乌江流域东风水库水体中不同形态汞的时空分布特征

Spatial and Temporal Distribution of the Different Forms of Mercury in the Water of Dongfeng Reservoir,Guizhou Province

为弄清东风水库水体中不同形态汞的时空分布特征,在春季和夏季对东风水库进行采样,分别利用两次金汞齐-冷原子荧光法（CVAFS）和蒸馏-乙基化结合气相色谱冷原子荧光法（GC-CVAFS）测定总汞（THg）和甲基汞（MeHg）浓度。结果表明,东风水库THg（0.63~3.06 ng/L）和MeHg浓度（0.023~0.081 ng/L）与未受污染的天然湖泊水平相当,水库未受到明显的汞污染。夏季总汞（THg）、颗粒态汞（PHg）以及颗粒态甲基汞（PMeHg）浓度均值分别是春季的1.8、2.9和1.7倍,但春季总甲基汞（TMeHg）和溶解态甲基汞（DMeHg）高于夏季。季节性降雨强度的差异可能是导致东风水库水体不同形态汞浓度季节性变化的主要原因。此外,东风水库上游水体THg和PHg显著高于中下游水体,表明东风水库的修建对THg具有一定的拦截作用。

In order to find out the spatial and temporal distribution of the different species of mercury（Hg） in the waterbody of Dongfeng Reservoir（DR）.Mercury（Hg） and methyl mercury（MeHg） concentrations in the water of DR were analyzed by cold vapor atomic fluorescence spectrometry（CVAFS） and GC-CVAFS detection.The results showed that total Hg（THg） and MeHg were at the same level of uncontaminated reservoirs worldwide.It also showed that both of THg,particle mercury（PHg） and particle methyl mercury（PMeHg） in Summer were much higher than that in spring.However,dissolved methyl mercury（DMeHg） and Total methyl mercury（TMeHg） concentrations in summer were lower than those in spring.There were no significantly difference between dissolved mercury（DHg） concentrations in summer and those in spring.It indicated that seasonal rainfall intensity was an important factor which influenced the seasonal variation of mercury and methyl mercury.In addition,concentrations of THg and PHg in the upstream were higher than that in the middle and the downstreams,indicating that reservoir was in favor of desposition of mercury and interception of total mercury of river.