Trends and Health Risks of Dissolved Heavy Metal Pollution in Global River and Lake Water from 1970 to 2017

摘要

In recent decades, heavy metal pollution has become a global environmental issue and the prime focus of environmental security. Such heavy metals derive from both natural sources, such as rock weathering, and anthropogenic sources, such as mining, manufacturing, fertilizer and pesticide use, and waste discharge (Hu et al. 2015; Huang et al. 2015; Ren et al. 2015; Facchinelli et al. 2001; Muhammad et al. 2011). In the last half of the twentieth century, the global amount of heavy metals released to the environment amounted to 22,000 ton of Cd, 939,000 ton of Cu, 783,000 ton of Pb, and 1,350,000 ton of Zn (Singh et al. 2003).