Mining industry and sustainable development: time for change

Potential of Eucalyptus globulus for the phytoremediation of metals in a Moroccan iron mine soil-a case study

The contamination left by abandoned mines demands sustainable mitigation measures. Hence, the aim of this study was to examine the phytoremediator ability of Eucalyptus globulus Labill. to be used for cleaning up metal-contaminated soils from an African abandoned iron (Fe) mine (Ait Ammar, Oued Zem, Morocco). Plantlets of this species were exposed to a control (CTL), a reference (REF), and a mine-contaminated soil (CS). Morphological (growth, leaf area) and physiological stress biomarkers (photosynthetic efficiency, pigments content, leaf relative water, and malondialdehyde (MDA) levels) and metal bioaccumulation were assessed. The growth and leaf area of E. globulus increased overtime in all soils, although at a lower rate in the CS. Its photosynthetic efficiency was not markedly impaired, as well as MDA levels decreased throughout the experiment in CS. In this soil, higher metal contents were detected in E. globulus roots than in leaves, especially Fe (roots: 15.98-213.99 μg g^-1; leaves: 5.97-15.98 μg g^-1) and Zn (roots: 1.64-1.99 μg g^-1; leaves: 0.67-1.19 μg g^-1), indicating their reduced translocation. Additionally, though at low extent, the plants bioaccumulated some metals (Pb > Zn > Cu) from CS. Overall, E. globulus may be potentially used for the phytoremediation of metals in metal-contaminated soils.

Health risk assessment of radioactive footprints of the urban soils in the residents of Dera Ghazi Khan, Pakistan

The aim of the study was to evaluate the radiation levels, radiological doses and excess lifetime cancer risk possessed by the urban soils that were collected from the vicinity of the exclusive mining and excavation centers of Dera Ghazi Khan. The high purity germanium detector was utilized for assessment of naturally occurring radionuclides (NORMs) in soil and results showed that the average activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K (37 Bq/kg, 43.07 Bq/kg, 737 Bq/kg respectively) surpassed the world's average documented values (35 Bq/kg, 30 Bq/kg, and 400 Bq/kg respectively). Moreover, the average values of radiological hazards assessment like radium equivalent, internal and external hazard indices, absorbed dose rate, annual gonadal dose equivalent and excess lifetime cancer risk were 155.70 (Bq/kg), 0.4, 0.5, 73.96 (nGy/h) 90.73 (μSv/y), 476.24 (μSv/y) and 0.31(10^-3) respectively. The data acquired was analyzed using descriptive statistics, cluster analysis and principal component analysis. ArcGIS (10.5) software was utilized for developing maps of radionuclide's concentration for the study area. Results of the study may serve as an important baseline radiometric data for future epidemiological studies and monitoring initiatives in the study area.

The Policy Framework of Natural Resource Management in Oil-Dependence Countries

A variety of critical empirical studies are interested in and focused on complex issues related to natural resource management and resource curse, whilst less can be found combining diverse factors that affect the dynamics of this curse and mitigate it. The case study of Norway is used as the benchmark policy framework in oil-rich countries to invest oil revenues and set correct fiscal policies. In this study, an analytical framework was structured to evaluate the coherence of resource management with sustainability as a starting point, contributing to further assessments of how the adaptation of such policies is incorporated in resource management to mitigate the resource curse. The analysis also suggests that oil-rich countries can learn from Norway’s experience to mitigate this resource curse and utilize oil revenues in the interest of the country. In addition, the analysis helps in effective management and the protection of ecological resources as these are becoming an increasingly important strategic part of natural wealth. This study aimed to provide an overarching framework designed to help conceptualize key issues of natural resource management and the resource curse in oil-rich countries and understand the challenges facing those countries in managing the natural resources.

Recycled Aggregates Concrete Compressive Strength Prediction Using Artificial Neural Networks (ANNs)

The recycled aggregate is an alternative with great potential to replace the conventional concrete alongside with other benefits such as minimising the usage of natural resources in exploitation to produce new conventional concrete. Eventually, this will lead to reducing the construction waste, carbon footprints and energy consumption. This paper aims to study the recycled aggregate concrete compressive strength using Artificial Neural Network (ANN) which has been proven to be a powerful tool for use in predicting the mechanical properties of concrete. Three different ANN models where 1 hidden layer with 50 number of neurons, 2 hidden layers with (50 10) number of neurons and 2 hidden layers (modified activation function) with (60 3) number of neurons are constructed with the aid of Levenberg-Marquardt (LM) algorithm, trained and tested using 1030 datasets collected from related literature. The 8 input parameters such as cement, blast furnace slag, fly ash, water, superplasticizer, coarse aggregate, fine aggregate, and age are used in training the ANN models. The number of hidden layers, number of neurons and type of algorithm affect the prediction accuracy. The predicted recycled aggregates compressive strength shows the compositions of the admixtures such as binders, water–cement ratio and blast furnace–fly ash ratio greatly affect the recycled aggregates mechanical properties. The results show that the compressive strength prediction of the recycled aggregate concrete is predictable with a very high accuracy using the proposed ANN-based model. The proposed ANN-based model can be used further for optimising the proportion of waste material and other ingredients for different targets of concrete compressive strength.

Metalliferous Mining Pollution and Its Impact on Terrestrial and Semi-terrestrial Vertebrates: A Review

Metalliferous mining, a major source of metals and metalloids, has severe potential environmental impacts. However, the number of papers published in international peer-reviewed journals seems to be low regarding its effects in terrestrial wildlife. To the best of our knowledge, our review is the first on this topic. We used 186 studies published in scientific journals concerning metalliferous mining or mining spill pollution and their effects on terrestrial and semi-terrestrial vertebrates. We identified the working status of the mine complexes studied, the different biomarkers of exposure and effect used, and the studied taxa. Most studies (128) were developed in former mine sites and 46 in active mining areas. Additionally, although several mining accidents have occurred throughout the world, all papers about effects on terrestrial vertebrates from mining spillages were from Aznalcóllar (Spain). We also observed a lack of studies in some countries with a prominent mining industry. Despite >50% of the studies used some biomarker of effect, 42% of them only assessed exposure by measuring metal content in internal tissues or by non-invasive sampling, without considering the effect in their populations. Most studied species were birds and small mammals, with a negligible representation of reptiles and amphibians. The information gathered in this review could be helpful for future studies and protocols on the topic and it facilitates a database with valuable information on risk assessment of metalliferous mining pollution.

Soil-to-crop transfer of natural radionuclides in farm soil of South Africa

The activity concentration of natural radionuclides in farm soil and most common indigenous food crops (maize, potato, cowpea) in oil-producing (Philippi, Uitenhage, and Hertenbos farms) and non-oil-producing (Ukulinga farm) areas of South Africa was measured using a Hyper Pure Germanium detector. Consequently, the transfer of these radionuclides from soil-to-crops was estimated. The mean activity concentration of ²²⁶Ra, ²³²Th, and ⁴⁰K for farm soil samples are 30.71 ± 11.77, 31.97 ± 8.90, 345.97 ± 98.62 Bq.kg^-1 for Philippi; 18.67 ± 6.70, 31.55 ± 11.48, 191.93 ± 33.39 Bq.kg^-1 for Uitenhage; 38.03 ± 17.44, 41.18 ± 31.54, 381.89 ± 163.40 Bq.kg^-1 for Hartenbos; and 8.47 ± 2.87, 8.65 ± 3.52, 94.22 ± 25.97 ± 25.97 Bq.kg^-1 for Ukulinga. The mean activity concentration of ²²⁶Ra, ²³²Th, and ⁴⁰K for crop samples are 4.54 ± 1.47, 4.87 ± 1.69, 140.18 ± 35.38 Bq.kg^-1 for Philippi; 9.17 ± 4.79, 3.85 ± 1.87, 136.75 ± 22.04 Bq.kg^-1 for Uitenhage; 7.97 ± 2.91, 4.62 ± 2.40, 105.97 ± 48.65 Bq.kg^-1 for Hartenbos; and 4.23 ± 1.63, 2.72 ± 1.19, 48.36 ± 15.55 Bq.kg^-1 for Ukulinga. The activity concentration and soil-to-crop transfer factors for ⁴⁰K were found to be much higher, possibly because this element is critical in crop growth. The results showed that the crop samples' transfer factor is in the order cowpea>potato>maize. This study showed that activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in crops and the corresponding transfer factors depend on activity concentrations of the same radionuclides in soil.

Bacterially assembled biopolyester nanobeads for removing cadmium from water

Cadmium (Cd)-contaminated waterbodies are a worldwide concern for the environment, impacting human health. To address the need for efficient, sustainable and cost-effective remediation measures, we developed innovative Cd bioremediation agents by engineering Escherichia coli to assemble poly(3-hydroxybutyric acid) (PHB) beads densely coated with Cd-binding peptides. This was accomplished by translational fusion of Cd-binding peptides to the N- or C-terminus of a PHB synthase that catalyzes PHB synthesis and mediates assembly of Cd2 or Cd1 coated PHB beads, respectively. Cd1 beads showed greater Cd adsorption with 441 nmol Cd mg^-1 bead mass when compared to Cd2 beads (334 nmol Cd mg^-1 bead-mass) and plain beads (238 nmol Cd mg^-1 bead-mass). The Cd beads were not ecotoxic and did attenuate Cd-spiked solutions toxicity. Overall, the bioengineered beads provide a means to remediate Cd-contaminated sites, can be cost-effectively produced at large scale, and offer a biodegradable and safe alternative to synthetic ecotoxic treatments.

Review of GIS-Based Applications for Mining: Planning, Operation, and Environmental Management

In this study, geographic information system (GIS)-based methods and applications utilized for mine development were reviewed. Three types of GIS-based studies, namely studies on mine planning, operation, and environmental management, were examined to describe the role of GIS as a decision-making support tool in mine development. This review was conducted by classifying previous GIS-based studies into several subtopics that pertain to mine development activities and the range of environments to be managed. Because the use of GIS is appropriate for spatial data management related to ore deposits and mine environment conditions at various scales, the applications of GIS-based methods in mine development could be expanded further.

Conflicting Demands on the Natural Resources in Northern Sweden: A Participatory Scenario Development Study

Globalisation strongly influences social, environmental and economic resources, especially in those territories characterised by a historical dependency on a single industry, as in the case of mining. Our study aimed to envision possible future development paths for the mining city of Gällivare, in Northern Sweden, using a participatory approach. Four different transformative narratives were developed depicting a wide range of choices along an ideal anthropocentric-wild gradient. Through applying complementary methodologies for social-ecological system assessment (e.g., Q-methodology, ARDI approach), the expected social, economic and environmental impacts of the scenarios were explored. Results highlight the conflicting demands on natural resources in Northern Sweden and provides a deeper understanding of different perceptions and potential societal acceptance of each scenario from local and nonlocal stakeholder. This paper contributes to local discussions on future development in the area as well as to methodological advancements by providing a framework for the creation of a participative decision-making arena in similar transformative contexts.

Relationship between Mg, B and Mn status and tomato tolerance against Cd toxicity

Distinct tomato genotypes possess different tolerance degree to cadmium (Cd), but the mechanisms behind this phenomenon are scarcely understood. To this end, the physiological, biochemical, anatomical, nutritional and molecular mechanisms associated to the plant tolerance against Cd toxicity were investigated in five tomato accessions with contrasting sensitivity to Cd exposure. Firstly, the data revealed that larger biomass loss was not always coupled to higher Cd concentration, indicating that other events, in addition to the internal Cd accumulation, impact tomato performance at early stages of Cd exposure. Secondly, the results indicated that the fine regulation of nutrient status, particularly magnesium (Mg), boron (B) and manganese (Mn), is associated to the mitigation of Cd toxicity. Magnesium status was coupled to the modulation of root development, resulting in changes in root hair formation and biomass allocation. Boron accumulation in leaves was linked to Cd toxicity, suggesting that tolerance mechanisms involved strategies to decrease or even avoid B excess in photosynthetic tissues. Disturbances in Mn status, i.e. Mn excess in leaves and Mn deficiency in roots, were also related to tomato sensitivity to Cd exposure. Thirdly, plant capacity to maintain leaf blade expansion is a relevant strategy for a better tomato development after short-term Cd exposure. Fourthly, tomato tolerance to Cd-induced stress does not depend on CAT activity enhancements in such conditions. In conclusion, tomato ability to quickly manage its nutritional status is necessary for alleviation of the Cd effects at early stages of exposure to this metal. The better understanding about tolerance mechanisms and mode of action of Cd toxicity in plants can help in the establishment of strategies to mitigate its impacts on crops.

Natural radioactivity in urban soils of mining centers in Armenia: Dose rate and risk assessment

Soil radioactivity levels, dose rate and radiological health risk were assessed in metal mining centers of Armenia, at the towns of Kapan and Kajaran. Archive soil samples of the multipurpose soil surveys implemented in Kapan and Kajaran were used for estimation of total alpha and total beta activity levels using gas-less iMatic™ alpha/beta cօunting system (Canberra). Ten representative soil samples per town were randomly selected from different urban zones for naturally occurring radionuclide measurements (238U, 232Th, 40 K) using high purity germanium detector. Four radiological indices: radium equivalent activity, outdoor absorbed dose rate, annual effective dose equivalent and excess lifetime cancer risk were estimated based on naturally occurring radionuclide activity concentrations in soils. Results suggest that in Kapan the soil radioactivity, although enhanced by copper and gold-polymetallic mining, are not a significant risk factor to human health. In Kajaran, the soil radioactivity levels were above the background and world average values provided by UNSCEAR, but radionuclides originated in a natural geogenic source and not from mining activities. Generally, in this region no significant radiological risks were identified in relationship with molybdenum, copper, and gold-polymetallic ore mining.

Authentic leadership and work engagement: The indirect effects of psychological safety and trust in supervisors

Orientation: The orientation of this study was towards authentic leadership and its influence on psychological safety, trust in supervisors and work engagement.Research purpose: The aim of this study was to investigate the influence of authentic leadership on trust in supervisors, psychological safety and work engagement. Another aim was to determine whether trust in supervisors and psychological safety had an indirect effect on the relationship between authentic leadership and work engagement. An additional objective was to determine if authentic leadership indirectly influenced psychological safety through trust in supervisors.Motivation for the study: Globally, businesses are faced with many challenges which may be resolved if leaders are encouraged to be more authentic and employees more engaged. In this study, investigating the role of trust in supervisors and psychological safety on the relationship between authentic leadership and work engagement is emphasised.Research design, approach and method: This study was quantitative in nature and used a cross-sectional survey design. A sample of 244 employees within the South African mining industry completed the Authentic Leadership Inventory, Utrecht Work Engagement Scale, Workplace Trust Survey and Psychological Safety Questionnaire.Main findings: The results indicated that authentic leadership is a significant predictor of both trust in supervisors and psychological safety. This study further found that authentic leadership had a statistically significant indirect effect on work engagement through trust in supervisors.Practical or managerial implications: The main findings suggest that having more authentic leaders in the mining sector could enhance trust in these leaders. Authentic leadership thus plays an important role in creating a positive work environment. This work environment of authenticity and trust could lead to a more engaged workforce.Contribution or value-add: Limited empirical evidence exists with regard to the relationship between authentic leadership, work engagement, psychological safety and trust in supervisors. This is particularly true in the mining sector. This study aimed to contribute to the limited number of studies conducted.

Environmental impact assessment studies for mining area in Goa, India, using the new approach

The mining industry is a fundamental source for building infrastructures and an enabler for a country's growth. Over the last decade, the act of mining has been among the top in the list of human activities which has the most disturbing and catastrophic impacts on environment, therein extensively affecting the ecological, economic, and social elements in the vicinity. There is an exigency for a pragmatic balance to exist between the global demand satisfaction of metal and environmental sustenance. In this paper, a comprehensive case study on Environmental Impact Assessment (EIA) of a mining site has been presented using the new approach. This new approach is an improved version of the traditional matrix method, incorporating a modified version of Rapid Impact Assessment Matrix (RIAM) integrated with analytical hierarchy process (AHP), thereby knocking out the limitations in the existing EIA techniques. The data used in this study is an outcome of a broad survey conducted among the people associated in both direct and indirect ways to the project actions related to the mining industry and, hence, minimizing issues such as assessors' reproducibility, subjectivity, and non-inclusivity of all stakeholders' opinion, which can contribute to misleading outcomes. This new approach delivers more precise and practical results for the assessment of environmental impact data.

Cadmium toxicity degree on tomato development is associated with disbalances in B and Mn status at early stages of plant exposure

Cadmium (Cd) toxicity is frequently coupled to its accumulation in plants, but not always the highest Cd concentration triggers the worst damages, indicating that additional events influence the magnitude of Cd side-effects. We investigated the early mechanisms behind the differential Cd-induced impacts on plant development of four tomato accessions with contrasting tolerance to Cd toxicity. At organ level, the highest Cd concentration was not associated with the largest biomass losses. In leaves, changes in superoxide dismutase and catalase activities were not related to differences in Cd concentration, which was unable to provoke H₂O₂ overproduction on the sixth day of plant exposure to this metal. Further investigation in the mineral profile revealed that magnitude of Cd toxicity depends probably on synergic effects from increased B status, in addition to the own Cd accumulation. Furthermore, disbalances in Mn status (i.e., excess in leaves and deficiency in roots) may enhance Cd toxicity degree. According to data, however, the low magnesium (Mg) status can be linked to tomato tolerance against Cd toxicity. In conclusion, the tomato tolerance degree under short-Cd exposure depends on actively, finely regulation of mineral homeostasis that results in different development of plant organs. The better understanding on the mode of action of Cd toxicity in plants can help in the establishment of strategies to mitigate its impacts on crop yield.

The Sustainable Management of Metals: An Analysis of Global Research

The objective of this study was to analyze research trends in the field of sustainable management of metals on a global level between 1993 and 2017. To do so, a bibliometric analysis was carried out on a total of 6967 articles. The results revealed the growing interest in this research field, particularly over the last five year-period during which 63% of all articles were published. The three journals in which most articles had been published were the Journal of Cleaner Production, ACS Sustainable Chemistry and Engineering, and Chemsuschem. The countries that published the most articles were China, the United States, India, Germany, and the United Kingdom. A sizeable network of collaboration has been established between countries for the joint publication of studies. The main lines of research have been focused on metal decontamination in water and soil, waste management oriented towards reuse and recycling, and the innovation of processes for cleaner and more efficient production. The results revealed the need for comprehensive studies that integrate different disciplines within the same analytical framework, and to promote research that contributes to the different dimensions of sustainability (environmental, economic, and social).

Estimating tomato tolerance to heavy metal toxicity: cadmium as study case

This work aimed to develop a reliable and fast approach to estimate the plant tolerance degree to heavy metal (HM) phytotoxicity. Two independent experiments were carried out using tomato accessions, with contrasting morphological features, that were grown in a hydroponic solution containing different CdCl₂ concentrations for 7 days. Plant dry weight and chlorophyll content (SPAD units) were evaluated, and tolerance degree to Cd toxicity was estimated according to the tolerance index (TI), which is a new mathematical formula based on plant biomass proposed in this study. Although with different magnitudes, tomato exhibited reductions in their dry weight concurrently with the increasing CdCl₂ concentration. By contrast, chlorophyll content presented no standard response, decreasing and even increasing according to CdCl₂ concentrations, indicating that only under certain conditions (particularly, at CdCl₂ 50 μM), this parameter can be used to estimate plant tolerance to Cd toxicity. TI was efficiently able to segregate tomato cultivars with similar performance (based on the total dry weight of plants), and such segregation was optimized when the hydroponic solution contained from 25 to 50 μM CdCl₂. Within this range, data pointed at 35 μM CdCl₂ as the best concentration to be employed in studies related to the tomato tolerance/sensitivity to Cd toxicity. In conclusion, TI proved to be a reliable estimator of tolerance degree to Cd exposure in genetically distinct tomato accessions. Moreover, TI can be used for this same purpose in plants under other HM-induced stresses.

Sea Buckthorn (Hippophae rhamnoides L.) and Quince (Cydonia oblonga L.) Juices and Their By-Products as Ingredients Showing Antimicrobial and Antioxidant Properties for Chewing Candy: Nutraceutical Formulations

Sustainable and environmentally friendly approaches to the production of health foods have become very popular. The concept of this study was to develop chewing candy (CC)—nutraceutical formulations based on sea buckthorn (Hippophae rhamnoides L.) and quince (Cydonia oblonga L.) juice and juice by-products (BuJ, QuJ, BuBP, and QuBP, resp.), as ingredients showing antimicrobial properties against Klebsiella pneumoniae, Salmonella enterica, Pseudomonas aeruginosa, Acinetobacter baumannii, Proteus mirabilis, methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, E. faecium, and Bacillus cereus. Two texture-forming agents (agar and gelatin) were tested for CC formulation. BuJ, QuJ, BuBP, and QuBP showed antimicrobial activity against all the pathogens tested, and the largest inhibition zones against Bacillus and Proteus mirabilis were observed for BuJ and QuJ, respectively. Agar and/or gelatin selection has a significant influence on CC texture (p=0.0001), and interactions of agar and/or gelatin selection × juice or juice by-products and sea buckthorn or quince × juice or juice by-products were also significant (p=0.0001). The best acceptability was shown for CC prepared with agar and BuBP (131.7) and with gelatin and QuJ (132.0). The addition of BuJ, QuJ, BuBP, and QuBP increases the antioxidant activity of CC by five times. Finally, not just juice, but also juice by-products, have great potential as desirable antimicrobial ingredients for the food industry.

Extremophilic Microfactories: Applications in Metal and Radionuclide Bioremediation

Metals and radionuclides (M&Rs) are a worldwide concern claiming for resilient, efficient, and sustainable clean-up measures aligned with environmental protection goals and global change constraints. The unique defense mechanisms of extremophilic bacteria and archaea have been proving usefulness towards M&Rs bioremediation. Hence, extremophiles can be viewed as microfactories capable of providing specific and controlled services (i.e., genetic/metabolic mechanisms) and/or products (e.g., biomolecules) for that purpose. However, the natural physiological plasticity of such extremophilic microfactories can be further explored to nourish different hallmarks of M&R bioremediation, which are scantly approached in the literature and were never integrated. Therefore, this review not only briefly describes major valuable extremophilic pathways for M&R bioremediation, as it highlights the advances, challenges and gaps from the interplay of ‘omics’ and biological engineering to improve extremophilic microfactories performance for M&R clean-up. Microfactories’ potentialities are also envisaged to close the M&R bioremediation processes and shift the classical idea of never ‘getting rid’ of M&Rs into making them ‘the belle of the ball’ through bio-recycling and bio-recovering techniques.