Heavy Metal Contamination and Potential Ecological Risk Assessment of Sediments in Yangzonghai Lake

The contents and characteristics of ten heavy metals in surface sediments from Yangzonghai Lake in Yunnan, China were analyzed. Ecological risk index presented by Håkanson to assess the potential ecological risk of Yangzonghai Lake was utilized. The results showed that the average concentrations of titanium(Ti), manganese(Mn), zinc(Zn), vanadium(V), chromium(Cr), copper(Cu), nickel(Ni), cobalt(Co), lead(Pb) and arsenic(As) in surface sediments of Yangzonghai Lake were up to 9413.1, 617.9, 149.2, 189.6, 145.8, 97.6, 55.1, 27.4, 40.3 and 31.4mg/kg, respectively, which are higher than their natural background values. Pearson´s correlation analysis indicated that Zn, Cr, Pb and As were highly correlated, and the similar distributions in sediment indicated that they might originate from activities. Ti, Mn, V, Cu, Ni, and Co were also well correlated, and the distributions indicated that they were mainly from natural factors. The evaluation of pollution index revealed a clear accumulation of the 10 heavy metals, all reaching the level of moderate pollution. As, Cu and Cr were the most important environmental contaminants in Yangzonghai Lake. As a whole, heavy metals reached the level of low ecological risks, and in some parts, they reached the moderate level. Heavy metals in Yangzonghai Lake in the descending order of their ecological risks were As, Cu, Co, Ni, Pb, Cr, V, Zn, Mn and Ti. As was more prominent than other heavy metals in terms of the ecological risk and thus the most important factor of potential ecological risk in surface sediment of Yangzonghai Lake.