| 长寿湖水库垂直剖面不同形态汞的季节变化特征及其影响因素 |
| 摘要点击 2064 全文点击 1389 投稿时间：2015-04-24 修订日期：2015-05-31 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 水体 汞 甲基汞 长寿湖水库 间隙水 |
| 英文关键词 water body mercury methylmercury Changshou Reservoir porewater |
|
| 中文摘要 |
| 分别于2013年9月至2014年7月,在三峡库区长寿湖水库设置5个采样点,分季节、分层次对水样和沉积物间隙水进行了采集和分析,考察了水库水体和沉积物间隙水不同形态汞浓度及垂向分布特征,并研究了沉积物中汞向上覆水的扩散通量. 结果表明,长寿湖水库水体总汞浓度平均值为(14.77±12.24)ng·L-1,总甲基汞浓度平均值为(0.41±0.47)ng·L-1. 夏秋季采样点溶解态甲基汞浓度在表层下4~8 m出现峰值,随之其值降低近湖底部再次跃增. 颗粒态甲基汞浓度峰值出现在表层下8~20 m而非在沉积物-水体界面处,主要与上层水体颗粒物吸附甲基汞的沉降有关. 长寿湖水库垂直剖面间隙水甲基汞峰值出现在表层下16 cm和28 cm,可能硫酸盐还原细菌活动扩展到更深的区域,从而导致了沉积物深处甲基化率的提高. 间隙水溶解态甲基汞在秋季和夏季向上覆水体扩散通量分别为28.2 ng·(m2·d)-1和30.0 ng·(m2·d)-1,远高于冬季3.8 ng·(m2·d)-1,这与夏秋两季水温较高有关. 夏季、春季水体DMeHg浓度与DO相关关系(r=-0.482**,P<0.05;r=-0.339*,P<0.01),秋季和冬季不具有相关性. |
| 英文摘要 |
| The vertical distribution of mercury (Hg) species were investigated in water and porewater of Changshou reservoir during the period from September 2013 to July 2014.Water samples were collected seasonally from five sampling sites, and the concentrations of Hg species were evaluated.Diffusion fluxes of Hg from sediment to overlaying water were also obtained.The results showed that the average concentrations of total Hg and total methylmercury (MeHg) were (14.77±12.24) ng·L-1and (0.41±0.47) ng·L-1, respectively.The concentrations of dissolved MeHg (DMeHg) was highest in 4-8 m under surface water, and then decreased with the increasing water depth with a subsequent increase in the bottom of Changshou Reservior.Peak particulate MeHg (PMeHg) values were found in 8-20 m under surface water, but not in the interface of sediment-water, suggesting that the increasing PMeHg might be related to the deposition of MeHg adsorbed to particulates from upper water.Two peak MeHg levels in pore water appeared in 16 and 28 cm under sediment surface, probably due to the extension of living region for sulfate reduction bacteria (SRB) to deeper sediment which resulted in increased methylation rate there.The diffusion fluxes of DMeHg from pore water to overlaying water were 28.2 ng·(m2·d)-1 and 30.0 ng·(m2·d)-1 in autumn and summer, which were significantly higher than that in winter 3.8 ng·(m2·d)-1.It may be associated with the higher temperature in those two seasons.An obvious negative correlation was observed between DMeHg and dissolved oxygen (DO) in summer and spring(r=-0.482**,P<0.05;r=-0.339*,P<0.01);however, similar correlations were not found in autumn and winter. |
|
|
|
