An approach to quantify heavy metals and their source apportionment in coal mine soil: a study through PMF model

Spatial distribution, source apportionment, and health risks assessment of trace elements in pre- and post-monsoon soils in the coal-mining region of North Karanpura basin, India

Coal mining activities in the North Karanpura basin have significantly increased the trace element (TE) concentrations in the soil, resulting in soil pollution and potential health risks. To assess this, 113 soil samples, along with coal, shale, and overburden rocks, were collected from open-cast mining areas during pre-monsoon (Pre-M) and post-monsoon (Post-M) seasons. Seasonal analysis revealed higher TE concentrations in the Post-M period, especially in the SE direction, followed by NE and NW, likely due to surface runoff and deposition, demonstrating temporal variability in TE distribution which corroborated from the spatial distribution maps. Positive matrix factorization (PMF) model identified four factors: mixed sources (F1Pre-M: 37.6 %; F4Post-M: 28.9 %), coal-fired emissions (F2Pre-M: 20.5 %; F3Post-M: 26.0 %), overburden rocks (F3Pre-M: 25.5 %; F2Post-M: 16.7 %), and agricultural and lithogenic origin (F4Pre-M: 16.4 %) during the Pre-M period, attributed to coal mining. Post-M sources were similar, but agricultural and lithogenic origins were replaced by atmospheric deposition (F1Post-M: 28.4 %), enhanced by monsoon effects. Carcinogenic risk assessment revealed that As, Cr, and Ni exceeded acceptable levels for children via ingestion, though adults remained within safe limits. Inhalation and dermal contact were also considered, but ingestion posed the highest risk. The hazard index (HI) via ingestion showed that children had an HI of 1.6 in Pre-M, increasing to 2.66 in Post-M, highlighting their potential vulnerability to non-carcinogenic risks, while adults stayed within safe limits. The expansion of mining areas in the study region led to decrease in vegetative areas which could affect agriculture and local communities, raising a comprehensive environmental and public health issues. These results underline the need for implementing effective biannual soil monitoring and mitigation strategies, such as phytoremediation, bioremediation, rock dust remediation, chemical amendments and improved waste management, to reduce TE contamination.

A 6-year review status on soil pollution in coal mining areas from Europe

Coal is an essential component in achieving the goal of fulfilling the energy demands of the world. Nevertheless, the extensive practice of coal mining has resulted in environmental contamination through the release of both organic and inorganic pollutants, including polycyclic aromatic compounds and potentially toxic elements, into various mediums, notably soil. The escalating coal-mining activities across Europe have amplified the concentration of specific elements in the soil. Therefore, a thorough and meticulous assessment of these environmental impacts is imperative to furnish policymakers, industries, and communities with valuable insights, facilitating the formulation and adoption of effective mitigation strategies. Considering the results of studies from 2018 to 2023, this review thoroughly evaluates the current state of soil pollution in the coal mining areas of Europe, focusing on polycyclic aromatic hydrocarbons and potentially toxic elements. By analyzing the acquired data, this study aims to evaluate the levels of contamination by these pollutants in soils. The findings reveal that low molecular weight polycyclic aromatic hydrocarbons dominate the polycyclic aromatic compounds present, while potentially toxic elements including Zn, Pb, Mn, and Cr emerge as major contributors to soil contamination in coal mining areas from Europe.

Review of soil environment quality in India near coal mining regions: current and future predictions

Production and utilization of coal are one of the primary routes of accumulation of Toxic Elements (TEs) in the soil. The exploration of trends in the accumulation of TEs is essential to establishing a soil pollution strategy, implementing cost-effective remediation, and early warnings of ecological risks. This study provides a comprehensive review of soil concentrations and future accumulation trends of various TEs (Cr, Ni, Pb, Co, Cu, Cd, Zn, Fe, Mn, and As) in Indian coal mines. The findings revealed that average concentrations of Cr, Mn, Ni, Cu, Zn, Pb, and Co surpass India's natural background soil levels by factors of 2, 4.05, 5.32, 1.77, 9.6, and 6.15, respectively. Geo-accumulation index values revealed that 27.3%, 14.3%, and 7.7% of coal mines are heavily polluted by Ni, Co, and Cu, respectively. Also, the Potential Ecological Risk Index indicates that Cd and Ni are primary contaminants in coal mines. Besides, the health risk assessment reveals oral ingestion as the main exposure route for soil TMs. Children exhibit a higher hazard index than adults, with Pb and Cr being major contributors to their non-carcinogenic risk. In addition, carcinogenic risks exist for females and children, with Cr and Cu as primary contributors. Multivariate statistical analysis revealed that TEs (except Cd) accumulated in the soil from anthropogenic sources. The assessment of future accumulation trends in soil TE concentrations reveals dynamic increases that significantly impact both the ecology and humans at elevated levels. This study signifies a substantial improvement in soil quality and risk management in mining regions.

Assessing environmental health impacts of coal mining exploitation in Iran: A Rapid Impact Assessment Matrix (RIAM) approach for environmental protection

Environmental Impact Assessment is the process of evaluating the effects caused by a project on the environment. The outcomes generated by this assessment can lead to a reduction of the negative effects and an increase in the positive effects caused by mine projects. The present study was conducted to evaluate the environmental impact assessment of the Goliran Coal Mine in northern Iran. In the descriptive-analytical study, to achieve the objectives, observatory surveys were conducted around the coal mine using a checklist, which was about the positive and negative effects of a coal mine. Then the data were entered into the RIAM and the positive and negative effects were ranked and the most important effects were determined. In RIAM, one point is assigned to each component. 17 important activities for environmental impacts were identified using a checklist. Among the activities carried out at the coal mine site, the major ones included tunnel excavation, construction of the rail line collection and disposal of coal mine effluent, coal transportation, collection and disposal of mine tailings, and technical defects and leakage. The scores of each environmental factor were based on the four environmental components: physical/chemical, biological/ecological, social/cultural, and economic/operational. The results of the present study showed that the most negatively affected environmental components are the physical/chemical components derived from three activities; the construction of the underground tunnel; the construction of a coal transport rail line; and the actual transportation of coal extracts. The scores of each environmental factor based on the four components at the Goliran coal mine in northern Iran indicate that the highest negative score was -64, corresponding to the physical/chemical component, and was assigned to air pollution. On the other hand, the highest positive score corresponds to the economic/operational component with +54, assigned to the income that employees earn from the mine. Overall results showed that the coal mine in northern Iran had negative effects on the environment but the effects were not severe. It is suggested that for future research, corrective measures should be taken in the form of an environmental management plan to reduce the negative effects caused by coal mining, and then prospective research should be done to check the extent of reducing the negative effects.

Monitoring trace element concentrations with environmentally friendly biomonitors in Artvin, Turkey

Air pollution is the change in air composition that disrupts human health and environmental balance. Although natural and anthropogenic processes include crustal movements, photosynthesis, and plant and animal emissions, other sources of contamination also include industrial operations, transportation activities, household resources, and the chemical and metal industries. Thus, biomonitoring can be employed as a quick, affordable, and efficient method for estimating air pollution. In this study, some inorganic pollutants were detected using olive trees (Olea europaea L.) at eleven different points, depending on the traffic density in Artvin, Turkey. Trace element concentrations (Cr, Ti, Fe, Ni, Co, Cu, Zn, Pb, Al, and Mn) were measured in soil once a year and seasonally in plant samples with ICP-OES. Furthermore, basic component analyses total carbon (TC), total nitrogen (TN), total hydrogen (TH), and total sulfur (TS) were done with an elemental analyzer, total chlorophyll contents with a portable chlorophyll meter, and morphological and particle-based plant analyses with SEM-EDS. The pollution levels of these metals were calculated using the enrichment factor (EF) and geoaccumulation index (Igeo) parameters. Furthermore, the accuracy and validity tests of the analyses for trace metals were tested by applying certified reference materials (CRM) (ERM-CD281) for the plant samples and CRM (LGC-6187) for soil samples. Results indicated that soil trace element pollution distributions were ranked according to the following descending order: Fe (37,873.33 mg/kg) > Al (13,300 mg/kg) > Mn (1101.33 mg/kg) > Ti (353.5 mg/kg) > Zn (252.86 mg/kg) > Cu (87.77 mg/kg) > Cr (30.52 mg/kg) > Pb (19.65 mg/kg) > Ni (17.07 mg/kg) > Co (7.65 mg/kg). Moreover, air pollution from anthropogenic sources substantially increased average trace metal concentrations and sulfur emissions in autumn and winter. The average highest values of Fe (321.08 mg/kg) > Al (304.05 mg/kg) > Mn (32.75 mg/kg) > Zn (31.01 mg/kg) > Cu (17.92 mg/kg) > Ti (11.07 mg/kg) Cr (2.57 mg/kg) > Ni (17.07 mg/kg) were found in leaf samples taken from the roadside in autumn and winter. According to the EF and Igeo values, the main polluting trace elements in the soil were Zn, Cu, and Pb, while in the plant, these were detected as Fe, Al, Ti, Cr, Ni, and Cu. Kruskal-Wallis and correlation analysis statistically supported this relationship among metals. Results show that olive leaves are an effective bioindicator for detecting urban air pollution.