Adult and child urinary 2,4-D in cities with and without cosmetic pesticide bylaws: a population-based cross-sectional pilot study.

We evaluated 2,4-dichlorophenoxyacetic acid (2,4-D) exposure in four municipalities with and without cosmetic pesticide bylaws in British Columbia, Canada. We recruited a child (aged 1.5-5 years) and adult from 10 households in each city, who provided urine samples in May and June, 2009. No households had used pesticides for 7 days prior to sample collection. We quantified urinary 2,4-D using LC/MS/MS. Quantities of 2,4-D in urine were similar across cities and below biomonitoring equivalents corresponding to references doses in the United State of America and Canada. When adult's and children's urines were analyzed together in linear mixed-effects regression models, natural log urinary 2,4-D was significantly associated with having a diet of ⩾50% organic food (β=-0.6 (0.3) μg/l, P=0.05). Without natural log transformation, median concentration of urinary 2,4-D among those who ate ⩾50% organic food (n=12) was 1.4 μg/l versus 1.5 μg/l for others (n=59). Lack of a significant association (two-sided alpha=0.05) between pesticide bylaws and urinary 2,4-D might reflect small sample size, lack of recent acute exposure, or that 2,4-D exposure is primarily influenced by sources of exposure not addressed through bylaws. Food might be a route of exposure to 2,4-D, consistent with other studies. Future research will require larger sample sizes for sufficient statistical power.