’s respiratory health.