Declining trends and regional variations of organophosphate ester contamination in indoor dust from mainland China: Insights from a filed study and meta-analysis.

This study investigated the presence of 20 organophosphate esters (OPEs) in indoor dust samples collected from the Chinese cities of Lanzhou, Xining, and Lhasa. The results demonstrate the ubiquitous presence of most OPEs in these three cities, with the highest concentrations of ΣOPEs found in Xining. We also summarized the occurrence of OPEs in indoor environments from 38 studies with 1875 samples collected across various regions of mainland China from 2012 to 2023. The weighted-median concentration of ΣOPEs in indoor dust exhibited region-specific variations, range from 381.9 to 6622.5 ng/g. Chloroalkyl-OPEs (Cl-OPEs) (e.g., tris(2-chloroethyl) phosphate (TCEP), tri(1-chloro-2-propyl) phosphate (TCIPP), and tri (1,3-dichloro-2-propyl) phosphate (TDCIPP)) predominated in all seven regions (range: 38.9 %-71.4 %). TCIPP was predominant in the Central China, North China, Northeast China, Northwest China, Southwest China, and Southwest China regions, while TCEP dominated in the Eastern China region. A significant downward trend in OPE concentrations in indoor environments was observed during the investigated period. Dust ingestion was identified as the predominant pathway of human exposure to OPEs indoors. The hazard quotients for Cl-OPEs were below the non-carcinogenic threshold, suggesting significant health risks are unlikely. This study underscores the widespread occurrence of OPEs in indoor dust across mainland China, emphasizing the necessity for ongoing monitoring and regulation of these chemicals.