Multi-pathway exposure assessment of organophosphate flame retardants in a southern Chinese population: Main route identification with compound-specificity

In this study, we conducted comprehensive organophosphorus flame retardant (PFR) exposure assessments of both dietary and non-dietary pathways in a rural population in southern China. Skin wipes were collected from 30 volunteers. Indoor and outdoor air (gas and particles), dust in the houses of these volunteers, and foodstuffs consumed by these volunteers were simultaneously collected. The total PFR concentrations in dust, gas, and PM2.5 varied from 53.8 to 5.14 × 105 ng/g, 0.528 to 4.27 ng/m3, and 0.390 to 16.5 ng/m3, respectively. The forehead (median of 1.36×103 ng/m2) and hand (median of 920 ng/m2) exhibited relatively high PFR concentrations, followed by the forearm (median of 440 ng/m2) and upper arm (median of 230 ng/m2). The PFR concentrations in the food samples varied from 0.0700 to 10.9 ng/g wet weight in the order of egg > roast duck/goose and vegetable > pork > chicken > fish. Tris(1-chloro-isopropyl) phosphate (TCPP) was the main PFR in the non-diet samples, whereas the profiles of PFR individuals varied by food type. Among the multiple pathways investigated (inhalation, dermal exposure, dust ingestion, and food ingestion), dermal absorption and dust ingestion were the predominant pathways for tris(2-chloroethyl) phosphate (TCEP) and bisphenol A-bis(diphenyl phosphate) (BDP), respectively, whereas dietary exposure was the most important route for other chemicals.