Green Algae as Bioindicators of Heavy Metal Contamination in the Korba Industrial Region, Chhattisgarh, India

Biosorption of heavy metals from wastewater using Saccharomyces cerevisiae as a biosorbent: A mini review

The increasing levels of toxic heavy metals in aquatic environments pose significant threats to ecosystems, biodiversity, and human health. The Diva-Motagaon Creek, located in Thane District, Mumbai, is one such site under investigation in this study, which aims to analyze the concentrations of various toxic heavy metals in sediment samples. As a reliable and accurate method, Atomic Absorption Spectroscopy (AAS) was used to study the effects of long-term pollution load and the buildup of heavy metal contaminants in this estuarine ecosystem.Sediment samples were collected from four strategically selected stations along the Diva-Motagaon Creek, covering four seasons from January 2023 to December 2023. The four seasons—pre-monsoon, monsoon, post-monsoon, and summer—were chosen to capture the seasonal variations in pollution levels, as aquatic environments are highly dynamic and pollutant concentrations can fluctuate due to factors like rainfall, industrial runoff, and human activities. The collected samples were analysed for the presence of chromium (Cr), copper (Cu), iron (Fe), lead (Pb), and zinc (Zn), which are commonly found in environmental pollution, particularly industrial effluents, urban runoff, and agricultural practices.The analysis revealed notable variations in the concentrations of these heavy metals across different seasons and geographical locations within the creek. Zinc was found to be the most abundant heavy metal, followed by iron, copper, lead, and chromium, in that order. The fact that the concentration changes with the seasons suggests that the metal levels are affected by things like industrial discharges, monsoon runoff, and human activities in the area, such as religious events like immersing Ganapati idols. Among the studied metals, zinc showed the highest concentrations, which may be attributed to local industrial activities and sewage discharge into the creek.The results of this study demonstrate that heavy metal pollution in Diva-Motagaon Creek is influenced by a combination of natural processes and anthropogenic activities. High levels of metals like lead, copper, and chromium are especially bad for the environment because they can build up in aquatic organisms and make fish, invertebrates, and other marine life sick. Zinc, while essential in trace amounts for aquatic organisms, can become toxic in higher concentrations, disrupting the health of aquatic ecosystems.The study’s findings are crucial for environmental management and policy development, as they offer a scientific basis for monitoring and controlling pollution in the Diva-Motagaon Creek. The findings indicate the need for immediate action to reduce the heavy metal concentrations in the creek, particularly through effective waste management practices, industrial regulation, and pollution control strategies. The fishing industry is prevalent in the area, and the study's results emphasise the importance of protecting aquatic resources to ensure the safety of local livelihoods and the sustainability of the marine ecosystem.This study sets a baseline for the current level of pollution, which is very important for future research and actions that will be taken to help the environment and lessen the harmful effects of heavy metal pollution. The results can inform the rational planning of pollution control strategies and support efforts to restore and protect the health of Diva-Motagaon Creek. The results also show how important it is for scientists to keep an eye on things all the time to learn more about how heavy metal toxicity changes over time and how it affects marine and estuarine environments over time.The increasing levels of toxic heavy metals in aquatic environments threaten ecosystems, biodiversity, and human health. Atomic Absorption Spectroscopy (AAS) is used to look at heavy metal contamination in sediment samples from Diva-Motagaon Creek in Thane District, Mumbai. In 2023, samples were taken from four locations during four seasons: pre-monsoon, monsoon, post-monsoon, and summer. The goal was to see how the concentrations of chromium (Cr), copper (Cu), iron (Fe), lead (Pb), and zinc (Zn) changed with the seasons.Results revealed significant seasonal and spatial variations, with zinc being the most abundant metal, followed by iron, copper, lead, and chromium. High metal levels, especially during and after the monsoon season, are a sign of pollution from factories, urban runoff, and human activities like immersing Ganapati idols. While zinc is essential in trace amounts, its high concentrations, along with toxic levels of lead, copper, and chromium, pose ecological risks through bioaccumulation in aquatic organisms.These findings highlight the urgent need for pollution control measures, including industrial regulation, improved waste management, and continuous environmental monitoring. Given the creek’s significance to local fisheries, mitigating heavy metal contamination is crucial for preserving marine ecosystems and safeguarding livelihoods. This study establishes a baseline for future research and policy interventions to restore and protect Diva-Motagaon Creek.

Prospective bioremediation of toxic heavy metals in water by surfactant exopolysaccharide of Ochrobactrum pseudintermedium using cost-effective substrate.

Heavy metal pollution is a significant global health concern, posing risks to both the environment and human health. Exposure to heavy metals happens through various channels like contaminated water, food, air, and workplaces, resulting in severe health implications. Heavy metals also disrupt the gut's microbial balance, leading to dysbiosis characterized by a decrease in beneficial microorganisms and proliferation in harmful ones, ultimately exacerbating health problems. Probiotic microorganisms have demonstrated their ability to adsorb and sequester heavy metals, while their exopolysaccharides (EPS) exhibit chelating properties, aiding in mitigating heavy metal toxicity. These beneficial microorganisms aid in restoring gut integrity through processes like biosorption, bioaccumulation, and biotransformation of heavy metals. Incorporating probiotic strains with high affinity for heavy metals into functional foods and supplements presents a practical approach to mitigating heavy metal toxicity while enhancing gut health. Utilizing probiotic microbiota and their exopolysaccharides to address heavy metal toxicity offers a novel method for improving human health through modulation of the gut microbiome. By combining probiotics and exopolysaccharides, a distinctive strategy emerges for mitigating heavy metal toxicity, highlighting promising avenues for therapeutic interventions and health improvements. Further exploration in this domain could lead to groundbreaking therapies and preventive measures, underscoring probiotic microbiota and exopolysaccharides as natural and environmentally friendly solutions to heavy metal toxicity. This, in turn, could enhance public health by safeguarding the gut from environmental contaminants.

Effects of Paenibacillus polymyxa WZ14 inoculation on phytoextraction efficiency and rhizosphere soil bacterial characteristics in multi-heavy metals contaminated soil.

Cadmium (Cd) and lead (Pb) contamination in soils pose a serious environmental challenge requiring urgent remediation. This study aimed to evaluate the efficiency of Serratia marcescens 2G5 and Amorpha fruticosa L. in the synergistic remediation of heavy metal-contamination in soil, and to investigate the effect of 2G5 inoculation on the bioaccumulation and translocation of Pb and Cd in A. fruticosa L. and the rhizosphere soil microbiomes. The results showed that 2G5 inoculation mitigated the negative impacts of Cd and Pb stress on A. fruticosa L., increasing total plant biomass by 22.19 % and enhancing the phytoextraction efficiency of Cd and Pb by 64.18-102.87 %. The positive effects of 2G5 inoculation on the growth and soil remediation of A. fruticosa L. were probably attributed to the significant improvements in soil enzyme activities (urease, acid phosphatase, catalase, and sucrase) and soil nutrient contents [Total phosphorus (TP), available phosphorus (AP) and hydrolyzed nitrogen (AN)]. Principal co-ordinate analysis revealed that both heavy metal contamination and 2G5 inoculation significantly influenced the bacterial community structure in the rhizosphere soil, with the influence of heavy metals being greater than that of the inoculation. Patescibacteria (27.02 %-30.12 %) have replaced Proteobacteria (22.38-24.02 %) as the dominant phyla in contaminated soil. The Mantel test results indicated that soil heavy metals, along with AP and urease, were the primary environmental factors influencing the bacterial community at the phylum level under heavy metal contamination. Furthermore, linear discriminant analysis effect size (LEfSe) identified Ellin6067 (Nitrosomonadaceae) and Dongia (Rhodospirillaceae) as the key bioindicators of heavy metal contamination and Sphingomonas and Micropepsis as the key bioindicators of 2G5 inoculation. In conclusion, the findings of this study revealed the potential and feasibility of combining S. marcescens 2G5 and A. fruticosa L. for the remediation of soil heavy metal- contamination, offering a viable strategy for microbial agents and plants to cooperate in mitigating heavy metal contamination in soil.

Heavy metal accumulations in tropical seaweed and seagrass species as the basis of an ecological risk assessment.

The biosorption of several toxic heavy metals (Pb, Cd, Co, Ni, Zn and Cu) by the exopolysaccharide (EPS) produced by Paenibacillus jamilae, a potential biosorbent for metal remediation and recovery was studied. Firstly, the biochemical composition of this bacterial polymer was determined. Glucose was the most abundant neutral sugar, followed by galactose, rhamnose, fucose and mannose. The polymer presented a high content of uronic acids (28.29%), which may serve as binding sites for divalent cations. The presence of carboxylic groups was also detected by infrared spectroscopy. The EPS presented an interesting affinity for Pb in comparison with the other five metals. Lead biosorption (303.03 mg g−1) was tenfold higher (in terms of mg of metal adsorbed per gram of EPS) than the biosorption of the rest of metals. Biosorption kinetics, the effect of pH and the effect of competitive biosorption were determined. Finally, we found that the EPS was able to precipitate Fe(III), but the EPS-metal precipitate did not form with Fe(II), Pb(II), Cd(II), Co(II), Ni(II), Cu(II) and Zn(II).

Heavy metals, the most potent contaminants of the environment, are discharged into the aquatic ecosystems through the effluents of several industries, resulting in serious aquatic pollution. This type of severe heavy metal contamination in aquaculture systems has attracted great attention throughout the world. These toxic heavy metals are transmitted into the food chain through their bioaccumulation in different tissues of aquatic species and have aroused serious public health concerns. Heavy metal toxicity negatively affects the growth, reproduction, and physiology of fish, which is threatening the sustainable development of the aquaculture sector. Recently, several techniques, such as adsorption, physio-biochemical, molecular, and phytoremediation mechanisms have been successfully applied to reduce the toxicants in the environment. Microorganisms, especially several bacterial species, play a key role in this bioremediation process. In this context, the present review summarizes the bioaccumulation of different heavy metals into fishes, their toxic effects, and possible bioremediation techniques to protect the fishes from heavy metal contamination. Additionally, this paper discusses existing strategies to bioremediate heavy metals from aquatic ecosystems and the scope of genetic and molecular approaches for the effective bioremediation of heavy metals.

Synthetic biology techniques to tackle heavy metal pollution and poisoning

Heavy metal bioaccumulation in aquatic organisms of open water aquatic ecosystems was detected globally, including Bangladesh. This study evaluated the hypothesis of whether heavy metal contamination in aquatic habitats impacts fish growth and reproduction using wild Channa punctata as an experimental animal. The growth and reproductive health of a wild freshwater fish, C. punctata, collected from five freshwater habitats, were assayed with heavy metal bioaccumulation. Atomic absorption spectrometry detected the bioaccumulation of cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb) in the muscle of C. punctata. Cd, Cr, and Pb concentrations were the highest in the specimen collected from the Turag River and the lowest in the Dharla River. The highest concentration of Hg was found in C. punctata specimens collected from the Karatoya River (0.093±0.004mg/kg). The length-weight relationship and condition factor of C. punctata indicated a negative allometric growth pattern (b<3.0) and poor wellness (F<1.0) in all the stocks except Dharla River. We estimated the size at first sexual maturity (L50), ova diameter, fecundity, and gonadosomatic index (GSI) to assess reproductive health and determined the correlation with heavy metal bioaccumulation. We found that higher bioaccumulation of heavy metal impairs the reproductive health of C. punctata by lowering spawning performance. This study showed that heavy metal bioaccumulation impaired fish's growth and reproductive health, potentially affecting future recruitment and fishery sustainability.

Paramecium bursaria is an unicellular organism, widely distributed in the freshwater environment, where heavy metals are common contaminants. The ciliates, also including Paramecium bursaria, are a very abundant group in aquatic ecosystems, what makes them effective biological indicators of water pollutants. Paramecium bursaria is the only Paramecium which has evolved a mutualistic relationship with algae and it harbors these endosymbionts in its own cytoplasm. The algae are also very effective bioindicators of some pollutants because of their ability to biosorption and bioaccumulation of heavy metals. The aim of this study was to determine the acute toxicity of two metals’ compounds: nickel chloride (NiCl2) and zinc chloride (ZnCl2) to Paramecium bursaria and its endosymbionts. The ciliates were incubated in solutions with 5x10-8 to 5x10-2g/dm3 of NiCl2 and with 5x10-8 to 5x10-2g/dm3 of ZnCl2, at the temperature of 180C, in the light/dark conditions (12L/12D). Microscopic observations of cell divisions rate, cell shape changes as well as the swimming behavior, were conducted after 24, 48, 72 and 120 hours of incubation in the tested solutions and were compared to the control sample. Microscopic observations revealed the lethal doses for both compounds, for nickel chloride 5x10-5g/dm3 and for zinc chloride 5x10-3. These observations also revealed that in lesser concentrations than the lethal one, the slowdown and characteristic movements occur after metal addition. The PEA measurements of Fv/Fm parameter were carried out within 4 days, the first one after 24 hours of incubations. The results of this investigation has given us a view of a fluorescence efficiency by revealing that both compounds solutions can have the stimulating effect on Photosystem II, because the lowest fluorescence efficiency was measured in control samples.

TiO2 nanoparticles enhance bioaccumulation and toxicity of heavy metals in Caenorhabditis elegans via modification of local concentrations during the sedimentation process

The potential bioaccumulation of hazardous transitional heavy metals in components of the aquatic environment (such as water column, sedimentary matter, plants) constitutes one of the concerns in environmental protection engineering. This experimental investigative study used systematic measurements of the presence of selected heavy metals (cadmium, chromium, copper, lead, nickel and zinc) in components of the aquatic environment to give an indication of their availability and their potential bioaccumulation in the perennial wetland plants. Through environmental quality data processing, this study allowed both the assessment of interphase partitioning constants of these metals throughout the analyzed aquatic environment and the estimation of their cumulative toxicity coëfficiënt. The data analysis highlighted the different potential degrees of dangers caused by metals as pollutants and the synergistic way in which they act on the aquatic environment.

Phytohormones as regulators of heavy metal biosorption and toxicity in green alga Chlorella vulgaris (Chlorophyceae)