Polybrominated diphenyl ethers and new polybrominated flame retardants in tree bark from western areas of China

Tree bark samples were collected from 15 sites across western China in 2013, and the polybrominated diphenyl ether (PBDE) and new polybrominated flame retardant (NBFR) concentrations in the samples were determined. The mean total PBDE concentration was 51.8 ng/g lipid weight, which was 85.2% to 99.4% lower than in Chinese eastern coastal areas and the E-waste recycling areas. The dominant PBDE congener was BDE209, and its mean concentration was 49 ng/g lipid weight. The mean 2,3,5,6-tetrabromo-p-xylene, pentabromobenzene, pentabromotoluene, and hexabromobenzene concentrations were 0.61 ng/g, 0.97 ng/g, 0.68 ng/g, and 0.68 ng/g lw, respectively. The PBDE and NBFR concentrations in the air at the sampling sites were estimated from the concentrations in the tree bark samples. The estimated mean total PBDE and total NBFR concentrations in air were 58.5 pg/m(3) and 2.76 pg/m(3) , respectively. The sources of NBFR emissions were found to be different from the sources of PBDE emissions, as no relationship was found between the NBFR and PBDE concentrations, and it appeared that sources of measured hexabromobenzene, pentabromobenzene, and pentabromotoluene in tree bark in western China include industrial activity related to the aluminum industry. Environ Toxicol Chem 2016;35:1364-1370. © 2015 SETAC.