Occurrence and distribution of organophosphate esters in sediment from northern Chinese coastal waters

[Display omitted] •Fourteen OPEs were measured in coastal sediment from northern China.•ΣOPEs in surface and core sediments ranged 1.76–49.9 and 8.58–169 ng/g dw, respectively.•TCIPP, TiBP, and TnBP were the predominant OPEs in sediment.•OPEs concentrations in sediment core showed an increasing trend during the past decade. Organophosphate esters (OPEs) are used as flame retardants and plasticizers in many consumer products. Owing to OPEs’ toxicity, exposure of organisms in aquatic ecosystems is a concern. Information that pertains to the occurrence and distribution of OPEs in marine aquatic environment, however, is scarce. In this study, concentrations and profiles of 14 OPE triesters were determined in sediment collected in coastal waters (Bohai Sea and East China Sea) of northern China. The total concentrations of OPEs (ΣOPEs) in surface sediment were in the range of 1.76–49.9 (median: 9.13) ng/g dry weight (dw), which were comparable to or lower than the range of concentrations reported for surface sediments worldwide. Tris(2-chloro-propyl) phosphate (TCIPP), tris(2-chloroethyl) phosphate (TCEP), tri-isobutyl phosphate (TiBP), and tri-n-butyl phosphate (TnBP) were the predominant OPEs found in surface sediment, collectively accounting for 81% of the total concentrations. ΣOPE concentrations in sediment core (range: 8.58–169, median: 31.6 ng/g dw) were generally higher than those found in surface sediment. The vertical distribution of OPEs in sediment core showed a gradual increasing trend in concentrations during the past decade.