原子荧光光谱法测定环境水及土壤样品中的汞形态含量

采用氢化发生-冷原子荧光光谱法，测定了厦门市集美周边地区的几种水和土壤样品中汞的不同形态含量。在仪器优化条件下直接进样测定水中微量无机汞的含量，再用溴酸钾-溴化钾消解水样并测定其总汞含量，由总汞与无机汞含量之差计算出有机汞含量；采用微波消解体系测定土壤样品中的总汞含量，同时用连续化学浸提法提取测定包括可交换态汞、盐酸溶汞、元素汞、腐殖酸结合态汞、有机质结合态汞和硫化汞的不同汞形态含量，并最终测定残态汞含量。实验结果表明，实验室排放水中汞含量高于Ⅰ类污水综合排放标准(GB 8978—1996)，说明实验室排放水是严重的汞环境污染源之一。而公路边土壤、近海沉积物和菜园土壤的汞形态含量均低于相应的国家标准，但由于人为污染造成菜园土壤汞的不断积累应引起高度重视。实验同时对水和土壤样品的测量检出限及方法回收率进行试验，结果表明在优化的实验条件下水和土壤汞的检出限分别为0.000 8 μg·L-1和0.072 3 μg·kg-1,3个水平的加标平均回收率分别为93.7%和93.8%，方法准确、可靠。

Determination of Trace Mercury Species in Water and Soil Samples with Atomic Fluorescence Spectrometry

With hydride generation-cold atomic fluorescence spectrometry (HG-AFS), the method of determining trace mercury species in water and soil samples in Jimei, Xiamen city, China was established. The content of inorganic mercury in water was measured by sample direct injection, while the total mercury was measured after digestion with the reagents of KBrO3-KBr. The soil samples were digested with microwave for total mercury measurement. Sequential extraction procedure was carried out for determining different mercuric species in soil samples. The results indicated that the mercury concentration of wastewater from chemical laboratory exceeded the limit of the integrated wastewater discharge standard of China (GB 8978-1996). It is one of the serious pollution sources of mercury in environment. The mercury contents from soil samples including the sideward soil of highway, the sea sediment and the garden soil were under the limits of relative national standards of China. However, attention should be paid to the accumulation of mercury in garden soil due to the artificial pollution. Meanwhile, the average recoveries for water and soil samples tested with adding standards were 93.7% and 93.8%, respectively. Meanwhile, the detection limits estimated with 3-fold standard deviation were 0.000 8 microg x L(-1) for water and 0.072 3 microg x kg(-1) for soil, respectively. The results indicated that the established method, with the merits of high sensitivity and precision, was suitable for the measurement of trace mercury species in environmental samples.