Search Results (318)

Heavy metals in water are a global concern due to their persistence, toxicity, and bioaccumulation potential, highlighting the need to assess their effects on aquatic organisms. The ecotoxicity of eight potentially toxic metal nitrates (Cd (0.002 mg/L), Co (0.02 mg/L), Cr (0.02 mg/L), Cu (0.001 mg/L), Mn (0.04 mg/L), Ni (0.005 mg/L), Pb (0.002 mg/L), Zn (0.1 mg/L) up to 1000 mg/L for all metals) was assessed on the aquatic macrophyte Lemna minor, in a multilevel study. Growth responses, measured as frond number and average specific growth rate, were used to generate dose–response curves, but also to calculate EC₅₀ (Median Effective Concentration) and E_rC₅₀ (50% Effect Concentration based on growth rate) values. Based on EC₅₀, toxicity followed the order Cd > Co > Ni > Zn > Cu > Cr > Pb > Mn, while E_rC₅₀-based ranking was Cd > Ni > Co > Zn > Cu > Cr > Pb > Mn. Metals were classified as highly toxic (Cd, Ni; Co based on EC₅₀), moderately toxic (Co based on E_rC₅₀, Zn based on EC₅₀), slightly toxic (Cu, Cr; Zn based on E_rC₅₀, Pb based on EC₅₀), or practically non-toxic (Pb based on E_rC₅₀, Mn). Biochemical responses regarding photosynthetic pigments, primary metabolites, and oxidative-stress-related enzymes were investigated, revealing physiological effects for most metals. Species sensitivity distribution-based comparison indicated that L. minor sensitivity varies across metals, ranging from typical to relatively low within the broader species sensitivity distribution. Although the toxicity of potentially toxic metals to L. minor has been extensively investigated, data on ErC50 values for several of the metals investigated in the present study remain limited, highlighting the need for further ecotoxicological research. Full article

Microplastic pollution has emerged as a pervasive stressor in aquatic ecosystems, with aquatic invertebrates playing central roles in particle uptake, retention, and transfer within food webs. This review synthesises evidence on microplastic ingestion, bioaccumulation, trophic transfer, and biomagnification across major aquatic invertebrate groups, including arthropods, molluscs, sediment-associated worms, suspension feeders, and echinoderms. A structured literature search identified 66 studies spanning freshwater, estuarine, and marine environments. Evidence indicates that microplastic uptake occurs through multiple pathways, including filter feeding, deposit feeding, grazing, and predator–prey interactions. Across the reviewed studies, feeding strategy, habitat-specific exposure, and particle characteristics were recurrently associated with variation in microplastic ingestion, retention, and trophic transfer. While ingestion and bioaccumulation were widely documented, quantitative understanding of trophic transfer within aquatic invertebrate food webs remained limited, and no conclusive evidence of biomagnification was identified. To interpret recurring patterns, this review proposes the Trait–Habitat–Particle (THP) framework as a conceptual tool linking biological and functional traits, habitat-mediated exposure, and particle properties. Methodological inconsistencies, limited representation of certain taxa and habitats, and insufficient quantification of trophic transfer remain important knowledge gaps. Future research should prioritise methodological standardisation and ecologically realistic long-term studies. Full article

Microplastics are increasingly recognized as prevalent contaminants in freshwater ecosystems, where they interact with a wide range of co-occurring pollutants, including heavy metals, pesticides, pharmaceuticals, and persistent organic pollutants. Evidence indicates that microplastics can act as vectors, enhancing pollutant mobility and facilitating trophic transfer, while also modulating toxicity through synergistic or antagonistic effects. Ecotoxicological studies reveal adverse impacts on aquatic organisms, ranging from physiological stress and impaired reproduction to altered community dynamics, with implications for ecosystem functioning and human health. Despite growing knowledge, significant gaps remain in understanding long-term environmental behavior, standardized methodologies, and risk assessment frameworks. This review synthesizes current findings on microplastic–pollutant interactions in freshwater systems, highlights emerging ecotoxicological risks, and identifies critical research needs to inform effective management and policy interventions. Full article

Mining flotation effluents may contain residual collectors that pose risks to aquatic environments when discharged without adequate treatment. Among these compounds, sodium diethyl dithiophosphate (SDE DTP) is of particular concern due to its persistence and potential ecotoxicological effects. This study evaluated the removal of SDE DTP from aqueous media using commercial activated carbon and thermochemically modified activated carbon prepared through nitric acid oxidation and urea treatment. Batch adsorption experiments were conducted using synthetic SDE DTP solutions and a laboratory-generated flotation effluent obtained from a copper sulfide ore containing approximately 0.5 wt.% Cu. A UV–visible spectrophotometric method was applied for the quantification of SDE DTP in both systems. The effects of adsorbent dosage, solution pH, and surface modification were investigated. Adsorption performance increased with activated carbon dosage and was strongly influenced by pH. Thermochemical modification significantly enhanced adsorption performance, increasing SDE DTP removal from 40% for unmodified carbon to 93% for the modified material. The modified adsorbent also maintained high efficiency in real flotation effluent, achieving 88% removal despite competing dissolved species. These results demonstrate that thermochemically modified activated carbon is a promising functional material for treating flotation effluents contaminated with dithiophosphate collectors. Full article

Aquatic animals are increasingly exposed to complex mixtures of emerging environmental toxicants, including microplastics, nanoplastics, per- and polyfluoroalkyl substances (PFAS), and endocrine-disrupting chemicals (EDCs). This raises serious concerns for reproductive health, offspring survival rates, and long-term population stability. This narrative review synthesizes the available peer-reviewed evidence on the reproductive and developmental effects of these contaminant groups in aquatic animals. Growing evidence indicates that these contaminants adversely affect reproductive processes, impair offspring development, and reduce survival and fitness across a wide range of aquatic species. Their effects are mediated through interconnected pathways involving oxidative stress, endocrine disruption, inflammation, mitochondrial dysfunction, and epigenetic alterations, ultimately leading to reproductive and developmental abnormalities. These changes may weaken wild fish populations, reduce aquaculture productivity, and compromise aquatic biodiversity. However, interpretation of the available evidence is constrained by substantial heterogeneity in species, contaminant properties and concentrations, exposure durations, and reproductive endpoints, together with the predominance of laboratory-based single-contaminant studies. This review integrates current knowledge on the reproductive and developmental impacts of emerging contaminants by connecting mechanistic toxicity pathways with population-level and ecosystem consequences. Overall, this review emphasizes that protecting aquatic reproductive health requires an integrated framework linking contaminant monitoring, mechanistic biomarkers, reproductive performance, and ecosystem-level risk assessment. Full article

Radioactive and chemical contamination of aquatic systems remains a key environmental concern in areas affected by historical nuclear testing. The objective of this study was a comprehensive geochemical and ecotoxicological screening assessment of bottom sediments in the Shagan River, which partially flows through the Balapan test site within the Semipalatinsk test site. This 2 km stretch is potentially affected by groundwater discharge hydraulically connected to the Atomnoye Lake retaining zone. A total of 21 bottom sediment samples were collected over a 2 km stretch, and their elemental composition was determined using inductively coupled plasma mass spectrometry (ICP-MS). Bottom sediment quality was assessed using the geoaccumulation index (Igeo) and ecotoxicological criteria, including the threshold effect concentration (TEC), probable effect concentration (PEC), least impact level (LEL), and high impact level (SEL). The results revealed significant spatial heterogeneity in the element distribution and local geochemical anomalies. Manganese (Mn) and molybdenum (Mo) corresponded to the Igeo index category of severe contamination, while zinc (Zn) demonstrated an extremely high contamination level (Igeo = 6), exceeding the PEC threshold by 16 times. Mn concentrations also exceeded the SEL by 15 times. These results provide a baseline geochemical profile for a previously understudied and ecologically sensitive section of the Shagan River, identifying zones of local geochemical enrichment in bottom sediments and laying the foundation for further hydrogeochemical, mineralogical, granulometric, and ecotoxicological studies. Full article

Water pollution and its ecological consequences have become central concerns in watershed governance and aquatic ecosystem conservation. Conventional ecotoxicological research on water pollution has long relied on physicochemical monitoring, laboratory-based single-species exposure tests, and morphology-based biological surveys. Although these approaches have provided essential support for pollutant identification, toxicity characterization, and environmental standard setting, they remain insufficient for resolving community-level responses, food-web perturbations, and ecosystem degradation under multiple-stressor conditions. Environmental DNA (eDNA) has emerged as a promising molecular tool because it is non-invasive, highly sensitive, high-throughput, and capable of detecting multiple taxa simultaneously. In aquatic systems, eDNA applications have expanded from biodiversity detection to pollution diagnosis, ecological health assessment, restoration monitoring, and early warning of ecological risk, while increasingly being integrated with eRNA, multi-omics approaches, machine learning, hydrological modeling, and ecological network analysis. However, several challenges still constrain its broader application, including incomplete methodological standardization, false-positive and false-negative detections, insufficient reference databases, limited quantitative capacity, scale mismatches caused by transport and mixing, and difficulties in causal attribution. This review synthesizes recent progress in the use of eDNA for water-pollution research, with emphasis on its technical workflow, major application domains, integrative analytical frameworks, and methodological boundaries. More specifically, three main points are highlighted: (1) eDNA is shifting water-pollution research from single-species toxicity characterization toward community- and ecosystem-level ecological interpretation; (2) its greatest value lies in its integrative role at the interface of biodiversity monitoring, ecological risk assessment, and management-oriented decision support; and (3) future progress will depend on improvements in standardization, quantitative inference, regional reference databases, and multi-source data integration. Overall, this review clarifies how eDNA can contribute to more robust, ecologically meaningful, and management-relevant assessment of water pollution. Full article

Meloxicam, a selective cyclooxygenase-2 inhibitor, is commonly used as non-steroidal anti-inflammatory drug in both human and veterinary medicine. Owing to its heterocyclic structure, toxicity to invertebrates, vertebrates, and microorganisms, and potential to biomagnify through the food webs, meloxicam persists in the environment and poses a risk to ecological health. There is still a paucity of information on meloxicam as a pharmaceutical contaminant. It is not included in priority lists, which means its environmental risk is often underestimated. This paper provides an integrative overview of the currently available literature (2009–2026) on the environmental occurrences, ecotoxicity, transport pathways, and removal strategies of meloxicam. The distribution of meloxicam has been most extensively studied in aquatic environments, whereas information on soils, plants, and terrestrial fauna remains limited. Bioaugmentation is the most promising strategy for reducing ecotoxicological risk, although its effectiveness against meloxicam has so far been confirmed only in a few model systems. The evidence presented here underscores the importance of strict regulation of meloxicam use and routine environmental monitoring. We hope this review will be useful to ecologists, microbiologists, and regulatory agencies developing strategies to mitigate pharmaceutical contamination. Full article

Carbon-based materials like activated carbon (AC) are frequently applied for water treatments and remediation. The increasing use and functionalization of AC, especially with the recent mandate to implement quaternary treatments to remove organic micropollutants (Directive 2024/3019), may inadvertently introduce AC or leachate products to aquatic bodies. Such occurrences pose potential risks to inhabiting organisms, which have been understudied. This study assessed the environmental safety of an AC obtained from spent brewery grains (SBG)—a lignocellulosic biomass—through microwave pyrolysis with potassium carbonate activation. The resulting AC (SBG-AC) was washed, sieved (powder, particle size ≤ 180 µm), and tested for its ecotoxicological effects on the marine mussel Mytilus galloprovincialis at doses of 5, 25, and 50 mg/L. After 28 days of exposure (with weekly water renewal), biochemical parameters related to the mussels’ metabolic capacity and oxidative status were evaluated. Exposure to SBG-AC stimulated the energy metabolism in M. galloprovincialis, at the expense of internal energy reserves (such as glycogen). Although SBG-AC exposure induced antioxidant responses, the significant increase in lipid peroxidation and protein carbonylation at the higher doses (particularly 50 mg/L) suggests that these protective mechanisms were insufficient to prevent oxidative damage. Overall, while SBG-AC offers an effective alternative for water treatment, its ecotoxicity at higher doses raises concerns, emphasizing the need for careful risk assessment and containment measures. Full article

The simultaneous occurrence of amphetamine (AMP) and other illicit drugs, such as 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), butylone (BTL), and 3,4-dimethylmethcathinone (3,4-DMMC), in wastewater and aquatic ecosystems has been frequently reported. These psychoactive substances share similar modes of action and pose a significant threat to freshwater organisms and human health due to their neurotoxicity and physiological harmful effects. The individual adverse effects of AMP and illicit drugs on non-target aquatic organisms have been demonstrated; however, the combined effects of these drugs have been considerably less explored. This study investigated the ecotoxicity of a mixture of these substances at an environmentally relevant concentration (0.1 μg L⁻¹) and at a 10-fold higher concentration (1.0 μg L⁻¹), using the freshwater microcrustacean water flea (Daphnia magna) exposed for 14 days. Several endpoints were evaluated. No significant changes were observed in swimming behavior or reproduction parameters, but some changes were noted for morphophysiological and biochemical endpoints. A significant increase was observed in the organisms’ heart rate and in catalase activity. Overall, the mixture did not induce significant ecotoxicological effects under the tested conditions. Nevertheless, the presence of other contaminants and longer exposure periods in natural environments may increase the ecological risks associated with these psychoactive substances. Full article

The freshwater crustaceans Macrobrachium borellii and Palaemon argentinus are key components of benthic communities and are widely distributed throughout South American freshwater ecosystems. As native species, they inhabit environments frequently impacted by pollutants from agricultural activity. Due to their marked sensitivity to these chemical stressors, both species have been proposed as valuable bioindicators for monitoring freshwater pollution. The aim of this study was to synthesize available information regarding the effects of several pesticide classes on standard ecotoxicological endpoints. Specifically, the review examines lethal concentration values (e.g., LC₅₀) and sublethal effects including metabolic disorders, histopathological alterations, and behavioral changes used as biomarkers. These biological responses were evaluated across different life stages, including embryos, larvae, and adults. Reports to date show that both species are highly sensitive to pesticides with different mechanisms of toxicity. Such biological responses are significantly influenced by concentration, exposure time, and developmental stage. The information collected on the biological and ecological characteristics of M. borellii and P. argentinus supports their suitability for ecotoxicological research and underscores their role as reliable indicator organisms for assessing the health of South American aquatic ecosystems. Full article

Formulation strategies that modify the physicochemical behavior of herbicides may influence their environmental fate and toxicity. In this context, this study investigates the effect of β-cyclodextrin (β-CD) complexation on the solubility and aquatic toxicity of chlorpropham (CLP), monuron (MON), and propanil (PRO), herbicides still in use in different parts of the world and frequently detected in aquatic environments at concentrations ranging from ng/L to µg/L. The solubility enhancement mediated by β-cyclodextrin was explored using UV-Vis and NMR spectroscopy, evaluating the impact of complexation on herbicides’ water solubility. Ecotoxicological evaluations were performed in Raphidocelis subcapitata (R. subcapitata) and Brachionus calyciflorus (B. calyciflorus), representing primary producers and consumers. Acute toxicity in B. calyciflorus significantly increased following complexation, with LC50 values decreasing from 178.09 µM (CLP), 32.32 µM (MON), and 20.77 µM (PRO) to 4.89, 2.55, and 2.29 µM, respectively. Chronic exposure further confirmed heightened sensitivity in rotifers (EC50: 0.04 µM for β-CD: MON; 0.02 µM for β-CD:PRO). R. subcapitata exhibited higher sensitivity to CLP (EC50: 2.57 µM), consistent with its mitosis inhibition mechanism. Risk Quotient (RQ) analysis, based on current environmental concentrations, revealed an ecotoxicological concern for MON and PRO. Overall, our study indicates that although β-cyclodextrin enhances herbicides solubility, it may also increase their bioavailability and toxicity underlining the necessity to evaluate a novel formulation not only from the point of view of the efficacy enhancement. Full article

Freshwater ecosystems are increasingly exposed to metal contamination arising from natural and anthropogenic activities, potentially affecting fish physiology and ecosystem health. However, limited information is available regarding metal accumulation and associated biological responses in fish populations from Dukan Lake, northern Iraq. Therefore, this study investigated metal concentrations in water and tissues of common carp (Cyprinus carpio) and evaluated their relationships with selected fish health indicators. Water and fish samples were collected monthly from Dukan Lake, and a total of 60 fish were classified into three length groups (20–29 cm, 30–39 cm, and 40–49 cm). Metal concentrations in water, liver, and gonad tissues were analyzed using ICP-OES, while condition factor (CF), gonadosomatic index (GSI), and hepatosomatic index (HSI) were used to assess fish physiological condition. Sodium (Na), magnesium (Mg), potassium (K), iron (Fe), zinc (Zn), and barium (Ba) were detected in both water and fish tissues, with concentrations in water ranging from 50 to 7069 μg/L. In contrast, chromium (Cr), manganese (Mn), nickel (Ni), selenium (Se), silver (Ag), cadmium (Cd), antimony (Sb), lead (Pb), copper (Cu), and arsenic (As) were below detection limits. Biometric analysis revealed significant differences (p < 0.05) in the gonadosomatic index (GSI) among fish length groups, indicating size-dependent reproductive development. However, no significant relationship was observed between fish length and either the CF or HSI, suggesting relatively stable somatic condition or liver status across size classes. Correlation analysis showed no significant associations between water metal concentrations and CF or GSI. A significant positive correlation was identified between Zn concentration and HSI in the 30–39 cm length group, indicating a possible link between Zn exposure and hepatic physiological response. The findings indicate that essential elements dominate the metal profile in Dukan Lake, with limited evidence of toxic metal contamination. No major adverse effects on the general condition of the fish were observed. These results contribute to understanding metal bioaccumulation patterns and their implications for fish health in freshwater ecosystems. Full article

Micro- and nanoplastics (MNPs) are emerging global pollutants that pose a significant threat to living organisms due to their widespread presence, ingestion by aquatic species, and ability to cross biological barriers, including the blood–brain barrier. Zebrafish is a well-established and convenient model for ecotoxicological research because of its small size, optical transparency, fully sequenced genome, high genetic homology to humans, ease of breeding, and short life cycle. Exposure to MNPs affects multiple organ systems in zebrafish, including the brain, eyes, liver, intestine, gills, and reproductive system. These particles can induce oxidative stress, inflammation, and interference with diverse biomolecules, leading to adverse biological effects. An analysis of transcriptomic alterations induced by MNPs exposure can contribute to understanding the mechanisms of these adverse effects. In this narrative review, we classify existing studies on MNPs exposure in zebrafish by affected organ system and summarize the gene expression-based evidence of MNP-induced toxicity with a particular focus on high-throughput approaches such as RNA sequencing and single-cell RNA sequencing. Full article

Zinc oxide (ZnO) nanoparticles are semiconductor nanomaterials widely used in biomedical, environmental, and catalytic applications due to their unique physicochemical properties. However, their increasing environmental release has raised concerns regarding potential toxicity in aquatic ecosystems. In this study, pure ZnO, 1% Au-modified ZnO, and 5% Au-modified ZnO nanoparticles were synthesized via a reflux-assisted method to evaluate the effects of Au incorporation on morphology, crystallinity, optical behavior, surface chemistry, and ecotoxicological responses, using Artemia salina as a marine bioindicator. Structural characterization was performed using high-resolution transmission electron microscopy (HRTEM), electron diffraction, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and energy-dispersive X ray spectroscopy (EDS) elemental mapping, while optical and surface analyses were conducted using UV–Vis and Fourier-transform infrared (FT-IR) spectroscopy. Although Au-rich domains were identified, the available data do not allow definitive determination of whether Au is incorporated into the ZnO lattice or present as surface-associated metallic Au. Increasing Au content promoted greater nanoparticle agglomeration and broader particle size distributions while preserving the hexagonal wurtzite ZnO crystalline structure. UV-Vis and FT-IR analyses demonstrated that Au modification altered the optical response and surface chemical environment of the nanoparticles. Toxicological evaluations revealed concentration- and time-dependent toxicity. Pure ZnO nanoparticles exhibited LC₅₀ values of 531.25 ppm after 24 h and 65.15 ppm after 48 h exposure. In contrast, 1% Au-modified ZnO nanoparticles showed reduced toxicity, whereas 5% Au-modified ZnO nanoparticles exhibited increased toxicity after prolonged exposure. These findings demonstrate that Au modification significantly influences the physicochemical properties and biological interactions of ZnO nanoparticles. Full article