Harmful Metals Research Articles

Natural freeze concentration of wastewater for nutrient recovery

Water and food are vital needs for all humans and animals living on the earth, and intensive crop cultivation that requires plentiful nutrients and water has evolved to meet food production demands. As population grows and the supply of raw material nutrient deposits and clean water begin to run out, effective recycling becomes increasingly important. However, recovering nutrients from urban waste streams is not yet technically or economically feasible. New energy efficient separation technologies are needed to meet the demand. Making use of the colder climates of polar regions is an opportunity to achieve a more efficient and economical transition to a circular economy. Hence, this study focuses on a natural cold-climate freeze concentration technique that enables the recovery of both water and material concurrently in a single process.Experiments were carried out in a winter simulator device using various waste streams originating from landfill and a biogas production plant. Average partition coefficients between 1.5 and 3 for the concentrates and 0.08 and 0.4 for the ice were achieved for different concentrate mass yields with different water quality measures, essential ions, and elements, including harmful metals. These results confirm that freeze concentration is a potential option when developing new technologies that combine water and material reclamation from wastewater towards sustainable circularity.

Comparative study of phytoremediation of chromium contaminated soil by Amaranthus viridis in the presence of different chelating agents

Chromium is a harmful heavy metal to the environment due to the toxicity induced by it to plants and other living organisms. High concentration of Cr in soil poses severe toxicological problems ecosystem. Phytoremediation using different plants is an economical and environment-friendly method for removing Cr from soil. The addition of chelating agents augments the phytoextraction using plants.The present study aimed to augment the Cr phytoremediation capacity of Amaranthus virdis, a predominant plant species in the Cr-contaminated open dumpsites of Bangalore. . Phytoextraction of Cr by Amaranthus viridis was studied in the presence of different chelating agents viz. ethylenediaminetetraacetic acid (EDTA), citric acid (CA), growth promoting hormone- indoleacetic acid (IAA) and NPK fertiliser. A. viridis grown under different concentrations (5, 10 and 20 mg/Kg) of Cr were treated with 0.5g EDTA/Kg of soil, 0.5g CA/Kg of soil, 1mg IAA/Kg of soil and NPK (125 mg of nitrogen, 45 mg of phosphorous and 156 mg of potassium per Kg of soil). Results indicated that CA, at 10 mg/kg Cr supply, induced the highest uptake (up to 29.25 µg/plant). Furthermore, the study revealed that CA amendment induced maximum Cr uptake in A. viridis at all levels of Cr supply as compared to other amendments. This was due to the increased solubility of Cr in the presence of citric acid and the amelioration of oxidative stress due to Cr to plants by citric acid. This study inferred that the non-hyperaccumulating plant, A. virdis could be used as a phytoremediator for Cr in the presence of citric acid in the places where it is grown abundantly.

Maternal urinary metal(loid)s and risk of preterm birth: A cohort study in the Tibetan Plateau

Maternal metal(loid)s exposure has been related to preterm birth (PTB), but the results are still inconclusive. Previous studies have mainly discussed the harmful metal(loid)s, neglecting beneficial ones. We examined the association of maternal metal(loid)s with PTB and gestational age (GA) in a birth cohort from the Tibetan Plateau. We measured 29 metal(loid)s in urine samples from 1081 pregnant women in the third trimester. Information regarding demographics, socioeconomic status, diet, medication, and lifestyle was collected through standardized interviews. The associations of single metal(loid)s with PTB or GA were evaluated using a generalized linear mixed-effects model or linear mixed-effects model. Elastic net and Bayesian kernel machine regressions were used to explore the joint associations. Magnesium (Mg), Copper (Cu), and Tin (Sn) were the main “harmful” metal(loid)s positively and negatively associated with PTB or GA, respectively. Mg was the dominant “harmful” metal(loid)s associated with PTB in a J-shape. A one-fold increase in Mg was associated with a 38% increased risk of PTB [OR (95% CI) = 1.38 (1.15, 1.65), PFDR＜0.05] and 0.17 weeks shortening of GA [β (95% CI) = −0.25 (−0.35, −0.14), PFDR＜0.05]. Cesium (Cs), rubidium (Rb), and Molybdenum (Mo) were the main “beneficial” metals. Cs dominated the “beneficial” associations and was negatively associated with PTB in a linear manner. A one-fold increase in Cs was associated with a 67% decreased risk of PTB [OR (95% CI) = 0.43 (0.27, 0.67), PFDR＜0.05] and 0.24 weeks of prolonged GA [β (95% CI) = 0.35 (0.13, 0.56), PFDR＜0.05]. Ethnicity and living altitude modified the association of Mg and Cu with PTB or GA. In conclusion, Maternal urinary metal(loid)s were bi-directionally associated with PTB in a population in the Tibetan Plateau. Mg and Cs were the dominant “harmful” and “beneficial” metal(loid)s, respectively.

Multiple fluorescence polymer dots-based differential array sensors for highly efficient heavy metal ions detection

Water pollution caused by harmful heavy metal ions (HMIs) can significantly impact aquatic ecosystems and pose a high risk to human health. In this work, equipped with ultra-high fluorescence brightness, efficient energy transfer, and environmentally friendly performance, polymer dots (Pdots) were employed to construct a pattern recognition fluorescent HMIs detection platform. A single-channel unary Pdots differential sensing array was first developed to identify multiple HMIs with 100% classification accuracy. Then an "all-in-one" multiple Förster resonance energy transfer (FRET) Pdots differential sensing platform was constructed to discriminate HMIs in the artificial polluted water samples and actual water samples, exhibiting high classification accuracy in distinguishing HMIs. The proposed strategy leverages the compounded cumulative differential variation of diverse sensing channels for analytes, which is anticipated to find extensive applications in other fields for detection purposes.

Spillover benefits of carbon dioxide cap and trade: Evidence from the Toxics Release Inventory

AbstractReducing greenhouse gas emissions is necessary to meet climate goals, but these emissions are not the only harmful bi‐products of fossil‐fuel combustion. This paper shows how a regional cap‐and‐trade program designed to regulate CO2 emissions affects the release of federally‐regulated toxins in the Toxics Release Inventory. We find that the program reduces toxic releases from coal‐fired electric plants by 78%, and that harmful metal releases (e.g., lead, mercury) have fallen by 54%. There is no evidence of spillovers into non‐adopting areas. This unintended beneficial effect of the carbon dioxide cap‐and‐trade policy provides compelling evidence of the co‐abatement of harmful compounds alongside greenhouse gas emissions.

A case study of environmental pollution by pathogenic bacteria and metal(oid)s at Soran Landfill Site, Erbil, Iraqi Kurdistan Region.

Environmental pollution is a serious issue all around the world, especially when it is caused by metal(oid)s and pathogenic microorganisms. This study reports here for the first time on the contamination of soil and water with metal(oid)s and pathogenic bacteria directly resulting from the Soran Landfill Site. Soran landfill is a level 2 solid waste disposal site that lacks leachate collection infrastructure. The site is potentially an environmental and public hazard caused by metal(oid)s content and significantly dangerous pathogenic microorganisms through leachate release into the soil and nearby river. This study reports on the levels of the metal(oid)s content of As, Cd, Co, Cr, Cu, Mn, Mo, Pb, Zn, and Ni obtained by inductively coupled plasma mass spectrometer in soil, leachate stream mud, and leachatesamples. Five pollution indices are used to assess potential environmental risks. According to the indices, Cd and Pb contamination is significant, whereas As, Cu, Mn, Mo, and Zn pollution is moderate. A total of 32 isolates of bacteria were defined from soil, leachate stream mud, and liquid leachate samples: 18, 9, and 5, respectively. Moreover, 16s rRNA analysis suggested that the isolates belong to three enteric bacterial phyla of Proteobacteria, Actinobacteria, and Firmicutes. The closest GenBank matches of 16S rDNA sequences indicated the presence of the genera: Pseudomonas, Bacillus, Lysinibacillus, Exiguobacterium, Trichococcus, Providencia, Enterococcus, Macrococcus, Serratia, Salinicoccus, Proteus, Rhodococcus, Brevibacterium, Shigella, Micrococcus, Morganella, Corynebacterium, Escherichia, and Acinetobacter. The identity percentage was mostly between 95%-100%. The results of this study show the levels of microbiological and geochemical contamination of soils, surface and potentially ground water with harmful microorganisms and toxic metal(oid)s originating specifically from Soran landfill leachate which subsequently incorporated into the surrounding environment, creating thus a considerable health and environmental risk.

Phytoremediation: A Sustainable Approach to Combat Heavy Metal Contaminated Soil - A Review

A significant threat to the environment is the contamination of soil with hazardous metals. Chemical methods to remove heavy metals from the environment, such as heat treatment, electroremediation, soil replacement, precipitation, and chemical leaching, are typically very expensive and inapplicable to land for farming. However, other methods are being employed to clean up polluted environmental systems. One of these is phytoremediation, which relies on the use of hyper-accumulator plant species that can withstand significant concentrations of hazardous HMs in the soil. In this technique, harmful metals are removed, degraded, or detoxified using green plants. The efficacy of plants as candidates for HMs decontamination can be improved by applying phytoremediation assisted with chemical inducers or chelating agents, plant growth-promoting bacteria, and AMF inoculation. The present review discusses the toxicity of HMs and the environmentally friendly methods used to clean them up, with a particular emphasis on phytoremediation. Moreover, some advanced and sustainable modern technologies for enhancing phytoremediation potential of plants are also discussed.

Assessment of contamination of marine sediments and their potential toxicity in the Uglovoy Bay, Peter the Great Gulf, Sea of Japan/East Sea.

The content of harmful heavy metals in the bottom sediments of the Uglovoy Bay (Peter the Great Gulf, Sea of Japan/East Sea) was studied based on the surveys carried out in 2016-2021. The contamination of the sediments in the bay was compared to the background concentrations of elements and to common contamination indices. The degree of contamination was calculated using the contamination factor (Cf), modified overall degree of contamination (mCd), and index of geoaccumulation (Igeo). The toxicity of marine sediment samples for each metal was evaluated using the threshold effect level/probable effect level (TEL/PEL) values and the sediment quality guideline quotient (SQG-Q). The sources of pollutants entering the studied water area were analyzed. It is shown that the contamination of the Uglovoy Bay occurs continuously as a result of economic activities on its coast. The dynamics of contamination of the bay for the period 2016-2021 is presented.

Cobalt, Chromium and lead heavy metals accumulation from animal dung, soil and rice grain through Vermic-activity by Lampito mauritii Kinberg

Heavy metals are a severe concern that causes a variety of health issues in both human beings and animals. They also have an impact on the variety of soil organisms and the ecosystem. The inoculation of earthworms in their natural environments can assist in monitoring heavy metal concentrations. The earthworm Lampito mauritii is a significant species for bioaccumulating highly toxic metals from soil and organic wastes for vermicomposting. This research aims to investigate the concentrations of heavy metals such as cobalt (Co), chromium (Cr), and lead (Pb) found in various animal dungs, earthworm Lampito mauritii body tissues before and after vermicomposting, soil, and rice grains (Oryza sativa L.). Compared to the initial feed mixture of various animal dungs, it was found that the Co, Cr, and Pb heavy metal concentrations decreased (P < 0.05) in the final vermicompost. When the soil was mixed with cow dung vermicompost that had been inoculated with the earthworm Lampito mauritii, the highest concentrations of cobalt (Co) and chromium (Cr) were found to decrease by nearly 44.03% and 17.08%, respectively, while the maximum concentration of lead (Pb) was significantly reduced by 32.46% when the soil was mixed with goat dung. Heavy metal concentrations in rice grains were measured both before and after harvesting. When the soil was combined with goat dung vermicompost, the highest concentrations of Co, Cr, and Pb were found to decrease. Before and after crop harvesting, heavy metal concentrations were also investigated in the earthworm body in soil and soil with vermicompost of different animal dungs. When soil and cow dung were combined, the highest amount of cobalt (Co) was found to increase by 29.91% in the earthworm Lampito mauritii body, whereas the highest concentrations of chromium (Cr) and lead (Pb) were found to increase by 18.05% and 30.22%, respectively, in the earthworm body when soil and buffalo dung were combined. For the protection of both the health of humans and the environment, vermicomposting and the utilization of Lampito mauritii are considered to be efficient methods for extracting these harmful metals from rice field soil.

Corrosion of Household Utensils: Causes, Effects and Remedies

This article was motivated by the avalanche of finance spent annually on addressing the harm caused by corrosion on household wares and buildings, industrial machines and facilities, hospital equipment and many other establishment of man in the universe. Corrosion is a universal phenomenon referred to as the deterioration of metallic material. Metal alloys like stainless steel and aluminium are extensively used in household utensils for their durability, affordability and corrosion resistance. However, these materials can leach heavy metals such as chromium, nickel, iron, and aluminium into food, posing serious health challenges. Stainless steel, despite its corrosion resistance, releases harmful metals when exposed to acidic foods, while aluminium utensils corrode and release harmful elements under certain conditions too. Hence, this article was aimed at examining the historical background of corrosion, the causes of corrosion in household wares and utensils, its impact especially on human health and economy, and the potential remedies. The findings indicated that acidic foods and prolonged storage increase metal leaching. Health concerns included increased risks of anemia, dementia, and osteomalacia due to excessive metal accumulation in the body. Mitigation strategies included using anodized aluminium, minimizing storage time of acidic foods in metal containers, and increasing public awareness about the potential health risks. Proper maintenance and selection of utensils could significantly reduce the hazards associated with metal leaching.

Mechanical and environmental properties of geopolymer-stabilized domestic waste incineration slag in an asphalt pavement base

Domestic waste incineration slag (WIS) includes fly ash and slag. Fly ash is classified as hazardous waste because it contains heavy metals. Most of slag are directly stacked or landfilled due to problems such as large output and low utilization rate. Harmless treatment is imminent. If WIS is used effectively in the road engineering, which can realize the high-quality and high-efficiency recycling of WIS, and it is of great significance to save resources and protect the environment. This study applies a geopolymer prepared from WIS fly ash as a stabilizing agent in WIS blending macadam for use as a pavement base mixture, and reports the mechanical properties (unconfined compressive strength, splitting strength, and resilience modulus) of the geopolymer-stabilized WIS blending macadam (GeoWIS). The leaching concentrations of harmful heavy metals of GeoWIS soaked in water were also investigated. Finally, the strength formation and heavy metal stability mechanisms were explored. The unconfined compressive strength, splitting strength, and compressive resilient modulus of GeoWIS all increased with increasing geopolymer content and decreasing WIS content. The strength of GeoWIS was derived from its geopolymerization and hydration products (C-S-H gel, N-A-S-H gel, and AFt). When the geopolymer content reached 12%–14%, the GeoWIS without natural macadam met the strength criterion of the asphalt pavement base. Through physical adsorption and chemical bonding, the geopolymer significantly reduced the leaching of harmful heavy metals. In GeoWIS with 50% WIS and stabilized with 10% geopolymer, the Cr, Ni, Cd, and Pb concentrations met the grade Ⅲ groundwater standard. Concentrations of heavy metals leached from GeoWIS are low and exert little impact on environment.

Impact of Pb Toxicity on the Freshwater Pearl Mussel, Lamellidens marginalis: Growth Metrics, Hemocyto-Immunology, and Histological Alterations in Gill, Kidney, and Muscle Tissue

Pb is one of the most extensively used harmful heavy metals in Bangladesh, and its occurrence in waters affects aquatic organisms significantly. The tropical pearl mussel, Lamellidens marginalis, was exposed to different concentrations (T1 21.93 mgL−1, T2 43.86 mgL−1, and T3 87.72 mgL−1) of Pb(NO3)2 and was evaluated against a control C 0 mgL−1 of Pb(NO3)2, followed by a 96 h acute toxicity test. The LC50 value was recorded as 219.32 mgL−1. The physicochemical parameters were documented regularly for each treatment unit. The values of % SGR, shell weight, soft tissue wet weight, and weight gain remained statistically higher for the control group in comparison with the treatment. No mortality was noted for control units, while a gradually decreased survival rate was recorded for the different treatment groups. Fulton’s condition factor was recorded as highest in the control and lowest in the T3 unit, while the condition indices did not vary between the control and treatment groups. The hemocyte was accounted as maximum in the control and T1, while minimum in T2 and T3. The serum lysosomal parameters also followed a similar pattern, and a significantly low level of lysosomal membrane stability, and serum lysosome activity was noted for T3 and T2 units in comparison to the control group. The histology of the gill, kidney, and muscle was well structured in the control group, while distinct pathologies were observed in the gill, kidney, and muscle tissue of different treatment groups. The quantitative comparison revealed that the intensity of pathological alteration increased as the dosage of Pb increased. The current study, therefore, indicated that intrusion of Pb(NO3)2 in the living medium significantly alters growth performance and hemocyte counts, and chronic toxicity induces histomorphological abnormalities in vital organs.

CeO2 quantum dots decorated g-C3N4 nanosheets: A potential scaffold for fluorescence sensing of heavy metals and visible-light driven photocatalyst

Herein, we report the synthesis of g-C3N4/CeO2 heterostructure using a facile co-precipitation method. The as-synthesized g-C3N4/CeO2 heterostructure was examined by several techniques in order to understand the morphology, thermal, structural, optical and compositional properties. A strong interfacial contact was observed between g-C3N4 nanosheets and CeO2 quantum dots (QDs) as CeO2 QDs were deposited on g-C3N4 nanosheets with slight agglomeration. The as-synthesized heterostructure was successfully applied as a probe for the fluorescence sensing of heavy transition metals (Cu(II), Hg(II) and Ag(I)) and a visible light active photocatalyst for the decomposition of tetracycline (TC) in an aqueous phase. The g-C3N4/CeO2 heterostructure exhibited remarkable selectivity towards the sensing of Cu(II), Hg(II) and Ag(I) heavy metal ions because of strong binding affinity of these metal ions towards nitrogen and oxygen containing functional moieties present in g-C3N4/CeO2 heterostructure. Furthermore, a good linearity was observed between the relative FL intensity and concentration of Cu(II), Hg(II) and Ag(I) ions with detection limit estimated to be 26.2 µM, 17.5 µM and 14.9 µM, respectively. The high selectivity for these ions was due to their strong binding affinity towards nitrogen and oxygen containing functional groups in g-C3N4/CeO2 heterostructure. Moreover, the removal efficiency of 77.95% was acquired for degradation of tetracycline in 160 min using g-C3N4/CeO2 heterostructure under optimized conditions. The photocatalytic results of the heterostructure could be accredited to the reduction in the recombination of excited carriers across the interface of the heterojunction. Therefore, the present work provides an effective strategy for the preparation of fluorescent photocatalytic materials that can be utilized for the FL detection of harmful heavy metal ions as well as degradation of pollutants in an aqueous phase.

Recent advances in conducting polymer-based magnetic nanosorbents for dyes and heavy metal removal: fabrication, applications, and perspective.

Globally, treating and disposing of industrial pollutants is a techno-economic challenge. Industries' large production of harmful heavy metal ions (HMIs) and dyes and inappropriate disposal worsen water contamination. Much attention is required on the development of efficient and cost-effective technologies and approaches for removing toxic HMIs and dyes from wastewater as they pose a severe threat to public health and aquatic ecosystems. Due to the proven superiority of adsorption over other alternative methods, various nanosorbents have been developed for the efficient removal of HMIs and dyes from wastewater and aqueous solutions. Being a good adsorbent, conducting polymer-based magnetic nanocomposites (CP-MNCPs) has drawn more attention for HMIs and dye removal. Conductive polymers' pH-responsiveness makes CP-MNCP ideal for wastewater treatment. The composite material absorbed dyes and/or HMIs from contaminated water could be removed by changing the pH. Here, we review the production strategies and applications of CP-MNCPs for HMIs and dye removal. The review also sheds light on the adsorption mechanism, adsorption efficiency, kinetic and adsorption models, and regeneration capacity of the various CP-MNCPs. To date, various modifications to conducting polymers (CPs) have been explored to improve the adsorption properties. It is evident from the literature survey that the combination of SiO2, graphene oxide (GO), and multi-walled carbon nanotubes (MWCNTs) with CPs-MNCPs enhances the adsorption capacity of nanocomposites to a large extent, so future research should lean toward the development of cost-effective hybrid CPs-nanocomposites.

Adsorption of toxic metals from landfill leachate onto guinea fowl eggshells in the era of green chemistry

One of the best and most affordable ways to remove harmful metals from water is by adsorption. This study investigated the efficiency of guinea fowl (Numida meleagris) eggshells as a low-cost adsorbent for cadmium (Cd) and nickel (Ni) removal from landfill leachate. In replicas, 100 mL wastewater was added to each of the weighed adsorbent dosages (1 g, 1.5 g, 2 g, 2.5 g, 3.0 g, and 3.5 g) in a flat-bottom flask and agitated for 60 minutes at pH of 7.82 and temperature 24 °C. The adsorption efficacy of cadmium and nickel by guinea fowl eggshells were 90.5% to 96.5% and 96.1% to 99.3%, respectively. The maximum adsorption capacity of cadmium was 4.89 × 10-2 mg/g and an adsorption equilibrium (KL) 22.74 mg/L. The Langmuir isotherm model was better fitted to the results of the experiment than the Freundlich isotherm model.

Metals Removal from Contaminated Aqueous Medium by Using Modified Cellulose-N(4)-Antipyrinyl Thiosemicarbazide

Water contamination by harmful heavy metal ions was considered the major problems in environmental health field. This work focused to synthesize of the modified cellulose and investigate it as a possible metal cations adsorbent. Modified cellulose was prepared and identified by elemental analysis, (X-ray), (SEM) and (FTIR) spectroscopy. The ability of modified cellulose to adsorb heavy metals ions was investigated by batch experiments according to various conditions for example pH of the solution, temperature degree, time of the contact between adsorbent and adsorbate, adsorbent weight and the concentration of the metal’s cations. SEM micrograph showed that the modified material has irregularly shaped pores and cavities. Elemental and FTIR analyses indicate the success of the addition process of N(4)-antipyrinyl thiosemicarbazide moiety onto cellulose. The obtained data showed that the maximum uptake efficiency (100%) of Pb2+, Cd2+, Mn2+, Ni2+ and Fe3+ reached at optimal pH= 7 for [Cd2+, Mn2+and Fe3+] and pH= 5 for [Pb2+and Ni2+]. The optimum used dosages are 0.07 g for [Pb2+and Ni2+] and 0.09 g for [Cd2+, Mn2+and Fe3+]. All experiments were achieved at 1 h contact time, room temperature and an initial concentration 3 ppm. Kinetic investigations showed that the uptake of metals ions onto modified cellulose was chemical adsorption and follow Langmuir adsorption model. Also, the results of thermodynamic characteristics show that the metal cation adsorption process is exothermic and spontaneous. Highlights Cel-ATH was prepared through the addition of N(4)-antipyrinyl thiosemicarbazide to cellulose. Modification was done to increase the removal ability of cellulose. The adsorption efficiency of Cel-ATH was examined via batch technique. The adsorption was examined on single component solution system. Cel-ATH removed different metals from wastewater sample.

High-Voltage and High-Temperature LiCoO2 Operation via the Electrolyte Additive of Electron-Defect Boron Compounds

Commercial LIBs have the problem of instability interface of electrolyte/cathode at high voltage and high temperature. This work reports a novel series of electron-defect boron compounds to construct stable interfaces of LCO/electrolyte. The results of theoretical calculation indicate that compounds of DPD scaffold can win in the competitive oxidation decomposition for interface regulation. F-rich and B-rich interface is designed by modifying the functional group of DPD scaffold. This strategy of in situ interface design successfully suppresses the dissolution of harmful transition metal ions and the nucleophilic reaction between electrolyte and cathode. Li/LCO cell can remain stable at high voltage (4.5 V) and high temperature (70 °C) in commercial carbonate electrolyte after DPD-F interphase formation. Meanwhile, faster Li+ extraction and insertion kinetics of DPD-F-interface make the Li/LCO cell stable at 4.6 V. Spectral characterizations and theoretical calculations uncover the secret of the forming process of this DPD-F-interface.

Effective and sustainable bioremediation of molybdenum pollutants from wastewaters by potential microalgae

Due to industrialization and growing population have greatly affected the quality of natural water resources globally. Molybdenum is a harmful metal that can cause serious health issues when exposed to >10 ppm levels. Several industries routinely discharged it, hence posing the environmental problems. For discharged industrial effluents, there are not any environmentally friendly and sustainable treatment method have developed for removing molybdenum hazards. The objective of this study was to design a green, sustainable approach for removing the molybdenum pollutant and to offset the treatment cost by obtaining values from microalgal by-products. Chlorella sorokiniana TU5 and Picochlorum oklahomensis, two fast-growing microalgal strains, were used for molybdenum treatment. The maximum removal efficiency was 115.65 mg L−1 with biomass and lipid yield of 2.35 g L−1 and 579.3 mg L−1, respectively, after 14 days of growth and further exposure to molybdenum pollutant. The molybdenum removal capacity was further increased by optimizing crucial factors, pH and temperature before removing biomass from the aqueous phase. Zeta potential study helped to determine the pH range that appropriately facilitate the strongest possible ionic bonds, leading to the enhanced molybdenum adsorption. In order to verify molybdenum adsorption and comprehend the dominating and quantitative interactions, FTIR was carried out to analyze the reactive groups in the algal cell surface. The current work analyses to control external parameters for improving the adsorption efficiency during harvesting of microalgal biomass, which efficiently improved the removal of molybdenum (V) from the liquid phase. The proposed technique aims to improve the bioremediation efficiency of molybdenum and other inorganic contaminants at an industrial scale by using microalgal treatment.

A REVIEW ON THE TOXIC EFFECT OF NICKEL INDUCED STRESS ON GROWTH AND DEVELOPMENT IN RICE SEEDLING (ORYZA SATIVA L.)

Rice (Oryza sativa L.) is the main food of different countries in the world. Currently, the demand for food is increasing along with the increase in population in the world therefore, the demand for rice is constantly increasing due to rice being the staple food of various countries. As the population and human need increase, the environment is continuously polluted. In order to grow good crops, we mix various chemicals in the soil, besides, many harmful heavy metals mixed in the soil from various factories and household waste. One of the most harmful heavy metals is nickel. Nickel comes into contact with rice plants and plant seeds. A certain amount of nickel is good for plant growth but above this level it causes physiological and chemical process changes as well as morphology of the plant, like germination rate plant root and shoot height, weight all decrease, the activity of various enzymes required for growth cycle of rice plant is inhibited. For this increasing nickel concentration level nitrogen metabolism may not function properly because the changes of amount of nitrate, nitrite, and ammonium. Elevated levels of Nickel cause damage the biological and chemical pathway of rice plants which are very harmful for them lifecycle. This review aims to summarize the different responses of rice like physiological, morphological, molecular and biochemical changes when nickel concentration increased rapidly.

Investigating the impact of toxicity on plant growth dynamics through the zero of a fifth-degree exponential polynomial: A mathematical model using DDE

The initial focus of our research was to study the distribution of zero in a fifth-degree exponential polynomial. Subsequently, we utilized the findings to examine the impact of toxicity on plant populations. Plant growth by separating the plant into its root and shoot compartments and analysing various factors such as structural dry weight, nutrient levels, and the presence of harmful metals in the soil. They theorize that these metals can inhibit root absorption of essential nutrients and cause structural damage. By including a time delay in the movement of nutrients from roots to shoots, researchers have been able to examine this phenomenon and its impact on the system's stability using numerical simulations in MATLAB. This analysis has also revealed a Hopf-bifurcation caused by the crucial role of time delay.