Evaluation and Prediction of Environmental Capacities of Heavy Metals in the Surface Sediments of Lakes in Huoqiu County

Abstract

To clarify the environmental capacity of heavy metals in sediments of Chengxi Lake and Chengdong Lake in Huoqiu County, 30 sediment samples were collected from Chengxi Lake and Chengdong Lake, respectively. The environmental capacity characteristics and spatial distribution of heavy metals in sediments of Chengxi Lake and Chengdong Lake were studied using the comprehensive environmental capacity index, the static and dynamic environmental capacity was estimated, and the change trend of nearly one hundred years was predicted. The results showed that the average contents of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the sediments of Chengxi Lake and Chengdong Lake did not exceed the national soil risk screening values. The average values of the single environmental capacity index of heavy metals in the sediments of Chengxi Lake and Chengdong Lake were in the following orders:Ni(0.81)<Zn(0.83)<Cu(0.88)<Cr(0.91)<As(0.95)<Cd(0.98)=Pb(0.98)<Hg(1.00) and Ni(0.89)<Zn(0.91)<Cu(0.96)<Cr(0.98)=As(0.98)<Hg(1.01)=Pb(1.01)<Cd(1.17), respectively. Except for Hg, Pb, and Cd in the sediments of Chengdong Lake, the other elements were basically in the medium capacity. The mean of PI of Chengdong Lake was significantly higher than that of Chengxi Lake, and Chengxi Lake and Chengdong Lake were in the middle capacity level as a whole. The static total capacity of heavy metal elements in the sediments of Chengxi Lake was smaller than that of Chengdong Lake sediments, and the static total capacity was in the same order as the existing capacity, with the order of Zn>Cr>Pb>Cu>Ni>As>Hg>Cd. Within 5 to 20 years, the static and dynamic annual capacity changed faster than that of other years, and the dynamic annual capacity of each year was greater than the static annual capacity.