南宁城市内河沉积物中SVOCs的分布与风险评价

摘要

采用加速溶剂萃取-气相色谱-质谱联用技术对南宁市7条城市内河表层沉积物中的64种半挥发性有机物(SVOCs)进行了分析测定,定量检出12种SVOCs,包括7种多环芳烃类(PAHs)、1种酚类和4种酯类,其中属于我国优先控制污染物的有8种,属于美国优先控制污染物的有11种.南宁市城市内河沉积物中的SVOCs总量范围为6.75～34.45 μg/g(以干质量计),均值为15.85 μg/g(以干质量计),以竹排冲的含量最高,污染程度与工业污染源的关系十分密切.特征污染物为酞酸酯,在各测点的比重均占检出总含量的83％以上.除相思湖外的6条城市内河的沉积物均检出PAHs,区城内的工业生产活动对城市内河沉积物的PAHs有重要贡献.应用效应区间低值(ERL)和效应区间中值(ERM)指标对沉积物进行的生态风险评价表明,南宁市城市内河沉积物的生态风险较小.%The semi-volatile organic compounds (SVOCs) in the surface sediments from seven urban rivers in Nanning were determined using accelerated solvent extraction (ASE) and gas chromatograph/mass spectrometer (GC-MS) techniques.The result showed that twelve SVOCs were detected from the sixty-four substances detected,including seven polycyclic aromatic hydrocarbons (PAHs),one phenol and four esters.Among these pollutants,eleven substances are priority-controlled by USEPA and eight by China.The total concentration of SVOCs varied from 6.75 to 34.45 μg/g (dry weight) with an average value of 15.85 μg/g.The highest SVOCs concentration was found in sediment from Zhupai Creek,which was closely correlated to the industrial sources of pollution nearby.The dominant pollutant was phthalate,whose weight proportion in all the sediment samples was more than 83％.PAHs were detected in river sediments from the other six urban rivers except Acacia Lake.Industrial production in the area made a significant contribution to PAHs in the sediments.The ecological risk of PAHs in the rivers of Nanning City was evaluated by the ERL and ERM.It indicated there was low ecological risk in these areas.