Trace Metal Pollution in Topsoil Surrounding the Xiangtan Manganese Mine Area (South-Central China): Source Identification, Spatial Distribution and Assessment of Potential Ecological Risks

Abstract

In this study, we identified the sources of trace metals, investigated their spatial distribution in topsoil and assessed their potential ecological risk in the area surrounding a typical manganese mining area in Xiangtan, Hunan Province, China. The concentrations of Mn, Cu, Pb, Zn, Cd, Ni, Cr and Hg in the topsoil of the study area were measured. Except for Cr and Hg, all trace metals exceeded the corresponding soil background values for Hunan Province. The spatial variation in trace metals was visualized by GIS, and the results show that trace metals in topsoil are enriched mainly around mines and smelters. Two groups of trace metals were identified using the spatial distribution, trend analysis, Pearson’s correlation and principal component analysis: Mn, Cu, Pb, Zn, Cd and Ni can be attributed to industrial and mining activities, whereas Cr and Hg are of natural origin. The results also revealed the extent of the influence of secondary processes such as the prevailing wind direction, erosion of mine tailings and rainwater runoff play significant roles in the wider dispersal and transfer of trace metals. In addition, the environmental risk of metal pollution was evaluated by applying the geoaccumulation index and potential ecological risk index (PERI) to the study area. The accumulated PERI for metals of concern is at highest risk level in the main manganese mine area. This decreases to a moderate risk around the manganese mine area, highlighting locations for further risk management concern. Furthermore, nearly 80% of the potential ecological risk was from Cd across the study area.

Soil from an Abandoned Manganese Mining Area (Hunan, China): Significance of Health Risk from Potentially Toxic Element Pollution and Its Spatial Context

“…Precipitation is high, but the seasonal distribution is uneven and the inter-annual variation is large. The annual precipitation is 1200–1500 mm [ 5 , 10 , 11 ]. The overall topographical characteristics of Xiangtan City presents a sharply undulating landscape with a maximum height of 150 m ASL with highest areas to the north, west, and south, and low lying areas in the central region and to the east.…”

“…The Xiangtan City region is rich in mineral resources with the Mn-mineral deposits that are dominated by sedimentary manganese carbonate and secondary manganese oxide ore, as well as some non-metallic minerals, such as limestone, dolomite, coal, and gypsum [ 12 ]. We previously demonstrated the significance of surface processes in other locations of the mining region from the dispersal by wind blow and surface run off of residues close to former mining extraction points [ 5 ] and extended the work to mixed land use areas close to smelting and mining areas where farming had developed post-closure, to assess the impact of residual materials on the significance of exposure through the food chain [ 11 ]. This study identifies a residential location in the region, with external exposure from a range of sources, including mineral processing operations to provide a case to identify potential health impact from surface materials through external exposure (inhalation, dermal contact) pathways.…”

“…Enriched levels can have a number of impacts such as creating wasteland, and affecting the growth and reproduction of biological organisms [ 1 ]. In addition, PTEs in the soil can enter the human body through the enrichment in the food chain, direct ingestion, dermal contact and inhalation, and eventually cause harm to the human body and cause various diseases [ 1 , 4 , 5 ]. Some relevant examples are the accumulation of Mn in the human body which can cause mental illness and even Parkinson’s syndrome [ 6 ]; excessive Cd can cause renal insufficiency and prostate disease [ 2 ] and the accumulation of Pb can lead to high circulation in the blood and damage the endocrine and immune systems [ 1 , 7 ].…”

“…This study extends our foundation work in the region supporting the re-development and utilization of soil in the abandoned manganese mining area in Xiangtan. The spatial assessment provides direction for soil development and utilization and serves as a template for risk assessment in other mining areas in China [ 5 , 10 , 11 ].…”

Efficient Removal of Cd(II) Using SiO2-Mg(OH)2 Nanocomposites Derived from Sepiolite

“…In recent years, due to the high toxicity, non-degradability, enrichment of heavy metals and the potential threat to human health through water pollution, the problem of heavy metal pollution has attracted more and more attention [1,2]. The heavy metal cadmium(Cd) is a non-essential element of the human body and is widely used in electroplating, batteries, smelting and chemical production processes, resulting in a considerable amount of cadmium in wastewater, waste gas and waste residue [3]. After entering the environment, it cannot be biodegraded.…”