The Impact of Anthropogenic Activities Recorded by Mercury in the Sediment From Dianshan Lake

Abstract

The mercury in sediment cores from Dianshan Lake, Shanghai is studied in this study and it indicates that the mercury level changing from 52.78-145.66 μg kg^-1 in sediment can be obviously divided into three sections responding to the development of economy of Shanghai. Mercury decreases with depth in 0-11 cm underground, which is corresponding to the depositing period after 1980; and it is in less change with depth in 11-16 cm, which is corresponding to the period of middle 1960s-1980s. Below 16 cm Hg is decreasing with depth more obviously, which is corresponding to the period from the establishment of the People’s Republic of China to the beginning of the Culture Revolution in 1970s. These indicate that the pollutants transported to the Dianshan Lake before 1980s are less than that after 1980 and in the period of 1970s Hg transportation to the Dianshan Lake is relatively decreasing with time. This mercury-increasing trend in the Dianshan Lake is consistent with the mercury release from coal combustion and non-coal sources in Yangtze Delta (mainly including Jiangsu, Zhejiang provinces and Shanghai) and is also a reflection of the economy development in Shanghai; It is, however, not associated that close to the protection of the lake. These facts indicate that the atmospheric deposition is probably the main source of mercury in the Dianshan Lake and the mercury level would probably be evidently increasing in this lake in certain period of time in the future even though protection efforts are now in process in Shanghai.