重庆几种地表类型土/气界面汞交换通量

Soil/air interface mercury exchange fluxes of several ground surface in Chongqing

应用RA915+汞分析仪与动力通量箱(DFC)联用技术,在重庆市不同区域选取几种地表类型(3个林地、2个草地和1个耕地)进行了土气界面间汞交换通量的研究.结果表明,汞交换通量范围为-59～733.8ng·m-2·h-1,平均值为115.8ng·m-2·h-1,汞交换通量大小顺序为污染区(气象站)>裸地(耕地)>大学园区(草地)>清洁区(林地).土壤汞含量、光照强度、相对湿度、土壤温度等环境因素对汞交换通量有较大影响.同时对区域汞释放进行了初步的估算,2003年重庆市从林地、耕地(旱地)和草地释放到大气中的总汞量约为791kg,释放强度为17.1g·km-2·a-1.

The mercury exchange fluxes between soil and air in Chongqing were measured using RA-915^＋ mercury analyzer and dynamic flux chamber technique. The surface types of ground, including forestland, grassland and cultivated land were studied. The results indicated that the mercury exchange fluxes were from -59 to 733.8 ng·m^-2 ·h ^-1 , and the average was 115 ng ·m^-2 ·h^-1 . The mercury exchange flux was in the order of polluted district （weather station） 〉 cultivated land 〉 grassland 〉 forestland. There were close relationships between mercury fluxes and environmental parameters, such as mercury content of soil, solar radiation, relative humidity, soil temperature, and so on. This indicated that environmental factors had a strong impact on mercury emission fluxes from soil. Meanwhile, regional mercury emission was preliminary estimated based on the climate characteristic of Chongqing. The result showed that the total mercury amount released from forestland, cultivated land （upland） and grassland in Chongqing was 791 kg in 2003, the emission intensity was 17.1 g·km^-2·a^-1.