#51 Pesticides in carpet dust and self-reported pesticide use in four areas of the us

PURPOSE: As part of a case-control study of non-Hodgkinʹs lymphoma (NHL), exposure to home/garden pesticides is being assessed based on self-reported pest treatments and analysis of carpet dust samples. Here, we compare the study centers in terms of reported pesticide use and pesticide levels in carpet dust sampled from control subjectsʹ current homes. METHODS: Of 1,057 controls, 53 refused dust collection (5%). About half of those who consented were eligible (owned carpets 5 years and used vacuum cleaner within past year) (530 subjects). Southwest Research Institute sieved and extracted dust from a used vacuum cleaner bag collected from each subjectʹs current home. For 513 samples with sufficient dust (78 in Detroit, 147 in Iowa, 127 in Los Angeles, and 161 in Seattle), analysis for 30 pesticides was performed by GC/MS. RESULTS: In LA, 85% of subjects treated for crawling insects in/around the home (excluding lawns/gardens), higher than any other site. Dust from LA had the highest median levels of propoxur, chlorpyrifos, diazinon, and permethrin, insecticides often used for crawling insects. Termite treatments were most prevalent in LA, consistent with LAʹs relatively high median levels of chlorpyrifos, permethrin, and chlordane. Although lawn/garden insects were treated most often in Seattle (61%), none of the lawn/garden insecticides analyzed were detected most frequently in Seattle. The herbicides 2,4-D and dicamba were highest in Iowa, which had the highest reported treatment of lawn/garden weeds (69%). The agricultural herbicides atrazine, alachlor, and metolachlor were detected only in Iowa. CONCLUSION: Dust levels of residential pesticides were generally reflective of self-reported pest treatment practices. Seattleʹs relatively low prevalence of lawn/garden insecticides in dust, despite high reported use of these pesticides, is perhaps related to the relatively moist climate in Seattle.