The game changer of biofilm in microplastic pollution and potential environmental risks: Unveiling the pivotal roles on surface modification, metal adsorption, and biological uptake.

Effects of short-term exposure to ferrous sulfate on bioaccumulation, oxidative stress biomarkers, immunity, and intestinal microbiota in Litopenaeus vannamei.

Microplastics representa significant environmental threat owingto their persistence and resistance to degradation. Their co-occurrencewith heavy metals in aquatic environments exacerbates the risks ofcomplex pollution. While most current research focuses on conventionalmicroplastics such as polyethylene and poly­(vinyl chloride), functionalizedmicroplastics, which exhibit richer functional groups and more complexenvironmental behaviors, remain insufficiently studied. This researchexamines the adsorption behaviors of cadmium (Cd2+), copper (Cu2+), and lead (Pb2+) onto three types of functionalized microplastics: polyacrylate(PAT), biobased polyurethane (BPU), and petroleum-based polyurethane(PPU). Analyses based on Langmuir and Freundlich isotherm models indicatethat microplastics with a particle size of 150 μm exhibit significantlyenhanced adsorption capacities for Cd2+, Cu2+, and Pb2+, showing increasesof 5–18.62, 12.91–18.04, and 8.7–12.31%, respectively,compared to larger particles (1–2 mm). Among the tested materials,polyacrylate (PAT) exhibited the strongest adsorption affinity, withLangmuir maximum capacities (qm) of 34.68,29.85, and 12.31 mg/g for Pb2+, Cu2+, and Cd2+, respectively, followingthe order: Pb2+ > Cu2+ > Cd2+. Furthermore, UV aging increasedtheadsorption capacity of PAT for Cd2+ from 7.07to 11.22 mg/g, as described by the pseudo-second-order model. However,the rate constant (k2) decreased from0.027 to 0.006 g/(mg·min), indicating slower adsorption kinetics.These findings provide valuable insight into the interaction mechanismsbetween microplastics and heavy metals, offering a scientific basisfor assessing their copollution behavior and ecological risks.

Heavy metals in aquatic environments pose significant environmental and human health risks, highlighting the urgent need for innovative remediation strategies. This study explores the role of bacterial extracellular polymeric substances as active binding surfaces for copper, in planktonic cells and biofilm-based adsorption systems. Serratia plymuthica strain As3-5a(5) achieved 92% Cu(II) biosorption (from an initial concentration of 3.14 mM) within 4 min in a non-proliferating planktonic cell system, and 98% biosorption in a biofilm-based system on sintered glass. Maximum metal biosorption was achieved by late stationary phase grown cells (72 h), likely due to an increased protein fraction in the tightly bound extracellular polymeric substances. When in the presence of real electroplating wastewater containing 40 mM Cu(II) at pH 1.9, planktonic cell system (1011 cells mL−1) achieved 97% Cu(II) biosorption. These results highlight the strong potential of Serratia plymuthica strain As3-5a(5) for developing efficient biological systems for heavy metal removal from industrial wastewater. Furthermore, this work provides valuable insights into sustainable biotechnological approaches for copper remediation, with potential applications in catalytic processes and metal recovery within a circular economy framework. Future studies should involve synthetic biology approach to improve copper sequestration and to investigate the scalability of these systems to higher technology readiness levels under real industrial wastewater conditions.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10532-026-10245-6.

Water pollution usually results from discharge of untreated or partially treated human and industrial waste into water bodies, and nanomaterials are increasingly being recognized as a sustainable alternative remediation approach. The aim of the present study is to determine the structural properties and possible adsorption property of hydrothermally synthesized MnO2 nanoparticles. The synthesized nanoparticles were characterized using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller surface area analysis, Fourier-transform infrared spectroscopy and UV-Visible spectroscopy. The nanoparticles primarily exhibited small crystallite sizes, structural disorder, and mostly amorphous material. Manganese was dominant in the nanoparticles as evidenced by surface shape and chemical composition but diminished with rising temperature. The surface area peaked at 110oC and decreased at higher temperatures possibly due to pore collapse and sintering effect, suggesting that annealing temperature had a significant impact on the mesoporous structure. FTIR and UV-Visible data suggest the presence of surface hydroxyl groups evidenced by moisture absorption, an O-Mn-O stretching that promotes hydrogen bonding and bandgap energies that allow for possible visible-light photocatalysis. Incorporating these results with existing research, the adsorption mechanism is expected to include electrostatic interactions controlled by surface charge, chemisorption via redox-active Mn sites, cation exchange regulated by potassium intercalation, and synergistic physisorption. The study also suggests that controlled thermal treatment enhanced adsorption performance as nanoparticles annealed at 90-110°C are expected to exhibit optimal adsorption qualities. Overall, findings from this study offer a starting point for producing efficient MnO2-based adsorbents capable of removing organic pollutants and heavy metals in aquatic environment.

Mechanistic insights into microalgal removal of ciprofloxacin-copper co-contaminants: Extracellular polymeric substances adsorption, intracellular degradation, and combined toxicity.

Bioremediation of heavy metals in aquatic environment: A review

A novel electrochemical sensor based on an AuNPs–chitosan/g-C 3 N 4 nanocomposite was fabricated for the sensitive detection of Pb 2+ ions. The modified electrode exhibited a significantly high electroactive surface area (0.099 cm 2 ) and improved charge transfer properties, which was reflected in a reduced R ct value (304 Ω) compared to the bare GCE (506 Ω). Under optimized conditions (acetate buffer, pH 5.0; Cs:g-C 3 N 4 ratio 0.1:1; AuNP loading 11%; 5 μl drop-casting), the sensor displayed excellent analytical performance, including a wide linear range of 1–12 μM (R 2 = 0.997), a low limit of detection (LOD 0.014 μM) and limit of quantification (LOQ 0.046 μM), and high sensitivity (264.6 μA · μM −1 · cm −2 ). The electrode also showed good repeatability (RSD = 1.1%, n = 4), high selectivity against coexisting metal ions (Cd 2+ , Zn 2+ , Fe 2+ , Fe 2+ , and Cu 2+ ), and satisfactory recoveries (89%–94%, RSD <5%) in tap and irrigation water samples. The sensing mechanism involves adsorption of Pb 2+ and complexation with chitosan and g-C 3 N 4 , followed by electrochemical reduction and anodic reoxidation. These results underline the great potential of the Au/Cs/g-C 3 N 4 nanocomposite for the development of reliable electrochemical sensors for monitoring heavy metals in aquatic environments.

Introduction. The presence of heavy metals in aquatic environments creates environmental problems. Sorption treatment with zeolite from the Shankanai deposit is a promising method for removing heavy metal ions from aqueous solutions due to its high selectivity, cost-effectiveness and environmental sustainability. The aim of the work is to study the sorption properties of natural zeolite with respect to Co2+, Ni2+ and V4+ cations from aqueous media using the saturation method. Results and discussion. Studies were carried out using the saturation method on the sorption of individual Co2+, Ni2+ and V4+ cations by natural zeolite and in two metal-containing systems: "Ni2+–Co2+–NZ–H2O"; "Ni2+–V4+–NZ–H2O"; "Co2+–V4+–NZ–H2O" from an aqueous environment. Increasing the concentration of both cobalt (II) and nickel (II) cations in solutions to 10 mg/L increases the degree of Ni2+ sorption by 2.5 times and Co2+ by 4.8 times compared to solutions containing 5.0 mg/L. Maxima are recorded on the sorption curves at C(Ni/Co) = 10 mg/l. The degree of cation sorption in the Ni2+/Co2+/V4+ – H2O systems with the working concentration of the studied cations does not exceed 55% on average. Zeolite in the Ni2+–Co2+–NZ–H2O system exhibits preferential sorption capacity with respect to Ni2+ cations; at CNi = 30 mg/L it absorbs 0.72 mg/L of CO(II) cations and 28.3 mg/L of Ni (II) cations, i.e. RNi>RСо. In the Ni2⁺–V4⁺–PC–H₂O system, the amount of vanadium (IV) absorbed by NZ increases from 18 to 116 mg/L, which is significantly higher than that of sorbed divalent nickel (5 mg/L). This may be a potential evidence of a weak competing effect of Ni2⁺ in the system with an excess of V4⁺ cations. In the Co2+–V4⁺–NZ–H2O system, which includes the vanadium (IV) cation, the cation with a constant content is first completely sorbed by NZ, and then it is additionally saturated with the second cation. At CCo= (0.5-1.0) and 10 mg/L, 97.0 and 95.8% of vanadium, as well as 86.3 and 88.4% of cobalt are simultaneously sorbed. Conclusion. In all the studied systems, an unstable nature of sorption is observed, caused by the effect of coordination interaction between different types of cations, due to the sorption ↔ desorption process occurring in an aqueous solution.

Natural water sources are increasingly contaminated with a wide range of pollutants including heavy metals and pharmaceuticals. Arsenic, particularly in its more toxic trivalent form, i.e. As-(III), remains a significant environmental and public health concern due to its widespread presence and carcinogenic effects. In addition to that, pharmaceutical products like metronidazole (MNZ) and nalidixic acid (NAL), persistent in the environment due to their limited biodegradability, also pose significant threats to both ecosystems and human health. Recent research has highlighted the formation of antibiotic-metal complexes (AMCs) where antibiotics interact with heavy metals in aquatic environments, leading to altered physicochemical properties and increased toxicity. The main objective of the present work is a speciation study on As-(III)-antibiotic complexes and particularly interaction between As-(III) and MNZ or NAL in aqueous solution. Several temperatures and ionic strengths were probed by potentiometry to determine the formation constants and other thermodynamic parameters of As-(III)-MNZ and As-(III)-NAL complexes. UV spectrophotometric titrations were also employed to confirm formation constants of both systems. An estimation of the sequestering ability of both ligands toward As-(III) under relevant natural water conditions has also been performed. Further, density functional theory calculations have been executed with the purpose of investigating the molecular structure of these complexes and their relative stability. It turns out that MNZ binds to As-(III) in either a neutral (AsMNZ) or protonated (As-(MNZ)-H) form via As-N and As-O interactions, with the hydroxyl oxygen being the preferred binding site in AsMNZ and both the nitro and hydroxyl groups being equally effective in As-(MNZ)-H, while NAL forms a stable chelated complex through bidentate coordination. Findings reported in this study contribute to a deeper understanding of the complexes formed by As-(III) with pharmaceuticals and pave the way toward the development of improved technologies for the water treatment and remediation of AMCs.

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.

Mechanism of dynamic interaction between aging microplastics and heavy metal ions under different hydrodynamic environments

Heavy metals are among the most persistent and hazardous pollutants affecting aquatic ecosystems worldwide. Their presence in water bodies is influenced by both natural processes and anthropogenic activities such as industrial discharge, agricultural runoff, mining, and urbanization. Seasonal variations significantly affect the concentration, distribution, and chemical behavior of heavy metals in aquatic environments by altering hydrological conditions, physicochemical parameters, and biological activity. These seasonal dynamics directly influence the bioavailability of metals and their subsequent uptake by aquatic organisms, particularly fish. Fish accumulate heavy metals in various tissues through direct absorption from water and through dietary intake, leading to seasonal variations in bioaccumulation patterns. Elevated temperatures and increased metabolic activity during warmer seasons often enhance metal uptake, while colder seasons may reduce accumulation rates. Seasonal bioaccumulation of heavy metals poses serious ecological risks to aquatic life and potential health hazards to humans through fish consumption. This theoretical review highlights the seasonal dynamics of heavy metals in aquatic environments and their bioaccumulation in fish tissues, emphasizing the importance of seasonal monitoring for environmental management and public health protection.

Microplastics (MPs) can serve as vectors for heavy metals in aquatic environments; however, the adsorption behavior of MPs on multiple heavy metal systems is still unclear. This study investigated the adsorption characteristics of biodegradable poly (butylene succinate) (PBS) for cadmium (Cd(II)) and arsenic (As(III)) in both single and binary systems. Adsorption isotherms were studied using the Linear, Langmuir, and Freundlich models, and further analysis of MPs adsorption characteristics was conducted using site energy distribution theory and density functional theory. The results indicate that the maximum adsorption capacities of PBS for Cd(II) and As(III) are 2.997 mg/g and 2.606 mg/g, respectively, with the Freundlich model providing the best fit, suggesting multilayer adsorption on heterogeneous sites. As(III) has a higher adsorption affinity for PBS than Cd(II), with a binding energy of −11.219 kcal/mol. Additionally, the adsorption mechanisms of Cd(II) and As(III) on PBS include electrostatic interactions and surface complexation, with the primary adsorption sites at the C=O of the carboxyl group and the hydroxyl group. The comprehension of interfacial interactions between biodegradable plastics and heavy metals is facilitated by a combination of theoretical calculations and experimental investigations.

Studies using host-parasite dynamics as bioindicator of effects and accumulators of heavy metals for assessing environmental quality are still scarce, particularly in developing countries. This study aimed at elucidating the possible use of parasites of fish in monitoring and assessing water quality. 102 samples of 18 species of parasites of Clarias gariepinus were analyzed for copper, lead, manganese, iron, zinc and cadmium concentrations. Heavy metal concentrations were determined using atomic absorption spectrophotometer. Physico-chemical parameters were measured on sites using Hanna instrument. The nutrients and non-toxic constituents of water were also determined using methods by (American Public Health Association, 1999). The data obtained were analyzed using analysis of variance and significant differences accepted at p ≤ 0.05. Duncan Multiple range test was used to compare the heavy metal accumulation in the parasites and sample t- test was used to compare the values of physico-chemical parameters, nutrients and non-toxic constituents of the water. The heavy metal concentrations in parasites of C. gariepinus were in the order of Lead>Cadmium>Copper>Iron>Magnese>Zinc. Bioindicating capacity of parasites were in the order Nematodes>Cestodes>Protozoan>Trematodes. All physico-chemical parameters of the water (pH, temperature, salinity, turbidity, electrical conductivity, total dissolved solid) except dissolved oxygen were within the permissible level of the WHO (2011) permissible limits. The water nutrients except fluoride were within the permissible limits of WHO (2011). The non-toxic constituents were within permissible limits except NH4+ in the control study sites and PO43- in both study sites that was not within permissible limits. This study revealed that parasites can be ideal indicators for both effects and accumulation of heavy metals in aquatic environments. Findings from this study demonstrate the need for an ecosystem friendly approach towards sustainable management of dams and rivers. This will curb aquatic pollution which can directly and indirectly affect the structure and composition of fish parasite communities and also lead to a health risk in people consuming aquatic resources contaminated with heavy metals.

Rice husk biochar (RBC) and mulberry biochar (MBC) have gained significant attention in the removal of heavy metals in aquatic environments. Their easy affordability and eco-friendly nature make these biochar's a powerful adsorbent for sustainable water remediation applications. Although their heavy metal adsorption characteristics of individual biochar's have been widely studied, a clear understanding of how the inherited mineral composition in RBC and MBC influences Pb2+, Cd2+, and Zn2+ removal in both deionized water (DIW) and Organization for Economic Co-operation and Development (OECD) water is currently lacking. In this study, heavy metal removal mechanisms of RBC and MBC in these water systems were investigated using various kinetic models and correlated them with their mineral composition. With the highest correlation coefficient of modified two-compartment first-order kinetic model (MTCFOKM), the measured qe values highlight MBC as a promising candidate for heavy metal removal in both acidic and alkaline conditions. pH edge experiments revealed significant differences in metal removal efficiency between these biochars, despite their similar specific surface areas and surface charges (pHpzc). XRD and FTIR characterization provided a strong support in explaining the high heavy metal removal ability of MBC stem from calcite mineral that inherited from biomass. Furthermore, the pH edge experiment combined with MINEQL+ speciation profiles revealed that heavy metal removal by MBC at low pH is linked to calcite leaching, shift in system pH, and heavy metal precipitation.

Water quality degradation due to heavy metal contamination poses serious threats to both human health and aquatic ecosystems. The rise in the concentration of heavy metals in aquatic environments is largely attributable to anthropogenic activities. These metals accumulate over time in water bodies, necessitating rigorous monitoring to accurately assess pollution levels. The present study is concerned with the assessment of heavy metal pollution in the Styr River (Ukraine) before and after the discharge of water from a nuclear power plant. The assessment is based on three indices: the Heavy Metal Pollution Index, the Heavy Metal Evaluation Index, and the Degree of Contamination. Therefore, heavy metals, including zinc (Zn), cadmium (Cd), lead (Pb), copper (Cu), nickel (Ni), manganese (Mn), arsenic (As) and chromium (Cr), were analyzed in this study. Water samples were collected at two locations on a monthly basis over the course of five years (2018–2022) and subsequently analysed using inductively coupled plasma optical emission spectroscopy. The results indicates a low contamination level at both sampling sites, indicating stable and uniform concentrations of metals across the study area. Moreover, statistical analysis highlights significant associations between certain metals and pollution indices, supporting the indices’ utility in tracking pollution trends and assessing environmental impacts. This dataset underscores the importance of ongoing monitoring for effective water quality management.

The toxicity levels of heavy metals accumulated in water and sediment due to hospital waste discharge not only impact the environment but also pose a significant threat to human health. Long-term accumulation of these metals in the body may lead to degenerative diseases such as cancer. This concern highlights the urgency of conducting laboratory-based experimental research to identify the distribution of heavy metals in aquatic environments caused by hospital waste. The study employs Nile tilapia (Oreochromis Niloticus) as a bioindicator, a species capable of absorbing metals through its tissues. The research subjects consisted of 35 Nile tilapia with a body length of 8–12 cm and a weight of 12–15 grams, alongside hospital waste samples collected from three discharge points. Data collection methods included sample preparation of both hospital waste and Nile tilapia, treatment with varying concentrations of lead nitrate (Pb(NO3)2), and maintenance durations of 7, 14, 21, and 28 days. The concentration of Pb in the gills and muscle tissue of the fish was measured using Atomic Absorption Spectroscopy (AAS). The analytical data, represented as heavy metal concentrations, were plotted on a graph showing the relationship between concentration variations and maintenance durations and analyzed using One-Way ANOVA with nonparametric Tukey's test. The analysis revealed that the highest Pb concentration was observed in the gills of Nile tilapia on day 28 at 1.57 ppm, while the Pb concentration in muscle tissue reached 0.25 ppm on day 21. According to BPOM standards, Pb levels in Nile tilapia muscle tissue remain within the safe consumption threshold (≤0.3 ppm), whereas Pb levels in the gills exceeded the tolerance limit. This study provides scientific evidence on the risks of heavy metal accumulation in aquatic biota due to hospital waste and underscores the importance of improved waste management practices to safeguard public health and the environment.

This review article details the advancements in detecting heavy metals in aquatic environments using remote sensing methodologies. Heavy metals are significant pollutants in aquatic environment, and their detection and monitoring are crucial for predicting water quality. Traditional in situ water sampling methods are time-consuming and costly, highlighting the advantages of remote sensing techniques. Analysis of the reflectance and absorption characteristics of heavy metals has identified the red and near-infrared bands as the sensitive wavelengths for heavy metal detection in aquatic environments. Several studies have demonstrated a correlation between total suspended matter and heavy metals, which forms the basis for retrieving heavy metal content from TSM data. Recent developments in hyperspectral remote sensing and machine (deep) learning technologies may pave the way for developing more effective heavy metal detection algorithms.

One increasing environmental concern is the extensive pollution of aquatic habitats by heavy metals and microplastics. Oceans, estuaries, lakes, and even deep-sea sediments are contaminated by microplastics, which are now found from the polar regions to the equator. They come from both primary sources, like synthetic fabrics, and secondary sources, like the breakdown of bigger plastic waste. Heavy metals, introduced through industrial, agricultural, and urban activities, interact with these microplastics, particularly after the particles undergo physical and chemical weathering in aquatic environments. The surface area, size, and type of polymer of the microplastics, as well as the water's salinity and pH, all affect these interactions. This article examines the complex dynamics between microplastics and heavy metals, shedding light on their combined impact on aquatic ecosystems and the broader implications for environmental health