Evaluation of Pollution Level, Spatial Distribution, and Ecological Effects of Antimony in Soils of Mining Areas: A Review

Abstract

The first global-scale assessment of Sb contamination in soil that was related to mining/smelting activities was conducted based on 91 articles that were published between 1989 and 2021. The geographical variation, the pollution level, the speciation, the influencing factors, and the environmental effects of Sb that were associated with mining/smelting-affected soils were analyzed. The high Sb values mainly occurred in developed (Poland, Italy, Spain, Portugal, New Zealand, Australia) and developing (China, Algeria, Slovakia) countries. Sb concentrations of polluted soil from mining areas that were reported in most countries significantly exceeded the maximum permissible limit that is recommended by WHO, except in Turkey and Macedonia. The soil Sb concentrations decreased in the order of Oceania (29,151 mg/kg) > North Africa (13,022 mg/kg) > Asia (1527 mg/kg) > Europe (858 mg/kg) > South America (37.4 mg/kg). The existing extraction methods for Sb speciation have been classified according to the extractant, however, further research is needed in the standardization of these extraction methods. Modern analytical and characterization technologies, e.g., X-ray absorption spectroscopy, are effective at characterizing chemical speciation. Conditional inference tree (CIT) analysis has shown that the clay content was the major factor that influenced the soil Sb concentration. Non-carcinogenic risks to the public from soil Sb pollution were within the acceptable levels in most regions. An Sb smelter site at the Endeavour Inlet in New Zealand, an abandoned open-pit Sb mine in Djebel Hamimat, Algeria, an old Sb-mining area in Tuscany, Italy, and Hillgrove mine in Australia were selected as the priority control areas. Cynodon dactylon, Boehmeria, Pteris vittata, and Amaranthus paniculatus were found to be potential Sb accumulators. All of the values of bioaccumulation factors for the crops were less than one. However, ingestion of Sb through crop consumption posed potential non-carcinogenic health risks, which should not be neglected. The soil variables (pH, Eh, total sulfur, carbon nitrogen ratio, total organic carbon, and sulfate), the total Sb and the bioavailable Sb, and heavy metal(loid)s (As, Pb, and Fe) were the major parameters affecting the microbial community compositions.

Soil Profile Concentration Distributions of Antimony and Bismuth across Southeastern Missouri (USA)

“…For the Alfisols and Ultisols, the antimony soil profile distributions show greater concentrations in the illuvial horizons than the eluvial horizons, whereas for the antimony soil profile distributions for the majority of the Entisols, Inceptisols, Mollisols and the solitary Vertisol show rather uniform concentrations. Zhao et al [23] noted that adsorption was an important phenomenon influencing antimony accumulation, with clay and iron oxyhydroxides important soil substrates. The magnitude of the antimony and bismuth concentrations are within the concentration ranges documented for pristine, non-impacted (geogenic) soils [4] [23] [24] [25] [26].…”

“…Tang et al [26] recently described sources of soil antimony pollution and its environmental impact, and proposed remediation techniques, noting use of ferrous sulfate, phosphate amendments, clay minerals and biochar for adsorption, selected bacterial communities, and phytoremediation. Antimony pollution sources include mining, pharmaceutical manufacturing, vehicle emissions, plastic waste leaching, shooting ranges, and others [23] [25] [26]. The maximum concentration of antimony for drinking water is 6 ppb by the United States Environmental Protection Agency and 20 ppb by World Health Organization [26].…”

The Legacy of Potential Environmental Soil Contamination in an Antimony Mining Heritage Area

“…Zhao et al [14] made a global-scale assessment of Sb contamination in soil that was related to mining/smelting activities which was conducted based on 91 articles that were published between 1989 and 2021. In Portugal, high soil Sb concentrations were detected in the Sarzedas mine in the Castelo Branco County (663.1 mg/kg) (Pratas et al, 2005 [15]) and in the São Domingos copper sulfide mine in the Baixo Alentejo Province (467.8 mg/kg) (Anawar et al, 2013, [16]).…”