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The aim of this study is the valorization of the Moroccan clays (QC-MC and QC-MT) from the Middle Atlas region as adsorbents for the treatment of water contaminated by cadmium Cd (II) ions. The physicochemical properties of natural clays are characterized by ICP-MS, XRD, FTIR, and SEM techniques. The adsorption process is investigated as a function of adsorbent mass, solution pH, contact time, temperature, and initial Cd (II) ion concentration. The kinetic investigation shows that the adsorption equilibrium of Cd (II) ions by both natural clays is reached after 30 min for QC-MT and 45 min for QC-MC and fits well to a pseudo-second-order kinetic model. The isotherm study is best fitted by a Freundlich model, with the maximum adsorption capacity determined by the linear form of the Freundlich isotherm being 4.23 mg/g for QC-MC and 5.85 mg/g for QC-MT at 25°C. The cadmium adsorption process was thermodynamically spontaneous and exothermic. The regeneration process showed that these natural clays had excellent recycling capacity. Characterization of the Moroccan natural clays before and after the adsorption process through FTIR, SEM, XRD, and EDX techniques confirmed the Cd (II) ion adsorption on the surfaces of both natural clay adsorbents. Overall, the high adsorption capacity of both natural clays for Cd (II) ions removal compared to other adsorbents motioned in the literature indicated that these two natural adsorbents are excellent candidates for heavy metal removal from aqueous environments. [ABSTRACT FROM AUTHOR]

Shallots have been widely planted as the primary commodity crop in Brebes Regency, Central Java, Indonesia. Information on the distribution of heavy metals in the shallot fields of Brebes Regency, Central Java, Indonesia, is not yet available. Hence, the present study was conducted to identify the concentration and spatial distribution of several heavy metals (Pb, Cd, Co, Cr, and Ni) and their possible sources in the shallot fields through a field survey and a series of laboratory and statistical tests. The total concentration of heavy metals was analyzed from 184 sampling points of the shallot fields in Brebes Regency, Central Java, Indonesia, during the dry season from August to October 2019. The heavy metals concentration was as follows: Cr > Ni > Pb > Co > Cd. The values of total Pb, Cd, Co, Cr, and Ni concentrations in the soils were 7.84–18.94, 0.99–2.31, 3.02–9.98, 10.40–49.55, and 10.17–26.62 mg kg−1, respectively. All these concentration values of heavy metals are still lower than the critical values for agricultural soils and lower than the topsoil background values except Cd. Based on the concentration of heavy metals, the shallot fields in Brebes Regency, Central Java, are classified as uncontaminated soils. Multivariate and geostatistical analyses were employed to determine and describe the metals' origin. Pb, Cr, and Ni mainly originate from a natural source, while Cd and Co are from anthropogenic sources (agricultural practices and industry). [ABSTRACT FROM AUTHOR]

This study was conducted to estimate the heavy metal pollution in groundwater, soil, fruits, and vegetables within the cement industry and its vicinity. Seven different fruits and vegetables and seven heavy metals (Cd, Zn, Ni, Co, Cu, Cr, and Mn) were selected for analysis in soil, groundwater, fruit, and vegetable samples by atomic absorption spectrometry (AAS). Results of this study were compared with the National and International Standards of Pak NSWQD, WHO, and USEPA. The pH of soil and groundwater samples was within limits (WHO and Pak NSDWQ standards are 6.5–8.5). The concentration of Cr and Cu in groundwater samples was above the WHO and Pak NSDWQ standards (Cr = 0.05 ppm; Cu = 2 ppm). Vegetable samples were contaminated with metals except for Ni and Mn, whereas, in fruit samples, Mn and Cd were not present (WHO limit for Mn = 5 ppm). The mean concentration of Ni was high in fruits (WHO limit = 10 ppm), Zn was high in vegetables (WHO limit = 100 ppm), and Cu was high in soil and groundwater (WHO limit for soil = 36 ppm; for groundwater = 2 ppm). The results of daily intake of metals (DIM) for fruits, vegetables, and groundwater were compared with TDI by USEPA and PTDI of the WHO/FAO, and all were within the recommended limits. Calculated BAF for the selected environmental sample, that is, Indian Squash, lime fruit, and so on, was in order of Co > Cr > Cu and THQ; HRI was calculated to estimate the human health risk, and they were in a trend of Ni > Co > Cd > Cr and for HRI Co > Cr. [ABSTRACT FROM AUTHOR]

Industrial solid waste has been widely used as an alternative additive for bituminous material modification. This study aims to evaluate the basic properties and quantify the leaching potential of modified asphalt binders incorporating crumb rubber powder (CRP) from waste tires and tin slag (TS) for a local smelting company. Three percentages of CRP and TS, at 5, 10, and 15%, were considered. The conventional asphalt binder (PEN 60/70), CRP, and TS-based modified asphalt binders were analyzed for toxicity, softening point, penetration value, elastic recovery, torsional recovery (TR), and coatability index. The findings indicated that the addition of the waste materials led to no significant heavy metal content in the asphalt binder mix. Moreover, the basic and physical properties of the asphalt binders were also improved by 5, 10, and 15% of the waste, respectively. However, TS waste exhibited limited effects on all the parameters and had a 5% optimum dosage. The modified binders' results showed that the CRP modified asphalt binders had fewer heavy metals and responded more to elastic recovery and coatability. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs) are a sustainable approach for the remediation of metals and the simultaneous production of energy. This paper highlighted the usage of mango extract to produce electricity as an organic source for bacteria and reduce metal ions from wastewater. The observed results were 51 mV in 15 days with 500 Ω of external resistance. The whole operation was carried out at room temperature. The observed current and power density were 28.947 mA/m2 and 0.972 mW/m2, respectively. The internal resistance was 150 Ω, which is lower than external resistance. The remediation performance varied with the metal ions as follows: Pb (II) shows 75%, Cd (II) shows 74.11%, and Cr (III) shows 80.50%. Finally, the detailed working mechanism of the present study, MFC challenges, and future research directions are covered in this paper. [ABSTRACT FROM AUTHOR]

21 sampling points were set in the West Lake of Hengshui Lake including 20 fish ponds and 1 natural pond to analyze the contents distribution of heavy metal elements including Cr, Zn, Pb, Cu, Cd, Hg, As, and Sb in sediment. The degree of heavy metal pollution was evaluated by the geoaccumulation index (Igeo) method. The results showed that the concentrations of Cr, Zn, Pb, Cu, Cd, and Hg at in all sampling points of the fish ponds were lower than soil risk screening values of agricultural land in soil environmental quality: risk control standard for soil contamination of agricultural land (trial) (GB 15618-2018). The concentrations of As at 5 sampling points were higher than soil risk screening values and lower than soil risk control values of agricultural land in GB 15618-2018. The concentrations of Sb were lower than soil risk screening values of construction land in soil environmental quality: risk control standard for soil contamination of development land (trial) (GB 36600-2018). The evaluation results of the geoaccumulation index method showed that the pollution degrees of Cd, Pb, and Hg were moderately contaminated in general, the pollution degree of Cu was uncontaminated to moderately contaminated in general, the pollution degrees of Cr and As were uncontaminated to moderately contaminated in some sampling points, and Zn and Sb could be regarded as uncontaminated in sediment of the fish ponds in the West Lake of Hengshui Lake. Otherwise, the average contents of other heavy metal elements in sediment of the fish ponds in the West Lake of Hengshui Lake were higher than the background value of soil in Hebei Province (BVSH) except for Zn and Sb. The average contents of seven heavy metal elements in sediment of the natural pond in the West Lake of Hengshui Lake were lower than BVSH except for Cr. The result can be regarded as no pollution in the natural pond because the values of Igeo were all lower than 0. The heavy metal pollution in the sediment of the West Lake of Hengshui Lake may be due to the introduction of feeding. The water environment of the West Lake of Hengshui Lake can be effectively improved by cleaning up the sediment of fish ponds and "returning fishing to wetland." [ABSTRACT FROM AUTHOR]

Ethylenediaminetetraacetic acid (EDTA) is one of the most popular chelating agents. This study was conducted to investigate the effect of EDTA on the growth and health physiology of beluga (38.47 ± 0.58 g) before and after heavy metal stress (HMS). Five experimental diets, including control, 0.5EDTA, 1EDTA, 1.5EDTA and 2EDTA, were formulated to feed fish for eight weeks. The results showed that fish was fed with dietary 1.5EDTA (108.37 g) had a higher weight gain as compared with control (p < 0.05). Blood performance in the control group after HMS decreased but not in fish fed supplemented diets with EDTA. EDTA reduced uric acid and creatinine levels in beluga. Fish fed dietary 1.5EDTA had a higher value of blood performance (55.17), glucose (50.3 mg/dl), superoxide dismutase (SOD U/ml) (75.8) and glutathione peroxidase (234.0 U/ml) after HMS as compared with the control. Additionally, lower values of uric acid (3.05 mg/dl), creatinine (0.27 mg/dl) and AST (61.47 U/ml) after HMS in the 1.5EDTA group were observed (p < 0.05). Correlation analysis revealed a strong positive correlation between EDTA level and protein efficiency, lipid efficiency, and blood performance and a strong negative correlation with some parameters after stress, including SOD, glucose, uric acid, creatinine and aspartate transaminase (p < 0.01). In conclusion, feeding fish with the 1.5EDTA diet improved growth and detoxified heavy metals. [ABSTRACT FROM AUTHOR]

Polychaetes are multi‐segmented worms, being exploited from the backwaters for shrimp hatcheries to be used as a maturation diet for shrimp broodstocks. Non‐selective collection of polychaete worms poses a severe hazard to the ecosystem; hence, a grow‐out system was developed for Marphysa gravelyi. Adult, M. gravelyi of 17 ± 0.4 cm length (n = 40) when reared in 100 L tanks, produced 1800 numbers of juveniles having an average length of 7 ± 0.2 cm with 80% survival in 4 months. The juveniles (7 ± 0.2 cm (n = 50) worms were reared again in 25 L tubs from which 45 adults (20 ± 0.3 cm) could be produced in 4 months with 90% survival. Juvenile, M. gravelyi (n = 500) when mass‐reared in 1000 L FRP tanks by feeding Skeletonema costatum (106​ CFU/ml), produced 400 adults (20 ± 0.2 cm) as biomass with 80% survival in 4 months. The nutrient profile of adult M. gravelyi revealed protein, carbohydrate and lipid to be 33, 14 and 40 g % respectively. Crude M. gravelyi extract showed the highest bacterial inhibition on Staphylococcus aureus (18 ± 0.3 mm) and lowest on Bacillus subtilis (14 ± 0.2 mm). The present study revealed that growing polychaete worms in a controlled condition is advantageous, compared to collection of polychaete worms from wild which might seriously deplete their natural stocks, and cause physical disturbance of soil exposing heavy metals with the release of ammonia, and phosphorus compounds leading to eutrophication. [ABSTRACT FROM AUTHOR]

In the present study, an electronic tongue (e‐tongue) system based on cyclic voltammetry (CV) with three electrodes (pencil graphite (PG), screen printed (SP), and glassy carbon (GC)) was fabricated to investigate and detect heavy metals, such as cadmium (Cd), lead (Pb), tin (Sn), and nickel (Ni) (at three concentrations of 0.05, 0.1, and 0.25 ppm) in sunflower edible oil. The results from cyclic voltammograms showed that GC, PG, and SP electrodes have the highest cathodic current peaks and show higher sensitivity to the presence of heavy metals in sunflower edible oil, respectively. Moreover, the principal component analysis method was used to classify heavy metals. The obtained results showed that the three intended electrodes were capable of well detecting data. Overall, PG, SP, and GC electrodes account for 84%, 98%, and 88% of the variance between data, respectively. Additionally, a support vector machine (SVM) and K‐nearest neighbor (K‐NN) were used for classification. High accuracies were obtained for the PG, SP, and GC electrodes. Besides, The K‐NN method combined with the intended electrodes could well perform classification, and GC was the best electrode. In the following, the partial least square method could predict data for PG, SP, and GC electrodes with an accuracy of 98%, 99%, and 81%, respectively. Finally, it can be said that the fabricated e‐tongue combined with chemometric methods could classify heavy metals, in edible oil with high accuracy. Practical applications: In this research, an e‐tongue system was developed based on three electrodes (PG, SP, and GC) to identify heavy metals in sunflower edible oil using chemometric methods. According to results, e‐tongue combined with chemometric method has high ability for food quality monitoring. [ABSTRACT FROM AUTHOR]

This article, titled "Retracted: A Brief Review on Heavy Metal Bioaccumulation Studies from Red Sea," has been retracted by Hindawi due to evidence of systematic manipulation of the publication process. The investigation revealed discrepancies in scope, description of the research, availability of data, inappropriate citations, and incoherent or irrelevant content. Hindawi cannot vouch for the reliability of the article's content. Wiley and Hindawi have implemented additional measures to ensure research integrity. The corresponding author has been given the opportunity to respond to the retraction. [Extracted from the article]

The article titled "Effects of Free Amino Acids, Metallothionein, and Chemical Forms of Heavy Metals on the Accumulation and Detoxification of Cadmium and Chromium in Chinese Goldthread (Coptis chinensis Franch.)" has been retracted by Hindawi due to evidence of systematic manipulation of the publication process. The investigation revealed discrepancies in scope, description of the research, availability of data, inappropriate citations, incoherent content, and compromised peer review. Hindawi acknowledges that the usual quality checks did not identify these issues before publication and has implemented additional measures to ensure research integrity. The corresponding author has been given the opportunity to respond to the retraction. [Extracted from the article]

This article, titled "Heavy Metal Removal from Aqueous Effluents by TiO2 and ZnO Nanomaterials," has been retracted by the publisher, Hindawi, due to evidence of systematic manipulation of the publication and peer-review process. The publisher cannot vouch for the reliability or integrity of the article. Wiley and Hindawi have implemented additional measures to safeguard research integrity. The corresponding author has been given the opportunity to respond to the retraction. [Extracted from the article]

Hydroxyapatite (HAP) was a highly efficient decontamination material for its strong adsorption capacity used in the immobilization of heavy metals, while the particle-size effect was insufficiently investigated during the sorption process. In the present study, the mechanisms of nickel (Ni(II)) adsorption on HAPs with two different particle sizes were investigated by combing batch experiments, desorption, and XRD analysis. The results showed that the adsorption capacity of 20 nm HAP (nano-HAP) was much higher than that of 12 μ m HAP (micro-HAP). It was noticed that the results of the present study also clarified the distinct mechanisms in each adsorption process. As for micro-HAP, Ni2+ adsorbed through slow diffusion and replacement with Ca2+ and then incorporated in the lattice at pH between 6.5 and 9.0, which was confirmed by the results of kinetics, thermodynamics, and desorption. And a more compact crystalline structure and irreversible desorption behavior of micro-HAP after Ni(II) adsorption was confirmed by results of XRD and desorption isotherms, respectively. At pH > 9.0 , lattice incorporation and precipitation controlled together. However, for nano-HAP, the sharp increase of Ni(II) adsorption and ionic strength dependent at pH 6.5 to 9.0 revealed that the dominant mechanisms were ionic exchange and inner-sphere complexation. XRD results showed that characteristic peaks of cassidyite appeared in Ni(II)-loading nano-HAP. At pH > 9.0 , a precipitate of Ni(II) was the dominant mechanism. The experimental finds demonstrated that nanoscale HAP was a more fast, efficient, and desorbable adsorbent than micro-HAP for Ni(II) removal. These findings would be favorable for investigating the removal mechanisms of heavy metals on the HAP materials and designing the synthesis methods. [ABSTRACT FROM AUTHOR]