环境分析化学杂志

This study was carried out on the low-grade chromite, Gedarif state, Sudan, at Umm Saqata- Qala Elnahal to achieve full characterization for the ore via Microscopic studies for the polish section samples, X-ray diffraction analysis (XRD), X-ray Fluorescence Analysis (XRF), Scanning electron microscopic with Energy Dispersive X-ray Spectroscopy (SEM-EDX), and physical properties tests. Microscopic study revealed that the liberation size of chromite mineral is in the range (0.30-0.05) mm. also the X-ray diffraction, X-ray fluorescence and scanning electron microscope with the Energy Dispersive X-ray analysis showed that main gangue of the ore is mineral silicates as Antigorite and contains 21.58-19.60% Cr₂O₃. The physical tests (saturated density and dry density) demonstrated that ore has low density in range 2.54-2.38 g/cm³ because it is low grade chromite ore, this can be attributed to the dominating mineral silicate (waste) which associated with chromite mineral.

In this study, a non-destructive analytical techniques (Energy dispersive X-Ray fluorescence) was used to analyze the concentration of seven heavy metals (Pb, Cr, As, Ni, Cd, Cu and Zn) in tin mine tailing from mining and control sites in Rim, Sharubutu and environs. The physicochemical results showed the pH for S1 and S2 from the mining and control sites were (5.31 and 4.97) and (6.32 and 5.71) respectively indicting that the mine sites is more acidic than the control sites. While their bulk density and electrical conductivity was good for planting. The concentration of the heavy metals were within the maximum permissible limits except for Pb and As in mining and control sites of range (270-300) mg/kg and (60-80) mg/kg, which are above the permissible limits (80 mg/kg and 0.07 mg/kg) respectively. This could be attributed to the mining activities and atmospheric depositions on the sites. The enrichment factor values for Pb, Cr, As, Ni, were S1 (1.07, 1.18 1.14 and 1.14) respectively while Cd, Cu and Zn were not detected, S2 (1.11, 1.19, 1.33, 1.14 and 1.11) for Pb, Cr, As, Ni, and Zn respectively, while Cd and Cu were not detected. The geo accumulation factor for S1 were (0.22, 0.24, 0.23 and 0.23) for Pb, Cr, As and Ni, while Cd, Cu and Zn were not detected, S2 (0.22, 0.24, 0.27, 0.23 and 0.22) for Pb, Cr, As, Ni, and Zn respectively, while Cd and Cu were not detected. This indicates environmental pollution. The result obtained for risk indent Ri where S1 (24.81) and S2 (28.04), these shows that the risk index of heavy metals in tin mine tailings of the studied areas posed low ecological risk to the ecosystem. The Fourier transform infra-red (FTIR) spectra analysis shows the functionality of Ag⁺, Ca²⁺, K⁺, and Mg²⁺ were within the band range of 700-2200 cm^-1. S1 showed absorption bands at (779.0 cm^-1) for silver bromate, (1038.2 cm^-1) for calcium sulphate and potassium metaborate, (2108.7 cm^-1) for magnesium per chlorate and sodium chromate. S2 showed absorption band at (2173.0 cm^-1) for magnesium per chlorate and sodium chromate. The surface morphology of the tin mine tailings through the use of Scanning electron microscopy (SEM) technique revealed Homogeneous small size and heterogeneous crystalline irregular shape.

Gaseous pollutants and particulate matter are released into the atmosphere at concentrations above their normal ambient level; this is caused by the increasing human activities which eventually have a measurable effect on humans, animals and plants. Particulate matter (PM) which can be inhaled into the human respiratory system is related to most serious health effect including pulmonary and cardiovascular illness. Based on the field study conducted, the concentrations of PM_2.5 at the different locations vary with respect to anthropogenic sources. The PM_2.5 levels obtained ranged from 14.00 to 32.67 μg/m³ during wet season and 18.67 to 34.67 μg/m³ during dry season. Trace elements especially heavy metals are significant components of PM_2.5 in industrial environments. The heavy metals are of particular concern due to their persistence in the environmental media and their human toxicity. The Enrichment Factor (EF) analysis showed very high enrichment for the elements; Pb, Cd, Cr, Cu and Ni in the fine fraction (PM_2.5). The Principal Component Analysis explained two common contributing sources of fine particulates (PM_2.5) such as entrained soil and combustion.