Search Results (617)

Microplastics (MPs) can affect fish health by inducing oxidative stress, but their impact on structural coloration remains poorly understood. This study investigated the effects of environmentally relevant concentrations (16 and 160 μg/L) of MPs and nanoplastics (NPs) exposure on growth, oxidative stress and structural coloration in blue strain guppy fish (Poecilia reticulata). Results showed exposure to 160 μg/L MPs significantly reduced specific growth rate of fish compared to controls. Plastic accumulation followed a dose-dependent pattern, especially within gut concentrations. Oxidative stress responses differed between MPs and NPs: 160 μg/L MPs decreased SOD activity in skin and reduced GSH levels, while 160 μg/L NPs increased MDA levels in gut tissues, indicating severe lipid peroxidation. Structural coloration analysis revealed exposure to 160 μg/L MPs decreased lightness and increased yellowness, demonstrating reduced blue coloration. This was accompanied by an increase in skin uric acid content, suggesting that guanine conversion might occur to combat oxidative stress. These findings demonstrate that MPs, particularly at high concentrations, impair growth and induce oxidative stress in guppies. To counteract stress, guanine in iridophores may be converted into uric acid, leading to a decline in structural coloration. This study is the first to reveal that MPs disrupt structural coloration of fish, providing new insights into the ecological risks of plastic pollution on aquatic organisms. Full article

Traditional ecotoxicology primarily investigates pollutant toxicity through physiological, biochemical, and single-molecular indicators. However, the limited data obtained through this approach constrain its application in the mechanistic analysis of pollutant toxicity. Omics technologies have emerged as a major research focus in recent years, enabling the comprehensive and accurate analysis of biomolecular-level changes. The integration of multi-omics technologies can holistically reveal the molecular toxicity mechanisms of pollutants, representing a primary emphasis in current toxicological research. This paper introduces the fundamental concepts of genomics, transcriptomics, proteomics, and metabolomics, while reviewing recent advancements in integrated omics approaches within aquatic toxicology. Furthermore, it provides a reference framework for the implementation of multi-omics strategies in ecotoxicological investigations. While multi-omics integration enables the unprecedented reconstruction of pollutant-induced molecular cascades and earlier biomarker discovery (notably through microbiome–metabolome linkages), its full potential requires experimental designs, machine learning-enhanced data integration, and validation against traditional toxicological endpoints within environmentally relevant models. Full article

Detecting pharmaceuticals in environmental matrices, particularly in wastewater, is crucial due to their potential environmental occurrence and unpredictable ecological and health-related consequences. These substances, often present in trace amounts, require highly sensitive and selective analytical methods for effective monitoring. A modified version of the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method was evaluated to evaluate 18 pharmaceuticals and 2 metabolites in wastewater samples using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The method’s performance was assessed using linearity, recovery, precision, limits of quantification (LOQ) and detection (LOD), and the matrix effect (ME). The final method was based on acetonitrile, Na₂EDTA, citrate buffer, and graphene oxide (GO). Finally, the calibration curves prepared in acetonitrile and the matrix extract showed a correlation coefficient of 0.99. Most of the compounds had LOQ values lower than 0.5 μg⋅mL⁻¹. Recoveries were achieved in the 70–98% range, with RSD lower than 13%. GO allowed the elimination of the ME, which occurred in the range of −11% to 15%. The results indicate that a low-cost and straightforward method is suitable for routinely monitoring pharmaceuticals in wastewater, which is crucial for minimizing the impact of pollutants on aquatic ecosystems. Full article

Water environments and sediments are important reservoirs for antibiotic resistance genes (ARGs). Under the pressure of antibiotics, ARGs can transform between microorganisms. Lanthanum-modified bentonite (LMB) is a phosphorus passivation material with good prospects in water environment restoration. After a treatment with LMB, the phosphorus forms in water and sediments will change, which may have an impact on microorganisms and the transmission of ARGs. To investigate the effects of LMB and antibiotics on ARGs and bacterial communities in sediment and aquatic environments, LMB and tetracycline (Tet) were added individually and in combination to mixed samples of sediment and water. The results showed that the addition of either LMB or Tet increased the abundance of intI1 and tetA genes in both the sediment and water, with the Tet addition increasing ARGs to more than 1.5 times the abundance in the control group. However, when LMB and Tet were present simultaneously, the abundance of ARGs showed no significant difference compared to the control group. Tet and LMB also affected the bacterial community structure and function in the samples and had different effects on the sediment and water. A correlation analysis revealed that the potential host bacteria of the intI1 and tetA genes were unclassified_Geobacteraceae, Geothrix, Flavobacterium, Anaeromyxobacter, and Geothermobacter. These findings indicate that Tet or LMB may increase the dissemination of ARGs by affecting microbial communities, while LMB may reduce the impact of Tet through adsorption, providing a reference for the safety of the LMB application in the environment and its other effects (alleviating antibiotic pollution) in addition to phosphorus removal. Full article

Aquatic plants, as sedentary lifestyle organisms that accumulate chemical substances from their surroundings, can serve as valuable indicators of long-term anthropogenic pressure. In Poland, water monitoring is limited both spatially and temporally, which hampers a comprehensive assessment of water quality. Since the implementation of the Water Framework Directive (WFD), biotic elements, including macrophytes, have played an increasingly important role in water monitoring. Moreover, running waters, due to their dynamic nature, are susceptible to episodic pollution inputs that may be difficult to detect during isolated, point-in-time sampling campaigns. The analysis of stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope signatures in macrophytes enables the identification of elemental sources, including potential pollutants. Research conducted between 2008 and 2011 encompassed 38 sites along 15 rivers and 108 sites across 21 lakes in northern Poland. This study focused on the isotope signatures of three pondweed species: Stuckenia pectinata, Potamogeton perfoliatus, and Potamogeton crispus. The results revealed statistically significant differences in the δ¹³C and δ¹⁵N values of plant organic matter between river and lake environments. Higher δ¹⁵N values were observed in rivers, whereas higher δ¹³C values were recorded in lakes. Spearman correlation analysis showed a negative relationship between δ¹³C and δ¹⁵N, as well as correlations between δ¹⁵N and the concentrations of Ca²⁺ and HCO₃⁻. A positive correlation was also found between δ¹³C and dissolved oxygen levels. These findings confirm the utility of δ¹³C and, in particular, δ¹⁵N as indicators of anthropogenic eutrophication, including potentially domestic sewage input and its impact on aquatic ecosystems. Full article

Korean rockfish, Sebastes schlegeli, a coastal species, is vulnerable to pollutants such as microplastics and bacteria. While interactions between microplastics and other pollutants have been studied, little is known about microplastic and bacteria interactions. This study examined the effects of combined exposure to polystyrene microplastics in the form of microbeads (MB; 0.2 µm, 5 and 50 beads/L) and Streptococcus iniae (1 × 10⁵ and 1 × 10⁷ CFU/mL) for five days on oxidative stress and apoptosis in Korean rockfish. We assessed the mRNA expression and activity of oxidative stress markers (SOD, CAT, H₂O₂, NO, CYP1A1, GST), plasma LPO levels, and caspase-3 expression in liver tissue. Co-exposure to high MB and S. iniae concentrations significantly elevated oxidative stress and apoptosis markers, suggesting enhanced toxicity. This may result from MB facilitating pathogen transport into the fish, indicating microplastics can act as vectors for bacterial infection in aquatic environments. Full article

Population growth has led to an increased volume of wastewater from industrial, domestic, and municipal sources, contaminating aquatic bodies in the state of Veracruz. This study aimed to assess the efficacy of a water treatment system incorporating a DAF stage, followed by the cultivation of a microalgal consortium to eliminate pollutants from the blended effluent. The cultivation of Nannochloropsis oculata in wastewater entailed the assessment of a single variable (operating pressure) within the DAF system, in conjunction with two supplementary variables (residence time and F:M ratio), resulting in removal efficiencies of 70% for CODt, 77.24% for CODs, 78.34% for nitrogen, and 77% for total organic carbon. The water sample was found to contain elevated levels of organic matter and pollutants, beyond the permitted limits set forth in NOM-001-SEMARNAT-2021. The obtained removal percentages indicate that the suggested physicochemical–biological process (DAF-microalgae) is a suitable method for treating mixed wastewater. This approach reduces atmospheric pollution by sequestering greenhouse gases such as carbon dioxide through the photosynthetic activity of N. oculata cells, so facilitating the production of oxygen and biomass while limiting their accumulation in the atmosphere. Full article

This study investigated the accumulation characteristics and associated health risks of 11 trace elements (Al, Rb, Cr, Ni, Mo, Sr, Pb, Ba, Ag, As, and Ga) in four crucian carp varieties: gene-edited intermuscular bone-free crucian carp (Carassius auratus, WUCI) and its sibling wild-type (Carassius auratus, WT), Fangzheng silver crucian carp (Carassius gibelio var Fangzheng, FZYJ), and Songpu silver crucian carp (Carassius gibelio var Songpu, SPYJ). Results showed that Al and Rb were the most abundant elements across all groups. WUCI exhibited distinct accumulation patterns, including significantly higher hepatic Mo concentrations (0.265 ± 0.032 mg/kg) and muscle/liver Rb levels (muscle: 8.74 ± 1.21 mg/kg; liver: 12.56 ± 2.05 mg/kg) compared to other varieties (p < 0.05), which supports the hypothesis of genotype-specific differences in heavy metal accumulation. Correlation analysis revealed that WUCI exhibited similar elemental interactions with WT and SPYJ (e.g., Al-Ni positive correlation, |rs| ≥ 0.8), while SPYJ displayed distinct patterns with fifteen negative correlations compared to three to five in others varieties, suggesting a potential alteration in elemental homeostasis. Pollution index (P_i) assessments indicated mild contamination for Pb in SPYJ liver (P_i = 0.265) and Cr/As in WUCI muscle (P_i = 0.247/0.218). Despite these values, all hazard indices remained below the established safety thresholds (THQ < 0.1, HI < 0.25, TCR < 10⁻⁶), reinforcing the overall safety of the tested fish. Notably, muscle As levels (0.86 ± 0.15 mg/kg) exceeded hepatic concentrations (0.52 ± 0.09 mg/kg), potentially due to differential detoxification mechanisms. These findings demonstrate the food safety of all tested varieties, while highlighting genotype-specific metabolic adaptations, providing critical data for evaluating gene edited aquatic products. Full article

The extensive use of herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA), coupled with its limited biodegradability, has led to its ubiquitous presence in aquatic environments. This work investigates the removal of MCPA (100 mg/L) in the aqueous phase via solar photo-Fenton. The process was carried out in a 700 mL reactor using a Xe lamp that simulates solar radiation (λ: 250–700 nm). A parametric study was conducted to assess the influence of dissolved O₂ on the reaction medium, Fe²⁺ dosage, H₂O₂ concentration and pH₀. The results indicate that dissolved O₂ boosts pollutant mineralization, even working at sub-stoichiometric H₂O₂ concentrations. Under optimal reaction conditions ([Fe²⁺]: 7.5 mg/L, [H₂O₂]₀: 322 mg/L (stoichiometric dose), pH₀: 3.5), the MCPA reached almost complete mineralization (X_TOC: 98.40%) in 180 min. Phytotoxicity and ecotoxicity assessments of treated effluents revealed that even working at sub-stoichiometric H₂O₂ dosages, toxicity decreases with the solar photo-Fenton treatment. Finally, the solar photo-Fenton process was evaluated in relevant matrices (river water and WWTP secondary effluent) and a realistic pollutant concentration (100 µg/L). In all cases, the pollutant degradation was ≥70% in 60 min, demonstrating the potential of this technology as a tertiary treatment. Full article

The Ghris watershed in southern Morocco is a significant ecological and agricultural area. However, due to the current impacts of climate change, farming activities, and pollution, data on its quality and biological importance need to be updated. Therefore, this study aimed to evaluate the physico-chemical and biological quality of surface water in the Ghris River. The Water Quality Index (WQI) and the Iberian Biological Monitoring Working Group (IBMWP) index were used to assess water quality along four sampling sites in 2024. The collected data were analyzed with descriptive and multivariate statistics. In total, 424 benthic macroinvertebrates belonging to seven orders were identified in the surface waters of the Ghris basin. These microfauna were significantly variable among the studied sites (p < 0.05). Station S4 is significantly rich in species, including seven orders and nine families of macroinvertebrates, followed by Station S2, with seven orders and eight families. Stations S3 and S1 showed less species diversity, with three orders and one family, respectively. The Insecta comprised 95.9% of the abundance, while the Crustacea constituted just 4.1%. The physico-chemical parameters significantly surpassed (p < 0.05) the specified norms of surface water in Morocco. This indicates a decline in the water quality of the studied sites. The findings of the principal component analysis (PCA) demonstrate that the top two axes explain 87% of the cumulative variation in the data. Stations 2 and 3 are closely associated with high concentrations of pollutants, notably Cl⁻, SO₄²⁻, NO₃⁻, and K⁺ ions. Dissolved oxygen (DO) showed a slight correlation with S2 and S3, while S4 was characterized by high COD and PO₄ concentrations, low levels of mineral components (except Cl⁻), and average temperature conditions. Bioindication scores for macroinvertebrate groups ranging from 1 to 10 enabled the assessment of pollution’s influence on aquatic biodiversity. The IBMWP biotic index indicated discrepancies in water quality across the sites. This study gives the first insight and updated data on the biological and chemical quality of surface water in the Ghris River and the entire aquatic ecosystem in southeast Morocco. These data are proposed as a reference for North African and Southern European rivers. However, more investigations are needed to evaluate the impacts of farming, mining, and urbanization on the surface and ground waters in the study zone. Similarly, it is vital to carry out additional research in arid and semi-arid zones since there is a paucity of understanding regarding taxonomic and functional diversity, as well as the physico-chemical factors impacting water quality. Full article

Cresols are aromatic organic compounds widely used in industrial and agricultural production. They have been detected in large quantities in aquatic environments, posing health risks such as skin irritation, gastrointestinal stimulation, and chronic neurological effects. In this study, we investigated the exposure concentration of cresols in the water bodies of Lake Xingkai (i.e., Daxingkai and Xiaoxingkai Lakes) during four typical hydrological periods (30 April, 22 June, 5 September, and 1 November 2021), assessed the human health risk from phenolic contaminants using the mean value method, and determined the health risk of adult cresol exposure in the Lake Xingkai watershed based on local population exposure parameters. This study developed a water environmental pollution health risk assessment model based on the methodology proposed by the United States Environmental Protection Agency (US EPA). It further evaluated the health risks to humans posed by phenolic pollutants via the drinking water pathway. The results revealed that the concentration range of cresols in water bodies was between 5.91 × 10⁻¹ ng·mL⁻¹ and 6.68 ng·mL⁻¹. The adult drinking water health risk values of cresols in the Lake Xingkai watershed were between 3.15 × 10⁻⁴ and 3.57 × 10⁻³, and all water samples from the 10 sites had hazard quotient (HQ) values less than 1, indicating that the non-carcinogen risk was small or negligible. The cresol HQ value in the water of Xiaoxingkai Lake was 4.6 times that found in Daxingkai Lake. Full article

4-Aminodiphenylamine (4-ADPA) is a common additive in rubber tires, known for its antioxidant properties. It plays a crucial role in enhancing tire durability by preventing issues such as drying, cracking, and degradation from prolonged exposure to environmental factors like heat, oxygen, and ozone. However, despite its advantages in extending tire lifespan, the use of 4-ADPA raises significant environmental concerns. As tires wear down, microscopic tire wear particles (TWPs) containing 4-ADPA are released into the environment with substantial leaching, contaminating the waterways. The 4-ADPA leachates pollute and pose a threat to aquatic ecosystems, affecting various forms of marine life. The current study investigates the ecotoxicological effects of 4-ADPA on the aquatic plant Lemna minor (L. minor), focusing on its impact on relative growth and physiological biomarkers. Several parameters were assessed to evaluate ecotoxicity, including frond morphology, fresh biomass, total frond number, chlorophyll content, and starch accumulation. L. minor was grown for 7 and 14 days under controlled laboratory conditions using Hoagland media with varying concentrations of 4-ADPA (10–100 μg/L), while a control group was maintained in media without 4-ADPA. The results indicate that exposure to 4-ADPA led to a dose-dependent reduction in fresh biomass, total frond number, and chlorophyll levels. Lugol’s staining revealed increased starch accumulation in the fronds after exposure to 4-ADPA. The biological effects observed in L. minor following exposure to 4-ADPA, even at environmentally relevant concentrations, demonstrate a significant ecotoxicological impact on aquatic ecosystems. Further research involving additional species and investigating the mechanisms behind 4-ADPA toxicity is recommended to better understand its long-term consequences. Full article

Utilizing a multi-biomarker approach, we assessed the potential adverse effects of pollutants on subcellular responses in the digestive gland of the freshwater mussel Unio crassus from a historically contaminated lowland section (KIZ) of the river Mrežnica compared to its less impacted upstream karstic section (REF) and their seasonality (spring vs. autumn). This approach accounted for the diverse modes of action of pollutants by including biomarkers of metal exposure (metallothioneins, MT), general stress (total cytosolic proteins, TP), antioxidative capacity (catalase, CAT; glutathione, GSH; glutathione-S-transferase, GST), oxidative damage (malondialdehyde, MDA), and neurotoxicity (acetylcholinesterase, AChE). Only in spring, MT concentrations were 15% higher at the REF site (4.38 ± 1.06 µg mg proteins⁻¹) compared to the KIZ site (3.69 ± 0.63 µg mg proteins⁻¹), likely related to elevated Cd bioaccumulation due to the karstic substrate. Regardless of the season, mussels from KIZ showed consistently lower TP and GSH, with significantly higher CAT, GST, and MDA levels, indicating elevated stress, activation of antioxidant defenses, and oxidative damage from chronic exposure to pro-oxidant pollutants, including metal(loid)s and organic contaminants (e.g., ibuprofen, nicotine). Compared to the REF site, AChE activity at the KIZ site was higher in late spring and lower in early autumn, indicating seasonal variability in AChE activity at the contamination-impacted location driven by fluctuating exposure to neurotoxicants, such as drugs and insecticides. Overall, biomarker responses indicated that mild historical pollution, reinforced by current low-capacity sources, has an observable impact on mussel health, posing long-term risks to sediment-dwelling aquatic organisms. Full article

This study presents a biomonitoring study of surface waters in the Krynka River basin, encompassing three major regional reservoirs: Khanzhenkovskoe, Olkhovskoe, and Zuyevskoe. These water bodies face significant anthropogenic pressure from mining effluents, industrial discharges, and domestic wastewater. Key pollutants identified are surfactants (SAAs), sulfates, phenols, chlorides, and manganese, with chemical oxygen demand (COD) exceeding regulatory limits. The research was conducted in September 2024. Based on the Specific Combinatorial Water Pollution Index, surface waters in the studied objects can be characterized as slightly polluted. To assess the negative impact of the identified pollutants on hydrobionts, the species composition of phytoplankton of the studied water bodies was analyzed. In the Olkhovskoe Reservoir and Olkhovaya River, cyanobacterial blooms (Oscillatoria agardhii G.) were observed, altering biodiversity in the Krynka River and Zuyevskoe Reservoir. Phytoplankton genera Synedra, Amphiprora, and Navicula—established bioindicators of aquatic ecosystem health—were dominant in Khanzhenkovskoe Reservoir, signaling nutrient enrichment and organic pollution. Changes in the species composition and structure of phytoplankton in the Krynka River, its tributaries and reservoirs, indicate a change in the level of saprobic water bodies from β to α-mesosaprobic, which indicates both the general level of surface water pollution and the accumulation of pollutants along the course of the river. The paper presents the results of fluorimetric analysis of photosynthetic activity of natural phytoplankton cells and demonstrates the possibility of using fluorescence induction curves for regular monitoring measurements. Fluorescence parameters indicate a general deterioration of photosynthetic activity of natural phytoplankton. The growth of Oscillatoria agardhii in the waters of the Olkhovskoe Reservoir and of green microalgae in the Zuevskoe Reservoir led to an increase in the fluorescence quantum yield (F_v/F_m) and the total photosynthetic activity index (PI), which makes it possible to use these parameters as indicator parameters reflecting the intensity of “blooming” of various phytoplankton species. Full article

Potamogeton crispus (P. crispus), with strong nitrogen uptake capacity, plays an important ecological role during winter and early spring when most aquatic plants are inactive. Its presence can also influence microbial denitrification in sediments by regulating oxygen levels and organic carbon availability. In this study, an indoor hydroponic simulation system was used to systematically evaluate the effects of P. crispus under different nitrogen-loading conditions on nitrogen removal from water, changes in sediment carbon and nitrogen fractions, microbial community structure, and greenhouse gas fluxes. The results showed that P. crispus effectively removed TN, NH₄⁺-N, NO₃⁻-N, and NO₂⁻-N, maintaining strong denitrification capacity even under high-nitrogen loading. Under all nitrogen conditions, TN removal exceeded 80%, while NH₄⁺-N and NO₃⁻-N removal efficiencies surpassed 90%, with effective suppression of NO₂⁻-N accumulation. Rhizosphere-mediated regulation by P. crispus enhanced the transformation and stabilization of DOC and NO₃⁻-N in sediments, while also mitigating nitrogen-induced disturbances to carbon–nitrogen balance. The plant also exhibited strong CO₂ uptake capacity, low CH₄ emissions with a slight increase under higher nitrogen loading, and N₂O fluxes that were significantly affected by nitrogen levels—showing negative values under low nitrogen and sharp increases under high-nitrogen conditions. Correlation analyses indicated that CO₂ and N₂O emissions were mainly regulated by microbial taxa involved in carbon and nitrogen transformation, while CH₄ emissions were primarily driven by methanogenic archaea and showed weaker correlations with environmental factors. These findings highlight the importance of water restoration during low-temperature seasons and provide a theoretical basis for integrated wetland management strategies aimed at coordinated pollution reduction and carbon mitigation. Full article