博斯腾湖湿地Cu、Ni和Pb的分布特征及其生态风险

为探讨博斯腾湖湿地重金属分布特征及其潜在生态风险,采集博斯腾湖湿地表层沉积物样品,利用HNO_3-HF-HClO_4体系及全自动石墨消解仪消解,以AAS原子吸收光谱仪-石墨炉法测定Cu、Ni和Pb的含量。研究发现:博斯腾湖湿地沉积物中Cu、Ni和Pb的含量分别达到12.11(7.37~28.75)mg·kg~(-1)、117.51(90.03~195.38)mg·kg~(-1)和6.94(0.99~23.19)mg·kg~(-1),Cu和Pb的含量均低于背景值,而Ni的含量远高于背景值,是背景值的4.66倍。重金属累积程度依次为:NiCuPb,Ni的地累积指数处于2级以上污染水平,Cu和Pb地累积指数均处于0级污染水平,Ni为博斯腾湖湿地沉积物中主要富集的重金属元素,Cu和Pb基本无富集;3种重金属累积程度均存在明显的空间差异,其中,博斯腾湖西岸的累积程度相对偏高。湿地沉积物中Cu、Ni和Pb的潜在生态风险均为低等级,可产生轻微生态危害;但Ni对湿地重金属综合潜在生态风险贡献度最高,其潜在生态风险不容忽视;就整个环湖区湿地来看,西岸潜在生态风险相对偏高,与累积程度的评价结果趋于一致。

Distribution of Cu,Ni and Pb and Ecological Risk in the Bosten Lake Wetland

In this study,the sediment samples were collected so as to explore the distribution and potential ecological risk of heavy metals in the Bosten Lake wetland.The samples were dispeled using a HNO3-HF-HClO4 system,and the contents of Cu,Ni and Pb were measured by an AAS atomic absorption spectrograph.The results indicated that the mean concentrations of Cu,Ni and Pb in sediments were 12.11 (7.37-28.75),117.51 (90.03-195.38) and 6.94 (0.99-23.19) mg · kg-1 respectively.Among them,the contents of Cu and Pb were lower than the background values,while the content of Ni was high,and it was 4.66 times higher than the background value.The accumulative degree of heavy metals was in an order of Ni ＞ Cu ＞ Pb.The accumulation index of Ni was above Level 2,and the accumulation indexes of Cu and Pb were at Level 0.According to the research,Ni was the mainly enriched heavy metal in sediment,and there was no enrichment of Cu and Pb.There was an obvious spatial difference in accumulation degree of 3 kinds of heavy metals.Among them,the accumulation degree on west lakeside was relatively high.The potential ecological risk of Cu,Ni and Pb was at low level.However,the Ni contribution to the potential ecological risk was the highest,and it could not be ignored.Holistically,the potential ecological risk on the west lakeside was relatively high,which was in accordance with the evaluated results of the accumulation degree of heavy metals.