Distribution and sources of ordinary monomeric and emerging oligomeric organophosphorus flame retardants in Haihe Basin, China

With the banning of poly-brominated Biphenyl ethers, organophosphorus flame retardants (OPFRs) have gained great development space as their alternatives. In this study, the concentration and partition of nine ordinary monomeric OPERs and two emerging oligomeric OPFRs (Resorcinol bis(diphenyl phosphate) (RDP) and bisphenol A bis(diphenyl phosphate) (BDP) in the Haihe Basin of China were studied, and their possible sources were analyzed. The Sigma OPFRs in the surface water, sediments and suspended particulate matters (SPMs) in Haihe Basin were 80.1-777 ng/L, 18.9-86.5 ng/g dw and 6.40-234 ng/g dw, respectively. The detection frequencies of both oligomeric OPFRs exceeded 85%, suggesting their environmental contamination was widespread. The mean concentrations of RDP and BDP were 2.09 and 6.03 ng/L in the surface water, 0.91 and 5.09 ng/g dw in the sediments, 1.08 and 2.61 ng/g dw in SPMs, respectively. With CI-OPFRs being predominant in all the three media, the proportions of alkyl-OPFRs, aryl-OPFRs, and oligomeric OPFRs in the sediments and SPMs were remarkably higher than those in surface water, suggesting that non-halogenated OPFRs preferred to distribute in solid phases. The water-sediment/SPM partition coefficients, logK(oc), of the OPFRs were calculated based on the paired samples. The logK(oc) values of RDP and BDP were reported for the first time, and their logK(oc) (water-sediment) were 4.36 +/- 0.47 and 4.76 +/- 0.25 and their logK(oc)( water-SPM) were 3.77 +/- 0.45 and 4.00 +/- 0.47, respectively. The obtained logK(oc) values were correlated with their octanol-water partition coefficient (log(ow)) significantly. It suggested that their partition to sediment or SPM was dominated by hydrophobic interaction. Principal component analysis indicated that the emissions from manufacturing plants and airport operation might be two important sources of OPFRs in the Haihe Basin of China. (C) 2021 Elsevier B.V. All rights reserved.