Mercury release flux and its influencing factors at the air-water interface in paddy field in Chongqing,China  

作　　者：ZHU JinShan WANG DingYong MA Ming 

机构地区：[1]Key Laboratory of Eco-environments in Three Gorges Reservoir Region of the Ministry of Education,College of Resources and Environment,Southwest University [2]Chongqing Key Laboratory of Agricultural Resources and Environment

出　　处：《Chinese Science Bulletin》2013年第2期266-274,共9页

基　　金：supported by the National Natural Science Foundation of China (40673063 and40973079);the "211" Ecology National Key Discipline of Southwest University;Postgraduates’ Science & Technological Innovation Fund of Southwest University (kb2010019)

摘　　要：The exchange of mercury(Hg) across the air-water interface is an important part of Hg biogeochemical cycle.Mercury fluxes across the air-water interface in paddy fields were measured by a Dynamic Flux Chamber(DFC) coupled with a Lumex multifunctional mercury analyzer RA-915+ at two sites(Chengjiang(CJ) and Caoshang(CS)) in Beibei,Chongqing,China in 2008.The results showed that mercury emission followed a power-law relationship with solar radiation and air temperature,and it increased exponentially with water temperature at both sites.Mercury emission was mainly influenced by the solubility of gaseous elemental Hg,photo-thermal effect,electron activity(Eh) and air Hg concentrations.Solar radiation made the greatest direct contribution to mercury emission during the daytime(0.80),with an 83.60% contribution,whereas at nighttime the water temperature(0.72) contributed to 71.65% of emissions.The temperature gradient between water and air might also influenced mercury emission across the air/water interface at nighttime.These findings suggest that paddy fields could act as a significant source of atmospheric mercury,and it can contribute significantly to the atmospheric mercury in a local region.The exchange of mercury （Hg） across the air-water interface is an important part of Hg biogeochemical cycle. Mercury fluxes across the air-water interface in paddy fields were measured by a Dynamic Flux Chamber （DFC） coupled with a Lumex multifunctional mercury analyzer RA-915＋ at two sites （Chengjiang （C J） and Caoshang （CS）） in Beibei, Chongqing, China in 2008. The results showed that mercury emission followed a power-law relationship with solar radiation and air temperature,, and it increased exponentially with water temperature at both sites. Mercury emission was mainly influenced by the solubility of gaseous elemental Hg, photo-thermal effect, electron activity （Eh） and air Hg concentrations. Solar radiation made the greatest direct contribution to mercury emission during the daytime （0.80）, with an 83.60% contribution, whereas at nighttime the water temperature （0.72） contributed to 71.65% of emissions. The temperature gradient between water and air might also influenced mercury emis- sion across the air/water interface at nighttime. These findings suggest that paddy fields could act as a significant source of atmospheric mercury, and it can contribute significantly to the atmospheric mercury in a local region.

关 键 词：空气 水界面 释放通量 测汞仪 重庆市 水田 影响因素 中国 生物地球化学循环 

分 类 号：X13[环境科学与工程—环境科学]