Remediation Of Heavy Metal Pollution Research Articles

Contamination Characteristics and Source Apportionment of Heavy Metal in the Topsoil of a Small Watershed in South Taihang

With the rapid development of industrialization and urbanization, the issue of soil environmental pollution is becoming more and more prominent, especially concerning heavy metal contamination, which has garnered significant scholarly attention. The surface watershed formed by waterline is influenced by various factors such as topography, industrial emissions, and agricultural runoff, resulting in a complex process of migration and accumulation of heavy metal elements from multiple sources. In this study, the pollution characteristics and sources of heavy metal elements Hg, As, Pb, Ni, Cd, Cr, Cu and Zn in 165 surface soil samples from the Manghe River watershed in Jiyuan City were comprehensively analyzed using a variety of methods, including statistics, geostatistics, enriched factor analysis and the Positive Matrix Factorization Model (PMF). The results showed that the concentrations of Hg, Cd, As, Cu, Pb and Zn exceeded their corresponding background values with varying degrees of enrichment. Notably, the average contents of Cd, Hg and Pb were 26.70 times, 3.69 times and 4.49 times higher than those in Chinese soils on average, respectively, showing obvious enrichment characteristics. Moreover, there were distinct spatial distribution patterns for each heavy metal element; Ni and Cr exhibited similar trends mainly controlled by the parent material, while human activities significantly affect the other six elements forming high-value areas around mining and related industries. It is noteworthy that Cu, Hg and Zn were influenced by dominant wind direction in autumn and winter, forming sub-high-value zones in southern forested areas; meanwhile, Cu and Zn were also influenced by agricultural fertilizer application as well as surface runoff, leading to secondary high-value areas in the dryland areas. Further analysis revealed a significant positive correlation among these heavy metal elements, suggesting that they may share common sources. Through the PMF Model, four main factors were identified, with factor 2 (36.25%), factor 1 (23.00%), factor 3 (21.20%) and factor 4 (19.55%) ranked in descending order of contribution rate. The heavy metal pollution in the study area was attributed to anthropogenic activities and natural factors, accounting for 63.75% and 36.25%, respectively. Coal mining, chemical industry smelting, vehicle emissions and excessive use of agrochemicals were identified as the main sources of heavy metal pollution. These pollutants entered the soil through direct emissions, atmospheric deposition, transportation and agricultural activities, exerting a significant impact on the soil environment. Therefore, delving into the spatial distribution pattern of soil heavy metal pollution and precise analysis of its sources are of great importance for effective treatment and remediation of soil heavy metal pollution in small watersheds, maintaining healthy soil ecology and safeguarding human health.

Adsorption of Cd2+ by Lactobacillus plantarum Immobilized on Distiller's Grains Biochar: Mechanism and Action.

Immobilized microbial technology has recently emerged as a prominent research focus for the remediation of heavy metal pollution because of its superior treatment efficiency, ease of operation, environmental friendliness, and cost-effectiveness. This study investigated the adsorption characteristics and mechanisms of Cd2+ solutions by Lactobacillus plantarum adsorbed immobilized on distiller's grains biochar (XIM) and Lactobacillus plantarum-encapsulated immobilized on distiller's grains biochar (BIM). The findings reveal that the maximum adsorption capacity and efficiency were achieved at a pH solution of 6.0. Specifically, at an adsorption equilibrium concentration of cadmium at 60 mg/L, XIM and BIM had adsorption capacities of 8.40 ± 0.30 mg/g and 12.23 ± 0.05 mg/g, respectively. BIM demonstrated noticeably greater adsorption capacities than XIM at various cadmium solution concentrations. A combination of isothermal adsorption modeling, kinetic modeling, scanning electron microscopy-energy dispersive X-ray spectroscopy, X-ray diffractometer (XRD), and Fourier-transform infrared spectroscopy (FTIR) analyses showed that cadmium adsorption by XIM primarily involved physical adsorption and pore retention. In contrast, the adsorption mechanism of BIM was mainly attributed to the formation of Cd(CN)2 crystals.

Sustainable Remediation of Soil and Water Utilizing Arbuscular Mycorrhizal Fungi: A Review.

Phytoremediation is recognized as an environmentally friendly technique. However, the low biomass production, high time consumption, and exposure to combined toxic stress from contaminated media weaken the potential of phytoremediation. As a class of plant-beneficial microorganisms, arbuscular mycorrhizal fungi (AMF) can promote plant nutrient uptake, improve plant habitats, and regulate abiotic stresses, and the utilization of AMF to enhance phytoremediation is considered to be an effective way to enhance the remediation efficiency. In this paper, we searched 520 papers published during the period 2000-2023 on the topic of AMF-assisted phytoremediation from the Web of Science core collection database. We analyzed the author co-authorship, country, and keyword co-occurrence clustering by VOSviewer. We summarized the advances in research and proposed prospective studies on AMF-assisted phytoremediation. The bibliometric analyses showed that heavy metal, soil, stress tolerance, and growth promotion were the research hotspots. AMF-plant symbiosis has been used in water and soil in different scenarios for the remediation of heavy metal pollution and organic pollution, among others. The potential mechanisms of pollutant removal in which AMF are directly involved through hyphal exudate binding and stabilization, accumulation in their structures, and nutrient exchange with the host plant are highlighted. In addition, the tolerance strategies of AMF through influencing the subcellular distribution of contaminants as well as chemical form shifts, activation of plant defenses, and induction of differential gene expression in plants are presented. We proposed that future research should screen anaerobic-tolerant AMF strains, examine bacterial interactions with AMF, and utilize AMF for combined pollutant removal to accelerate practical applications.

Modification of Yarrowia lipolytica via metabolic engineering for effective remediation of heavy metals from wastewater

With the increasing demand for heavy metals due to the advancement of industrial activities, large proportions of heavy metals have been discharged into aquatic ecosystems, causing serious harm to human health and the environment. Existing physical and chemical methods for recovering heavy metals from wastewater encounter challenges, such as low efficiency, high processing costs, and potential secondary pollution. In this study, we developed a novel approach by engineering the endogenous sulphur metabolic pathway of Yarrowia lipolytica, providing it with the ability to produce approximately 550 ppm of sulphide. Subsequently, sulphide-producing Y. lipolytica was used for the first time in heavy metal remediation. The engineered strain exhibited a high capacity to remove various heavy metals, especially achieving over 90 % for cadmium (Cd), copper (Cu) and lead (Pb). This capacity was consistent when applied to both synthetic and actual wastewater samples. Microscopic analyses revealed that sulphide-mediated biological precipitation of metal sulphides on the cell surface is responsible for their removal. Our findings demonstrate that sulphide-producing yeasts are a robust and effective bioremediation strategy for heavy metals, showing great potential for future heavy metal pollution remediation practices.

Peptides Used for Heavy Metal Remediation: A Promising Approach.

In recent years, heavy metal pollution has become increasingly prominent, severely damaging ecosystems and biodiversity, and posing a serious threat to human health. However, the results of current methods for heavy metal restoration are not satisfactory, so it is urgent to find a new and effective method. Peptides are the units that make up proteins, with small molecular weights and strong biological activities. They can effectively repair proteins by forming complexes, reducing heavy metal ions, activating the plant's antioxidant defense system, and promoting the growth and metabolism of microorganisms. Peptides show great potential for the remediation of heavy metal contamination due to their special structure and properties. This paper reviews the research progress in recent years on the use of peptides to remediate heavy metal pollution, describes the mechanisms and applications of remediation, and provides references for the remediation of heavy metal pollution.

Molecular Basis of Energy Crops Functioning in Bioremediation of Heavy Metal Pollution

Heavy metal pollution is a gradually growing environmental issue that hinders the growth and development of plants, and also destabilizes soil. Consequently, eco-friendly phytoremediation methods have gained traction, with energy crops emerging as a particularly effective solution. Energy crops not only provide high-quality plant materials for detoxification and remediation of heavy metal pollution, but also possess energy properties conducive to biofuel production. Therefore, this paper delves into the tolerance mechanism of energy crops towards heavy metal toxicity, elucidating processes such as root complex-mediated inhibition of metal migration and response to reactive oxygen species (ROS) through heavy metal-related proteins, enzyme systems, reactive nitrogen species (RNS), and hormones. Moreover, it summarizes the heavy metals remediation mechanisms of energy crops, including uptake, translocation, chelation, immobilization, and sequestration. This paper explores applications of energy crops in heavy metal pollution remediation, emphasizing the methods for efficient biochar remediation and biofuel generation. Furthermore, potential challenges in using energy crops for heavy metal pollution remediation are outlined. By systematically examining the function mechanisms and prospective applications of energy crops in heavy metal pollution bioremediation, this paper serves as a valuable reference for both research and practical implementation in this field.

Exploring the mechanism of removing Cd from polluted soil using electrochemical leaching with straw carbon film electrode

The study presents a novel approach to remediating heavy metal-contaminated soil using electrochemical technology and chemical leaching. The researchers developed a new electrode material from waste straw and an environmentally friendly leaching agent using straw fermentation liquid. Combining electrochemical technology with chemical leaching provides a powerful remediation solution for heavy metal-contaminated soil, demonstrating efficiency and thoroughness. However, challenges include developing recyclable electrode materials and environmentally friendly leaching agents. This study addresses these challenges by pioneering a biochar-based electrode material and an eco-friendly leaching agent. Waste straw undergoes pyrolysis at 1000 °C to produce a conductive biochar, which is then combined with ethyl cellulose to form a film, creating biochar electrode materials. The developed straw fermentation solution, an environmentally friendly leaching agent, is used for Cd-contaminated soil remediation through combined electrochemical-chemical leaching. Results show soil Cd removal efficiency peaking at 59.5% with a singular chemical leaching agent. The combined method increases the Cd removal rate to a maximum of 91%. Furthermore, the study elucidate the potential mechanism of cadmium removal through techniques such as XRD, SEM, and infrared spectroscopy. To evaluate the efficacy of our approach, the study conducted Chinese cabbage pot-cultivation experiments. Remarkably, the physicochemical properties of soil remained largely unchanged after the reaction, while Chinese cabbage growth in treated soil surpassed that of the control group. This study not only removes Cd from the soil, reducing secondary pollution, but also establishes electrode recyclability, offering a prospective solution for large-scale soil heavy metal pollution remediation.

Physiological and transcriptomic analyses reveal the cadmium tolerance mechanism of Miscanthus lutarioriparia.

Miscanthus lutarioriparia is a promising energy crop that is used for abandoned mine soil phytoremediation because of its high biomass yield and strong tolerance to heavy metals. However, the biological mechanism of heavy metal resistance is limited, especially for applications in the soil restoration of mining areas. Here, through the investigation of soil cadmium(Cd) in different mining areas and soil potted under Cd stress, the adsorption capacity of Miscanthus lutarioriparia was analyzed. The physiological and transcriptional effects of Cd stress on M. lutarioriparia leaves and roots under hydroponic conditions were analyzed. The results showed that M. lutarioriparia could reduce the Cd content in mining soil by 29.82%. Moreover, different Cd varieties have different Cd adsorption capacities in soils with higher Cd concentration. The highest cadmium concentrations in the aboveground and belowground parts of the plants were 185.65 mg/kg and 186.8 mg/kg, respectively. The total chlorophyll content, superoxide dismutase and catalase activities all showed a trend of increasing first and then decreasing. In total, 24,372 differentially expressed genes were obtained, including 7735 unique to leaves, 7725 unique to roots, and 8912 unique to leaves and roots, which showed differences in gene expression between leaves and roots. These genes were predominantly involved in plant hormone signal transduction, glutathione metabolism, flavonoid biosynthesis, ABC transporters, photosynthesis and the metal ion transport pathway. In addition, the number of upregulated genes was greater than the number of downregulated genes at different stress intervals, which indicated that M. lutarioriparia adapted to Cd stress mainly through positive regulation. These results lay a solid foundation for breeding excellent Cd resistant M. lutarioriparia and other plants. The results also have an important theoretical significance for further understanding the detoxification mechanism of Cd stress and the remediation of heavy metal pollution in mining soil.

Iron-based materials functionalized with carbon and phosphorus recovered from sludge enhanced the formation of stable minerals to passivate lead and chromium in wastewater and soil

The bioaccumulation and toxicity of heavy metals are serious threats to human activities and ecological health. The exploitation of environmentally friendly passivated materials is major importance for the remediation of heavy metal contaminated soil. This research developed a new type of environmental functional material with a core-shell structure, which is an iron-based material functionalized with phosphorus and carbon from sludge for heavy metal pollution remediation. The results indicated that the C/P@Fe exhibits excellent heavy metal removal ability, and the maximum removal rates of the two heavy metals in simulated wastewater could reach 100% under optimum reaction conditions. It also effectively converts the labile Cr/Pb into the stable fraction after 28 days of incubation, which increased the maximum residual fraction percentage of Cr and Pb by 32.43% and 160% in soil. Further analysis found that the carbon layer wrapped around the iron base could improve the electron transport efficiency of reducing iron, phosphorus and ferrum could react with heavy metal ions to form stable minerals, such as FeCr2O4, FeO·Cr2O3, Pb5(PO4)3OH, PbCO3, 2PbCO3·Pb(OH)2 and PbS, after reacting with C/P@Fe. The study demonstrated that the Iron-based materials functionalized with carbon and phosphorus from sludge provided a more efficient way to remove heavy metals.

Research Progress in Remediation of Heavy Metal Pollution in Lead-zinc Mines by Phosphorous-based Materials

Research Progress in Remediation of Heavy Metal Pollution in Lead-zinc Mines by Phosphorous-based Materials

Synergistically Effect of Heavy Metal Resistant Bacteria and Plants on Remediation of Soil Heavy Metal Pollution

Synergistically Effect of Heavy Metal Resistant Bacteria and Plants on Remediation of Soil Heavy Metal Pollution

Phosphate-solubilizing bacteria improve the antioxidant enzyme activity of Potamogeton crispus L. and enhance the remediation effect on Cd-contaminated sediment

Phosphorus-solubilizing bacteria (PSB) assisted phytoremediation of cadmium (Cd) pollution is an effective method, but the mechanism of PSB-enhanced in-situ remediation of Cd contaminated sediment by submerged plants is still rare. In this study, PSB (Leclercia adecarboxylata L1–5) was inoculated in the rhizosphere of Potamogeton crispus L. (P. crispus) to explore the effect of PSB on phytoremediation. The results showed that the inoculation of PSB effectively improved the Cd extraction by P. crispus under different Cd pollution and the Cd content in the aboveground and underground parts of P. crispus all increased. The μ-XRF images showed that most of the Cd was enriched in the roots of P. crispus. PSB especially showed positive effects on root development and chlorophyll synthesis. The root length of P. crispus increased by 51.7 %, 80.5 % and 74.2 % under different Cd pollution, and the Ca/Cb increased by 38.9 %, 15.2 % and 8.6 %, respectively. Furthermore, PSB enhanced the tolerance of P. crispus to Cd. The contents of soluble protein, MDA and H2O2 in 5 mg·kg−1 and 7 mg·kg−1 Cd content groups were decreased and the activities of antioxidant enzymes were increased after adding PSB. The results showed that the application of PSB was beneficial to the in-situ remediation of submerged plants.

Lanthanum(III) − 2,5 − Pyrazinedicarboxylate framework as an antibacterial adsorbent for highly efficient and selective capture of Pb(II) and Cd(II) from wastewater

Removing heavy metal ions and microorganisms from wastewater remains a persistent challenge in wastewater treatment. The development of a novel metal–organic framework (MOF), synthesized from 2,5-pyrazine-dicarboxylic acid and lanthanide (La(III), Ce(III), Pr(III)), targeting the concurrent remediation of heavy metal and bacterial pollutants in wastewater. La-PzDC demonstrated remarkable efficacy in removing Pb(II) and Cd(II), achieving maximum adsorption capacities of 697.72 mg g−1 and 398.26 mg g−1, respectively. La-PzDC achieved rapid adsorption equilibria—within 10 min for Pb(II) and 20 min for Cd(II), and conformed to the pseudo-second-order kinetics and Langmuir isotherm models. La-PzDC captured Pb(II) and Cd(II) from actual wastewater, and its residual levels met the relevant wastewater discharge standards. La-PzDC also exhibited excellent reusability and selectivity for Pb(II) and Cd(II). The adsorption mechanism through spectroscopic analysis and density functional theory (DFT) calculations, pinpointing coordination with oxygen and nitrogen-containing groups as a key factor. Significantly, La-PzDC achieves nearly 99 % bacterial elimination against E. coli and S. aureus. The above results indicated that La-PzDC has high selectivity, rapid removal capacity and excellent antibacterial activity, offering a new strategy for the dual challenge of heavy metal and bacterial contamination in wastewater treatment.

Machine learning-based prediction and experimental validation of heavy metal adsorption capacity of bentonite

As a natural adsorbent material, bentonite is widely used in the field of heavy metal adsorption. The heavy metal adsorption capacity of bentonite varies significantly in studies due to the differences in the properties of bentonite, solution, and heavy metal. To achieve accurate predictions of bentonite's heavy metal adsorption capacity, this study employed six machine learning (ML) regression algorithms to investigate the adsorption characteristics of bentonite. Finally, an eXtreme Gradient Boosting Regression (XGB) model with outstanding predictive performance was constructed. Explanation analysis of the XGB model further reveal the importance and influence manner of each input feature in predicting the heavy metal adsorption capacity of bentonite. The feature categories influencing heavy metal adsorption capacity were ranked in order of importance as adsorption conditions > bentonite properties > heavy metal properties. Furthermore, a web-based graphical user interface (GUI) software was developed, facilitating researchers and engineers to conveniently use the XGB model for predicting the heavy metal adsorption capacity of bentonite. This study provides new insights into the adsorption behaviors of bentonite for heavy metals, offering guidance and support for enhancing its application efficiency and addressing heavy metal pollution remediation.

Plant growth-promoting bacteria improve the Cd phytoremediation efficiency of soils contaminated with PE–Cd complex pollution by influencing the rhizosphere microbiome of sorghum

Composite pollution by microplastics and heavy metals poses a potential threat to the soilplant system and has received increasing attention. Plant growth-promoting bacteria (PGPB) have good application potential for the remediation of combined microplastic and heavy metal pollution, but few related studies exist. The present study employed a pot experiment to investigate the effects of inoculation with the PGPB Bacillus sp. SL-413 and Enterobacter sp. VY-1 on sorghum growth and Cd accumulation under conditions of combined cadmium (Cd) and polyethylene (PE) pollution. Cd+PE composite contamination led to a significant reduction in sorghum length and biomass due to increased toxicity. Inoculation with Bacillus sp. SL-413 and Enterobacter sp. VY-1 alleviated the stress caused by Cd+PE complex pollution, and the dry weight of sorghum increased by 25.7% to 46.1% aboveground and by 12.3% to 45.3% belowground. Bacillus sp. SL-413 and Enterobacter sp. VY-1 inoculation increased the Cd content and accumulation in sorghum and improved the phytoremediation efficiency of Cd. The inoculation treatment effectively alleviated the nutrient stress caused by the reduction in soil mineral nutrients due to Cd+PE composite pollution. The composition of the soil bacterial communities was also affected by the Cd, Cd+PE and bacterial inoculation treatments, which affected the diversity of the soil bacterial communities. Network analyses indicated that bacterial inoculation regulated the interaction of rhizospheric microorganisms and increased the stability of soil bacterial communities. The Mantel test showed that the changes in the soil bacterial community and function due to inoculation with Bacillus sp. SL-413 and Enterobacter sp. VY-1 were important factors influencing sorghum growth and Cd remediation efficiency. The results of this study will provide new evidence for the research on joint plantmicrobe remediation of heavy metal and microplastic composite pollution.

In Situ Construction of a Type II Heterojunction UiO/BMO‐x for Improving the Photocatalytic Reduction of Cr (VI)

AbstractPhotocatalytic reduction of Cr(VI) to Cr(III) is one of the most promising technologies to remove Cr(VI) pollution because of its environmental friendliness, cost‐effective and energy saving. In this experiment, two‐dimensional Bi2MoO6(BMO) nanosheets and cerium‐based MOFs UiO‐66(Ce) were synthesized by solvent thermal method, and in the presence of BMO, the UiO/BMO‐x heterojunction composites were constructed in situ to explore its photocatalytic reduction properties of Cr(VI). The experiment showed that 4 mM of Cr (VI) solution could be reduced 100 % to Cr (VI) by 15 mg catalyst under optimal reaction conditions. The composite photocatalyst prepared in this experiment can realize the green treatment of Cr(VI) in the environment under photocatalytic conditions, and has potential application value in the remediation of heavy metal pollution.

Effects of heavy metal contamination on fungal diversity in Pinus brutia shoots

The effects of heavy metal pollution have become a significant global issue in recent years. The primary objective of the present study was to compare the heavy metal concentrations in Pinus brutia shoots grown in an organized industrial zone (OIZ) and a forested area (Adalar) and to examine how these heavy metals affect fungal microbiota. The results achieved here showed that Ni and V concentrations were lower than the detectable limits in both the Adalar and the OIZ region, whereas Se and Cu concentrations were lower than the detectable limits in the shoots collected from the Adalar. Concentrations determined in samples collected from the OIZ were approximately 6 times higher for Cr and 16 times higher for Zn in comparison to the samples collected from the Adalar. Metagenomic analysis revealed that the most common fungal genera were Aureobasidium, Gibberella, Hazslinszkyomyces, Alternaria, Cladosporium, Buckleyzyma, Lasiodiplodia, and Hormonema for the OIZ area and Hormonema, Aureobasidium, Alternaria, Cladosporium, Arthrinium, Fonsecazyma, and Truncatella for the Adalar region. In the future, this study may serve as a reference for the development of innovative strategies for the remediation of heavy metal pollution for a sustainable and clean environment using biological sources.

Study on The Transport and Transformation of Heavy Metal Lead from Agricultural Land in An Abandoned Mining Area in Southwestern Yunnan

In this paper, the heavy metals in the agricultural land around an abandoned mine in southwest Yunnan Province were taken as the object of study, 15 samples of topsoil, middle soil and deep soil were collected, and 5 maize plants were randomly selected in the soil sampling points to study the migration and transformation of heavy metal lead in the soil-maize system in the agricultural land around the abandoned mine. The results showed that the soils in the study area were enriched with heavy metal Pb, which was generally expressed as surface soil > middle soil > deep soil; the migration capacity of heavy metal Pb in different organs of maize: roots > leaves > stems and kernels. The results of the study can be used as a basis for judging the migration and transformation of heavy metals in soil-crop systems, providing new theoretical support for the migration of heavy metals in soils around abandoned mining areas, and promoting the ecological remediation of heavy metal pollution in agricultural land.

The effects of different electrode materials on the electric field-assisted co-composting system for the soil remediation of heavy metal pollution

The electric field-assisted composting system (EACS) is an emerging technology that can enhance composting efficiency, but little attention has been given to electrode materials. Herein, an EACS was established to investigate the effects of electrode materials on humic substance formation and heavy metal speciation. Excitation-emission matrix analysis showed that carbon-felt and stainless-steel electrodes increased humic acid (HA) by 48.57 % and 47.53 %, respectively. In the EACS with the carbon-felt electrode, the bioavailability factors (BF) of Cu and Cr decreased by 18.00 % and 7.61 %, respectively. Despite that the stainless-steel electrodes decreased the BF of As by 11.26 %, the leaching of Cr, Ni, Cu, and Fe from the electrode itself is an inevitable concern. Microbial community analyses indicated that the electric field increased the abundance of Actinobacteria and stimulated the multiplication of heavy metal-tolerant bacteria. Redundancy analysis indicates that OM, pH, and current significantly affect the evolution of heavy metal speciation in the EACS. This study first evaluated the metal leaching risk of stainless-steel electrode, and confirmed that carbon-felt electrode is environment-friendly material with high performance and low risk in future research with EACS.

An environmentally friendly strategy for reducing the environmental risks of heavy metals adsorbed by kaolinite

Plenty of heavy metals (HMs) that are adsorbed on clay minerals (such as kaolinite), in addition to low molecular-weight organic acids (such as oxalic acid (OA)) with high activities, are widespread in the natural environment. In the present study, the effects of OA on the environmental behaviors of Pb2+/Cd2+ adsorbed by kaolinite have been investigated. The effectiveness and mechanisms of calcium silicate (CS) and magnesium silicate (MS) in reducing the environmental risks of the HMs have also been studied. The results showed that the releases of Pb2+/Cd2+ increased with an increasing concentration of OA. When different dosages of CS/MS were added to the aging system, a redistribution of HMs took place and the free form of Pb2+/Cd2+ decreased to very low levels. Also, the unextractable Pb2+/Cd2+ increased to high levels. Furthermore, a series of characterizations showed that the released HMs were re-captured by the CS/MS. In addition, the CS immobilized the OA in the solution during the aging process, which also facilitated an immobilization of the carbon element in the environment. In general, the present study has contributed to a further understanding of the transport behaviors of the HMs in natural environments, and of the interactions between CS (or MS), the environmental media, and the heavy metal contaminants. In addition, this study has also provided an eco-friendly strategy for an effective remediation of heavy metal pollution.