西藏鄂雅错盐湖砷和汞的分布特征研究

A Study on the Distribution Characteristics of Arsenic and Mercury in the Salt Lake of Ayacuo, Tibet

本研究对西藏鄂雅错盐湖和主要支流中不同形态的砷(亚砷酸盐As(Ⅲ)、砷酸盐As(Ⅴ)、一甲基砷酸MMA、二甲基砷酸DMA)和总汞(THg)含量进行了测定,并与主要水质参数进行相关性分析研究,结果表明鄂雅错盐湖As主要以As(Ⅴ)形态存在,其次分别为As(Ⅲ)、DMA和MMA,其中无机砷的含量明显大于有机砷。相比较其他砷的形态,盐湖中As(Ⅲ)与主要水质参数的相关性显著,与总溶解性固体(TDS)、总溶解态氮(DTN)呈显著的强正相关性,与水温、溶解氧(DO)、氧化还原电位(Eh)、pH呈显著负相关性。总汞浓度较低,且与主要水质参数相关性不显著。通过风险评价发现鄂雅错湖水中砷存在一定的致癌健康风险,汞不存在风险。本研究丰富了西藏盐湖和支流水体中砷、汞分布特征及其环境影响因素的认识,对于环境保护具有一定的意义。

In this study, the contents of arsenic(arsenite As(Ⅲ), arsenate As(Ⅴ), monomethyl arsoate MMA, dimethyl arsenic acid DMA) and total mercury(THg) in different forms of Ayacuo salt lake and major tributaries in Tibet were measured, and the correlation analysis was carried out with the main water quality parameters, and the results showed that As(V) existed mainly in Ayacuo salt Lake, followed by As(Ⅲ), DMA, and MMA, of which the content of inorganic arsenic was significantly greater than that of organic arsenic. Compared with the morphology of other arsenic, As(Ⅲ) had a significant correlation with the main water quality parameters in the salt lake, a strong positive correlation with total dissolved solids(TDS) and total dissolved nitrogen(DTN), and a significant negative correlation with water temperature, dissolved oxygen(DO), oxygen reduction potential(Eh), and pH. Total mercury concentrations are low and not significantly correlated with the main water quality parameters. Through the risk assessment, it was found that there was a certain carcinogenic health risk of arsenic in the water of Ayacuo Lake, and there was no risk of mercury. This study enriches the understanding of the distribution characteristics of arsenic and mercury in salt lakes and tributaries of the Tibet Plateau and their environmental impact factors, which has certain significance for environmental protection.