Environment
Reyhaneh Khashtabeh; Morteza Akbari; Ava Heidari; Ali Asghar Najafpour; Rokhsareh Khashtabeh
Abstract
The Heavy Metal (HM) contamination in surface soils poses significant environmental and health concerns near the mining operations. This study examined the concentrations and health risks of the five HMs lead (Pb), nickel (Ni), copper (Cu), arsenic (As), and iron (Fe) in soils surrounding the Sangan ...
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The Heavy Metal (HM) contamination in surface soils poses significant environmental and health concerns near the mining operations. This study examined the concentrations and health risks of the five HMs lead (Pb), nickel (Ni), copper (Cu), arsenic (As), and iron (Fe) in soils surrounding the Sangan iron ore mines in eastern Iran. Sixty soil samples were collected at depths of 0-20 cm from sites adjacent to the mining area and one control site. The HM concentrations were compared to the global shale values. Soil contamination was quantified using the geo-accumulation index (Igeo). Health risks to the local residents were assessed using the US Environmental Protection Agency's Human Health Risk Evaluation Index. The analysis revealed that the lead concentrations near the mine exceeded the global shale standards, while the arsenic levels remained marginally below permissible limits established by global soil standards. The Igeo values indicated low to moderate the contamination levels for both Pb and As in the mining-adjacent areas. The risk assessment results showed that non-carcinogenic risk indices were within acceptable limits for both children and adults. However, arsenic posed a significant carcinogenic risk to adults through two exposure pathways: ingestion (3.36E-04) and dermal absorption (1.36E-04). These findings highlight the importance of implementing regular monitoring protocols for potentially hazardous elements in the mining region to prevent and mitigate pollution-related health risks.
R. Dabiri; E. Amiri Shiraz
Abstract
This paper describes a preliminary study of the adsorption of toxic elements from synthetic wastewater in a batch mode. Clay minerals have been highly considered as inexpensive available adsorbents that adapt with the environment due to a special level and a high potential of adsorption. In the present ...
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This paper describes a preliminary study of the adsorption of toxic elements from synthetic wastewater in a batch mode. Clay minerals have been highly considered as inexpensive available adsorbents that adapt with the environment due to a special level and a high potential of adsorption. In the present research work, low-cost natural minerals of speiolite from the Iliato mine (located in NE Iran) and zeolite from the Aftar mine (located in north of Iran) are used to remove nickel(II), antimony(III), and arsenic(V) from synthetic wastewater. The adsorption experiments are conducted by varying the initial concentrations of the elements, pH values, adsorption times, and adsorbent dosage. The experimental isotherm data is analyzed using the Langmuir and Freundlich equations. Concerning a higher Langmuir coefficient R2 in nickel and antimony, the mechanism of adsorption of these elements is mono-layer and homogenous. Based on the Freundlich model, adsorption of arsenic is multi-layer and heterogeneous. The kinetic studies show that the Ni, Sb, and As adsorption mechanism is well-described by a pseudo-second-order kinetic model. The thermodynamic parameters indicate that the adsorption process has an exothermic character and is more feasible with decreasing temperature. Based on the experimental results, it can be concluded that natural sepiolite and zeolite has the potential of application as an efficient adsorbent for the removal of toxic elements from synthetic wastewater.
