Identifying dermal exposure as the dominant pathway of children's exposure to flame retardants in kindergartens

Exploration of multiple sources of brominated (BFRs) and organophosphate flame retardants (OPFRs) for children promotes the understanding of exposure pathways and health risk. 10 BFRs and 9 OPFRs were measured in skin wipes from hands, forehead, and arms of 30 children, and surface wipe samples from sills, toys, desks and floors, and indoor air samples of kindergartens from Xinxiang, China. Higher ∑9OPFRs concentrations were observed in the forehead (1840 ng/m2), followed by hand (1420 ng/m2) and arm wipes (1130 ng/m2), and the ∑8BFRs concentrations in forehead, hand and arm wipes were 116, 315 and 165 ng/m2, respectively. The total concentration of OPFRs and BFRs in floor wipes (66.1 and 24.5 ng/m2) were lower than those in toy (205 and 535 ng/m2), sill (227 and 30.1 ng/m2) and desk (84.4 and 139 ng/m2) wipes. Concentrations of FRs in forehead wipes were significantly correlated with those in gaseous air (p < 0.05), moderate correlations were found between the hand wipes and surface wipes (p = 0.054). We estimated the daily average dosages (DADs) of children exposure to FRs via multiple pathways. Compared to DADs via inhalation and hand-to-mouth transfer, dermal exposure was determined to be the predominant exposure pathway to ∑9OPFRs and ∑8BFRs.