夏季红枫湖地区农田土壤—大气界面汞交换通量的初步研究

Study of Mercury Exchange Rate between Air and Soil Surface in Summer Season at the Hongfeng Reservoir Region, Guizhou, China

采用动力学通量箱法(DynamicFluxChamber)与高时间分辨率大气测汞仪联用技术对贵州红枫湖地区土壤-大气界面间汞交换通量进行了初步研究。结果显示,红枫湖地区土壤-大气界面间汞交换通量变化范围为-8 6ng215 3ng·m-2·h-1,平均27 4±40 1ng/m2·h(n=255);且土壤与大气界面间的汞交换是双向的:既有土壤汞的释放,又有大气汞的沉降,主要以土壤汞的释放为主(n释放=253,n沉降=2n)。土壤汞的释放通量与土壤温度、气温、光照强度有强相关关系,相关系数分别为0 80、0 83、0 74。

In summer of 2002, the exchange flux of mercury between air and soil surface was measured using the method of Dynamic Flux Chamber (DFC) at the Hongfeng reservoir region. At the same time, the meteorological parameters, such as air temperature, soil temperature, wind speed and solar radiation were recorded using a multi-function mini-weather station (global water III). The soil, moss and fertilizer samples in study area were also collected. The mercury fluxes of air/soil surface were in the range from -8.6 ng/m^(2)·h to 215.3 ng/m^(2)·h , averaged at 27.4±40.1 ng/m^(2)·h(n=255). The data showed that the exchange of mercury was bi-directional between air and soil surface, i.e. both emission and deposition of mercury occurs, but mercury emission was much more frequent than deposition process (n_(deposition)=2,n_(emission)= 253).Mercury emission fluxes significantly correlated with soil temperature,air temperature and intensity of solar radiation,and the correlation coefficients are 0.80,0.83,and (0.74),respectively.