Spatial Variation and Source of Dissolved Heavy Metals in the Lancangjiang River, Southwest China

Abstract

Dissolved heavy metals are not only the essential micronutrients, but also the toxic elements for human bodies. To investigate the heavy metal sources and assess the water quality of the Lancangjiang River, dissolved Cr, Ni, Cu, Zn, Mo, and Pb were detected in this study. The results show that dissolved Ni and Mo, Cr and Pb, and Cu and Zn were similarly distributed within the drainage basin. The correlation analysis exhibited that dissolved Ni and Mo had correlation with water parameter, and dissolved Cu was weakly correlated with Ni, indicating that they might be affected by natural processes. The principal component analysis explained 68.342% of the total variance for three principal components, of which dissolved Ni, Mo, and Cu were controlled by natural inputs; dissolved Cu and Cr were affected by anthropogenic activities; and dissolved Zn was influenced by agricultural activities in the downstream. The water quality showed that the water in upstream was worse than in midstream and downstream, and the whole drainage basin had water of excellent quality. Water within the drainage basin poses no risks to human bodies via daily diets and dermal routes. Dissolved Zn, Cu, and Mo occupied the major proportion of heavy metals transporting into the Mekong River. The agricultural inputs of dissolved Zn might pose potential risks to the Mekong River.

COVID-19 and urban rivers: Effects of lockdown period on surface water pollution and quality- A case study of the Zarjoub River, north of Iran

“…For example, the effluents of aluminum, smelting, electroplating, and pharmaceutical factories in the industrial city of Rasht might be the sources of Al, Cu, Cr, and Se (Wang et al 2013 ; Giri and Singh, 2014 ). Several studies also reported that Al, Cr, and Cu can be associated with domestic and hospital solid wastes (Kuo et al, 1999 ; Saffarzadeh et al 2016 ; Nguyen et al 2020 ; Liang et al 2020 ). According to the field observation, the high concentration of these elements in the urban area implies direct dumping of solid waste into the river (Ghodrati et al 2012 ).…”

Source and Risk Assessment of Trace Metals in Red Soils from Yunnan Province, Southwest China

“…Furthermore, this situation is also consistent with previous studies on the environmental pollution of Yunnan province. [ 13,66 ] Surprisingly, the RI values of As and Cd in soils in S1 are higher than those of Cr, Cu, Ni, Pb, and Zn, suggesting that As and Cd are pollutants of high ecological risk. Previous studies concerning the red soils in Yunnan province have reported that the contamination of As and Cd could accumulate in plants over the past few years.…”

“…[ 1,4,7–9 ] Trace metals are naturally found in the Earth's surface system. [ 6,10,11 ] However, trace metals could also cause severe human disease (such as nervous disorders, visceral dysfunction, and cancers), [ 12–14 ] if their concentrations exceed certain limits.…”

“…[ 18,19 ] Furthermore, Yunnan province is one of the most metal‐polluted regions in western China, [ 20 ] where anthropogenic activities, such as agricultural production, transportation, discharge of domestic wastes, metallurgy, mining, coal combustion, metal smelting, and urban construction, threaten the soil ecosystem. [ 6,13,21–28 ] Trace metals in soils mainly derive from two sources: i) the weathering from bedrocks and ii) anthropogenic inputs. The spatial and vertical distributions and patterns of trace metals contain information of sources in geological time, which are of great significance to explore their possible sources.…”

The Positive Impacts of Exhibition-Driven Tourism on Sustainable Tourism, Economics, and Population: The Case of the Echigo–Tsumari Art Triennale in Japan

“…A correlation analysis is a statistical method used to evaluate the strength of the relationship between two quantitative variables. A high correlation means that two or more variables have a strong relationship with each other, while a weak correlation means that the variables are hardly related [86][87][88]. In addition, when two random variables (X and Y) are normally distributed, the population's Pearson product moment correlation coefficient [89] is given by…”