regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2010-0383-0015). selleckchem A multi-chemical approach considering model variance and co-variance structure and co-occurrence of chemicals is described in the SHEDS-Multimedia technical manual. Data from the U.S. Department

of Agriculture was used to identify those raw agricultural commodities where detection limit substitutions were needed (http://www.nass.usda.gov/Statistics_by_Subject/index.php?sector=CROPS). The Diversity and Autocorrelation (D & A) method (Glen et al., 2008) was used to construct longitudinal data for the residential and dietary exposure estimates. Indoor awake time was set as a key variable for the residential exposure estimates, with D and A statistics set to 0.25 and 0.4, respectively. Total caloric consumption was used as the key variable for the dietary exposure estimates, with D and A statistics set to 0.3 and 0.1, respectively (based on longitudinal data from Lu et al., 2006). The cumulative exposure for one year was simulated and statistics for 21 days were matched with NHANES biomarker data for model evaluation. To combine the dietary and residential module outputs we used the methodology described in Zartarian et al. (2012) and depicted in Fig. 1. This approach has been previously externally peer-reviewed

(FIFRA SAP, 2007 and FIFRA SAP, 2010) and also evaluated in the Zartarian et al., 2012 permethrin case study. Here we briefly describe the procedure: 1) Assemble longitudinal data from cross-sectional data for both residential and dietary using the D & A method; 2) form bins with key variables such as age and gender; and 3) create 5 small bins from each BIBF 1120 molecular weight Methane monooxygenase bin formed by key variables by percentile range by total caloric consumption weighted by body weight for dietary and averaged MET weighted by body weight for residential. The SHEDS-Multimedia residential and dietary modules were each applied to estimate exposures for 3–5 year olds. We generated and analyzed population variability results for annual averaging time to identify key chemicals and pathways. The built-in

pharmacokinetic (PK) model to estimate absorbed dose (Glen et al., 2010) was used for the initial exposure pathway contribution analysis. A sample size of ~ 4000 individuals was used for the one year variability simulations. Results are reported for an annual averaging time and for separate and aggregated pathways. Skin surface loadings in human dermal studies are typically several orders of magnitude higher than real-world levels. When surface loading exceeds a uniform monolayer over the course of study, dermal absorption is flux-limited, yet when surface loading is sparse, as happens in real-world scenarios, absorption transitions to a supply-limited state (Kissel, 2011). Thus, when fractional absorption is determined from such dermal studies, high surface loadings decrease the apparent fractional absorption, ultimately biasing the modeled dermal contribution.