Human Impacts on Heavy Metals in Lake Sediments of Northern China: History, Sources, and Trend Prediction

Lake sediments are important indicators of human activities and environmental changes, while lakes in northern China receive little attention. Heavy metal elements in core sediments from Bosten Lake (BST) in the arid area, Wuliangsuhai Lake (WLS) in the semi-arid area, and Chagan Lake (CG) in the semi-humid area of northern China, based on the precise dating of 210Pb and 137Cs, were analyzed to evaluate the characteristics and sources of heavy metal pollution, analyze the influence of different types and intensities of human activities on heavy metals, and predict the development trend of heavy metal content in lake sediments in the future. The content of heavy metals in the sediments of the three lakes has gradually increased over time, with a decreasing trend of CG > WLS > BST, which is in accordance with the intensity of human activities. Co, Cu, Zn, Cd, As, and Pb are greatly influenced by human activities and mainly come from wastewater, waste residue, and waste gas produced by industrial activities, pesticide residues from agricultural activities, and pollution from domestic sewage, while, Cr and Ni come from both natural sources and human activities. Mn and Fe are relatively stable and mainly come from natural sources. The development trend of heavy metal content in the sediments of various lakes in the future is predicted by regression analysis. Fe and As in WLS and Cr, Mn, Ni, and Cu in BST show upward trends, indicating that the influences of industrial activities, agricultural activities, domestic emissions, and air pollutants on heavy metal pollution in lake sediments have a continuous effect. The results can provide a scientific basis for the effective control and environmental governance of heavy metal pollution in lakes.