Determinants of atrazine contamination in the homes of commercial pesticide applicators across time.

Twenty-nine commercial pesticide applicator households in eastern Iowa were enrolled to investigate in-home contamination of atrazine, the most commonly used corn herbicide in the Unites States. From each home, four vacuum dust samples were collected during atrazine application season (Visit 1) and again 6 months later during winter months (Visit 2). Samples were taken from the following locations: primary entryway for pesticide applicator, living room, master bedroom, and kitchen. The applicator completed an atrazine handling log and household questionnaire with spouse. Of the 230 dust samples, only 2 were below the level of detection, 2 ng of atrazine per gram (ng/g) of fine dust (dust particle size 5-150 μm). Dust levels were standardized to chemical loading. During application season the entryway (2.68 ng/cm(2)) and kitchen (0.47 ng/cm(2)) had the highest geometric mean atrazine chemical loading. The entryway chemical loading during Visit 2 was the second highest aggregate (0.55 ng/cm(2)). Aggregate concentrations were significantly higher at Visit 1 compared with Visit 2 when paired by location (p≤0.02). Analysis showed that job (application, mixing/loading, or both) was not associated with in-home atrazine contamination. Linear regression showed a strong positive association between atrazine handling (number of acres applied with atrazine, number of days atrazine handled, and pounds of atrazine handled) and aggregate dust chemical loading from both visits (p = 0.06, 0.03, and 0.10, respectively). Frequency of vacuuming was inversely associated with Visit 2 concentrations (p = 0.10) and showed a weaker association with Visit 1 (p = 0.30). Removing shoes outside the home was associated with lower atrazine chemical loading (p = 0.03), and applicators changing work clothes in the master bedroom had significantly increased atrazine chemical loading in master bedrooms (p = 0.01). Changes in hygiene practices for commercial pesticide applicators could significantly reduce atrazine and, likely, other pesticide contaminations in the home.