| Benzotriazoles(BTs) UV-Filters are widely used as ultraviolet absorbents which have a potential hazard to human health. Urban sewage treatment plant is an important sink and pollution source of receiving water of BTs UV-Filter, the chemical behaviors of the objects have a serious effect on the ecological environment of the receiving water. It is imperative to carry out urban sewage system study on the fate of BTs UV-Filter. Water and sludge sample pretreatment methods and gas chromatography- tandem mass spectrometry(GC-MS/MS) analysis method for BTs UV-Filter were developed to study the removal and residue of BTs UV-Filter systematically.A GC-MS/MS method was developed to analyze 9 BTs UV-Filter in water and sludge in this study. The method limit of detection was 0.1~0.5 ng/L, and the recovery was 73.66~111.99%. The target compounds in real samples could be perfectly analyzed using this method.In sewage samples, UV-326 and UV-329 were found in all samples. UV-329 became the most abundant BTs UV-Filter. The removal rates of BTs UV-Filters was more than 85% in A/O process, and 60-80% in BAF process, except for UV-350. The secondary sedimentation tank played a major role in the A/O process, whereas biological aerated filter was the most important unit for the BAF process. The concentration of BTs in receiving water ranged from not detected to 4.26 ng/L. The concentrations of UV-234, UV-350, UV-P and UV-PS in receiving water significantly increased due to their high concentrations in the effluent of wastewater treatment plant.The detection rates of BTs in sludge samples were higher than those in sewage samples, with the mean concentration range of 0.90~300.47 ng/g. Among them, the concentration of UV-234 highest, which was higher than those from other areas in China. According to the variance analysis, the usage of UV-234, UV-326 and UV-328 in municipal sludge has shown the regional differences.Seasonal variation could affect the residues and removal rates of BTs. There was no significant difference of influent concentrations of the BTs among different seasons. However, UV-329 and UV-326 showed the significant seasonal difference in the effluent of A/O process. The removal rates of UV-328 showed the significant seasonal difference in A/O process. In the effluent of BAF process, BTs have not shown the significant seasonal difference.The risk quotient of 9 BTs in the effluent and sludge of the wastewater treatment plant in Harbin was within the moderate risk level, however, more attention should be paid on UV-234. Over all, the concentration and risk quotient of BTs in Songhua River in Harbin segment is lower than those in other rivers. |
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