Metals In Effluents Research Articles

Proximate and elemental composition of tea effluents obtained from various tea processing factories in Kenya

Tea undergoes intricate processing in factories, generating substantial effluents that pose significant environmental challenges. This study explored the proximate and elemental composition of tea effluents obtained from various factories to determine their potential benefits, especially in agriculture and health. The proximate composition analysis revealed significant (P<0.05) variations in ash, crude fiber, carbohydrates, proteins, and lipids across samples from different factories. Notably, ash content in fluff samples from Mudete and Ogembo, and fly-off from Kionyo factories, is statistically comparable (P>0.05) but significantly higher than other samples (P<0.05). The cyclone fluff from the Kinoro factory exhibited significantly lower ash content than all other samples (P<0.05). The study further examined microelement minerals (calcium, potassium, magnesium, sodium, phosphorus) in tea samples, showcasing significant variations. The fluff sample from the Ogembo factory showed significantly higher calcium levels than others (P<0.05), while the cyclone sample from Mogogosiek displays significantly lower calcium concentrations than other samples (P<0.05). Regarding micronutrient/trace mineral elements, the fluff sample from the Gitambo factory has significantly higher Boron concentrations than other tea samples (P<0.05). Significant differences were observed in Cobalt concentrations, with cyclone fluff samples from Chelal and Momul factories showing significantly higher levels than others (P<0.05). The concentration of heavy metals (Aluminium, Chromium, Lead) in tea effluents varies significantly among samples from different factories (P<0.05). The cyclone fluff samples from Boito and Chelal factories and fluff samples Mogogosiek factory showed significantly higher Aluminium concentrations than others (P<0.05). The cyclone fluff sample from the Kinoro factory exhibited significantly lower Aluminium levels than others (P<0.05). Therefore, future research should delve into specific processes contributing to these variations, enabling tailored strategies for sustainable waste management in the tea industry. Moreover, adopting environmentally conscious approaches, informed by a nuanced understanding of metal concentrations in tea effluents, is imperative for ensuring the long-term viability of the tea industry and safeguarding environmental health. Key words: Tea waste, micronutrients, macronutrients; heavy metals, nutritive value

Fe3O4 nanoparticles decorated on N-doped graphene oxide nanosheets for elimination of heavy metals from industrial wastewater and desulfurization

Finding an effective and excellent pertinent single catalyst material for multipurpose application for the purification of hydrocarbons in fuels (desulfurization), and for efficient removal of heavy metals from industrial effluent is greatly endowed. In the present work, a hybrid nanocomposite of ultrafine magnetite (Fe3O4) nanoparticle embedded on the surface of in-situ nitrogen doped layered GO (NGO) sheets were fabricated by sol-gel method and treatment with microwave irradiation technique is reported for the first time. The results show a high removal efficiency of 97 % for multiple heavy metals (Pb2+, Cd2+, Cu2+, Cr+2, Mn+2etc.) in industrial effluent and as well as in synthetic water with a very good retention performance of 99 %. The composites were tested against the elimination of sulfur from thiophene is 1.495 mmol g−1 is reported high is due to coupling and coordination of nitrogen with FeO and C. Recycling studies showed that the developed composites had excellent recyclability, with <82 % removal at the 5th cycle; its feasibility was evaluated using industrial effluent water and in synthetic water. Surface phenomena studies presented here revealed that the adsorptive removal processes of heavy metals involved π electron donor-acceptor interactions, ion exchange, and electrostatic interactions, along with surface complexation that showed an excellent synergism. A high stability, and retention performance is better than the pure Fe3O4 and NGO sheets. We hope that this study will motivate and give further scope for scientists working on magnetite-based graphene nanocomposites.

Comparative Study of Biosorption and Traditional Methods for Heavy Metal Removal from Industrial Wastewater in Panipat

In this research paper, I have thoroughy described about the topic Comparative Study of Biosorption and Traditional Methods for Heavy Metal Removal from Industrial Wastewater in Panipat.” Industrial wastewater contamination by toxic heavy metals poses a significant environmental threat globally, especially in rapidly industrializing regions like Panipat District in Haryana, India. Panipat, renowned for its extensive textile and chemical industries, generates substantial volumes of wastewater laden with heavy metals such as lead (Pb), cadmium (Cd), and mercury (Hg). Recent studies have revealed that the concentrations of these metals in Panipat's industrial effluents frequently surpass the permissible limits set by environmental regulations. Traditional methods for heavy metal removal, including chemical precipitation and ion exchange, are widely utilized but often entail high operational costs and the generation of secondary pollutants like sludge. Biosorption, an emerging and sustainable technology, offers a promising alternative by utilizing biological materials such as algae, bacteria, and agricultural waste to adsorb heavy metals from wastewater. This study aims to investigate the effectiveness, cost-effectiveness, and environmental impact of biosorption compared to traditional methods in Panipat District. By examining heavy metal removal efficiencies, conducting cost analysis, and assessing environmental implications, this research seeks to provide valuable insights into sustainable wastewater treatment practices.

Toxic Effect of Heavy Metal Poisoning on Living Organisms in Water and Health Risk: A Central India Study

The main causes of this environmental catastrophe are pollutants such as iron, zinc, lead, nickel, and chromium that have entered the water system as a result of uncontrolled industrial effluent discharge in the area. This study finds resistant bacteria and shows the toxicity of heavy metals in industrial effluent near the steel industry. Five separate locations were used for water sampling, and 16s RNA sequencing of the microorganisms that were found was done along with physicochemical parameter analysis and atomic absorption spectrophotometer use. Different water samples’ conductivity, TDS, salinity, DO, turbidity, and pH levels indicate changes in the quality of the water. In addition to having higher values for each of these characteristics, Sample D3’s water samples had greater concentrations of heavy metals, suggesting contamination. Aspergillus niger and Aspergillus terreus were identified in all samples. Both Gram-negative and Gram-positive Bacilli’s resistance to heavy metals has been found to be a sign of microbial adaptation to exposure to heavy metals. 16s rRNA sequencing of microorganisms revealed their roles in heavy metal bioremediation processes. The delicate balance between the flora and fauna in the affected water bodies has been upset by the devastating losses in aquatic life. In this study, we presented the biological methods for eliminating heavy metals, which comprised both metabolically dependent and independent techniques.

Model based analysis of trace metal dosing strategies to improve methane yield in anaerobic digestion systems

Favourable effects of trace metals (TMs) on regulating anaerobic digestion (AD) performance are extensively utilised to improve methane yield. This study discusses a model-based approach to find out the best TM dosing strategies. The model has been applied to compare continuous, preloading, pulse dosing and in-situ loading. Simulations were also carried out to comprehend appropriate dosing form, dosing time and quantity of metals to be dosed. Model results show that the best way to dose TMs is repeated pulse dosing at low concentration levels in the optimum range with high frequency. Best dosing strategy for the system in this study was found to be 5 µM pulse loading at 5 days intervals as it gave maximum methane production and low effluent metal loss. Preferable dosing form depends on reactor configuration and this has been verified after model calibration with experimental data. Easily dissociable metal chlorides are ideal for continuous reactors.

Bioremoval of tannins and heavy metals using immobilized tannase and biomass of Aspergillus glaucus

BackgroundThe presence of inorganic pollutants and heavy metals in industrial effluents has become a serious threat and environmental issues. Fungi have a remarkable ability to exclude heavy metals from wastewater through biosorption in eco-friendly way. Tannase plays an important role in bioconversion of tannin, a major constituent of tannery effluent, to gallic acid which has great pharmaceutical applications. Therefore, the aim of the current study was to exploit the potential of tannase from Aspergillus glaucus and fungal biomass waste for the bioremediation of heavy metals and tannin.ResultsTannase from A. glaucus was partially purified 4.8-fold by ammonium sulfate precipitation (80%). The enzyme was optimally active at pH 5.0 and 40 °C and stable at this temperature for 1 h. Tannase showed high stability at different physiological conditions, displayed about 50% of its activity at 60 °C and pH range 5.0–6.0. Immobilization of tannase was carried out using methods such. as entrapment in Na-alginate and covalent binding to chitosan. The effects of Na-alginate concentrations on the beads formation and enzyme immobilization revealed that maximum immobilization efficiency (75%) was obtained with 3% Na-alginate. A potential reusability of the immobilized enzyme was showed through keeping 70% of its relative activity up to the fourth cycle. The best bioconversion efficiency of tannic acid to gallic acid by immobilized tannase was at 40 °C with tannic acid concentration up to 50 g/l. Moreover, bioremediation of heavy metal (Cr3+, Pb2+, Cu2+, Fe3+, and Mn2+) from aqueous solution using A. glaucus biomass waste was achieved with uptake percentage of (37.20, 60.30, 55.27, 79.03 and 21.13 respectively). The biomass was successfully used repeatedly for removing Cr3+ after using desorbing agent (0.1 N HCl) for three cycles.ConclusionThese results shed the light on the potential use of tannase from locally isolated A. glaucus in the bioremediation of industrial tanneries contained heavy metals and tannin.

ACTIVATED CARBON DERIVED FROM GROUNDNUT SHELL AND RICE HUSK FOR THE ADSORPTION OF HEAVY METALS IN TANNERY WASTEWATER

The Effluents from tanneries are considered to be one of the major environmental pollutants from industries. The challenge from leather processing arises from the nature and quality of the chemicals used along with the amount of wastes generated and discharged. Heavy metals present in tannery wastewater pose a significant risk to both the environment and public health. This study investigates the use of activated Carbon produced from Composite of Groundnut shell and Rice husk (GR-AC) to remove heavy metals (Pb, Cr and Cd) from tannery wastewater. The raw material was carbonized at temperature of 400 ͦ C for 1 hour to obtain bio char. The obtained char was impregnated with NaOH and H 3PO 4 for 24 hours thereafter, filtered and washed several times until a neutral pH was obtained. A measured amount of the adsorbent, 0.5g was introduced into 250mL vessel with 50mL wastewater, it was stirred at 250rpm for 60minutes and later subjected to centrifugation and the concentrations of residual Lead, Chromium and Cadmium was determined using Flame Atomic Absorption Spectrometry. The produced adsorbent was characterized using Fourier transform infrared (FTIR) spectroscopy, Energy-dispersive X-ray fluorescence (EDXRF) and scanning electron microscopy (SEM), elemental composition analysis. The effects of adsorbent dosage and contact time on the adsorption process were studied in a batch system. From the research conducted, it shows that pH, adsorbent dosage, contact time, initial Concentration and temperature plays a vital role in the uptake of heavy metals. Optimal conditions for effective adsorption were determined at a pH range of 7 to 8, an adsorbent dosage of 0.5g, contact time of 60 min and a temperature of 40 0C. The maximum adsorption capacities of Pb, Cr and Cd adsorbed onto GR-AC were found to be 98.2, 82.4 and 75.2 mg/g respectively. Therefore, the GR-AC can be effectively utilized as agricultural waste to remove heavy metals in tannery effluents.

Mechanism of microplastics effects on the purification of heavy metals in piggery effluents by microalgae

Microalgae is an effective bioremediation technique employed for treating piggery effluent. However, there is insufficient study on how the presence of microplastics (MPs) in wastewater affects the ability of microalgae to remove heavy metals from piggery effluent. This study aims to investigate the influence of two prevalent heavy metals found in piggery wastewater, Cu2+ (2 mg/L) and Zn2+ (2 mg/L), on their removal by microalgae (Desmodesmus sp. CHX1) in the presence of four types of MPs: polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), and polyethylene terephthalate (PET). The results revealed that smaller particle size MPs promoted chlorophyll accumulation, while larger particles inhibits it. Additionally, higher concentrations of MPs promoted chlorophyll accumulation, while lower concentrations inhibited it. As for heavy metals, the presence of microplastics reduced the removal efficiency of Cu2+ and Zn2+ by Desmodesmus sp. CHX1. The highest inhibition of Cu2+ was 30%, 10%, 19%, and 16% of the control (CK), and the inhibition of Zn2+ was 7%, 4%, 4%, and 13%, respectively, under the treatments of PE, PVC, PP and PET MPs. Furthermore, Desmodesmus sp. CHX1 can secrete more extracellular polymeric substances (EPS) and form heterogeneous aggregates with MPs to counteract their pressure. These findings elucidate the impact of MPs on microalgae in bioremediation settings and offer useful insights into the complex relationships between microalgae, MPs, and heavy metals in the environment.

Isolation and Characterization of Heavy Metal-Tolerant Bacterial Isolates from Industrial Effluents in Uttar Pradesh, India

Industrial activities over the past century have significantly increased human exposure to pollutants such as heavy metals. Industrial emissions of heavy metals, which are carcinogenic, mutagenic and toxic, contaminate natural water supplies and the agricultural environment. Due to the high concentration of heavy metals in industrial effluents, the bacteria present there naturally develop resistance to heavy metals. The aim of this study is to isolate and characterize bacteria resistant to heavy metal, lead (Pb), copper (Cu), chromium (Cr), cadmium (Cd), and nickel (Ni) from sites contaminated by industrial effluents in Uttar Pradesh, India. A total of 58 bacterial isolates were isolated from 9 samples according to their various morphological parameters and 32 isolates were found positive for all heavy metals, which revealed that samples contained metal-resistant bacterial diversity. Two isolates were identified up to species level based on their physiological, biochemical and molecular characterization as Comamonas testosteroni (S4C1) and Bacillus cereus (S5C3). Both isolates are highly resistant to lead (Pb), copper (Cu), chromium (Cr), cadmium (Cd), and nickel (Ni) and they show different MICs against the above heavy metals at different levels. A growth experiment showed that the presence of heavy metals concentration had no discernible impact on the growth rate among the isolates. Gel analysis showed interesting patterns of protein expression were observed in the presence of various heavy metals. MALDI-TOF analysis found that specific proteins (S layer protein, F0F1ATP synthase subunit b, Flagellin, 50S ribosomal protein L4, Molecular chaperone) were overexpressed in the presence of heavy metals. As a result, identifying the heavy metal resistance bacteria and their proteins study could be useful as a preliminary investigation for the development of prospective bioremediation agents of potentially hazardous waste treatment technology.

Trace metal transfer to passerines inhabiting wastewater treatment wetlands

Wastewater treatment wetlands are cost-effective strategies for remediating trace metals in industrial effluent. However, biogeochemical exchange between wastewater treatment wetlands and adjacent environments provides opportunities for trace metals to cycle in surrounding ecosystems. The transfer of trace metals to wildlife inhabiting treatment wetlands must be considered when evaluating wetland success. Using passerine birds as bioindicators, we conducted a multi-tissue analysis to investigate the mobilization of zinc, copper, and lead derived from wastewater to terrestrial wildlife in treatment wetlands and surrounding habitat. In addition, we evaluate the strength of relationships between metal concentrations in non-lethal (blood and feathers) and lethal (muscle and liver) sample types for estimation of toxicity risk. From July 2020 to August 2021, 177 passerines of seven species were captured at two wetlands constructed to treat industrial wastewater and two reference wetlands in the coastal plain of South Carolina. Feather, blood, liver, and muscle samples from each bird were analyzed for fourteen metals using inductively coupled plasma mass spectrometry and direct mercury analysis. Passerines inhabiting wastewater treatment wetlands accumulated higher concentrations of zinc in liver, copper in blood, and lead in feathers than passerines in reference wetlands, but neither blood nor feather concentrations were correlated with internal tissue concentrations. Of all the detected metals, only mercury in the blood showed a strong predictive relationship with mercury in internal tissues. This study indicates that trace metals derived from wastewater are bioavailable and exported to terrestrial wildlife and that passerine biomonitoring is a valuable tool for assessing metal transfer from treatment wetlands. Regular blood sampling can reveal proximate trace metal exposure but cannot predict internal body burdens for most metals.

Deciphering the removal of antibiotics and the antibiotic resistome from typical hospital wastewater treatment systems

Hospital wastewater treatment systems (HWTSs) are a significant source and reservoir of antibiotic resistance genes (ARGs) and a crucial hub for transmitting ARGs from clinical to natural environments. However, there is a lack of research on the antibiotic resistome of clinical wastewater in HWTSs. In this study, we used metagenomics to analyze the prevalence and abundance of ARGs in five typical HWTSs. A total of 17 antibiotics from six categories were detected in the five HWTSs; β-lactam antibiotics were found at the highest concentrations, with up to 4074.08 ng·L−1. We further found a total of 21 ARG types and 1106 subtypes of ARGs with the highest percentage of multi-drug resistance genes (evgS, msbA, arlS, and baeS). The most abundant last-resort ARGs were mcr, which were detected in 100 % of the samples. HWTSs effluent is a major pathway for the transmission of last-resort ARGs into urban wastewater networks. The removal of antibiotics, antibiotic-resistant bacteria, and ARGs from HWTSs was mainly achieved by tertiary treatment, i.e., chlorine disinfection, but antibiotics and ARGs were still present in the HWTSs effluent or even increased after treatment. Moreover, antibiotics and heavy metals (especially mercury) in hospital effluents can exert selective pressure for antibiotic resistance, even at low concentrations. Qualitative analyses based on metagenome-assembled genome analysis revealed that the putative hosts of the identified ARGs are widely distributed among Pseudomonas, Acidovorax, Flavobacterium, Polaromonas, and Arcobacter. Moreover, we further assessed the clinical availability of ARGs and found that multidrug ARGs had the highest clinical relevance values. This study provides new impulses for monitoring and removing antibiotics and ARGs in the hospital sewage treatment process.

Removal of Lead, Cadmium, and Mercury in Monometallic and Trimetallic Aqueous Systems Using Chenopodium album L.

The presence of heavy metals in water represents a risk to the life of all species on the planet. Phytoremediation is an effective alternative to remove heavy metals from contaminated aqueous environments. In the present research, Chenopodium album L. was examined for the remediation of waters contaminated with Cd, Pb, and Hg. Studies were carried out in waters containing each metal separately (monometallic aqueous systems) and in mixtures (trimetallic aqueous systems). First, the adaptation of Chenopodium album to different concentrations of Hoagland's nutrient solution (HNS) was evaluated, then, a phytotoxicity study was carried out to determine the appropriate concentrations of each metal to test the tolerance of the plant during the accumulation study, and finally, the bioaccumulation capacity of Chenopodium album for Cd, Pb, and Hg was evaluated. Chenopodium album showed tolerance to levels of 5 mg/L Hg and 10 mg/L Cd and Pb in 25% HNS. The bioaccumulation tests showed that Chenopodium album can remediate Cd, Pb, and Hg contaminated waters in both monometallic and trimetallic aqueous systems. These findings suggest important future applications in the food industry for the production of Chenopodium album as we demonstrate that this species adapts and grows in hydroponic media. In particular, the ability of Chenopodium album to adapt to extreme conditions could be exploited for further studies on phytoremediation of heavy metals in river water, irrigation water, wastewater, effluents, and mine tailings.

Hydrothermal metal recovery of metal-contaminated wastewater with forest residue: a zero waste discharge process

This study demonstrates a zero-waste discharge, hydrothermal treatment of industrial metal effluent infused with agricultural waste for co-generation of a hydrogen-rich gas mixture and nanometal carbon composites for diverse applications.

High-efficiency removal of Pb (II) and Cu (II) by amidoxime functionalized silica aerogels: Preparation, adsorption mechanisms and environmental impacts analysis

In this work, a novel adsorbent was evaluated for eliminating heavy metal ions from water. The cyano-functionalized silica aerogels (ANSA-X) were fabricated by functionalizing silica aerogel with 2-cyanoethyltriethoxysilane, and then further by the reaction with hydroxylamine hydrochloride to obtain amidoxime-functionalized silica aerogels (AOSA-X) with a large specific surface area. The FTIR and NMR analysis indicated that cyano was successfully transformed into amidoxime groups. Adsorption experiments showed the adsorption performed well with the Langmuir isotherm, and AOSA3 exhibited the optimum adsorption property with 598.05 mg/g for Pb (II) and 534.10 mg/g for Cu (II). The thermodynamic results indicated that spontaneous endothermic process was the nature of the adsorption. The adsorption rate of AOSA3 was above 86% after five successive adsorption–desorption cycles. XPS analysis and DFT calculations demonstrated that the N and O atoms participated in the chelating adsorption of Pb (II) and Cu (II), and the N atom on the amidoxime groups played a dominant role. Life Cycle Analysis (LCA) evaluated the environmental effect of the preparation of 1 kg AOSA3 adsorbent, identified the environmental factors with high environmental impact, proposed alternative solutions, proved the feasibility of preparing a novel high-efficiency amidoxime-based adsorbent, and provided a guideline for the sustainable mass production of AOSA3 adsorbent. In conclusion, AOSA3 demonstrated to have promising application perspectives in heavy metal effluent treatment.

In-situ hydrogen production and battery electrode materials from metal effluent and biomass

Supercritical water gasification (SCWG) is an effective technique for the conversion of biomass into hydrogen-rich fuel gas. This work addresses two important aspects of the SCWG process by employing the concept of waste to wealth: first, the requirement of heterogeneous catalysts for better efficiency, and second, the safe disposal of byproducts of the process. Metal-contaminated aqueous effluent (Zn-EPW) is used as the reaction medium with the catalyst for single-step hydrothermal conversion of banana pseudo-stem (BPS) to synthesize multi-dimensional value-added products such as H2-rich fuel gas, nano metal–carbon hybrids (NCH), and treated aqueous phase. This study demonstrates the enhanced conversion of biomass into hydrogen-rich gas and recovery of heavy metals (HMs) in the form of nanometal carbon hybrids, which can be utilized to fabricate carbon-based electrodes in Li-S batteries. A comparative study of feedstock, such as a combination of Zn-EPW adsorbed on BPS (MA-BPS) with Millipore water, direct treatment Zn-EPW with BPS, and Millipore water with BPS (without HMs), was performed. The results inferred the catalytic effect of heavy metals increased the yield of hydrogen about ∼2.9 times with Zn-EPW and BPS and ∼1.7 times with MA-BPS and Millipore water over the non-catalytic operation. Furthermore, the obtained NCH were characterized to evaluate their performance for electrodes in energy storage devices. The electrochemical performance of NCH obtained after multi-step SCWG of MA-BPS with Millipore water and single-step treatment of Zn-EPW with BPS at 600 °C, have specific capacity of 610 and 615 mAh.g−1 at 0.1C respectively.

Determination of Some Selected Heavy Metals in Effluents from Lubricants Manufacturing and Associated Contamination of Oysters (Crassostrea cucullata) and Soil near Discharge Points in Mombasa, Kenya

Purpose: Available reports on heavy metal contamination along the Kenyan coastal zone focused on concentration levels in marine and coastal waters, sediments and biota, with indications of potential sources. However, information on contribution of specific sources to the heavy metal load into the marine and coastal environment is scanty or unavailable. Thus, this study addressed the need to assess specific potential sources and their contribution to heavy metal contamination. The generated data can be applied for monitoring discharge loads of heavy metals from lubricant manufacturing processes into the environment, its level of contamination to the environment and the potential risk to man through food chain.&#x0D; Materials and Methods: Concentrations of selected heavy metals Cd, Cr, Cu, Pb, and Hg in effluents filtrates, residues (SPM), Oysters (Crassostrea cucullata) and soil samples were determined using ICP-OES. The procedures of the analytical methods and instruments used were validated with analysis of a multi-element certified reference material (CRM IAEA-452) for the elements Cd, Cr, Cu, Pb and Hg in the effluent samples and standard reference material (SRM 1566b) from National institute standards and technology for the elements Cd, Cr, Cu, Pb and Hg in the marine bivalve tissues. Physico – chemical parameters Temperature, PH, Conductivity, Dissolved oxygen and Total organic carbon were also determined in the effluent samples. Sampling was done in the year 2021 and 2022. Effluent samples were collected from OLA energy Kenya limited, VIVO energy Kenya limited and TOTAL energy Kenya limited. Oyster samples and soil sediment samples were collected from Makupa creek. Data analysis was carried out using (SPSS) for Windows (Version 16) and one way analysis of variance (ANOVA) at 95% confidence level. The difference in mean concentrations of heavy metals within and between groups were considered significant at P˂0.05. The interrelationships of heavy metals contamination in the samples were determined using the Pearson correlation coefficient. It was considered significant at P value ˂0.05.&#x0D; Findings: This study showed presence of heavy metals that varied in concentrations in effluents samples, soils samples and Oyster samples. The mean concentrations of heavy metals in the effluents filtrates ranged as follows Pb = 0.0038±0.0004 mg/l – 0.0025 ± 0.003 mg/l, Cu = 0.0054±0.0038 mg/l – 0.0019±0.0002 mg/l, Cr = 0.0071±0.0021mg/l – 0.0045±0.0022 mg/l, Cd = 0.0041±0.0026 mg/l – 0.0013±0.0001 mg/l and Hg = 0.0063±0.0018 mg/l – 0.0026±0.0004 mg/l. The range of values for the mean concentrations of the heavy metals in the Oysters showed that Pb = 0.0227±0.0091mg/kg – 0.019 ± 0.006 mg/kg, Cu = 0.0618±0.0171mg/kg – 0.0601±0.0168 mg/kg, Cr = 0.0265 ± 0.0277 mg/kg – 0.0152 ± 0.0009 mg/kg, Cd = 0.0464±0.0282 mg/kg – 0.0273 ± 0.0117 mg/kg and Hg = 0.0264±0.0158 mg/kg – 0.025±0.0080 mg/kg. The range of values for the mean concentrations of the heavy metals in the soil samples showed that Pb = 0.0523 ± 0.0189 mg/kg – 0.0447±0.0181 mg/kg, Cu = 0.3010 ± 0.0282 mg/kg – 0.2437 ± 0.2690 mg/kg, Cr = 0.6564 ± 0.1468 mg/kg – 0.5862 ± 0.3073 mg/kg, Cd = 0.5434 ± 0.2207 mg/kg – 0.3506±0.2157 mg/kg and Hg = 0.2679 ± 0.1923 mg/kg – 0.2366±0.1584 mg/kg. The range values for the Physico-chemical parameters in the effluent samples were PH = 7.31±0.198 – 6.53±0.459, Temperature = 27.53±0.378oC – 23.3±0.2oC, Dissolved oxygen = 6.81±0.191mg/l – 3.11±0.242 mg/l, conductivity = 2740.0±901.041 uS/cm – 1523.33±55.075 uS/cm, Total organic carbon = 15.18±1.2750 mg/l – 0.92±0.1026 mg/l. Concentrations of heavy metals were at safe limits set by WHO, US – EPA and NEMA (2017) except Hg in soil samples was slightly above permissible limits. Concentration of mercury was lower in effluent filtrates and effluents residues samples than in soil and Oysters samples. &#x0D; Implications to Theory, Practice and Policy: This study recommends that frequent inspection be carried out on wastes emanating from industries, at its disposal sites and in living organisms at the vicinity of the wastes disposal sites. Industrialists should adopt best practices of wastes disposal and management to reduce emissions of harmful substances into the environment. Public education and awareness should be carried out to enlighten the residents about the impacts on health upon interaction with the polluted environment and feeding on organisms that reside in such contaminated environments.

Comprehensive pollution and ecological risk of heavy metals in an industrial region of south-west Bangladesh

Deterioration of water, soil and sediment due to industrial operation is well known. This study aimed to evaluate physicochemical properties of surface water and heavy metals in industrial effluent (n = 13), river water (n = 14), pond water (n = 5), soil (n = 11) and sediment (n = 19) collected from an industrial zone in south-west Bangladesh. Among the physicochemical parameters, pH and dissolved oxygen (DO) indicated relatively higher values in most of the samples than their respective lower guideline values of 6 and 4.5 mg L-1 and showed significant variation across environments. Based on the average concentration, none of the heavy metals in any environment surpassed the guideline values in the study area, except, Cr in both industrial effluent (0.034 ± 0.055 mg L-1) and river water (0.011 ± 0.005 mg L-1), Cd in both soil (1.11 ± 0.47 mg kg−1) and sediment (1.41 ± 1.04 mg kg−1). Possibly, continuous discharge of industrial effluents might increase the heavy metal concentrations in the effluent receiving environment. Concentration of others heavy metals were below the respective guideline values but varied significantly among the environments. Depth-wise variation was negligible which might be dependent on metal chemistry in soil and sediment. A very high pollution and ecological risk were observed for Cd, specifically in soil and sediment. Multivariate statistics showed strong correlation among heavy metals, which indicated considerable contribution from industrial effluent. Industrial operations control physicochemical properties of surface water, but temperature is dependent of meteorological conditions. This study concludes that the lower concentrations of heavy metals than guideline values in environmental samples still pose significant levels of pollution and ecological risks.

Polydopamine/Fe3O4 modified wood-based evaporator for efficient and continuous water purification

Solar interfacial evaporation is a highly promising technology for seawater desalination and wastewater treatment, while the simple preparation processes and efficient production of clean water based on biomass interfacial evaporators still need further exploration and development. Here, we reported a wood-based evaporator (PFDW) loaded with Fe3O4 and polydopamine (PDA) after simple immersion treatment at room temperature for efficient and continuous water purification. The synergistic photothermal effect of PDA coating and Fe3O4 particles enables the evaporator to achieve high photothermal conversion efficiency in the longer wavelength range, while combined with the rapid water transport capacity endowed by the vertically aligned microporous structure of natural wood, it achieved an evaporation rate of 1.70 kg m-2h−1 and an energy efficiency of 98.0% under 1 kW m−2 irradiation. In addition, the prepared PFDW exhibited sustainable desalination stability and excellent removal efficiency for different water sources including organic dye wastewater, heavy metal effluent, oil–water emulsion and river water. This work provides a new avenue for efficient salt-tolerant portable evaporators.

Efficiently Removing Heavy Metals from High-Salinity Wastewater via Ionic Liquid-Based Aqueous Biphasic Systems.

For the separation of metal ions, ionic liquid-based aqueous biphasic systems (IL-ABSs) offer a promising alternative to solvent extraction. However, the incorporation of an extensive quantity of inorganic salts restricts their practical application. Because heavy metal wastewater often contains high concentrations of inorganic salts, it offers good prospects for the application of IL-ABSs in the separation of heavy metals. In this work, an IL-ABS was formed by tributyltetradecylphosphonium chloride ([P44414]Cl), and simulated high-salinity wastewater (NaCl and Na2SO4 as the main inorganic salts) was used for the separation of heavy metals. The phase diagram results indicated that the formation of a two-phase system required a relatively high salt concentration. The extraction process followed the mechanism of anion exchange; thus, heavy metals such as zinc and cadmium that formed complexes with chloride ions could be effectively extracted (extraction rate >99.5%) with a very fast rate (extraction time <1 min) at a wide pH range (pH = 2-7). After extraction, the metals could be stripped well (stripping rate >99.5%) after contact with the NaOH solution. This research provided a new approach for treating heavy metals in high-salinity effluents, which has the advantages of IL-ABS and avoids the disadvantages of adding large amounts of inorganic salts at the same time.

Hydrogeochemical Study and Geospatial Analysis of Water Quality Using GIS based Water Index and Multivariate Statistics in Kombolcha City, Ethiopia

The study was carried out to evaluate hydro geochemistry and the risk of groundwater and surface water pollution in the Kombolcha area. To achieve this, hydrogeochemical analysis, water heavy metal, geospatial data analysis, ion ratio, correlation matrix, principal component analysis, Heavy metal Pollution Index (HPI), and Water Quality Index (WQI) methodologies were employed. A total of 36 samples (both water and effluent samples) had been collected and assessed for major physicochemical variables and heavy metals and samples were taken from hand dug wells, Borehole, springs, and rivers in the area. Hydrogeochemical methods showed groundwater mineralization due to (1) silicate weathering, (2) cation exchange processes, and (3) anthropogenic sources (i.e., contaminated discharge of sulphate, carbonate, and trace metal effluents). The study result revealed that major ions dominating the area are Ca2+ &gt;Na+ &gt; Mg2+ &gt;K+, HCO3- &gt;SO4 2- &gt; Cl- &gt; NO3-, and Fe&gt; Mn &gt;Pb&gt; Cr&gt; Cd for cations, anions and trace metals respectively with all heavy netals had mean concentrations above the WHO recommended limits. Calculated Pollution indices revealed 50.7% of the sample belongs to a low level of pollution, while 35% and 14.3% belong to a medium and high level of pollution respectively which consequently translating the area into high groundwater pollution zones. The correlation matrix revealed that no significant correlation exists between the water quality variables (Cl and NO3- with Fe, Pb, Cr, Mn, and Cd). PCA was applied on the data set to identify the spatial sources of pollution in groundwater and in the first principal component analysis, Mn, Fe, Cr, Pb, and Cd (in descending order) were found in amounts greater than 0.5, confirming that these metals were from anthropogenic sources. The combined assessments based on WQI and HPI, the study showed that water samples in the proximity of industrial sites are polluted by factories effluent and uncontrolled waste disposal due to urbanization.