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Spatial and temporal variation of vegetation cover in the main mining area of Qibaoshan Town, China: Potential impacts from mining damage, solid waste discharge and land reclamation

Yu H, Zahidi I

Sci Total Environ, 2023 Feb 10;859(Pt 2):160392.
PMID: 36423851 DOI: 10.1016/j.scitotenv.2022.160392

The increasing frequency of mining activities in the world has led to many environmental pollution problems, such as mine wastewater discharge, mine solid waste dumps, and mine dust dispersion. These problems have negative implications for the environment and the public health of people living nearby the mining areas. Despite this, there are few methods to determine the state of mine pollution on a regional scale. Therefore, we applied remote sensing technologies to assess the mine pollution situation, especially the mine solid waste pollution, of a mining area, taking Qibaoshan Town, Liuyang City, Hunan Province, China, as an example. In our research, we have calculated the vegetation cover change of the Qibaoshan Town over the years (2000-2020), charted the vegetation coverage grade maps, and analysed the tendency of vegetation cover changes, to infer the mine pollution situation, the progress of pollution treatment and the efforts made by the local government and the mines on mine pollution disposal and the land reclamation. Additionally, mining damage can bring about geological hazards such as surface subsidence leading to vegetation destruction, while mining solid waste pollution and discharge can occupy a large amount of land and thus lead to vegetation reduction. As a result, this method of calculating FVC changes in a mining area is particularly suitable for assessing the extent of mining damage, the status of solid waste pollution and discharge, and the progress of land reclamation. In the abstract, we claim that this short communication article serves as a guide to start a conversation, and encourages experts and scholars to engage in this area of research.
Environmental hazards posed by mine dust, and monitoring method of mine dust pollution using remote sensing technologies: An overview

Yu H, Zahidi I

Sci Total Environ, 2023 Mar 15;864:161135.
PMID: 36566867 DOI: 10.1016/j.scitotenv.2022.161135

The over-exploitation of mineral resources has led to increasingly serious dust pollution in mines, resulting in a series of negative impacts on the environment, mine workers (occupational health) and nearby residents (public health). For the environment, mine dust pollution is considered a major threat on surface vegetation, landscapes, weather conditions and air quality, leading to serious environmental damage such as vegetation reduction and air pollution; for occupational health, mine dust from the mining process is also regarded as a major threat to mine workers' health, leading to occupational diseases such as pneumoconiosis and silicosis; for public health, the pollutants contained in mine dust may pollute surrounding rivers, farmlands and crops, which poses a serious risk to the domestic water and food security of nearby residents who are also susceptible to respiratory diseases from exposure to mine dust. Therefore, the second section of this paper combines literature research, statistical studies, and meta analysis to introduce the public mainly to the severity of mine dust pollution and its hazards to the environment, mine workers (occupational health), and residents (public health), as well as to present an outlook on the management of mine dust pollution. At the same time, in order to propose a method for monitoring mine dust pollution on a regional scale, based on the Dense Dark Vegetation (DDV) algorithm, the third section of this paper analysed the aerosol optical depth (AOD) change in Dexing City of China using the data of 2010, 2014, 2018 and 2021 from the NASA MCD19A2 Dataset to explore the mine dust pollution situation and the progress of pollution treatment in Dexing City from 2010 to 2021. As a discussion article, this paper aims to review the environmental and health risks caused by mine dust pollution, to remind the public to take mine dust pollution seriously, and to propose the use of remote sensing technologies to monitor mine dust pollution, providing suggestions for local governments as well as mines on mine dust monitoring measures.
Spatiotemporal variation of vegetation cover in mining areas of Dexing City, China

Yu H, Zahidi I, Liang D

Environ Res, 2023 May 15;225:115634.
PMID: 36889570 DOI: 10.1016/j.envres.2023.115634

Dexing City is an important mining city in China, abounding in copper ore, lead ore, zinc ore, and other metal resources, and there are two large open-pit mines in its territory, Dexing Copper Mine and Yinshan Mine. The two open-pit mines have been expanding their mining production scale since 2005, with frequent mining activities; and the expansion of the pits and the discharge of solid waste will undoubtedly increase the land use and cause the destruction of vegetation. Therefore, we plan to visualize the change in vegetation cover in Dexing City from 2005 to 2020 and the expansion of the two open-pit mines by calculating changes of the Fractional Vegetation Cover (FVC) in the mining area using remote sensing technology. In this study, we calculated the FVC of Dexing City in 2005, 2010, 2015 and 2020 using data from NASA Landsat Database via ENVI image analysis software, plotted the FVC reclassified maps via ArcGIS, and conducted field investigations in the mining areas of Dexing City. In this way, we can visualize the spatial and temporal changes of vegetation cover in Dexing City from 2005 to 2020, and appreciate the situation of mining expansion and its solid waste discharge in Dexing City. The results of this study showed that the vegetation cover of Dexing City remained stable from 2005 to 2020, as the expansion of mining scale and mine pits was accompanied by active environmental management and land reclamation, setting a positive example for other mining cities.
Mine land reclamation, mine land reuse, and vegetation cover change: An intriguing case study in Dartford, the United Kingdom

Yu H, Zahidi I, Liang D

Environ Res, 2023 May 15;225:115613.
PMID: 36870554 DOI: 10.1016/j.envres.2023.115613

Dartford, a town in England, heavily relied on industrial production, particularly mining, which caused significant environmental pollution and geological damage. However, in recent years, several companies have collaborated under the guidance of the local authorities to reclaim the abandoned mine land in Dartford and develop it into homes, known as the Ebbsfleet Garden City project. This project is highly innovative as it not only focuses on environmental management but also provides potential economic benefits, employment opportunities, builds a sustainable and interconnected community, fosters urban development and brings people closer together. This paper presents a fascinating case that employs satellite imagery, statistical data, and Fractional Vegetation Cover (FVC) calculations to analyse the re-vegetation progress of Dartford and the development of the Ebbsfleet Garden City project. The findings indicate that Dartford has successfully reclaimed and re-vegetated the mine land, maintaining a high vegetation cover level while the Ebbsfleet Garden City project has advanced. This suggests that Dartford is committed to environmental management and sustainable development while pursuing construction projects.
Fulltext Potential application of spent mushroom compost (SMC) biochar as low-cost filtration media in heavy metal removal from abandoned mining water: a review

Madzin Z, Zahidi I, Raghunandan ME, Talei A

Int J Environ Sci Technol (Tehran), 2023;20(6):6989-7006.
PMID: 36373081 DOI: 10.1007/s13762-022-04617-7

Overpopulation and rapid development have put an increasing burden on the environment, leading to various water crisis. Importing water from abandoned mines as an alternative raw water source could be the next answer to alleviate water scarcity problems globally. However, due to its high heavy metals content, there is a need to find an economical and effective method to remove heavy metals before reusing it as potable water source. Biochar, a low-cost and carbon-rich biosorbent, has received increasing attention on its application as a remediating agent to remove heavy metals from water. Previous studies have revealed the potential properties of biochar as a heavy metal removal agent including high cation exchange capacity, high surface area, active surface functional groups, as well as efficient adsorption. Apparently, the most important factor influencing the sorption mechanism is the type of feedstock materials. Spent mushroom compost (SMC), a waste product from mushroom cultivation, has been found as an excellent biosorbent. SMC has received global attention as it is low cost and eco-friendly. It also has been proved as an efficient heavy metals remover from water. Nevertheless, its application as biochar is still scarce. Therefore, this review focuses on the potential of transforming SMC into modified biochar to remove heavy metals, especially from abandoned mining water. The present review emphasizes the current trends in adsorption methods for heavy metal removal from water, assembles data from previous studies on the feedstock of biosorbents to biochars, and discusses the potentials of SMC as a biochar for water treatment.
Fulltext Reclaiming abandoned mine tailings ponds for agricultural use: Opportunities and challenges

Yu H, Zahidi I, Fai CM

Environ Res, 2023 Sep 01;232:116336.
PMID: 37321336 DOI: 10.1016/j.envres.2023.116336

Tailings ponds, large man-made structures conceived during the mining process for waste storage, often become deserted post-mining, leaving behind a stark, contaminated landscape. This paper posits that these forsaken tailings ponds can be rejuvenated into fertile agricultural land through adept reclamation efforts. Serving as a discussion paper, it engages in a stimulating exploration of the environmental and health risks linked to tailings ponds. It sheds light on the potential and impediments in the transformation of these ponds into agricultural land. The discussion concludes that despite the substantial hurdles in repurposing tailings ponds for agriculture, there are encouraging prospects with the application of multifaceted efforts.
Fulltext Vegetation as an ecological indicator in assessing environmental restoration in mining areas

Yu H, Zahidi I, Chow MF

iScience, 2023 Sep 15;26(9):107667.
PMID: 37680487 DOI: 10.1016/j.isci.2023.107667

As global demand for natural resources escalates, the environmental impact stemming from resource extraction has risen to the forefront of contemporary discussions. This paper probed the potential of using vegetation cover as an ecological barometer to gauge the level of environmental damage and restoration in mining areas: a decline in vegetation cover may signify detrimental impacts from intense mining activities, while an increase may indicate effective local environmental stewardship. Therefore, this paper undertook an assessment and discussion of mining damage and environmental management at China's Ta'ershan Mining Area since 2007, calculating and visualizing FVC (Fractional Vegetation Cover) of the Ta'ershan Mining Area to track changes in vegetation cover between 2007 and 2021. Changes in vegetation cover in the Ta'ershan Mining Area could act as a reflection of both mining-induced damage and subsequent successful environmental management by local authorities, providing a practical way to evaluate ecological effects in resource development.
Water Quality Modelling for River Activities Management: Example from a Low- and Middle-Income Country

Zahidi I, Wilson G, Brown K, Hou FKK

J Health Pollut, 2020 Dec;10(28):201207.
PMID: 33324504 DOI: 10.5696/2156-9614-10.28.201207

Background: Rivers are susceptible to pollution and water pollution is a growing problem in low- and middle-income countries (LMIC) with rapid development and minimal environmental protections. There are universal pollutant threshold values, but they are not directly linked to river activities such as sand mining and aquaculture. Water quality modelling can support assessments of river pollution and provide information on this important environmental issue.
Objectives: The objective of the present study was to demonstrate water quality modelling methodology in reviewing existing policies for Malaysian river catchments based on an example case study.
Methods: The MIKE 11 software developed by the Danish Hydraulic Institute was used to model the main pollutant point sources within the study area - sand mining and aquaculture. Water quality data were obtained for six river stations from 2000 to 2015. All sand mining and aquaculture locations and approximate production capacities were quantified by ground survey. Modelling of the sand washing effluents was undertaken with the advection-dispersion module due to the nature of the fine sediment. Modelling of the fates of aquaculture deposits required both advection-dispersion and Danish Hydraulic Institute ECO Lab modules to simulate the detailed interactions between water quality determinants.
Results: According to the Malaysian standard, biochemical oxygen command (BOD) and ammonium (NH4) parameters fell under Class IV at most of the river reaches, while the dissolved oxygen (DO) parameter varied between Classes II to IV. Total suspended solids (TSS) fell within Classes IV to V along the mid river reaches of the catchment.
Discussion: Comparison between corresponding constituents and locations showed that the water quality model reproduced the long-term duration exceedance for the main body of the curves. However, the water quality model underestimated the infrequent high concentration observations. A standard effluent disposal was proposed for the development of legislation and regulations by authorities in the district that could be replicated for other similar catchments.
Conclusions: Modelling pollutants enables observation of trends over the years and the percentage of time a certain class is exceeded for each individual pollutant. The catchment did not meet Class II requirements and may not be able to reach Class I without extensive improvements in the quality and reducing the quantity of both point and non-point effluent sources within the catchment.
Competing Interests: The authors declare no competing financial interests.
Fulltext Sungai Lembing's green tourism: Pioneering the future of resource-based urban renewal

Yu H, Gunaratna G, Zahidi I, Fai CM

Innovation (Camb), 2024 Mar 04;5(2):100578.
PMID: 38445020 DOI: 10.1016/j.xinn.2024.100578
From waste to wealth: The "Blue Circle" vision for a sustainable ocean future

Yu H, Zahidi I, Fai CM, Liang D, Madsen DØ

Sci Bull (Beijing), 2024 Apr 30;69(8):993-996.
PMID: 38433031 DOI: 10.1016/j.scib.2024.02.024
Fulltext Thermal and Mechanical Properties of Concrete Incorporating Silica Fume and Waste Rubber Powder

Lakhiar MT, Kong SY, Bai Y, Susilawati S, Zahidi I, Paul SC, et al.

Polymers (Basel), 2022 Nov 11;14(22).
PMID: 36432983 DOI: 10.3390/polym14224858

Using waste rubber tires for concrete production will reduce the demand for natural aggregate and help to reduce environmental pollution. The main challenge of using waste rubber tires in concrete is the deterioration of mechanical properties, due to poor bonding between rubber and cement matrix. This research aims to evaluate the mechanical and thermal properties of rubberised concrete produced by using different proportions of rubber powder and silica fume. Ordinary Portland cement was partially replaced with silica fume by amounts of 5%, 10%, 15% and 20%, while sand was replaced by 10%, 20% and 30% with waste rubber powder. Tests were carried out in order to determine workability, density, compressive strength, splitting tensile strength, elastic modulus, thermal properties, water absorption and shrinkage of rubberised concrete. The compressive strength and splitting tensile strength of concrete produced using waste rubber powder were reduced by 10-52% and 9-57%, respectively. However, the reduction in modulus of elasticity was 2-36%, less severe than compressive and splitting tensile strengths. An optimum silica fume content of 15% was observed based on the results of mechanical properties. The average shrinkage of concrete containing 15% silica fume increased from -0.051% to -0.085% at 28 days, as the content of waste rubber powder increased from 10% to 30%. While the thermal conductivity of rubberised concrete was reduced by 9-35% compared to the control sample. Linear equations were found to correlate the density, splitting tensile strength, modulus of elasticity and thermal conductivity of concrete with silica fume and waste rubber powder.
Fulltext Plastic pollution: What have we done? What more can we do?

Yu H, Deng Z, Zahidi I, Fai CM, Liang D, Madsen DØ

Ecotoxicol Environ Saf, 2024 Nov 01;286:117164.
PMID: 39396399 DOI: 10.1016/j.ecoenv.2024.117164