Papers by Keyword: Heavy Metals

Abstract: Theoretical and experimental investigations have revealed significant spatial variations in the chemical element content of wastewater, primarily due to anthropogenic pressures from mining and industrial complexes. This indicates the diverse nature of pollution sources and the complex impact they exert. The most pronounced exceedances of permissible concentrations were observed for manganese, potassium, magnesium, and calcium, attributed to the leaching of elements from rock dumps and chemical weathering processes. Analysis of the total pollution index (Zc) helped identify areas with high levels of technogenic impact, necessitating urgent environmental protection and reclamation measures. Spatial models illustrating element distribution demonstrate a direct correlation between toxicant concentrations in aquatic environments and the location of technogenic objects, particularly spoil heaps. The findings are crucial for future planning of environmental protection initiatives in mining and industrial regions. They enable the identification of areas with the highest ecotoxicological burden and will be utilized for environmental monitoring of water bodies, forecasting ecological risks, and establishing a database for decision-making regarding reclamation and water resource quality management.

Abstract: The danger to environmental productivity posed by many human activities is making water contamination an essential problem. Assessing oxidative stress biomarkers as markers of environmental contamination in water hyacinth and Nile tilapia from the Wupa River in Abuja that is damaged by effluent is the goal of this study. Samples were gathered and examined according to established protocols. Biomarker result shows hydrogen peroxide activities in the leaves of water Hyacinth (101.76 ±11.70-104.17 ± 17.78 mol/L) stem (81.22 ± 9.86-87.68 ± 10.31 mol/L). Superoxide anion of the leaves (25.33 ± 3.56-28.06 ± 6.09 mol/m³), stem (24.51 ± 2.99 - 26.16 ±1.84 mol/m³). Catalase enzymatic activities (43.57±2.12 - 48.23 ± 19.06), stem (39.73±4.95-47.12 ± 5.00). The Malondialdehyde of the leaves (348.04 ± 220.43-455.08 ± 137.99 g/mol) and the stem (180.08 ± 151.08-252.04 ±147.67 g/mol). In the Fish, Hydrogen peroxide (H₂O₂) levels were highest in the liver, ranging from 363.62 ± 46.16 mol/L (upstream) to 362.81 ± 225.78 mol/L (downstream), significantly exceeding those in the heart and gills. Superoxide anion concentrations followed a similar pattern, with liver values ranging from 41.03 ± 8.75 mol/m³ (downstream) to 82.61 ± 64.88 mol/m³ (upstream), again surpassing levels in the heart and gills. Catalase activity was relatively stable across tissues, with values in the liver ranging from 33.75 ± 5.49 (upstream) to 38.51 ± 2.04 (downstream). Malondialdehyde (MDA) levels, an indicator of lipid peroxidation, were significantly elevated in the gills, particularly upstream (30.89 ± 10.87 g/mol), when compared to liver and heart values. The Biomarker results demonstrate that water hyacinth and Nile Tilapia can be effectively used to assess the pollution status of the Wupa River, with the biomarkers such hydrogen peroxide, catalase and superoxide anion levels reflecting the organism’s response to environmental stressors.

Abstract: Contamination of water by heavy metals is a major environmental problem in modern world as pollutants enter aquatic systems through various means such as effluent discharge, industrial, urban and agricultural run-off. This study is evaluated the bioaccumulation potentials of Eichornia crassipe (Water hyacinth) on some selected heavy metals in effluent impacted Wupa River. The result shows Water Cadmium (0.10 ± 0.01-0.12 ± 0.00 mg/L), Copper (0.01 ± 0.01-0.04 ± 0.02 mg/L), Iron (0.57 ± 0.23-0.83 ± 0.26mg/L), Nickel (0.11± 0.01-0.15±0.10 mg/L), Lead (0.98 ± 0.86-1.04 ± 0.64 mg/L), Zinc (0.02 ± 0.00-0.03 ± 0.00 mg/L). Sediment heavy metal Copper mean (0.13 ± 0.03-0.28 ± 0.06mg/L), Nickel (0.02 ± 0.02-0.18 ± 0.12mg/L), Zinc (0.03 ± 0.04-0.05 ± 0.04mg/L), Cadmium (0.004 ± 0.05-0.01 ± 0.01mg/L), Lead (5.09 ± 5.38-5.69 ± 1.61mg/L), Iron (2.00 ± 1.77 to 5.65 ± 2.03 mg/L). Molecular identification reveals high percentage identities ranging from 88.69% to 98.74% with known chloroplast sequences of E. crassipes. Water hyacinth root had high bioconcentration factor metals such as iron and copper while the leaves had highest BCF in Lead. The heavy metal removal efficiency of iron and copper was significantly low (p<0.05) in the root of water hyacinth when compared to the leave and stem of same plant. While the lead heavy metal removal was significantly (p<0.05) low in the stem when compared to the root and leaves of water hyacinth.

Abstract: Nigeria's growing aquaculture sector faces critical water quality challenges that threaten fish health and food safety, yet limited systematic assessment exists for urban fish farming environments. This study comparatively assessed physicochemical, bacteriological, and heavy metal quality of water in three selected fish farms in Abuja, Nigeria. The study was conducted over five weeks (November 2024–January 2025), with water samples collected in triplicates from inlet and outlet points and analyzed using standard APHA methods for physicochemical parameters, culture and molecular techniques for bacterial identification, and Atomic Absorption Spectroscopy for heavy metals. Data were analyzed using ANOVA and Kruskal-Wallis tests. Results revealed that all farms exhibited suboptimal water quality with dissolved oxygen levels critically below standards (0.18 ± 0.07 mg/L vs. recommended >5 mg/L), acidic pH (6.4 ± 0.41), and elevated chemical oxygen demand (98.72 ± 19.90 mg/L). Nine bacterial species were identified from thirty isolates, with Escherichia coli being predominant (60%), followed by Staphylococcus sp. and Shigella sp. (10% each), while Campylobacter, Proteus, Enterococcus, Salmonella, Enterobacter, and Bacillus species were each detected at 3.3%. Heavy metal concentrations varied significantly across farms with manganese concentrations ranging from 0.18 ± 0.12 mg/L in Farm A to 0.24 ± 0.25 mg/L in Farm C. Zinc (Zn) levels were highest in Farm V at 0.28 ± 0.21 mg/L and lowest in Farm A at 0.20 ± 0.11 mg/L. Nickel (Ni) concentrations remained relatively consistent across all farms. The study concludes that critical water quality deficiencies across all examined fish farms pose significant risks to fish health and public safety, necessitating urgent implementation of water quality management interventions and strengthened regulatory oversight for sustainable urban aquaculture development.

Abstract: This study explored the feasibility of removing nickel (Ni) and Pb (II) from water solutions using the adsorption technique by cellulose recovered from office paper waste. Metal removal is required to reduce the direct or indirect exposure of industrial waste to the environment, due to its potential for harm to human health and ecosystems. The release criterion is maintained to keep the efficient wastewater treatment of the metals of concern, which are toxic to both humans and other organisms. The cellulose was first prepared from office paper waste. The removal values can be rationalized as follows: Lead removal efficiencies of were obtained upto %95.0632, while the removals of nickel were obtained as 54.3866%. The adsorption process was effective with the initial metal concentration and the adsorbent dose used. In addition, the study focused on the competition between the adsorption of lead and nickel ions, which inhibited their removal in a mixture. To sum up, in the present study, the prospects of removing heavy metals by low-cost renewable materials are demonstrated, and in general, those concerning the protection of the environment and the minimization of waste.

Abstract: The adsorption behavior of Pb²⁺, Cu²⁺, and Cr³⁺ from aqueous solutions onto bacterial cellulose/magnetite (BC/Fe₃O₄) composite in multiple systems was systematically investigated, with particular focus on competitive adsorption and inorganic ion effects. The BC/Fe₃O₄ composite demonstrated significant adsorption capacity for the three heavy metals through mechanisms involving surface complexation and electrostatic interactions. Binary and ternary competitive adsorption studies revealed that the adsorption capacity followed the sequence of Pb²⁺ (0.847 mmol/g) > Cu²⁺ (0.673 mmol/g) > Cr³⁺ (0.556 mmol/g), correlating inversely with their hydration energies. The presence of inorganic ions (Na⁺, K⁺, Mg²⁺, Ca²⁺) showed inhibitory effects on heavy metal adsorption, primarily due to competition for adsorption sites. Conversely, Al³⁺ and Fe³⁺ enhanced adsorption performance through synergistic effects. Notably, Pb²⁺ adsorption remained relatively unaffected by competing ions due to its strong affinity for BC/Fe₃O₄, while Cr³⁺ showed unique behavior in competitive systems. EDTA demonstrated superior desorption efficiency compared to HNO₃, with efficiencies ranging from 61.2% to 68.4%. This study highlights the potential of BC/Fe₃O₄ composite as an effective adsorbent for heavy metal removal from complex water matrices.

Abstract: The increasing concentrations of heavy metals (HM) in the water bodies, primarily caused by the rapid use of fertilizers in farming and increasing industrialization, pose a serious threat to the deteriorating earth’s environment and human health. This pollution is dangerous to water-dwelling life forms and is also of concern because it is believed to be a carcinogen. To overcome these challenges, constant water quality analysis must be done. Out of all the remediation methods, the adsorption-based techniques are considered one of the most suitable means of addressing the problem of heavy metal toxicity in wastewater. The latest trends in the application of Functionalized Magnetic Nanomaterials (MNPs) attached to nanocomposites, including carbon-based materials like carbon nanotubes (CNTs), Graphene Oxide (GOx), and Graphene Quantum Dots (GQDs) and inorganic supports like Zeolites (ZLs) and Metal-Organic Frameworks (MOFs), demonstrate high efficiency in the extraction of heavy metals (HM). These nanocomposites possess a higher rate of active surface area and can adsorb properties, which make them reusable over multiple cycles of treatment in various forms of wastewater. This review will discuss the preparation method of engineering MNPs on CNTS and GOx and analyze modern materials' role in removing heavy metals. Besides, due to the observed effects of the substances on the biota, the study will highlight the need to conduct more research on the ecotoxicological effects of the materials and design suitable methods that can guarantee the effectiveness of the materials in promoting a sustainable environment.

Abstract: The use of activated carbon for waste water treatment has been established based on sustainability and cost. This study delves into the intricate process of producing activated carbon from cow and goat bones and explores the efficiency of this material in removing contaminants from distillery wastewater. The samples were carbonized at 700°C in a muffle furnace, then crushed in a mortar after cooling. The crushed samples were activated using 0.4M phosphoric acid for 24 hours and washed with distilled water, and finally oven dried. The elemental and microstructural was carried on the prepared activated carbon (AC) samples using X-ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM). The heavy metals in the treated water were tested using Atomic Absorption Spectroscopy (AAS). The AC was used to treat waste water and factors on which adsorption depend, such as contact time (35 minutes and 60 minutes), adsorbent dosage (2.5g and 5g), and initial contaminant concentration (100% and 50%) were varied for each activated carbon sample (cow bone AC, goat bone AC, and a mixture of equal ratios of both). It was reported that activated carbon prepared from animal bones is rich in calcium. Also, chemical activation with phosphoric acid led to an increase in the external surface area of the particles with irregular cavities and pores. AC prepared from the mixture of cow and goat bones was most effective for distillery wastewater purification.

Abstract: This study investigates the tunable photoluminescence emission properties of carbon dots (CDs) derived from hemicellulose and lignin extracted from agricultural waste. Key aspects examined include production yield, fluorescence characteristics, and fluorescence quenching mechanism in the presence of heavy metal ions. Freeze-dried carbon dots from corn cobs (CC-CDs) exhibited a yield of 3.69%, which increased to 16.8% with alkali treatment (CCN-CDs). The CDs demonstrated excellent aqueous stability and emitted green fluorescence under ultraviolet light irradiation. Ultraviolet-visible spectroscopy revealed distinct absorption peaks at 200-300 nm and 300-350 nm, attributed to aromatic sp² core transitions and surface functional groups. Atomic force microscopy confirmed a spherical morphology with diameters of 35 nm for CCN-CDs and 51 nm for CC-CDs. Fourier-transform infrared spectral analysis identified functional groups such as phenolic hydroxyl, amines, nitrile, and carboxyl, which contribute to the tunable optical properties of the CDs. Photoluminescence spectra showed excitation-dependent emission features, with a redshift observed due to surface oxidation. The fluorescence quenching induced by ferric ions demonstrated a linear relationship between the quenching effect and concentration, with a more pronounced effect at lower concentrations of heavy metal ions, indicating the potential of these carbon dots as sensor. The quenching phenomenon was attributed to the electron transfer processes between ferric ions and CDs, providing insights into the underlying mechanisms governing their fluorescence behavior.

Abstract: The scope of generation, accumulation and use of ash and slag waste of thermal power plants in different countries has been analyzed. The results of the study of the phase, mineralogical and chemical composition of ash and slag waste obtained with the dominance of solid and liquid fuel in the energy balance have been presented. It has been shown that the newly formed and previously accumulated ashes and slags of thermal power plants, with their correct and effective use, are a powerful source of expansion of raw materials in various industries. The existing methods of using ash and slag waste, which have been developed based on their mineral composition and the content of trace elements and impurities in them, have been considered. The most effective application of these wastes is in the construction industry, as well as when used as a raw material for obtaining compounds of rare metals, for example, vanadium.