Heavy Metal-contaminated Water Research Articles

Heavy Metals and Physicochemical Parameters Evaluation in the Upper Reaches of Bonny River, Niger Delta, Nigeria

The objectives of the study were to determine distribution of heavy metal contamination in water, sediments and biota (Callinectes amniciola) of the upper reaches of the Bonny Estuary and to determine the impact on physicochemical characteristics of the water body. Sampled was from January to June 2020. The physicochemical parameters of the water varied slightly across the months but were within FEPA/WHO (2003) acceptable limits. Furthermore; the study compared the seasonal variations and determination of Bio-accumulation Factor (BF) of C. amnicola with respect to sediment. The study site is a tidal creek that drains into the main Bonny River channel within Niger Delta, Nigeria. The sampled locations/stations include Trans-Amadi slaughter in Azuabie {N4°81'49.9 and E7°04'63.4}, Okpoka Creek in Abuloma {N4°78'02.43 and E7°06'66.12} and Okirika Jetty {N4°73'70.04 and E7°09'56.93}. Samples of surface water, sediments and swimming crabs were collected from three different stations which were at least 1000 meters apart. The results of this study show that concentrations of the heavy metals (Fe and Zn) were both higher in the three media than the approved limits prescribed by the local regulatory authority. Although Cu was relatively within acceptable limit in the three media. There is therefore the need to control the anthropogenic activities within or around the river. This will help to prevent effluent and solid waste discharges that lead to increase in the concentration of heavy metals in the aquatic environment. Routine monitoring should be encouraged to identify the major sources of heavy metals introduction into the river and their impacts on the aquatic resources.

Functionalized Activated Carbon Derived from Palm Kernel Shells for the Treatment of Simulated Heavy Metal-Contaminated Water.

Heavy metal contamination in water poses a great risk to human health as well as to the lives of other creatures. Activated carbon is a useful material to be applied for the treatment of heavy metal-contaminated water. In this study, functionalized activated carbon (FAC) was produced by the induction of nitro groups onto activated carbon using nitric acid. The resulting material was characterized in detail using the XRD, Raman, BET, FTIR, and FESEM techniques. The FAC was used for the treatment of heavy metal-contaminated water using different adsorption parameters, i.e., solution pH, contact time, adsorbent dosage and heavy metal ion concentrations, and these parameters were systematically optimized. It was found that FAC requires 90 min for the maximum adsorption of the heavy metal ions; Cr6+, Pb2+, Zn2+ and Cd2+. The kinetic study revealed that the metal ion adsorption follows the pseudo-second-order. The Freundlich and Langmuir isotherms were applied to determine the best fitting adsorption isotherm models. The adsorption capacities were also determined for each metal ion.

Bioconcentration of heavy metals by three plant species growing in Golmarz wetland, in northwestern Iran: The plants antioxidant responses to metal pollutions

In the present study heavy metal contaminations in water and sediments of the Golmarz wetland in northwestern Iran were determined. Moreover, bio-monitoring of metal pollution in the aquatic ecosystem and evaluating the role of some plant species in bioaccumulation and remediation of heavy metals from the environment were performed. The metal(loid) concentrations in water, sediment and plant samples were measured by inductively coupled plasma-mass spectroscopy (ICP-MS). It was established that there was no metal contamination in water samples, but the sediments were highly contaminated by Se and As. Typha latifoila was able to accumulate large amount of Cd, Pb, Ni, and Zn in its root and the amount of its enrichment coefficient of root for the elements was more than 1. Due to its large biomass and its high potential in elements uptake, T. latifolia was a suitable species for metal’s phytoremediation. Panicum maximum was capable to uptake and transporting Pb and Cd to its above-ground parts. Moreover, Scirpus lacustris showed good potential to accumulate of Cd and Pb in its root. The obtained results indicated that the activity of antioxidant enzymes and the amounts of phenol and flavonoids in three plant species were high in the most polluted sampling sites. Therefore, the plants try to adapt the existence of heavy metal by induction of their defense systems. • Determination of water and sediment pollution in Golmarz wetland. • Evaluation of phytoremediation potential of the indigenous plants. • Physiological responses of the plants in the polluted environment.

Assessment of heavy metal contaminations in water and sediment of River Godavari, India

Abstract The Godavari is the largest river of peninsular India and receives a significant quantity of pollutants from diverse sources, including many industries, urban developments and agricultural fields. Such pollution is more prominent in the upper stretch of the river. This work aimed to assess the water and sediment contaminations of River Godavari for the presence of trace metals Cd, Cr, Cu, Mn, Pb and Zn. Samples were collected from 10 sampling stations covering the entire stretch of the river. Sediment pollution characteristics and potential ecological risks were evaluated by calculating contamination factor, degree of contamination, pollution load index, geo-accumulation, and the potential ecological risk index. Pearson's correlation analysis and principal component analysis were used to predict the probable sources of heavy metals. The concentrations of studied heavy metals in water were mostly observed below the detection limit using the flame mode of an Atomic Absorption Spectroscope and recorded safe for the biotic community. The mean concentrations of metals in the sediments were calculated and also recorded to be safe with respect to the guideline values of the United States Environmental Protection Agency (USEPA, 1999). However, the sampling site-specific calculated contamination factors indicated moderate contamination of some of the stretches as: S1 for the presence of Cu, Mn, Zn; S2 for Cu, Zn; S3 and S4 for Cu; S5 for the dominance of Mn. The rest of the sites were free from sediment metal contaminations. The degree of contamination values specified S2 as moderately contaminated. Pollution load index indicated sites S1 and S2 as contaminated. Both geo-accumulation and potential ecological risk index designated lower levels of pollution in the river owing to sediment metal contaminations. Furthermore, a comparison of the heavy metal concentrations with sediment quality guidelines signified that the heavy metal pollutions (Cu, Cr, Mn and Zn) tend to pose occasional harmful effects on the ecosystem. From Pearson's correlation analysis and principal component analysis, two main sources of metal pollution were predicted. The Cu, Cr and Zn contaminants were mainly derived from human activities and Mn from natural sources as well as human activities.

Potential of live Spirogyra sp. in the bioaccumulation of copper and nickel ions: A study on suitability and sustainability.

Various industrial and municipal wastes are the major sources of heavy metal contamination in water causing significant environmental issues. Bioremediation is an effective and affordable solution for the removal of metals and metal pollutants from industrial wastewater. This study aimed to assess the efficacy of live and dead Spirogyra sp. for sorption of metals like of Cu2+ and Ni2+ . The live Spirogyra sp. was used for the uptake of Cu2+ and Ni2+ from their aqueous solutions. The equilibrium data were fitted using a Langmuir and Freundlich isotherm model; the maximum uptakes for Cu2+ and Ni2+ were 29 and 521mgg-1 , respectively. Scanning electron microscopic (SEM) and infrared (IR) spectroscopic studies of Spirogyra sp. and treated Spirogyra sp. with specific metal ions were used to assess the bonding site and extent of sorption mechanism. The initial study showed that this biomass takes up a significant amount of metal ions. Compared to the Langmuir model, the Freundlich model showed better sorption process. The pseudo-second-order rate model represented an enhanced kinetics of metal ion adsorption using live Spirogyra sp. As bioaccumulation technology is environmental friendly and potentially cost-effective, live Spirogyra sp. is expected to be a good candidate for managing industrial wastewater.

Insight into the mechanism of heavy metal removal from water by monodisperse ZIF-8 fine particles

Water pollution due to toxic heavy metals discharged by chemical industries and abandoned mines is one of the most serious environmental and public problems. Therefore, the purification of heavy metal-contaminated water has become a major topic in water treatment. Among the metal–organic frameworks used to this aim, zeolitic imidazolate framework 8 (ZIF-8) is particularly promising as a purifying agent for water treatment. Although several reports have dealt with the purification of heavy metal-contaminated water using ZIF-8, the removal mechanism remains controversial. In this study, monodisperse ZIF-8 fine particles were used for the removal of Pb2+ and Cu2+ ions, and the removal mechanisms were investigated. Accordingly, an adsorption mechanism is suggested for the Pb2+ removal, whereas the Cu2+ removal occurs through an ion-exchange phenomenon.

Hemicellulose and starch citrate chitosan foam adsorbents for removal of arsenic and other heavy metals from contaminated water

Arsenic and other heavy metal contaminants in water are a significant global health threat. In this study, low-cost, sulfur-free, sustainable, water-insoluble materials with heavy metal remediation properties were produced from renewable resources such as starch, xylan, citric acid, and chitosan. Synthesized starch citrate-chitosan (SCC) foam and xylan citrate-chitosan (XCC) foam were flexible, porous, and elastic. The foams’ arsenic uptake in water was significantly greater than five different commercial metal remediating agents. The mercury and lead uptakes with the synthesized foams were similar to the performance of a commercial sulfur-based product, SorbaTech 450 (ST450). However, the cadmium and selenium uptakes were comparatively lower. The complexation of arsenic with oxygen and nitrogen of the SCC foam was shown with time-of-flight secondary ion mass spectrometry (TOF-SIMS). The XCC foam was also shown to adsorb potassium iodide (KI) at a similar rate to sodium chloride. This may be used to remediate water contaminated with radioactive materials, such as iodine 131.

Prediction of the sorption efficiency of heavy metal onto biochar using a robust combination of fuzzy C-means clustering and back-propagation neural network

Heavy metal adsorption onto biochar is an effective method for the treatment of the heavy metal contamination of water and wastewater. This study aims to evaluate the heavy metals sorption efficiency of different biochar characteristics and propose a novel intelligence method for predicting the sorption efficiency of heavy metal onto biochar with high accuracy based on the back-propagation neural network (BPNN) and fuzzy C-means clustering algorithm (FCM), named as FCM-BPNN. Accordingly, the FCM algorithm was used to simulate the properties of metal adsorption data and divide them into clusters with similar features. The clustering results showed that the FCM algorithm simulated metal adsorption data's properties very well and classified them based on biochar characteristics and adsorption conditions. Afterward, BPNN models were well-developed based on these clusters, and their outcomes were then combined (i.e., FCM-BPNN). The results indicated that the FCM-BPNN model could predict heavy metal's sorption efficiency onto biochar with a promising result (i.e., RMSE of 0.036, R2 of 0.987, RSE of 0.006, MAPE of 0.706, and VAF of 98.724). Whereas the BPNN model, without optimizing the FCM algorithm, was proved with lower performance (RMSE = 0.050, R2 = 0.977, RSE = 0.011, MAPE = 0.802, and VAF = 97.662). These findings revealed that the FCM algorithm's presence impressively improved the BPNN model's accomplishment in predicting heavy metal's sorption efficiency onto biochar, and the proposed FCM-BPNN model can improve water/wastewater treatment plants' quality and provide a more efficient process for heavy metals with performance superiority.

DFT analysis of nitrogen and Boron doped Graphene sheet as lead detector

In the last few decades, the heavy metal contamination in water has affected the human health in a big way and hence an area of great scientific concern. Among these heavy metals, lead (Pb) is highly toxic and leads to the adverse effect on human body, causing severe health problems like anemia, hypertension, renal impairment, immunotoxicity, toxicity to the reproductive organs, cancer etc. here, the Boron and Nitrogen functionalized graphene sheets (B-Graphene and N-Graphene), have been analysed for its suitability to detect the lead, by computing the band structure, density of state, charge transfer and Current-Voltage characteristics, using the Density Functional Theory based ab-initio approach. The computed results demonstrate that the N-doped Graphene is relatively better sensor for lead in aqueous environment, with a sensitivity of ~ 67% at lower bias voltage, high detection range and short recovery time. However, the Pb sensitivity of the N-Graphene sheet at low bias is very high 329% in absence of water environment.

Facile synthesis and applications of carbon nanotubes in heavy-metal remediation and biomedical fields: A comprehensive review

Carbon nanotubes (CNTs) have drawn great attention due to the rich science underpinning their applications coupled with a unique combination of properties like large aspect ratios, superior thermal and electrical conductivity, excellent optical characteristics and high surface area. Through chemical modification, re-engineering and functionalization, control of parameters such as surface chemistry, size distribution, surface area, agglomeration and structure have been made possible leading to improved functionality. CNTs not only holds promise in a wide range of applications in medicine, nano and microelectronics, and environmental remediation but can also be used for laboratory experimental tenacities. More particularly, CNTs serve as an excellent adsorbent in the removal of heavy metal ions (HMI) from wastewater. Equally, they are capable of coupling with many therapeutic and diagnostic agents hence being used in biomedical applications such as tissue engineering, cancer therapy, drug delivery, biosensing and imaging. These two distinguished and noble applications have offered improved human health services and ensured a safer environment thus momentously revolutionizing human life. In that regard, this article has reviewed the advancements in the applications of CNTs in the treatment of heavy metal-contaminated water and biomedical applications drawn from several research articles and other publications.

Cadmium Removal by Adsorption: Enhancement by Surfactant Mediation

This work proposes to tackle the problem of heavy metal contamination of water, using adsorption phenomenon. We have tried to enhance the adsorptive cadmium uptake capacity of activated carbon by modifying its surface with the surfactant - Alpha olefin sulfonate. The effect of contact time and the initial concentration on the adsorption process has been determined. Study of the cadmium uptake by both the unmodified and surfactant modified carbon, with the adsorption data fitted to adsorption isotherms, showed the cadmium uptake capacity of the surfactant modified activated carbon to have enhanced two-fold over the unmodified activated carbon.

Millimeter-Shaped Metal-Organic Framework/Inorganic Nanoparticle Composite as a New Adsorbent for Home Water-Purification Filters.

Heavy-metal contamination of water is a global problem with an especially severe impact in countries with old or poorly maintained infrastructure for potable water. An increasingly popular solution for ensuring clean and safe drinking water in homes is the use of adsorption-based water filters, given their affordability, efficacy, and simplicity. Herein, we report the preparation and functional validation of a new adsorbent for home water filters, based on our metal-organic framework (MOF) composite containing UiO-66 and cerium(IV) oxide (CeO2) nanoparticles. We began by preparing CeO2@UiO-66 microbeads and then encapsulating them in porous polyethersulfone (PES) granules to obtain millimeter-scale CeO2@UiO-66@PES granules. Next, we validated these granules as an adsorbent for the removal of metals from water by substituting them for the standard adsorbent (ion-exchange resin spheres) inside a commercially available water pitcher from Brita. We assessed their performance according to the American National Standards Institute (ANSI) guideline 53-2019, "Drinking Water Treatment Units-Health Effects Standard". Remarkably, a pitcher loaded with a combination of our CeO2@UiO-66@PES granules and activated carbon at standard ratios met the target reduction thresholds set by NSF/ANSI 53-2019 for all the metals tested: As(III), As(V), Cd(II), Cr(III), Cr(VI), Cu(II), Hg(II), and Pb(II). Throughout the test, the modified pitcher proved to be robust and stable. We are confident that our findings will bring MOF-based adsorbents one step closer to real-world use.

Agricultural soils of the Animas River watershed after the Gold King Mine spill: An elemental spatiotemporal analysis via portable X-ray fluorescence spectroscopy.

In August 2015, 11.3 million L of heavy metal-contaminated water spilled into the Animas River from the Gold King Mine (Colorado, USA).National attention focused on water quality and agricultural production in areas affected by the spill. In response to local concerns, surface soil elemental concentrations were analyzed in three New Mexico agricultural fields to determine potential threats to agronomic production. Irrigated fields in the Animas watershed were scanned using portable X-ray fluorescence (PXRF) spectrometry to monitor the spatiotemporal variability of Pb, As, Cu, and Cr. A total of 175 locations were scanned using PXRF before and after the growing season for 3 yr. The geostatistical model with the lowest RMSE was chosen as the optimal model. The lowest RMSE for the elements ranged from to 0.10 to 0.44 m for As, from 0.50 to 0.98m for Cr, from 0.15 to 0.91m for Cu, and from 0.14 to 0.44m for Pb across the models selected. The spatial dependence between the measured values exhibited strong to moderate autocorrelation for all metals except for As, for which spatial dependence was strong to weak. Some areas in each field exceeded the New Mexico Environment Department soil screening limit of 7.07mg As kg-1 . All sampling locations were below the screening limit at last sampling time in 2019. Mixed models used for temporal analysis showed a significant decrease only in As below the screening value at the end of the study. Results indicate that the agricultural soils were below the soil screening guideline values.

Spatial Distribution of Heavy Metals and Pollution of Environmental Media Around a Used Lead-acid Battery Recycling Center in Ibadan, Nigeria.

Background.Heavy metals are usually present in trace amounts in various environmental media such as water, soil, and air, and many are poisonous to human health even at very low concentrations.Objectives.To assess the risk of heavy metal contamination of water, soil, and plants around a used lead acid battery (ULAB) recycling center in Ibadan, Nigeria.Methods.Environmental samples (water, soil, and plants) were collected using standard methods and concentrations of arsenic (As), cadmium (Cd), antimony (Sb), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), selenium (Se), and zinc (Zn) were determined using inductively coupled plasma-optical emission spectrometry at the International Institute of Tropical Agriculture, Ibadan, Nigeria.Results.The concentration of metals detected in water samples were higher than permissible limits at more than 50% of the sampling locations. In contrast, heavy metals in soil were within permissible limits. Most of the heavy metals except Pb were found to be present in the plant within permissible limits. Lead levels in water and plants from all locations exceeded the permissible limits. The contamination degree and pollution load index of water sources around the ULAB recycling center indicate a high degree of pollution of water sources with heavy metals, while soil samples were within the normal baseline levels. The transfer factor of Pb from soil to Amaranthus viridis was 1.92. This has implications for human health as the plant is often harvested and for sale in local markets as a source of food and medicine.Conclusions.The present study recommends improved technology for ULAB recycling and adequate treatment of effluent/runoff from recycling centers before discharge.Competing Interests.The authors declare no competing financial interests.

Heavy metal contamination in water of Indus River and its tributaries, Northern Pakistan: evaluation for potential risk and source apportionment

This study investigated the heavy metals (HM) contamination in the water of Indus River and its tributaries, northern Pakistan. Water samples (n=44) were collected along with the five geological units: Kohistan batholith, Chilas complex, Kamila amphibolites, Jijal complex, and Indian plate. Observed HM levels were within the WHO drinking water guidelines except for Ni (23.7 µg/L) in the Jijal complex and Pb (10.6 µg/L) at on the Indian plate. Hazard quotient (HQ) values were observed < 1, suggesting no health risk through water consumption. Statistical analyses revealed that bedrock geology plays a major role in the HM distribution in water of the study area.

Applications of Nanomaterials for Heavy Metal Removal from Water and Soil: A Review

Heavy metals are toxic and non-biodegradable environmental contaminants that seriously threaten human health. The remediation of heavy metal-contaminated water and soil is an urgent issue from both environmental and biological points of view. Recently, nanomaterials with excellent adsorption capacities, great chemical reactivity, active atomicity, and environmentally friendly performance have attracted widespread interest as potential adsorbents for heavy metal removal. This review first introduces the application of nanomaterials for removing heavy metal ions from the environment. Then, the environmental factors affecting the adsorption of nanomaterials, their toxicity, and environmental risks are discussed. Finally, the challenges and opportunities of applying nanomaterials in environmental remediation are discussed, which can provide perspectives for future in-depth studies and applications.

Efficient removal of selenate in water by cationic poly(allyltrimethylammonium) grafted chitosan and biochar composite

The discovery of cheap and eco-friendly functional materials for the removal of anionic heavy metal ions is still challenging in the treatment of heavy metal-contaminated water. Herein, a new poly(allyltrimethylammonium) grafted chitosan and biochar composite (PATMAC-CTS-BC) was introduced for the removal of selenate (SeO42−) in water. Results suggest that the PATMAC-CTS-BC showed a rapid removal of SeO42− with efficiency of >97% within 10 min and it followed a pseudo-second-order model. High capacity of SeO42− adsorption by the composite was achieved, with maximum value of 98.99 mg g−1 based on Langmuir model, considerably higher than most of reported adsorbents. The thermodynamic results reflected the spontaneous and exothermic nature of SeO42− adsorption onto the composite. The composite could be applied at a wide initial pH range (2–10) with high removal efficiency of SeO42− because of permanent positive charges of quaternary ammonium groups (=N+–). The removal mechanisms of SeO42− were mainly attributed to electrostatic interactions with =N+– and protonated –NH3+ groups, and redox-complexation interactions with –NH2, –NH–, and –OH groups. Besides SeO42−, the hexavalent chromium (Cr2O72−) was considered as example to further demonstrate the anion removal capability of cationic hydrogel-BC composite. The study outcomes open up new opportunities to efficiently remove anionic heavy metal ions (e.g., SeO42− and Cr2O72−) in water using these materials.

Assessment of heavy metal contamination in water, sediments, and Mangrove plant of Al-Budhai region, Red Sea Coast, Kingdom of Saudi Arabia

This study investigates the hydrographic parameters and contamination status of zinc (Zn), iron (Fe), copper (Cu), manganese (Mn), lead (Pb), cadmium (Cd), vanadium (V), and nickel (Ni), etc. in surface water, surficial sediments, and mangrove tree tissues (Avicennia marina). Samples were collected from nine sites in Al-Budhai area of Red Sea coast of Jeddah. The trend values of metal contamination factor were Ni (3.23) > Cd (2.99) > Pb (2.86) > Zn (2.69). Translocation factor (TF) of the metals showed Avicennia marina tissues have a dominant role in the phytoremediation process through toxic metal uptake.

Evaluation of alkaline-based activated carbon from Leucaena Leucocephala produced at different activation temperatures for cadmium adsorption

Heavy metal contamination in water is happening worldwide. Adsorption using activated carbon is a common choice for cleaning the wastewater. The drawback of activated carbon is the higher cost of production due to the need for high heat in the process. This work investigated on activated carbon produced from the abundantly available Leucaena leucocephala biomass in order to reduce the cost of raw material. The biomass was chemically activated at different activation temperatures. The produced activated carbon was characterized using SEM, FT-IR, surface analyzer, and TGA. Isothermic and thermodynamic studies were done to evaluate the adsorption properties of the activated carbon. It was found out that higher surface area can be obtained using the higher activation temperature. Higher NaOH to carbonized sample ratios also resulted in higher surface area for all activation temperatures, which are 662 m2g-1 for 700 °C activation temperature, 735 m2g-1 for 750 °C, and 776 m2g−1 for 800 °C. Isothermic studies showed that all of the activated carbon that is produced from Leucaena leucocephala biomass are fit to the Langmuir isotherm, regardless of any activation temperature. Lastly, the thermodynamic study found out the adsorption process is endothermic, reflected by the positive value of ΔHo. It can be concluded that Leucaena leucocephala is a promising alternative material for producing activated carbon.

A simple and rapid algal assay kit to assess toxicity of heavy metal-contaminated water.

This study presents a novel algal-based toxicity test suitable for simple and rapid assessment of heavy metal (Hg2+, Cr6+, Cd2+, Pb2+, or As3+)-contaminated water. A closed-system kit-type algal assay was developed using Chlorella vulgaris. Toxicity was assessed by oxygen evolution in the gaseous phase of the assay kits, which was measured via a needle-type oxygen sensor. Initial cell density, light intensity, and exposure time that enabled favorable test performance for the algal assay kits were 103cells/mL, 250μmolm-2s-1, and 18h, respectively. Results from the heavy metal toxicity tests demonstrate that Hg2+, Cr6+, Cd2+, and Pb2+ are more toxic in inhibiting algal photosynthetic activity than As3+. The 18h half-maximum effective concentrations (EC50) for Hg2+, Cr6+, Cd2+, Pb2+, and As3+ were determined to be 31.3±0.5, 179.6±7.5, 301.3±6.1, 476.1±10.5, and 2184.1±31.1μg/L, respectively. A strong correlation between oxygen concentrations in the headspace of the assay kits and chlorophyll a production indicates that oxygen evolution in the gaseous phase is able to represent algal photosynthetic activity and serve as the end-point in algal toxicity tests. High test sensitivity and reproducibility as well as an easy test protocol and rapid processing time make the algal assay kit a suitable tool for simple and rapid toxicity testing of heavy metal-contaminated water.