Preliminary Study Of Organophosphate Ester Flame Retardants In Rivers Around The Bohai Sea

Flame retardants have been reducing the risk of fires in everyday products such as buildings, cars, ships, airplanes, trains, electronics, plastics, furniture and clothes. Organophosphate esters(OPEs) are important organophosphorus flame retardants with good flame retardant effect, low production cost and uncomplicated production process. Since brominated flame-retardants(BFRs) such as polybrominated diphenyl ethers(PBDEs) have gradually been restricted worldwide due to environmental concerns, OPEs, have increasingly been used as alternatives to BFRs in many industrial applications and household products. While the environmental problems caused by OPEs has gradully attracted attention of scientific community, OPEs has become a new hot spot of the research of emerging organic pollutants. As potential persistent organic pollutants, many studies have demonstrated that a few of OPEs are biological toxic, and a few OPEs especially chlorinated alkyl phosphate esters are recalcitrant in natural environment and OPEs may go on mediun and large scale migration by absorbed on particles. Researches in China were mostly focused on the synthesis and performance optimization of OPEs. However, few literatures on concentraion levels and distributions have been reported.The river basins in the study area have been subjected to heavy anthropogenic influences owing to the high-speed development of the agriculture, industry and overall economy. Rivers are one of the major sources/pathways for terrestrial pollutants into the sea. The Bohai Sea is a semi-enclosed Chinese water body, and these rivers are the major sources for pollutants to the Bohai Sea. This study focused on the occurrence and spatial distribution of OPEs in 40 major rivers entering into the Bohai and Yellow Seas and the riverine input of OPEs was estimated. In this study, analytical methods based on Soxhlet Extraction liquid-liquid extration and soxhlet extraction coupled to gas chromatograph-mass spectrometer(GC-MS) were established for determination of OPEs in river water and sediment samples. High quality QA/QC data were obtained. OPEs were determined in water samples from 40 rivers and in sediment samples from 35 rivers. The results showed that the detection rates of OPEs in aqueous phase and sediment were 100% and OPEs were widely distributed and in a wide range. Total OPEs(∑12OPEs) in aqueous phase ranged from 10 to 1549 ng/L, with an average of 300 ng/L. The most common OPEs detected in river water were TCPP, TCEP and TPPO, at mean concentrations of 186 ng/L, 80 ng/L and 224 ng/L, respectively. Priority attention should be given to TPPO contamination in rivers around the Bohai Sea, especially in the Yalu(5852 ng/L) and Jiehe(1283 ng/L) Rivers. Total OPEs(∑8OPEs) in sediment particle phase ranged from <MDL to 148 ng/g, with an average of 27 ng/g. The most common OPEs detected in river sediments were TBEP, TCPP and TCEP, at mean concentrations of 14 ng/L, 4 ng/L and 2 ng/L, respectively. The concentrations of the three most common products of organophosphate esters were consistent in aqueous phase and sediment particle phase: TCPP>TCEP>TDCPP.According to the sample concentrations and annual runoff, the total riverine input of OPEs was estimated to be 16.0±3.2 t/yr and the total riverine input of TPPO was estimated to be 113±22.6 t/yr. Liaodong Bay received relatively high riverine input of 12 organophosphorus compounds(7.0±1.4 t t/yr) in comparison to Bohai Bay(3.4±0.7 t/yr) and Laizhou Bay(1.5 ± 0.3 t/yr).The study found that the sources of OPEs from the Bohai area were similar and their distribution patterns in aqueous phase were similar.TOC, TN, Corg/Ntotal, sediment particle size and particle size fractions(clay, silt and sand) didn’t influence the concentration of OPEs in sediment. Log KOW value of OPEs was an improtant factor contrlling the OPEs distribution in particle phase and aqueous phase. The lower the log KOW value was, the more likely OPEs was inclined to distribute in aqueous phase. The greater the log KOW value was, the more likely OPEs was inclined to distribute in particle phase. The aqueous phase was an important input way for OPEs and allocating in the aqueous phase resulted to the good correlations between OPEs.This paper helped to understand the pollution situation and regional distribution of OPEs in Chinese surface water, to lay the groundwork for OPEs study in water body, to provide reference data for environmental risk assessment of OPEs. Surface water pollution has become the most prominent factor affecting water security in China. Attention should be given to traditional pollutants such as COD, ammonia and nitrogen pollution and eutrophication as well as organic pollutants such as OPEs.