Department of Chemistry and Biochemistry, Laurentian University, Ontario, Canada.
Sci Total Environ. 2010 Mar 1;408(7):1676-83. doi: 10.1016/j.scitotenv.2009.11.049. Epub 2009 Dec 16.
The concentrations of total mercury (Hg), methylmercury (MeHg) and total selenium (Se) were determined in muscle, liver and brain tissues of young-of-the-year walleye (Stizosedion vitreum) specimens collected from 8 boreal lakes that are located within 107km around the Sudbury smelters in Ontario, Canada. Dry weight basis concentrations of Hg were highest in muscle and lowest in brain (p<0.05), those of MeHg were higher in muscle than in liver and brain but there was no significant difference between liver and brain (p<0.05). The highest Se concentrations were found in liver and the lowest in brain (p<0.05). Considering the biomass of the studied tissues, muscle was the part of the body where most of Hg, MeHg and Se were accumulated. In fish muscle, the percentage of MeHg over Hg was the highest and this percentage was the lowest in liver. The concentrations of Hg, MeHg and Se in the studied tissues were closely related to the concentrations of total dissolved Se in lake waters which vary with the distance of the lakes from the smelters. Thresholds of Se concentrations in tissues were revealed (6.2, 12.0 and 3.5mgkg(-1) dry wt., for muscle, liver and brain, respectively), above which a significant reduction of MeHg concentrations was observed in all studied tissues compared to lower Se levels in the same tissues. Based on the collected information and data analysis, possible mechanisms for the biological processes behind the observed inverse relationships between Se and Hg in fish tissues are discussed.
在加拿大安大略省萨德伯里冶炼厂周围 107 公里范围内的 8 个北方湖泊中，采集了当年幼的白斑狗鱼（Stizosedion vitreum）标本的肌肉、肝脏和脑组织，并测定了总汞（Hg）、甲基汞（MeHg）和总硒（Se）的浓度。以干重为基础，Hg 的浓度在肌肉中最高，在大脑中最低（p<0.05），MeHg 的浓度在肌肉中高于肝脏和大脑，但肝脏和大脑之间没有显著差异（p<0.05）。最高的 Se 浓度出现在肝脏，最低的出现在大脑（p<0.05）。考虑到研究组织的生物量，肌肉是积累 Hg、MeHg 和 Se 最多的身体部位。在鱼类肌肉中，MeHg 占 Hg 的百分比最高，而在肝脏中则最低。研究组织中 Hg、MeHg 和 Se 的浓度与湖水中总溶解 Se 的浓度密切相关，而湖水的浓度又随湖泊与冶炼厂的距离而变化。还揭示了组织中 Se 浓度的阈值（肌肉、肝脏和大脑中的浓度分别为 6.2、12.0 和 3.5mgkg(-1)干重），高于该阈值时，与同一组织中较低的 Se 水平相比，所有研究组织中的 MeHg 浓度都显著降低。基于收集的信息和数据分析，讨论了鱼类组织中观察到的 Se 和 Hg 之间反向关系背后的生物过程的可能机制。
