In the present study, the authors determined the concentrations and compositions of a suite of isopropylated and tert-butylated triarylphosphate ester (ITP and TBPP) isomers in house dust from the city of Guangzhou located in South China and the city of Carbondale in Midwestern United States. These two groups of organophosphate esters (OPE) are structurally analogous to triphenyl phosphate (TPHP), but have rarely been investigated for environmental occurrences and human exposure risks. The majority of target ITP and TBPP isomers were 100% detected in house dust from the two locations. Median concentrations of ?ITPs (including all ITP isomers) and ?TBPPs (including all TBPP isomers) were 63.4?ng/g (range: 16.0-500?ng/g) and 35.4?ng/g (8.1-198?ng/g) in South China house dust, respectively, compared with 476?ng/g (140-1610?ng/g) for ?ITPs and 81.3?ng/g (35.2-800?ng/g) for ?TBPPs in Midwestern U.S. dust. The profiles of ITP or TBPP isomers were similar between the two locations and were dominated by 2-isopropylphenyl diphenyl phosphate (2IPPDPP) and 4-tert-butylphenyl diphenyl phosphate (4tBPDPP), respectively. Although the levels of ?ITPs and ?TBPPs were generally one order of magnitude lower than those of TPHP in the same dust samples, the broad occurrences of most of these isomers in house dust from the two locations likely suggest their wide applications in household consumer products. Estimated intakes of ?ITPs and ?TBPPs via dust ingestion were generally three orders of magnitude lower than the reference dose proposed for TPHP. However, these emerging OPE chemicals merit continuous environmental surveillance, given their possible applications as specific commercial mixtures or as components/impurities in other flame retardant/plasticiser mixtures.
Authors: Guan Q, Tan H, Yang L, Liu X, Fiedler H, Li X, Chen D.
; Full Source: Science of the Total Environment. 2019 Oct 10; 686:1113-1119. doi: 10.1016/j.scitotenv.2019.06.055. Epub 2019 Jun 5.