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Showing papers in "Critical Reviews in Environmental Science and Technology in 2013"


Journal ArticleDOI
TL;DR: The present analysis provides a useful framework to identify priorities for future research in order to achieve more robust risk assessments of nanopesticides.
Abstract: Published literature has been reviewed in order to (a) explore the (potential) applications of nanotechnology in pesticide formulation, (b) identify possible impacts on environmental fate, and (c) analyze the suitability of current exposure assessment procedures to account for the novel properties of nanopesticides within the EU regulatory context. The term nanopesticide covers a wide variety of products and cannot be considered to represent a single category. Many nanoformulations combine several surfactants, polymers, and metal nanoparticles in the nanometer size range. The aims of nanoformulations are generally common to other pesticide formulations, these being to increase the apparent solubility of poorly soluble active ingredients, to release the active ingredient in a slow/targeted manner and/or to protect against premature degradation. Nanoformulations are thus expected to (a) have significant impacts on the fate of active ingredients and/or (b) introduce new ingredients for which the environmenta...

389 citations


Journal ArticleDOI
TL;DR: A review of works on the conversion of biomass into bio-hydrogen and biomethane with the comprehensive description of biomass composition and features that may impact on its anaerobic conversion and the impact of different kinds of pretreatment on these features and on the performance of bio hydrogen and methane production is presented in this paper.
Abstract: Production of energy from lignocellulosic biomass or residues is receiving ever-increasing interest. Among the different processes, dark fermentation for producing biohydrogen and anaerobic digestion for producing biomethane present considerable advantages. However, they are limited by the accessibility of holocelluloses that are embedded in the lignin network. The authors propose a review of works on the conversion of biomass into biohydrogen and biomethane with the comprehensive description of (a) biomass composition and features that may impact on its anaerobic conversion and (b) the impact of different kinds of pretreatment on these features and on the performance of biohydrogen and methane production.

346 citations


Journal ArticleDOI
TL;DR: In this article, a number of transport pathways, processes, factors, and mathematical models often are needed to describe pathogen fate in agricultural settings, and the level of complexity is dramatically enhanced by soil heterogeneity, as well as by temporal variability in temperature, water inputs, and pathogen sources.
Abstract: An understanding of the transport and survival of microbial pathogens (pathogens hereafter) in agricultural settings is needed to assess the risk of pathogen contamination to water and food resources, and to develop control strategies and treatment options. However, many knowledge gaps still remain in predicting the fate and transport of pathogens in runoff water, and then through the shallow vadose zone and groundwater. A number of transport pathways, processes, factors, and mathematical models often are needed to describe pathogen fate in agricultural settings. The level of complexity is dramatically enhanced by soil heterogeneity, as well as by temporal variability in temperature, water inputs, and pathogen sources. There is substantial variability in pathogen migration pathways, leading to changes in the dominant processes that control pathogen transport over different spatial and temporal scales. For example, intense rainfall events can generate runoff and preferential flow that can rapidly transport...

197 citations


Journal ArticleDOI
TL;DR: In this paper, the main machinery of the process, the microbes, and their conditions, which decide the fate of this heavy metal, should be appropriate for efficient bioremoval of hexavalent chromium [Cr(VI) by bacteria.
Abstract: The anthropogenic inputs of hexavalent chromium [Cr(VI)] have increased enormously during the past few decades and has become a challenge for life on earth and hence removal of this carcinogen has become the need of the hour. Cr(VI) removal through common physicochemical techniques is highly expensive and inappropriate at low concentration. Microbial reduction of Cr(VI) to trivalent form is considered a favorable technique for Cr(VI) removal from wastewater, as it reduces the highly toxic form of Cr to less toxic form and therefore the article conveys essential fundamental information on removal of Cr(VI) by bacteria. For efficient bioremoval of Cr(VI),the main machinery of the process, the microbes, and their conditions, which decide the fate of this heavy metal, should be appropriate. Hence, the authors cover vast information about the isolation of chromium-resistant bacteria from various environment and their Cr(VI) resistance capability. An extensive report is given on information pertaining to the fa...

176 citations


Journal ArticleDOI
TL;DR: In this article, the authors summarize the data available for the physicochemical properties and aquatic toxicity of poly-and perfluorinated compounds (PFCs) in order to have a clear overview of the available data.
Abstract: Because of their global distribution, environmental persistence, and potential risk to human beings and ecosystems, poly- and perfluorinated compounds (PFCs) are of particular concern to scientific and regulatory communities. Despite this concern, data about the physicochemical properties and aquatic toxicity of PFCs are still limited, and there are big debates regarding the actual values of some properties investigated. In order to have a clear overview of the data available, the authors summarize the data available for the physicochemical properties and aquatic toxicity of PFCs.

168 citations


Journal ArticleDOI
TL;DR: In this paper, the anaerobic digestion of rice straw has been studied for the past century, but the renewable energy potential is barely utilized, and research is lacking on the overall logistics for a full-scale system.
Abstract: The anaerobic digestion of rice straw has been studied for the past century, but the renewable energy potential is barely utilized. Greenhouse gas emissions from rice fields can be substantially reduced if straw is removed. Methane yields ranging from 92 to 280 l/kg of volatile solids have been achieved. Optimal digestion conditions such as pH (6.5–8.0), temperature (35–40°C), and nutrients (C:N ratio of 25–35) are defined. Pretreatment (i.e., fungi, acid, and alkali solutions) and microbial engineering can increase biogas production, but research is lacking on the overall logistics for a full-scale system.

145 citations


Journal ArticleDOI
TL;DR: In this paper, the long-term impacts of forest fires on climate, new sophisticated tools have recently become available (observational and modeling) to understand the processes involved and the environmental consequences of fires.
Abstract: Fire has a role in ecosystem services; naturally produced wildfires are important for the sustainability of many terrestrial biomes and fire is one of nature's primary carbon-cycling mechanisms. Under a warming climate, it is likely that fire frequency and severity will increase. There is some evidence that fire activity may already be increasing in Western U.S. forests and recent exceptionally intense fire events, such as the Australian Black Saturday fires in 2009 and Russian fires in 2010, highlight the devastation of fires associated with extreme weather. The impacts of emissions from fires on global atmospheric chemistry, and on the atmospheric burden of greenhouse gases and aerosols are recognized although gaps remain in our scientific understanding of the processes involved and the environmental consequences of fires. While significant uncertainty remains in the long-term impacts of forest fires on climate, new sophisticated tools have recently become available (observational and modeling). These t...

141 citations


Journal ArticleDOI
TL;DR: The authors summarize the studies concerning response of growing cells to metals toxicity in terms of growth rate, biomass production, and morphological/structural adaptations along with latest reports involving genomics and proteomics approach to indicate bright potential of metal resistant strains or strains with hormesis phenomenon for field application.
Abstract: Removal of hazardous metals through biological means has received considerable attention in the last few decades. Nevertheless, only a fraction of these studies employed growing microbial cells that harbor multiple mechanisms of metal sequestration and thus may hold greater metal uptake capacities. The authors summarize the studies concerning response of growing cells to metals toxicity in terms of growth rate, biomass production, and morphological/structural adaptations along with latest reports involving genomics and proteomics approach. The studies indicate bright potential of metal resistant strains or strains with hormesis phenomenon for field application. In the second part of the review they focuses on the effect of nutritional conditions and process parameters on metal removal capacities and the performance in simultaneous removal of multiple pollutants. Reports demonstrating effective treatment of actual industrial effluents using growing cells have been summarized. With ample evidence available ...

135 citations


Journal ArticleDOI
TL;DR: In this article, the authors trace new developments and trends on road-deposited sediments (RDS) pollutant characteristics with respect to their distribution in time and space, total and labile fractions in the different particle size and density fractions, source apportionment, and chemical speciation, as well as on the management of the pollutants.
Abstract: Road-deposited sediments (RDS) often contain elevated concentrations of inorganic and organic pollutants such as heavy metals, metalloids, and polycyclic aromatic hydrocarbons. The authors trace new developments and trends on RDS pollutant characteristics with respect to their distribution in time and space, total and labile fractions in the different particle size and density fractions, source apportionment, and chemical speciation, as well as on the management of the pollutants. Recent research provides more reliable information to understand pollutants’ origin, bioavailability, transport pathways, and methods to minimize their risks. Use of special chemical, physical, mineralogical, and statistical methods has contributed to a better understanding of source apportionment of many of the pollutants but more research is needed on others. The degree of accumulation of pollutants in RDS that are derived from roads and vehicles has been quantified by using enrichment factors. Many of the studies on RDS pollu...

113 citations


Journal ArticleDOI
TL;DR: In this paper, a review of conventional and innovative ex situational technologies for soil bioremediation is presented, where the principle of operation and recent applications are reported, and strategies to improve their efficiency are explored.
Abstract: Bioremediation as a sustainable alternative to chemical-physical processes is an attractive solution for soil decontamination and renewal of polluted sites. Depending on the site characteristics and target treatment requirements for the decontaminated soil, in situ or ex situ technologies are employed. Ex situ technologies are advantageous when a safe and effective intervention is required (i.e., in the presence of severe contamination of highly hazardous compounds). In this review, conventional and innovative ex situ technologies for soil bioremediation are presented. For each one the principle of operation and recent applications are reported. In addition, strategies to improve their efficiency are explored. Finally, the possibility of making these technologies more competitive by indicating research needs for their future development is highlighted.

111 citations


Journal ArticleDOI
TL;DR: The fluidized-bed configuration is an efficient way for acid mine drainage remediation due to the high biomass retention, the great resistance to inhibitors, and the possibility to use high organic, sulfate, and metal loading rates at low hydraulic retention times as mentioned in this paper.
Abstract: Acid mine drainage is an important environmental problem related to the release of acidic, sulfate-, and metal-containing wastewater into the environment. Sulfate-reducing bacteria can be used for treating mining wastewaters and recovering metals in several bioreactor configurations. The fluidized-bed configuration is an efficient way for acid mine drainage remediation due to the high biomass retention, the great resistance to inhibitors, and the possibility to use high organic, sulfate, and metal loading rates at low hydraulic retention times. Additional research is needed to assess the removal of the organic rest-pollution and the factors that promote a better metal recovery in single-stage processes.

Journal ArticleDOI
TL;DR: In this article, an extensive list of the production of activated carbon from oil palm biomass is presented, and the effects of various process parameters on the pyrolysis stage, characteristics, and influences of physical and chemical activating conditions on activation conditions are discussed.
Abstract: Commercial activated carbon has been a preferred adsorbent for the removal of various pollutants, and its widespread use is restricted due to its relatively high costs, which led to the researches on the possible alternative nonconventional and low-cost adsorbents. The use of agricultural products and by-products for instance has been widely investigated as a replacement for the current costly methods of removing various pollutants. In this critical review, an extensive list of the production of activated carbon from oil palm biomass is presented. The effects of various process parameters on the pyrolysis stage, characteristics, and influences of physical and chemical activating conditions on the production of activated carbons from oil palm biomass are discussed. A comparison in characteristics and applications of activated carbons from oil palm biomass with commercial activated carbons is made. It is evident from a literature survey of about 200 recently published articles that activated carbons from oi...

Journal ArticleDOI
TL;DR: The authors in this paper reviewed the historical development and current status of recycled water on a global scale with containing the evolvement of wastewater treatment technologies, water quality guidelines, and public attitudes.
Abstract: Recycled water provides a viable opportunity to supplement water supplies as well as alleviate environmental loads. The authors examine the sources of recycled water and discusses various end uses. They focus on reviewing the historical development and current status of recycled water on a global scale with containing the evolvement of wastewater treatment technologies, water quality guidelines, and public attitudes. The authors also illustrate typical case studies of recycled water in a number of countries and regions, including Australia, Asia, the United States, Latin America, Europe, the Middle East, and Africa. These pilot studies can be good examples for the future projects. They identify the good prospects of further expansion and exploration of current and new end uses while emphasizing the integrated water planning and management as well as challenging and tasks in the future.

Journal ArticleDOI
TL;DR: In this paper, the authors review the use of phytoremediation for both inorganic and organic substances and consider the evidence for the applicability of use of plants for the remediation of mixed contaminant sites.
Abstract: Contaminated sites often contain a mixture of different organic and inorganic compounds that necessitate a more complex remediation process. The authors review the use of phytoremediation for both inorganic and organic substances and consider the evidence for the applicability of the use of plants for the remediation of mixed contaminant sites. The literature suggests that the interaction between plant and microbial communities within the rhizosphere is critical to remediation success and the use of diverse communities may further enhance this potential, but a specific understanding of function within the community is required before this can be achieved.

Journal ArticleDOI
TL;DR: The mechanism of nitrous oxide emission during these processes and the specific control strategies are explained or proposed, and several urgent issues and significant perspectives related to these novel pathways and players have been addressed to evoke the involvement of researchers in broadening future studies.
Abstract: Ammonia oxidation is a central step in the global nitrogen cycle that involves several different-conditions and metabolic bioprocesses, including aerobic versus anaerobic ammonia oxidation, and autotrophic versus heterotrophic ammonia oxidation. With the development and application of metagenomics and other modern molecular approaches, some new organisms (particularly ammonia-oxidizing archaea) and novel pathways related to ammonia oxidation have been identified. Consequently, the understanding of nitrogen cycling processes and the microorganisms that mediate them have been greatly improved. Here the authors summarize the biochemistry, microbiology, and ecophysiology of these organisms (including autotrophic ammonia-oxidizing bacteria, heterotrophic nitrifying bacteria, anaerobic ammonia-oxidizing bacteria, and ammonia-oxidizing archaea) and discuss the current knowledge and important concepts associated with their corresponding pathways. Factors influencing their distribution, abundance, community struct...

Journal ArticleDOI
TL;DR: Wang et al. as discussed by the authors analyzed the impacts of vegetation restoration on soil erosion and sediment loads in terms of vegetation cover and vegetation species, and the spatial scale effect of soil erosion reduction benefit resulting from vegetation restoration was elaborated.
Abstract: China has been one of the countries suffering from the most serious soil erosion, which has severely degraded soil productivity and water quality, thus affecting agricultural activities and hindering economic and social development. During the past few decades, a large amount of effort has been made to combat soil erosion. Vegetation restoration as a major strategy is given equal importance compared to engineering measures. Although a measure of success has been achieved, many uncertainties remain unanswered such as to what extent the vegetation restoration has reduced soil erosion and sediment loads especially in large river systems. This paper first analyzes the impacts of vegetation restoration on soil erosion and sediment loads in terms of vegetation cover and vegetation species. Then, the spatial scale effect of soil erosion reduction benefit resulting from vegetation restoration is elaborated. Soil erosion reduction benefit decreases with increased vegetation planting area. In addition, a comprehensive discussion about the disputes between vegetation restoration and engineering measures is made by integrating published studies spanning large spatial and temporal scales. Finally, future research needs regarding vegetation restoration efforts are given. In order to evaluate the effects of vegetation restoration programs on soil erosion, assessments in shorter time interval and larger spatial scale should be undertaken. Further, the present assessment system mainly based on simple statistical methods has to be improved. Specific areas demanding immediate attention, including the western China in general and the upper Yangtze River basin in particular, are highlighted as well. Supplemental materials are available for this article. Go to the publisher's online edition of Critical Reviews in Environmental Science and Technology to view the supplemental file.

Journal ArticleDOI
TL;DR: In this paper, the authors highlight some of the research developments over approximately the last decade regarding pharmacological pollution in water including pollution characterization, analytical methods, removal via water and wastewater treatment plants, wastewater effluent and biosolids applied to agricultural land, environmental impacts, and methods to identify the most consequential PPCPs in terms of potential environmental impact.
Abstract: There has been an increasing awareness among environmental scientists in recent years of the presence and potential impacts of pharmaceuticals and personal care products (“PPCPs”) in environmental compartments including surface water, groundwater, soil, bed sediment, and in tissue. This work highlights some of the research developments over approximately the last decade regarding pharmacological pollution in water including pollution characterization, analytical methods, removal via water and wastewater treatment plants, wastewater effluent and biosolids applied to agricultural land, environmental impacts, and methods to identify the most consequential PPCPs in terms of potential environmental impact. Nonregulatory and regulatory responses are also discussed.

Journal ArticleDOI
TL;DR: In this paper, a comprehensive presentation of recent research into particle emissions from rail vehicles is presented, where both exhaust and nonexhaust particle emissions are considered when examining particle characteristics such as PM10, and PM2.5 concentration levels, size, morphology, composition, and adverse health effects.
Abstract: Particle emissions are a drawback of rail transport. This work is a comprehensive presentation of recent research into particle emissions from rail vehicles. Both exhaust and nonexhaust particle emissions are considered when examining particle characteristics such as PM10, and PM2.5 concentration levels, size, morphology, composition, and adverse health effects, current legislation, and available and proposed solutions for reducing such emissions. High concentration levels in enclosed rail traffic environments are reported and some toxic effects of the particles. The authors find that only a few limited studies have examined the adverse health effects of nonexhaust particle emissions and that no relevant legislation exists. Thus further research in this area is warranted.

Journal ArticleDOI
TL;DR: The authors review the current state of the knowledge in detecting cyanotoxins in the environmental water samples and provides a comparative evaluation of methods ranging from conventional biological and analytical methods to recently advancing molecular and biosensor approaches in terms of their capabilities.
Abstract: Cyanobacterial toxins are considered as an emerging threat to natural water reservoirs and drinking water supplies. When they are ingested, these toxins are responsible for human and animal poisonings. The main goal of water quality monitoring programs is to predict harmful algal blooms and maintain the water quality of drinking water supplies. The current methods used for routine monitoring are not able to detect all the types and variants of cyanotoxins. The authors review the current state of the knowledge in detecting cyanotoxins in the environmental water samples and provides a comparative evaluation of methods ranging from conventional biological and analytical methods to recently advancing molecular and biosensor approaches in terms of their capabilities. In addition, the recent advances made in the area of cyanotoxins detection by molecular methods and biosensor-based technologies are discussed for their practical applications in terms of their use in a total analysis system.

Journal ArticleDOI
TL;DR: In this article, the authors critically assess innovative developments in advanced oxidation, adsorption, biological uptake, and ion exchange for their ability to achieve very low total P concentrations in high-flow systems.
Abstract: Eutrophication caused by excess phosphorus (P) loading poses a serious environmental risk to freshwater bodies around the world. While conventional P-removal technologies often satisfy maximum effluent levels of 1,000 μg-P/l, the resulting environmental P concentrations can still contribute to eutrophication. The challenge remains to achieve low total P levels of ≤ 10 μg-P/l in very large water flows. This issue is often exacerbated by the presence of unreactive organic phosphorus. The authors critically assess innovative developments in advanced oxidation, adsorption, biological uptake, and ion exchange for their ability to achieve very low total P concentrations in high-flow systems. Adsorption appears to have the greatest potential for near-term implementation. Biological uptake and ion exchange show promise based on laboratory-scale research and may be long-term options. Pretreatment using advanced oxidation may be valuable in converting organic P to the more readily removable orthophosphate form.

Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the available information on the content of phytase-labile organic phosphorus in manures and soils, as well as the environmental factors and enzyme properties affecting catalytic behavior of PHytases in these environments, and critically analyzed the present and possible future biotechnological approaches for using phytases to access phytate Po pool present in soils and manures for plant nutrition.
Abstract: Organic phosphorus (Po) hydrolysis by microbial phytases has extensively been considered in diverse biotechnological applications, including environmental protection and agricultural, animal, and human nutrition. The authors review the available information on the content of phytase-labile Po in manures and soils, as well as the environmental factors and enzyme properties affecting catalytic behavior of phytases in these environments. In addition, they have critically analyzed the present and possible future biotechnological approaches for using phytases to access phytate Po pool present in soils and manures for plant nutrition, with the concomitant reduction of runoff P in the environment.

Journal ArticleDOI
TL;DR: In this paper, the authors investigate the sources and processes of groundwater contamination and their assessment within the drivers-pressures-state-Impact-response (DPSIR) framework.
Abstract: The authors investigate the sources and processes of groundwater contamination and their assessment within the Drivers-Pressures-State-Impact-Response (DPSIR) framework Naturally occurring substances, trace elements, radionuclides, nutrients, and salt (sodium chloride) are reviewed with emphasis on the assessment of the natural background load Some synthetic substances are also considered, these being petroleum hydrocarbons, chlorinated aliphatics, pesticides and organic-waste contaminants Newly emerging contaminants cannot be described within the DPSIR; therefore monitoring approaches and indicators of contamination are discussed in order to propose improved monitoring plans that combine physical, chemical and biological indicators and combine science with policy

Journal ArticleDOI
TL;DR: A review of articles published in peer-reviewed scientific journals about lead contamination in China can be found in this article, where the sources of that contamination include (a) deposits from previous emissions of leaded gasoline, which was finally eliminated in the past decade; (b) previous and continuing emissions from fossil fuel combustion, which are increasing markedly with the rapid industrialization of China; (c) previous emissions from other industrial activities, including mining, smelting and municipal waste incineration; and (d) previous additions of contaminated fertilizers, sewage, and untreated wastewater to agricultural
Abstract: Lead contamination in China has been extensively documented by scientists in China and elsewhere over the past two decades, as summarized in this review of articles published in peer-reviewed scientific journals. Sources of that contamination include (a) deposits from previous emissions of leaded gasoline, which was finally eliminated in the past decade; (b) previous and continuing emissions from fossil fuel combustion, which are increasing markedly with the rapid industrialization of China; (c) previous and continuing emissions from other industrial activities, including mining, smelting and municipal waste incineration; and (d) previous and continuing additions of contaminated fertilizers, sewage, and untreated wastewater to agricultural fields. Lead concentrations of some Chinese agricultural produce are also elevated by acid rain and acidic fertilizers, which increase the solubility and bioavailability of both natural and contaminant lead in soil. In addition, some Chinese products are contaminated wi...

Journal ArticleDOI
TL;DR: In this article, the authors classified the methanotrophs into two types, low affinity group and high affinity group, and classified them as Type I and Type II belonging to α-Proteobacteria, respectively.
Abstract: Methane (CH4) is one of the strongest greenhouse gases. Sources of CH4 are anthropogenic and natural, former playing ∼60% role. Major sink for CH4 are the atmospheric OH and Cl radicals (originating from CFCs), and biological system. Biological CH4 sink is mediated through the CH4 oxidation by the specialized group of bacteria called methanotrophs (MB). Methanotrophs have been reported from almost all the soil systems such as sediments, oceans, extremes of pH, salinity, and temperature. They oxidize methane aerobically in the presence of the enzyme methane monooxygenase (MMO). Anaerobic methane oxidation (AOM) also occurs in marine ecosystem where sulfate is final electron acceptor. Methanotrophs are of two types, first is cultured and low affinity group while the second is uncultured and high affinity group. Most of them can be grouped as Type I and Type II belonging to γ- and α-Proteobacteria, respectively. They may constitute up to 2% of total bacterial population in soil depending on physical factors ...

Journal ArticleDOI
TL;DR: In this article, the authors present a holistic view and an in-depth discussion of environmental informatics applied to solid and hazardous waste management from the onset to the present status, and to future trends aiming to advance the management potential.
Abstract: Environmental informatics has experienced extraordinarily rapid progress in the past decade and has made an invaluable contribution to planning, design, and operations for waste management. In many cases, however, the roles of these information technologies have been limited to stand-alone projects without synergistic effects. This article presents a holistic view and an in-depth discussion of environmental informatics applied to solid and hazardous waste management from the onset to the present status, and to future trends aiming to advance the management potential. With regard to building, maintaining, and developing knowledge-based or artificial intelligence systems, the spectrum of environmental informatics for solid and hazardous waste management can be classified into five categories: database system, geographical information system, decision support system, expert system, and integrated environmental information system. Supporting technologies in the integrated environmental information system can ...

Journal ArticleDOI
TL;DR: In this article, the authors review available literature on polymeric potable water pipes in use, known contaminants released from in-service and new piping, and their perceived sources, and outline future challenges in United States and abroad.
Abstract: Polymeric pipes are increasingly being installed in water distribution systems because of their many advantages. Contaminant migration from polymer pipes into drinking water is a growing concern in the United States and environmental engineers are evaluating the role of these materials on water quality, system operation, and regulatory compliance. To aid these efforts and serve as a source of background information, the authors critically review available literature on polymeric potable water pipes in use, known contaminants released from in-service and new piping, and their perceived sources, and outline future challenges in the United States and abroad.

Journal ArticleDOI
TL;DR: In this paper, the authors provide a comprehensive review of the metal mining industry, including the basic mining processes with reasons for mine closure, potential environmental and human health impacts associated with mining, potential techniques for impact mitigation, and the latest production statistics for the base and precious metals with identification of currently operational major metal mines for different countries, and how mining activities are regulated in different nations.
Abstract: With rising valuation of mineral commodities, mining has been envisioned as a profitable industry regardless of many challenges it entails. This comprehensive review provides the state of knowledge about several aspects of the metal mining industry, including (a) the basic mining processes with reasons for mine closure, (b) the potential environmental and human health impacts associated with mining, (c) the potential techniques for impact mitigation, (d) the latest production statistics for the base and precious metals with identification of currently operational major metal mines for different countries, and (e) how mining activities are regulated in different nations. Finally, the authors provide critical appraisal on the debatable issue of mining and sustainability to stimulate thoughts on how metal mining can be made sustainable, and suggest a path forward.

Journal ArticleDOI
TL;DR: In this article, the authors review and evaluate literature dedicated to the preparation of adsorbents such as activated carbon and clays and their modifications/activation by recycling different types of waste materials and also to their application in organic pollutant containing aqueous-phase treatments.
Abstract: A number of industries currently produce varying organic pollutant-laden waste streams, which is a serious environmental prblem owing to their potential human toxicity. Amongst all the treatments proposed, adsorption is one of the more popular methods for the removal of pollutants from wastewater. In particular, considerable work has been carried out on the use of natural materials, nonconventional adsorbents, and their modifications. These natural materials and nonconventional materials in many instances are relatively cheap, abundant in supply, or thrown away as waste and have significant potential for modification that ultimately leads to enhancement of their adsorption capabilities. The authors review and evaluate literature dedicated to the preparation of adsorbents such as activated carbon and clays and their modifications/activation by recycling different types of waste materials and also to their application in organic pollutant containing aqueous-phase treatments. It should be noted that the repo...

Journal ArticleDOI
TL;DR: The author examines the impact of humans on soil using a similar matrix and suggests strategies to improve human health by maintaining or improving soil health.
Abstract: Soils can beneficially or adversely affect human health, and likewise human activity can improve or destroy soil health. In the new anthropogenic era, it is worth examining the soil health–human health nexus. To do this, the author evaluates soil from the perspective of what infects us, what heals us, what contaminates us, what nourishes us, and what we breathe. Likewise, the author examines the impact of humans on soil using a similar matrix and suggests strategies to improve human health by maintaining or improving soil health.

Journal ArticleDOI
TL;DR: In this paper, a review of the synthesis pathways of sulfur-functionalization of chitin and chitosan and their metal uptakes is presented, with a special emphasis placed on the synthesis pathway of sulfur functionalization.
Abstract: Chitosan has low uptake for most heavy metals as well as high solubility in monoprotic acids. To address these problems, sulfur-containing functional groups have been introduced to enhance the sorption of heavy metals via formation of strong coordination bonds with heavy metals and also to improve its stability. The approaches to sulfur enrichment to the chitosan structure include grafting of sulfur-containing molecules to C2 amine or C6 hydroxyl groups. Crosslinking and grafting agents such as glutaraldehyde and epichlorohydrin have also been used in chitosan modification. In this review, special emphasis is placed on the synthesis pathways of sulfur-functionalization of chitin and chitosan and their metal uptakes. Generally, the uptake of soft acid metals such as Hg(II) and Cd(II) has been shown to increase with increasing sulfur content of modified chitosan. However, other factors such as the availability of thiol and amine groups as well as surface area of the modified chitosan also influence metal so...