title: Proximity to crops and residential exposure to agricultural herbicides in iowa.
abstract: Rural residents can be exposed to agricultural pesticides through the proximity of their homes to crop fields. Previously, we developed a method to create historical crop maps using a geographic information system. The aim of the present study was to determine whether crop maps are useful for predicting levels of crop herbicides in carpet dust samples from residences. From homes of participants in a case-control study of non-Hodgkin lymphoma in Iowa (1998-2000), we collected vacuum cleaner dust and measured 14 herbicides with high use on corn and soybeans in Iowa. Of 112 homes, 58% of residences had crops within 500 m of their home, an intermediate distance for primary drift from aerial and ground applications. Detection rates for herbicides ranged from 0% for metribuzin and cyanazine to 95% for 2,4-dichlorophenoxyacetic acid. Six herbicides used almost exclusively in agriculture were detected in 28% of homes. Detections and concentrations were highest in homes with an active farmer. Increasing acreage of corn and soybean fields within 750 m of homes was associated with significantly elevated odds of detecting agricultural herbicides compared with homes with no crops within 750 m (adjusted odds ratio per 10 acres = 1.06; 95% confidence interval, 1.02-1.11). Herbicide concentrations also increased significantly with increasing acreage within 750 m. We evaluated the distance of crop fields from the home at < 100, 101-250, 251-500, and 501-750 m. Including the crop buffer distance parameters in the model did not significantly improve the fit compared with a model with total acres within 750 m. Our results indicate that crop maps may be a useful method for estimating levels of herbicides in homes from nearby crop fields.
authors.affiliation: Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892, USA. wardm@mail.nih.gov
authors.forename: Mary H
authors.initials: MH
authors.lastname: Ward
authors.forename: Jay
authors.initials: J
authors.lastname: Lubin
authors.forename: James
authors.initials: J
authors.lastname: Giglierano
authors.forename: Joanne S
authors.initials: JS
authors.lastname: Colt
authors.forename: Calvin
authors.initials: C
authors.lastname: Wolter
authors.forename: Nural
authors.initials: N
authors.lastname: Bekiroglu
authors.forename: David
authors.initials: D
authors.lastname: Camann
authors.forename: Patricia
authors.initials: P
authors.lastname: Hartge
authors.forename: John R
authors.initials: JR
authors.lastname: Nuckols
mesh_terms: D016022:Case-Control Studies; D018556:Crops, Agricultural; D004781:Environmental Exposure; D006540:Herbicides / Q000633:toxicity*; D006801:Humans; D007484:Iowa
chemical_list: D006540:Herbicides