LAUSR

Numerous studies have reported the environmental contamination of traditional organophosphate triesters (tri-OPEs), but there is very little information on emerging tri-OPEs and organophosphate diesters (di-OPEs), especially in e-waste recycling area. In this study, we conducted a comprehensive survey to monitor a broad suite of 11 traditional tri-OPEs, 12 emerging OPEs and 10 di-OPEs in indoor dust collected from workshops (n = 42) and adjacent residential homes (n = 24) of a mega e-waste recycling industrial park in South China. In addition to traditional tri-OPEs, all the emerging OPEs and di-OPEs were frequently detected in the dust samples. Total concentrations of emerging tri-OPEs and di-OPEs were in the range of 1210-62900 and 2010-55600 ng/g in workshop dust, and 435-23700 and 186-4350 ng/g in local home dust, respectively, which were comparable to those of traditional tri-OPEs (1160-61500 and 370-13900 ng/g, respectively). Most OPEs exhibited significantly higher concentrations in workshop dust versus local home dust (p < 0.05), indicating that e-waste dismantling activities contributed to the high residues of OPEs in indoor dust. Correlation analysis revealed that tri-OPEs have some common emission sources, i.e., e-waste and household products, while di-OPEs could originate from different sources, e.g., tri-OPE degradation, direct commercial application, and impurity in tri-OPE formulas. For both occupational workers and local adults, the median estimated daily intake of emerging tri-OPEs (7.5 and 1.7 ng/kg bw/day, respectively) and di-OPEs (3.9 and 0.2 ng/kg bw/day, respectively) was comparable to that of traditional tri-OPEs (4.3 and 1.0 ng/kg bw/day, respectively), which suggests the important contribution of the emerging tri-OPEs and di-OPEs to the overall risks of human external exposure to OPE chemicals.