开封市公园灰尘重金属含量及潜在生态风险

采集河南省开封市区4个典型公园(清明上河园、龙亭公园、铁塔公园、相国寺)52个地表灰尘样品,采用原子荧光(AFS)法、电感耦合等离子体发射光谱法(ICP)和电感耦合等离子体质谱(ICP-MS)法测定灰尘重金属含量,并用调整后的Hkanson潜在生态危害分级标准对重金属潜在生态危害进行评价。结果表明:灰尘Cd、Hg、Pb、Zn、Cu富集显著。重金属单项生态风险指数(E)顺序为HgCdPbCuNiZnCoCrMnTi,除Hg和Cd出现强烈以上生态风险外,其他重金属风险轻微。所有公园灰尘重金属潜在生态总风险(RI)均在很强等级以上,其大小依次为RI相国寺RI龙亭公园RI铁塔公园RI清明上河园。灰尘Hg和Cd对RI的平均贡献率分别为45.28%和46.77%,是最主要的风险因子。

Potential Ecological Risk of Heavy Metals in Surface Dusts from Parks of Kaifeng City,China

Fifty-two dust samples were collected from four parks(Longting Park, Tieta Park, Qingmingshanghe Park, and Xiangguosi Park)located in Kaifeng City, China. Concentrations of heavy metals in dusts were analyzed by inductively coupled plasma mass-spectrometry(ICP-MS), inductive coupled plasma emission spectrometer(ICP), and atomic fluorescence spectrometry(AFS). Potential ecological risks of dust metals were assessed using risk index (RI) recommended by Håkanson in 1980. Results indicate that the dusts have accumulated many heavy metals, especially for Hg, Cd, Pb, Zn, and Cu. The single ecological risks(E) of dust Hg and Cd are higher than 160, suggesting that most sampling sites are at very high ecological risks of Hg and Cd, while other heavy metals are at low ecological risk(E<40). The average E of metals decrease in the order of Hg > Cd > Pb > Cu > Ni > Zn > Co > Cr > Mn > Ti. The average RIs of metals in dusts from the four parks are at very high ecological risks. The mean values of RIs of metals in different parks show the following order of Xiangguosi Park > Longting Park > Tieta Park > Qingmingshanghe Park. The contribution rate of E_Hg to RI is about 46.77%, and E_Cd to RI is about 45.28%, therefore cadmium and mercury are crucial factors for ecological risks in the four parks in Kaifeng City.