Heavy metals partitioning in fly ashes between various stages of electrostatic precipitator after combustion of different types of coal

Coal mining areas are prone to hazardous element contamination because of mining activities and the resulting wastes, mainly including Cr, Ni, Cu, Zn, Cd and Pb. This study collected 103 samples of farmland tillage soil surrounding a coal mine in southwestern Shandong province and monitored the heavy metal concentrations of each sample by inductively coupled plasma mass spectrometer (ICP-MS). Statistics, geostatistics, and geographical information systems (GIS) were used to determine the spatial pattern of the potentially toxic metals above in the coal mining area. The results show that the toxic metal concentrations have wide ranges, but the average values for Cr, Ni, Cu, Zn, Cd and Pb are 72.16, 29.53, 23.07, 66.30, 0.14 and 23.71 mg Kg−1, which mostly exceed the natural soil background contents of Shandong Province. The element pairs Ni-Cu, Ni-Zn, and Cu-Zn have relatively high correlation coefficients (0.805, 0.505, 0.613, respectively). The Kriging interpolation results show that the contents of soil toxic metals are influenced by coal mining activities. Moreover, micro-domain variation analysis revealed the toxic metals in the typical area of the coal transportation line. These findings offer systematic insight into the influence of coal mining activities on toxic metals in farmland tillage soil.

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Impact of the Coal Mining on the Spatial Distribution of Potentially Toxic Metals in Farmland Tillage Soil

The fragile Himalayan region could be regarded as the sink for various pollutants transported from urbanized and polluted areas of South Asia. Therefore, in order to understand the concentrations, spatial distribution, pollution, and risk assessments of toxic heavy metal, mercury (Hg), surface soil samples were taken from the central Himalayas in the Langtang region. The average THg concentration in the Langtang Himalayas was 35.75 ± 24.41(ngg⁻¹), which is comparable to the Tibetan top soil values and slightly lower than world average soil values. In addition, an inverse relationship of THg with elevation were observed (i.e. decrease in concentration with increase in elevation) in the Langtang Himalayan soils. Meanwhile, THg concentrations and TOC% were significantly positively correlated at both the depths (0–10 and 10–20 cm), inferring the sorption capacity of organic carbon for Hg. The results of the geo-accumulation index (Igₑₒ), enrichment factor (EF), and pollution index (PI) indicated limited or no pollution by Hg in the Himalayan soils. Further, surface soils had a low potential ecological risk in the region. Therefore, the Hg value from this study could be used for the further evaluation and calculation of Igₑₒ, EF, and PI for water, soil, and aerosol in the Himalayan region as background reference value. However, Hg pollution from long-range transport and atmospheric deposition (wet/dry) in future could not be ignored in the Himalayan region.

Concentration and risk assessments of mercury along the elevation gradient in soils of Langtang Himalayas, Nepal

Abundance and distribution pattern of rare earth elements and yttrium in vitrain band of high-rank coal from the Qinshui basin, northern China

https://hal-brgm.archives-ouvertes.fr/hal-02166644/document

Behavior of rare earth elements in an aquifer perturbed by CO2 injection: Environmental implications

Study of harmful trace elements and rare earth elements in the Permian tectonically deformed coals from Lugou Mine, North China Coal Basin, China

In this study, mercury (Hg) concentrations in dustfall and topsoil were investigated. Three hundred forty-four samples were collected, including dustfall and topsoil samples, across an area of ∼180...

Distribution of surface soil mercury of Wuda old mining area, Inner Mongolia, China

Hg emission flux from various land covers, such as forests, wetlands, and urban areas, have been investigated. China has the largest area of coalfield in the world, but data of Hg flux of coalfields, especially, those with coal fires, are seriously limited. In this study, Hg fluxes of a coalfield were measured using the dynamic flux chamber (DFC) method, coupled with a Lumex multifunctional Hg analyzer RA-915+ (Lumex Ltd., Russia). The results show that the Hg flux in Wuda coalfield ranged from 4 to 318 ng m−2 h−1, and the average value for different areas varied, e.g., coal-fire area 99 and 177 ng m−2 h−1; no coal-fire area 19 and 32 ng m−2 h−1; and backfilling area 53 ng m−2 h−1. Hg continued to be emitted from an underground coal seam, even if there were no phenomena, such as vents, cracks, and smog, of coal fire on the soil surface. This phenomenon occurred in all area types, i.e., coal-fire area, no coal-fire area, and backfilling area, which is universal in Wuda coalfield. Considering that many coalfields in northern China are similar to Wuda coalfield, they may be large sources of atmospheric Hg. The correlations of Hg emission flux with influence factors, such as sunlight intensity, soil surface temperature, and atmospheric Hg content, were also investigated for Wuda coalfield.

Chunhui Li

Papers

Study of harmful trace elements and rare earth elements in the Permian tectonically deformed coals from Lugou Mine, North China Coal Basin, China

Distribution of surface soil mercury of Wuda old mining area, Inner Mongolia, China

Soil surface Hg emission flux in coalfield in Wuda, Inner Mongolia, China

Mercury emissions flux from various land uses in old mining area, Inner Mongolia, China