In-residence, multiple route exposures to chlorpyrifos and diazinon estimated by indirect method models

One of the objectives of the National Human Exposure Assessment Survey (NHE XAS) is to estimate exposures to several pollutants in multiple media and d etermine their distributions for the population of Arizona. This paper pres ents modeling methods used to estimate exposure distributions of chlorpyrif os and diazinon in the residential microenvironment using the database gene rated in Arizona (NHEXAS-AZ). A four-stage probability sampling design was used for sample selection. Exposures to pesticides were estimated using the indirect method of exposure calculation by combining measured concentratio ns of the two pesticides in multiple media with questionnaire information s uch as time subjects spent indoors, dietary and non-dietary items they cons umed, and areas they touched. Most distributions of in-residence exposure t o chlorpyrifus and diazinon were log-normal or nearly log-normal. Exposures to chlorpyrifos and diazinon vary by pesticide and route as well as by var ious demographic characteristics of the subjects. Comparisons of exposure t o pesticides were investigated among subgroups of demographic categories, i ncluding gender? age, minority status, education, family income, household dwelling type, year the dwelling was built, pesticide use, and carpeted are as within dwellings, Residents with large carpeted areas within their dwell ings have higher exposures to both pesticides for all routes than those in less carpet-covered areas. Depending on the route, several other determinan ts of exposure to pesticides were identified, but a clear pattern could not be established regarding the exposure differences between several subpopul ation groups. (C) 2001 Elsevier Science Ltd. All rights reserved.