An Assessment of the Levels of Emerging and Traditional Organophosphate Ester Flame Retardants in Dairy Products in China and their Combined Dietary Risks.

A comprehensive survey was conducted by investigating 25 emerging and traditional organophosphate esters (OPEs) in 182 dairy products collected in China. The concentration of total OPEs (ΣOPEs) ranged from 0.0261 to 1178 ng/g wet weight (ww) in all the dairy samples. The major contaminants were triethyl phosphate (proportion: 93 %) and tris(1-chloro-2-isopropyl) phosphate (proportion: 2 %). Among types of dairy products, the concentrations of ΣOPEs decreased in the following order: milk powder (mean: 80.8 ng/g ww, proportion: 86 %) > cheese (9.43 ng/g ww, 10 %) > milk tablets (2.72 ng/g ww, 3 %) > liquid dairy (1.05 ng/g ww, 1 %). The significant correlation between emerging and traditional OPEs suggests that they likely share similar sources or are used together in commercial applications. OPEs contamination was related to the OPEs properties, local OPEs production and application, and dairy types. For the general Chinese population, the average and high estimated daily intakes of ΣOPEs via dairy products were 31.5 and 83.6 ng/kg bw/day, respectively. Dairy exposure in toddlers and children were higher than other age groups. Although the high-exposure risk of ΣOPEs was 3.50 × 10^-3, potentially toxic tris(1-chloro-2-isopropyl) phosphate accounted for 38 % of the total hazard quotients.