夜郎湖水库水体甲基汞的分布模式初步研究  

Preliminary Study on Methylmercury Distribution in Yelanghu Reservoir

作　　者：张军方[1,2,3] 冯新斌[2] 阎海鱼[2] 李平[2] 郭艳娜[2,3] 孟博[2,3] 姚珩[2,3] 

机构地区：[1]中国科学院地球化学研究所,环境地球化学国家重点研究实验室,贵阳550002 [2]中国科学院研究生院,北京100039 [3]贵州省水污染控制与资源化技术研究重点实验室,贵阳550002

出　　处：《地球与环境》2009年第3期293-298,共6页Earth and Environment

基　　金：国家自然科学基金重点项目(40532014)

摘　　要：本文通过对贵州夜郞湖水库水体的2006年7月、2007年1月及3月三次采样,研究了甲基汞的时空分布模式,并探讨影响其分布的不同控制因素。比较发现,夏季水体所有形态甲基汞(总甲基汞、溶解态甲基汞、颗粒态甲基汞)均显著高于其他两季(p<0.001),而冬春两季甲基汞浓度没有明显差异。空间分布表明,夏季总甲基汞平均浓度从水库上游至下游大坝处呈现稳步上升的分布趋势,大坝处总甲基汞是上游库体的1.72倍,是同期监测入库河流的2.58倍,这说明河流经水库蓄水后,甲基汞浓度在夜郞湖水库库体内升高和蓄集,并且下游水体具有更强的甲基汞蓄集能力。研究进一步发现,水质参数悬浮颗粒物(SPM)、水温(T)和硝酸盐(NO3-)与各形态甲基汞之间存在显著的正相关关系,表明这些参数对于各形态甲基汞的季节分布起着重要作用。在夏季丰水期,河流由于雨水带进大量的农田和土壤颗粒,而成为夜郞湖水体甲基汞的一个重要输入源,同时夏季相对活跃的农业耕作活动带来表层土壤的扰动增加,这可能是引起夜郞湖水体甲基汞水平升高的一个重要原因。A comprehensive study was conducted during July 2006, January 2007 and March 2007 to determine the distribution of methylmereury and the impacts of some major controlling factors in the Yelanghu Reservoir, Guizhou, China. By comparison, the concentrations of all methylmereury species （TMHg, PMHg and DMHg） in the summer campaign are significantly higher （p〈0. 001） than those in the winter and spring campaigns. While no statistically significant differences of concentrations of different mercury species are found between the latter two campaigns. In July, spatial distribution showed a steady increase of mean methylmercury from the upstream to the downstream of the reservoir. The mean concentration of TMHg in the downstream water column is 1.72 times higher than that of the upstream column and 2.58 times of the inflows of reservoir, which suggest TMHg in the river system could be increased by a dam effect. The spatial distribution also suggests that the downstream of the reservoir has a stronger accumulation capacity than the upstream. Further investigation revealed that SPM, T and NO3^- may play an important role in controlling the seasonal distribution of methylmercury in the reservoir. It is assumed that this seasonal distribution of mercury could also be a result of runoff impact. High runoff volume due to abundant precipitation in the summer carried Hg-containing particulates eroded from the agricultural dominated watershed into the reservoir. It is also found that relatively active agricultural activities in the summer season tended to increase the mercury levels in the Puding Reservoir.

关 键 词：夜郎湖水库 甲基汞 时空分布 控制因素 

分 类 号：X131.2[环境科学与工程—环境科学]