Organophosphate Esters in Foodstuffs from Multiple Provinces in China: Possible Sources during Food Processing and Implications for Human Exposure.

With increasing application of organophosphate esters (OPEs) as flame retardants and plasticizers in the world, the health and ecological risks posed by these chemicals have raised people's concern over the years. Despite the fact that dietary intake is an important pathway for human exposure to OPEs, monitoring on OPEs in foodstuffs is scarce. In this study, we measured 14 OPEs in both packaged ( = 229) and fresh ( = 58) foodstuffs collected across China with a new method that was developed by two-stage solid-phase extraction. The total concentrations of OPEs (ΣOPEs) in 12 categories of packaged foodstuffs and 5 categories of fresh foodstuffs were in the range of 0.212-273 ng/g wet weight (ww) [geometric mean (GM): 5.06 ng/g ww] and 0.189-2.82 ng/g ww (GM: 0.618 ng/g ww), respectively. Significantly higher levels of ΣOPEs were found in packaged food categories of fruits and meat than those in the corresponding fresh ones, implying the extra introduction of OPEs during the processing and storage of foodstuffs. Correlation analysis showed that the GM concentrations of individual OPEs in animal-derived foods with few industrial processing were positively correlated with their annual production volumes in China in 2020, emphasizing the significance of natural sources of OPEs in these food samples. Elevated levels of ΣOPEs (range: 8.94-4120 and GM: 274 ng/g) were found in food-packaging materials, and the predominant OPE analogues were consistent with those found in packaged food samples. The result implies that the food-packaging material can be an important contamination source of OPEs in packaged foodstuffs, which is in particular true for triphenyl phosphate, tris(2-chloroisopropyl) phosphate, tris(2-chloroethyl) phosphate, and 2-ethylhexyl diphenyl phosphate. The median daily intake of ΣOPEs via food was estimated as 65.4 ng/kg bw/day for adults in China, and the category of cereals was the major contributor (72.7%) of the dietary exposure to OPEs. The exposure risk of OPEs via food intake was generally low for the Chinese population. Overall, this study establishes a baseline concentration for OPEs in Chinese foodstuffs and uncovers food contact material as a potential source of OPEs in foods. It is expected that the research in terms of food safety and OPE contamination will benefit from this work.