The environmental impact of mercury released from the volcanic activity of Sakurajima

1. 为了阐明汞的垂直通量，在3米和12米高度每两小时调查一次大气汞的每小时变化，持续3天。结果表明，白天大气汞浓度高于夜间：3m高度（Hg_<3m>）的汞浓度白天为1.65 ~ 17.92 ng m^<-3>(5.96±3.47 ng m^<-3>)，夜间为1.50 ~ 12.81 ng m^<-3>(4.20±2.33 ng m^<-3>)， 12m高度（Hg_<12m>）的汞浓度分别为1.24 ~ 29.38 ng m^<-3>（4.74±3.61 ng m^<-3>）和1.38 ~ 14.82 ng m^<-3>（4.50±2.85 ng m^<-3>）。全年观测到汞浓度昼夜变化，显示出温度依赖性。Hg_<3m>在白天高于Hg_<12m>, Hg_<12m>在夜间高于Hg_<3m>，因为Hg_<3m>的昼夜变化明显大于Hg_<12m>。这些观测结果表明，汞是随着气温的升高而从土壤表面释放出来的，白天温度升高，夜间温度下降而沉积。为了阐明植物从自然环境中吸收汞的过程，测定了高山莲叶、茎和根中总汞的含量。茎部汞含量明显低于叶和根。根系中汞含量与土壤中汞含量呈正相关。植株下部叶片的汞浓度往往高于上部叶片。然而，叶片中的汞含量与土壤中的汞含量无关。这些观察结果表明，从土壤进入根部的汞并没有分布到整个植物体，叶片中的汞可能主要来自环境空气。研究了鹿儿岛湾沉积物中汞的垂直变化规律。海底喷气孔附近的沉积物含有较高浓度的汞。此外，沉积物中汞与有机质结合的含量也相当高。少

1. In order to elucidate vertical fluxes of the mercury, hourly variations of atmospheric mercury at 3m and 12m heights were investigated every two hours for three days. It was found that atmospheric mercury concentration in the daytime was higher than that in the nighttime: mercury concentration of 3m height (Hg_<3m>) ranged 1.65-17.92 ng m^<-3> (5.96±3.47 ng m^<-3>) in the daytime and 1.50-12.81 ng m^<-3> (4.20±2.33 ng m^<-3>) in the nighttime, and that of 12m height (Hg_<12m>) ranged 1.24-29.38 ng m^<-3> (4.74±3.61 ng m^<-3>) and 1.38-14.82 ng m^<-3> (4.50±2.85 ng m^<-3>), respectively. The variations of mercury concentration from day to night were observed through the year, showing the temperature dependency. Hg_<3m> is higher than Hg_<12m> in the daytime and Hg_<12m> is higher than Hg_<3m> in the nighttime, since the daytime-nighttime variation of Hg_<3m> was considerably larger than that of Hg_<12m>. Those observations suggest that mercury is emitted from soil surface with the ri … More se of temperature in daytime and deposits with the fall of temperature in nighttime.2. In order to elucidate the process of mercury uptake by plant from natural environment, total mercury contents in leaves, stems and roots of Solidato altissima L were determined. Mercury content in stems was considerably lower than that in leaves and roots. A positive correlation with mercury content in soil was observed in roots. The leaves at lower part of the plant tend to have higher concentration of mercury than the upper part. However, the mercury content of the leaves was independent of that in soil. These observations suggested that the mercury taken from soil into roots was not distributed to the whole plant bodies and the mercury in leaves might mainly be coming from ambient air.3. Vertical variation of mercury in sediment of Kagoshima Bay was investigated. Sediment near submarine fumaroles included higher concentration of mercury. Moreover, considerably higher content of mercury bind with organic matter was observed in the sediment. Less