阿哈水库沉积物重金属污染及潜在生态风险评价

Heavy Metal Pollution in the Sediments of Aha Reservoir and Assessment of Its Potential Ecological Risk

高原水库对改善当地气候环境、资源环境具有重要意义，而对高原水库的重金属污染及潜在生态风险评价报道甚少。以贵阳市重要饮用水源阿哈水库为研究对象，运用原子吸收、原子荧光法、ICP法对阿哈水库沉积物中7种重金属元素（Hg、Cd、Pb、As、Cu、Cr、Zn）进行测定，并根据Lars Hakanson潜在生态风险指数法对阿哈水库沉积物中重金属污染元素导致的生态风险进行分析。结果表明，沉积物中Zn的富集系数最高（Cf^i〉6），Cu次之（Cf^i=2．34）：潜在生态风险评价结果显示，Hg潜在生态危害系数在所有站位中均〉40，（Cd）仅在2站位〉40，其余站位均〈40；其他元素潜在生态风险较低。重金属潜在生态风险系数依次为Hg〉Cd〉As〉Cu〉Pb〉Zn〉Cr。研究表明，阿哈水库已存在一定的生态风险。

An investigation on Aha Reservoir, the major drinking water source in Guiyang, has been conducted. Seven species of heavy metals, namely mercury, cadmium, lead, arsenic, copper, chromium and zinc, in the sediments of Aha Reservoir were examined by using atomic absorption （AA）, atomic fluorescence and inductively coupled plasma （ICP） emission spectrometry. The ecological risk brought about by the heavy metal contamination in the sediments was analysed by means of Lars Hakanson potential ecological risk indexing method. It was found that in the sediments the accumulation coefficient of zinc stood the highest （Cf^i〉6） and followed by that of copper （Cf^i=2.34）. The risk evaluation has shown that the potential ecological hazard coefficient Ef^i of mercury was all in excess of 40 and that of cadmium was below 40 at all but two monitoring spots whilst that of the other elements being at lower levels. The potential ecological risk of those heavy metals was ranked in descending order as follows： mercury, cadmium, arsenic, copper, lead, zinc and chromium. It revealed that there has already been certain ecological risk in Aha Reservoir.