| Decabrominated diphenyl ether (DecaBDE) is a general purpose flame retardant and is used in any type of polymers, such as polycarbonates, polyester resins, polyolefins, ABS, polyamindes, polyvinyl chloride, and rubber. With their produce, usage, recycle and disposal, decaBDE and other polybrominated diphenyl ethers are ubiquitous in air, water, soil and sediment environments, the levels of these PBDEs seem to be increasing, and several trends, including in animal and humans. The decaBDE has become of increasing concern to scientists in recent years.In the present work, the dispersive Liquid-liquid microextraction (DLLME) method was applied to extracte decaBDE in water and sediment samples. The concentrations of decaBDE in real water and sediment samples from Songhua River were determined by DLLME with high performance liquid chromatography with UV detector (HPLC-UV). The proposed methods were applied successfully to determination of decaBDE in water and sediment collected from Songhua river and ecological risk assessment of decaBDE in the aquatic environment.This paper developed a method for the determination of decaBDE in water samples based on DLLME and HPLC-UV. The effect of various experimental factors on the extraction was investigated using interactive orthogonal array design and experimental design, Box-benhnken design and BP artificial neural network model, respectively. The optimical conditions were obtained as follow:1.00 mL of acetone as dispersive solvent, 10.0μL of tetrachloroethylene as extractive solvent, the percent of NaCl is 2 %, pH5~9 and 10min of extraction time. The enrichment factor (EF) was 783 and the extraction recovery (ER) was 100% or so. The decaBDE in water was separated with other compounds in samples at a Zorbax Eclipse XDB-C18 column (150 mm×4.6 mm, 5μm, Agilent) at 30oC , and the mobile phase was a mixture of methanol/water (97/3, v/v) with 1.0mL/min flow rate. The wavelength of UV detector was set at 226 nm. At these chromatographic conditions, the retention time of decaBDE was 15.9 min.The method of DLLME-HPLC-UV exhibited a linear eqution of Y=19.794 X +16.652 with R2 > 0.9999 in0.007– 100.0ng/mL. The limit of detection (LOD) and the limit of quantification (LOQ) of this method were 3.0 pg/mL (S/N=2) and 7.1 pg/mL (S/N=5), respectively. The recoveries of decaBDE was ranged from 94.11 to 106.76%, RSDs (n=3) were 6.34, 5.44, and 5.53%, respectively.A method for determination of decaBDE in sediment samples has been developed using dispersive liquid-liquid microextraction based on the solidification of floating organic drop (SFO-DLLME) and HPLC-UV. The effect of various experimental factors on SFO-DLLME was investigated using interactive orthogonal array design and optimized by experimental design or BP artificial neural network model. The optimical conditions were obtained as follow: 1.00 mL of methanol as dispersive solvent, 35.0μL of dodecanol as extractive solvent, the mass concentration of NaCl was 10.00% at pH 5, extraction time was 10 min and 0.061 mm of grain-size. The ER was 62.22%, the EF was 134. The decaBDE in sediment was separated with other compounds at a Zorbax Eclipse XDB-C18 column (150 mm×4.6 mm, 5μm, Agilent) at 30oC , and the mobile phase was a mixture of methanol/water (95/5, v/v) with 1.0mL/min flow rate. The wavelength of UV detector was set at 226 nm. At these chromatographic conditions, the retention time of decaBDE was 23.14min. The method using SFO-DLLME with HPLC-UV exhibited a linear equation of Y=101.51X+5.7553 in 3.5–1400 ng g–1 with R2 = 0.9928. The limit of detection (LOD) and the limit of quantification (LOQ) for this method were 2.3 pg g–1 (S/N = 2) and 5.6 pg g–1 (S/N = 5), respectively. The recoveries of real samples at different spiked levels of decaBDE ranged from 97.71% to 104.19%, and RSDs (n=3) were 3.72%,2.18% and 2.15%, respectively.Thirty eight waster water and one hundred six sediment samples from outfall, two river water and two sediment samples from river were collected from Songhua river in Jilin city. The proposed methods were applied to determination of decaBDE in these water and sediment samples. DecaBDE was not found in four water and sediment samples collected from River, which means the River is not polluted by decaBDE. The concentration of decaBDE in waster water ranged from below LOQ to o.165ng/mL. The concentration of decaBDE in sediment collected from outfall ranged from below LOQ to 9.17ng/g. Overall, the concentration of decaBDE in water and sediment from outfall were slightly lower than those from other waster environment worldwide. The investigation to situation suggested the decaBDE may be released to the environment because of daily life of people, but not the produce of polymers.The other seven PBDEs (BDE28, BDE47, BDE99, BDE100, BDE153, BDE154, BDE183) in water samples were extracted with the proposed DLLME method, and analysis by gas chromatography with mass spectrometry (GC-MS), and they were determinated using GC-MS method with Soxhlet extraction in sediment samples. The seven PBDEs were all not found in water and sediment samples from River, but they were found in sediment samples and some waster water samples. The concentration of BDE28 ranged from 2.23 to 9.38ng/g in six sediment samples, BDE99 was only found in one samples and was 1.11ng/g, BDE100 ranged from 1.09 to 29.77ng/g in nine samples, and the ranges of BDE153 and BDE154 were 1.29-8.94ng/g and 1.10-7.42ng/g, respersively. BDE47, BDE183, and BDE209 were ubiquitous found in sediment samples, their ranges were1.19-11.24ng/g, 0.94-95.92ng/g and 1.00-19.46ng/g, respectively. In outfall of Songhua River, BDE209 and BDE183 are the main congeners, BDE 47 is second congener.Because of lower concentration in water and sediment, many organic compounds can not anlysis using conventional method. The decaBDE at trace level in water or in sediment was concentrated using DLLME or SFO-DLLME method, and can be anlysis with conventional HPLC-UV method, so the DLLME technology make it easy to study behaviors of organic compounds in environment. Through experiment, the condition of concentration of decaBDE between water and sediment was as follow: pH no control, standing 48 hours at 25℃,and the initial concentration was 60ng/mL. At the optimic condition, the theroical concentrated factors were ranged from 468.0 to 487.1, and the mean value was 476.6. The practical concentration factors of decaBDE between water and sediment in Songhua River were ranged from 37.5 to 385.8, which were lower than the theroical value. The results suggested that decaBDE would be concentrated to sediment if the decaBDE increased in waster water in Songhua River.Based on"three stages"suggested by the evaluation framework of"Guide to Ecological Risk Assessment", the ecological risk of decaBDE in aquatic environment of Songhua River was assessed. In assessment, the evaluation endpoint was in biological level, and the conceptual model of ecological risk was builded. The multi-ethnic no effect concentrations (MS NOEC) of PBDEs in the water and sediment environment were calculated using the United States Environmental Protection Agency laboratory toxicity data extrapolation method. Evaluation results showed that the Q value is far lower than 1, which means there is no ecological risk in Songhua River from PBDEs and the risk comes mainly from the pressure of PeBDE, which mainly because it has more observably toxicity than others. Uncertain anlysis demonstrated that there are some uncertainty in ecological risk assessment, and were resulted mainly by analytical method, toxicity data, evaluation method, and risk resource.
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