Concentrations, Spatial Distributions, and Sources of Heavy Metals in Surface Soils of the Coal Mining City Wuhai, China

Abstract

Various studies have shown that soils surrounding mining areas are seriously polluted by heavy metals. In this study, 58 topsoil samples were systematically collected throughout the coal mining city Wuhai, located within the Inner Mongolia Autonomous Region of China. The concentrations of As, Hg, Cr, Ni, Cu, Zn, Cd, and Pb in these samples were measured and statistically analyzed. The mean concentrations of all heavy metals were lower than their Grade I values defined by the Chinese Soil Quality Standard. However, the mean concentrations of individual heavy metals in many samples exceeded their background values. The spatial distribution of heavy metals was analyzed by the ordinary kriging interpolation method. The positive matrix factorization model was used to ascertain contamination sources of the eight heavy metals and to apportion the contribution of each source. The most severely polluted area was the Wuhushan mine site in the Wuda district of Wuhai. Our results showed that coal mining strongly affected heavy metal contamination of the local soils. Results of source apportionment indicated that contributions from industrial activities, atmospheric deposition, agricultural activities, and natural sources were 31.3%, 26.3%, 21.9%, and 20.5%, respectively. This clearly demonstrates that anthropogenic activities have markedly higher contribution rates than natural sources to heavy metal pollution in soils in this area.

Restoration of damaged ecosystems in desert steppe open‐pit coal mines: Effects on soil nematode communities and functions

“…The average annual precipitation was 159.8 mm, the average annual evaporation was 3289 mm, and the altitude was 1237–1244 m a.s.l. (Bu et al, 2020; Wang et al, 2014). The steppe type in this area was desert steppe.…”

Spatial Heterogeneity of Vegetation Response to Mining Activities in Resource Regions of Northwestern China

“…The study area (106.36 • E-107.05 • E, 39.15 • N-39.52 • N) mainly comprised the whole city of Wuhai, and parts of Alxa League and Ordos according to the planning (2010-2030) of Wuhai and its surrounding areas. The whole study area is located in the middle of Inner Mongolia with six districts ( Figure 1a) and surrounded by three deserts-the Uulan Buh, the Kubuqi, and the Maowusu [47,48]. The north-south-oriented Yellow river runs through the whole city and forms irrigation districts of about 175 km 2 with a narrow river beach wetland and an agricultural oasis [47].…”

“…The whole study area is located in the middle of Inner Mongolia with six districts ( Figure 1a) and surrounded by three deserts-the Uulan Buh, the Kubuqi, and the Maowusu [47,48]. The north-south-oriented Yellow river runs through the whole city and forms irrigation districts of about 175 km 2 with a narrow river beach wetland and an agricultural oasis [47]. Topographically, the study area is low-lying in the northwest, and high-lying in the middle and east ( Figure 1b).…”

“…The study area belongs to the middle-latitude temperate continental climate zone, a region affected by the East Asian monsoon belt [49]. Annual precipitation is 160 mm, and annual evaporation is 20 times that of rainfall [47]. The main vegetation types in the study area are grassland and shrubland.…”

Retrieving zinc concentrations in topsoil with reflectance spectroscopy at Opencast Coal Mine sites

“…The area of coal mining increased from 7.12 to 355.95 km 2 , and the number of coal-mining increased from 82 to 651 during 1990–2015 in the Ordos 13 , 14 . It’s reported that the Zn pollution in the topsoil of mining areas of Inner Mongolia and other places is relatively common 15 , 16 . Land productivity, ecological integrity, and habitat security were seriously threatened by heavy metals pollutions in mining areas 16 – 20 .…”