Aquatic Ecosystem Health Research Articles

EFFECTS OF PESTICIDES RECIDUES ON TILAPIA ZILLII, SEDIMENT AND SURFACE WATER OF ERINLE DAM AND RIVER OSUN IN OSUN STATE

This study investigates the effects of selected pesticides on the health of aquatic ecosystems and humans in Erinle Dam and River Osun, Osun State, Nigeria. Focusing on Tilapia zillii, a commonly consumed fish in the region, the research assesses the potential health risks posed by pesticides found in the water, sediments, and fish tissues. Samples were collected following APHA guidelines and tested for pesticides like DDT, Heptachlor, Dieldrin, Aldrin, and Chlorpyrifos. The findings revealed high levels of DDT and Chlorpyrifos in both the water and fish, with Erinle Dam showing higher concentrations than River Osun. Specifically, DDT levels in River Osun's water averaged 199.08mg/kg, while Erinle Dam had 271.58mg/kg. Dieldrin and Chlorpyrifos also showed high concentrations, with Heptachlor and Aldrin absent in the water samples from both sites. Fish tissue analysis indicated higher pesticide levels in specimens from Erinle Dam compared to River Osun. DDT and Chlorpyrifos concentrations were notably high, while Dieldrin, Aldrin, and Heptachlor were present in lower amounts. Similarly, sediment analysis showed Erinle Dam with higher pesticide concentrations, particularly for DDT, Dieldrin, and Chlorpyrifos, while Heptachlor and Aldrin were absent.Overall, the study highlights significant pesticide contamination in Erinle Dam and River Osun, posing health risks to local fish consumers and indicating a need for stringent pesticide regulation and monitoring in the region.

Silver nanoparticles alter planktonic community structure and promote ecosystem respiration in freshwater mesocosms

The widespread use of silver nanoparticles (AgNPs) has resulted in their release into the aquatic environment, which threatens the health of aquatic ecosystems. Although the ecotoxicological effects of AgNPs have been widely reported at individual and population levels, the impact of long-term exposure to AgNPs on community structure and ecosystem function in aquatic ecosystems remains poorly understood. Herein, the present study investigated the effects of long-term exposure (28 d) to environmentally relevant concentrations (1 μg/L and 10 μg/L) of AgNPs on the community structure and function of freshwater ecosystems by artificially constructed 28 mesocosms freshwater ecosystem in experimental greenhouses, using plastic water tanks and food web manipulation. The results showed that long-term exposure to AgNPs significantly altered the community structure of zooplankton, phytoplankton, and bacterioplankton in the aquatic ecosystem. Exposure to 10 μg/L AgNPs significantly reduced the zooplankton density (70.3%, p < 0.05) and increased the phytoplankton biomass and bacterial richness and diversity via a “top-down effect.” With regards to ecosystem function, AgNPs exposure significantly increased the respiration in freshwater ecosystems but did not have a significant effect on decomposition. The partial least squares path modeling (PLS-PM) further revealed that AgNPs may have a negative impact on ecosystem functions by reducing zooplankton community density and thus increasing phytoplankton biomass. This study is the first to show that long-term exposure to environmentally relevant concentrations of AgNPs leads to alterations in plankton community structure and promotes respiration in freshwater ecosystems. It emphasizes the need for assessing the environmental risk of long-term exposure to AgNPs at the ecosystem level.

Low-frequency ultrasound assisted contact-electro-catalysis for efficient inactivation of Microcystis aeruginosa

Frequent cyanobacterial blooms pose a serious threat to the aquatic ecosystem and human health, so developing an efficient algae removal method is a long-term goal for bloom management. Current technologies for algal bloom control need urgent improvement in terms of algicide recovery, eco-friendliness and cost. Here we propose a contact-electro-catalytic method, using polytetrafluoroethylene (PTFE) film as a reusable catalyst. This contact-electro-catalytic approach involves the generation of reactive oxygen species (e.g., O2•–, HO•, 1O2 and H2O2) through water-PTFE contact electrification under the low-frequency ultrasonic waves, facilitating the inactivation of algae. The removal rate of the cyanobacterium Microcystis aeruginosa (M. aeruginosa) exposured to the water-PTFE contact-electro-catalytic system is almost five times greater than that of ultrasound alone after 5 h. A mechanistic investigation revealed that the contact-electro-catalytic system damaged the photosynthetic activity, antioxidant system and membrane integrity of the cells. Additionally, LC-MS metabolomic analysis indicated that this system caused substantial significant disruptions in the TCA cycle, amino acid metabolism, purine metabolism and phospholipid metabolism. Three-dimensional fluorescence spectroscopy suggested contact-electro-catalysis could further availably degrade the organic matter. We anticipate that this method can provide an eco-friendly, highly efficient and economic approach for effective control of harmful algal blooms.

Assessment of macrozoobenthic community dynamics in the Ijuk River: Implications for freshwater ecosystem health and conservation management

Background: Nestled within the Isau-Isau Wildlife Reserve, the Ijuk River stretches approximately 3 kilometers, serving as a vital conservation area. Its upstream region plays multiple ecological roles, including watershed management, hydrological regulation, microclimate control, soil fertility maintenance, microbial habitat provision, air quality regulation, and carbon sequestration. However, escalating human activities, particularly changes in land use, pose significant threats to its ecological balance. The particular concern is the conversion of forested areas into agricultural lands, primarily for coffee cultivation and mixed gardens, encroaching dangerously close to the riverbanks. This encroachment necessitates a critical reevaluation of the river's water quality, given its crucial role in supporting biodiversity and ecological equilibrium. Benthic insects dwelling in the riverbed serve as invaluable bioindicators, offering insights into the overall health of aquatic ecosystems. Methods: Conducted between January and July 2022 in the Isau-Isau Wildlife Refuge, Lawang Agung Village, Mulak Ulu District, Lahat Regency, the study aimed to assess the macrozoobenthic community structure across three river segments: upstream, midstream, and downstream. Employing field sampling, observational surveys, taxonomic identification, and data analysis, the research aimed to unravel the river's ecological dynamics. Findings: Through meticulous examination of benthic insect communities, the study revealed relatively favorable water quality in the Ijuk River. However, discernible declines in various ecological parameters, as evidenced by evaluation results, highlight the urgency of conservation efforts and proactive management strategies to mitigate further degradation and preserve the river's ecological integrity. Conclusion: Such endeavors are crucial for safeguarding the biodiversity and sustainability of this vital freshwater ecosystem. Novelty/Originality of this Study: The study uniquely assesses the macrozoobenthic community dynamics in the Ijuk River, revealing significant changes over two decades that highlight the river's ecological health and underscore the urgent need for conservation efforts. It offers a comprehensive, updated evaluation of the macrozoobenthic community structure, providing critical insights into the impacts of land use changes and human activities on freshwater ecosystems.

Long term study on the fate and environmental risks of favipiravir in wastewater treatment plants and comparison with COVID-19 cases

In recent years especially during COVID-19, the increased usage of antiviral drugs has led to increased interest in monitoring their presence in wastewater worldwide. In this study, it was examined the occurrence, fate and environmental risks of favipiravir which is used for COVID-19 treatment in two wastewater treatment plants (WWTPs) with different treatment processes in Istanbul, Turkey. Favipiravir was measured in WWTPs influent samples, effluent samples and sludge samples with maximum concentrations of 97 μg/L, 64.11 μg/L and 182.47 μg/g, respectively. Favipiravir had removal efficiency below 55 % for both WWTPs. Mass balance analysis showed that favipiravir removal in WWTPs mainly attributed to biodegradation/biotransformation. Statistical analysis revealed a significant correlation between favipiravir concentration and COVID-19 incidence in Istanbul. The microbial distribution analysis indicated that comparison of collected COVID-19 pandemic sludge and post-pandemic period sludge samples, a noteworthy reduction in the Chloroflexi and Actinobacteriota phyla at the phylum level was observed. Environmental risk assessment using risk quotients ranged from 168 to 704, indicating that the presence of this antiviral drug posed significant ecological risks to aquatic organisms. The study concluded that WWTPs were releasing antiviral drugs into the environment, thereby posing risks to both the aquatic ecosystem and public health. The results of this study demonstrate the persistence of favipiravir in WWTPs and offer crucial supporting data for further research into the advancement of wastewater treatment technology. Also, this study shows wastewater based monitoring is supplementary and early warning system for determining the occurrence of antiviral drugs.

Temporal variations in dissolved organic matter properties in a eutrophic lake under water dilution and aquatic plant litter decomposition: A simulated microcosm study revealing the environmental and microbial driving factors

Dilution by importing external clean water and restoration of aquatic vegetation are widely applied strategies for improving water quality of eutrophic lakes, while the influence of dilution or aquatic plant litter decomposition on dissolved organic matter (DOM) properties, which is closely associated with the health of aquatic ecosystems, is rarely known. In this study, the temporal variations of DOM properties in the overlying water of a eutrophic lake (Yilong lake in Yunnan, southwest China) under water dilution and aquatic plant litter decomposition were comparatively investigated via a simulated microcosm study using in situ samples. The results showed that water dilution reduced DOM concentration and bioavailability in the overlying water in a short term (about 45 d), and increased DOM humification, but such effect diminished over time. DOM concentration increased substantially during aquatic plant litter decomposition, and reed litter released much more amounts of DOM than that of cattail litter, which dominated by protein-like substances and characterized by high bioavailability and low humification degree. Nutrient (available phosphorus (AP), NH4+-N and TN) contents in the sediment indirectly affected DOM properties by remarkably influencing microbial community compositions and enzyme activities. The strong correlations between the relative abundances of dominant genera Bacillus and Clostridium and concentrations of DOM components implied the important roles of these taxa in DOM transformations. Our findings highlighted the effects and potential mechanisms of dilution and aquatic plant litter decomposition on DOM properties in eutrophic water bodies, and the necessity of proper water diversion and plant litter harvest to reduce endogenous organic pollution in lakes.

Assessment of the ecological status of the river water system in European North under conditions of ultra-fresh humus waters using biotic indices (Suna River, Lake Onega Basin, Russia).

Protecting rivers and lakes from pollution is crucial for maintaining the health of aquatic ecosystems and ensuring the well-being of both wildlife and humans. Present study intends to examine the water quality of the Suna River (Eastern Fennoscandia in the European North of Russia) to assess the ecological risk. Widespread methods for assessing water quality based on macrozoobenthos and phytoperiphoton were applied. It was found that in conditions of ultra-fresh waters with high humus content, biotic indicators may indicate pollution of water bodies that do not actually experience significant anthropogenic impact. Ratings ranging from 'poor' to 'excellent' were obtained for different stations, reflecting the influence of natural features of different sections of the river. 'Good' water quality was noted at the river stones biotopes. In river gravel, sand and silt biotopes, as well as all lake biotopes, 'mediocre' water quality was found. The low anthropogenic income on the river catchment allows us to conclude that most indices for assessing water quality significantly underestimate the results in the natural conditions of Eastern Fennoscandia. Biotic indices EPT, BBI and EBI are most accurate for assessing the water quality of rivers and lakes in Eastern Fennoscandia.

Exploring the nexus between water quality and land use/land cover change in an urban watershed in Uruguay: a machine learning approach.

The expansion of urban areas contributes to the growth of impervious surfaces, leading to increased pollution and altering the configuration, composition, and context of land covers. This study employed machine learning methods (partial least square regressor and the Shapley Additive exPlanations) to explore the intricate relationships between urban expansion, land cover changes, and water quality in a watershed with a park and lake. To address this, we first evaluated the spatio-temporal variation of some physicochemical and microbiological water quality variables, generated yearly land cover maps of the basin adopting several machine learning classifiers, and computed the most suitable landscape metrics that better represent the land cover. The main results highlighted the importance of spatial arrangement and the size of the contributing watershed on water quality. Compact urban forms appeared to mitigate the impact on pollutants. This research provides valuable insights into the intricate relationship between landscape characteristics and water quality dynamics, informing targeted watershed management strategies aimed at mitigating pollution and ensuring the health and resilience of aquatic ecosystems.

Towards a Canadian National River Water Quality-Modelling System: State of Science and Future Prospects

Water quality is of significant concern and ultimately critical to every Canadian’s quality of life and security. Canada has diverse and vast landscapes and stressors that impact various waterbodies differentially, with influencing factors including contaminant and nutrient loads from human activity (mining effluent, wastewater, agricultural runoff, plastics), landscape change (wetland drainage, urbanization) and climate change (warming water temperatures, longer open water seasons, extreme hydrological events, intensifying wildfires). Canadian rivers are especially important to the overall biogeochemistry, hydrology, biodiversity, and ultimate health of aquatic and terrestrial ecosystems. While each of Canada’s provinces and territories has extensive river water quality (physical, chemical, biotic) data and monitoring programs, Environment and Climate Change Canada coordinates various national programs that contribute to the collection and consolidation of these data and conducts extensive research into the study and modelling of key river water quality processes. Despite program-specific efforts, there remains poor capacity to predict current and future conditions in monitored and unmonitored Canadian rivers, particularly remote or northern rivers, due to a myriad of factors including lack of coordination amongst groups and examination of areas in which modelling efforts might be integrated. Herein, we review and analyse the current state of data availability, process studies, and modelling systems for Canadian river water quality. Our synthesis reveals that specific physical processes (water temperature, ice formation, permafrost thaw, sediment dynamics), biogeochemical processes (dissolved oxygen, dissolved organic matter, nutrient cycling, metals/contaminants) and ecological/biological features (biota mass, functional indicators) are well understood, though complex, and are amenable to empirical or mechanistic modelling. Review of this information assists us in identifying opportunities and challenges for developing a national water quality modelling system (NWQMS), that would eventually include similar modelling activities for parallel processes in lakes and integrated watersheds. We identify needs for stronger coordination of monitoring programs in remote areas, recommend use of novel remote sensing technologies, and development of a flexible, iterative ‘process’ for integrated modelling to which stakeholders beyond government can contribute. Such a platform would support short and long-term predictive models of Canadian water quality and ecosystem health, inform effluent concentration limits, and be an early warning system for source waters.

Optimizing Copper Adsorption from Aqueous Solutions with Modified Rice Straw Using Response Surface Methodology

Heavy metal contamination poses an impulsive threat to human and aquatic life and ecosystem health. To ensure safe and sustainable water accessibility, biosorption with low-cost adsorbents is acknowledged as a promising approach for the remediation of noxious pollutants. The current study was oriented to appraise the performance of modified rice straw for copper adsorption in hand with the optimization of its operational parameters. RSM-based Box-Behnken design was employed to optimize the operational variables encircling temperature, pH, and adsorbent dose. The results elucidated that the generated model exhibited an R-squared of 0.98, reflecting its validity in describing the experimental data well. The optimized conditions for attaining maximum copper adsorption were marked to be a temperature of 37.71 oC, a solution pH of 5.7, and an adsorbent dose of 11.26 g L-1. Under these optimized conditions, the adsorption efficiency was marked to be 86.65 %. The experimental adsorption efficiency under these conditions was noted to be approximately 86.43 %, reflecting the suitability of the RSM-based Box-Behnken design. Conclusively, it can be inferred that acid modified rice straw offers a promising low cost adsorbent for remediation of heavy metals in accordance with the principles of green chemistry.

Plasma Electrolytes Response in Mud Catfish, Clarias gariepinus (Burchell 1822) exposed to Different Regimes of Salinity and pH

Introduction: Aquatic organisms, especially fish, are highly sensitive to environmental changes that can profoundly affect their physiological processes essential for survival. Physico-chemical factors such as salinity and pH exert significant influences on osmoregulation and ion balance, which are critical for maintaining cellular homeostasis in fish. Aims: This study aims to explore how varying levels of salinity and pH affect plasma electrolyte concentrations in Clarias gariepinus, focusing on potassium (K+), sodium (Na+), chloride (Cl−), and bicarbonate (HCO3−) ions. The objective is to understand the physiological responses of C. gariepinus to these environmental factors and their potential as biomarkers for assessing aquatic ecosystem health. Materials and Methods: Juvenile C. gariepinus was exposed to different salinity levels (4 ‰, 6 ‰, 8 ‰) and pH levels (4, 6, 8) over 21 days. Plasma electrolyte concentrations were measured using an SFRI ISE 6000 Electrolyte Analyser. Statistical analysis included ANOVA and DMRT to identify significant differences (p &lt; 0.05) among experimental groups. Results: The study found significant variations in K+, Cl−, Na+, and HCO3- concentrations in C. gariepinus across different salinity and pH conditions. K+ levels decreased with increasing salinity, indicating stress-induced responses, while pH variations had less pronounced effects on K+ regulation. Cl− concentrations increased with higher salinity levels, suggesting adaptive osmoregulatory strategies. Na+ levels showed significant fluctuations across salinity and pH conditions, whereas HCO3− levels responded uniquely to changes in these parameters, demonstrating adaptive mechanisms in acid-base balance. Conclusion: This research underscores the adaptive responses of C. gariepinus to fluctuations in salinity and pH, highlighting their ability to maintain plasma electrolyte balance under varying environmental conditions. These findings contribute to understanding the ecophysiological adaptations of C. gariepinus and suggest the potential utility of plasma electrolytes as biomarkers for assessing the health of aquatic ecosystems.

The influence of burn severity on dissolved organic carbon concentrations across a stream network differs based on seasonal wetness conditions

Abstract. Large, high-severity wildfires in many regions across the globe have increased concerns about their impacts on carbon cycling in watersheds. Altered sources of carbon and changes in catchment hydrology after wildfire can lead to shifts in dissolved organic carbon (DOC) concentrations in streams, which can have negative impacts on aquatic ecosystem health and downstream drinking-water treatment. Despite its importance, post-fire DOC responses remain relatively unconstrained in the literature, and we lack critical knowledge of how burn severity, landscape elements, and climate interact to affect DOC concentrations. To improve our understanding of the impact of burn severity on DOC concentrations, we measured DOC at 129 sites across a stream network extending upstream, within, and downstream of a large, high-severity wildfire in Oregon, USA. We collected samples across the study sub-basin during four distinct seasonal wetness conditions. We used our high-spatial-resolution data to develop spatial stream network (SSN) models to predict DOC across the stream network and to improve our understanding of the controls on DOC concentrations. Spatially, we found no obvious wildfire signal – instead, we observed a pattern of increasing DOC concentrations from the high-elevation headwaters to the sub-basin outlet, while the mainstem maintained consistently low DOC concentrations. This suggests that effects from large wildfires may be “averaged” out at higher stream orders and larger spatial scales. When we grouped DOC concentrations by burn severity group, we observed a significant decrease in the variability of DOC concentrations in the moderate and high burn severity sub-catchments. However, our SSN models were able to predict decreases in DOC concentrations with increases in burn severity across the stream network. Decreases in DOC concentrations were also highly variable across seasonal wetness conditions, with the greatest (−1.40 to −1.64 mg L−1) decrease occurring in the high-severity group during the wetting season. Additionally, our models indicated that in all seasons, baseflow index was more influential in predicting DOC concentrations than burn severity was, indicating that groundwater discharge can obscure the impacts of wildfire in a stream network. Overall, our results suggested that landscape characteristics can regulate the DOC response to wildfire. Moreover, our results also indicated that the seasonal timing of sampling can influence the observed response of DOC concentrations to wildfire.

Spatiotemporal Variability of Channel Roughness and its Substantial Impacts on Flood Modeling Errors

AbstractManning's roughness coefficient, n, is used to describe channel roughness, and is a widely sought‐after key parameter for estimating and predicting flood propagation. Due to its control of flow velocity and shear stress, n is critical for modeling timing of floods and pollutants, aquatic ecosystem health, infrastructural safety, and so on. While alternative formulations exist, open‐channel n is typically regarded as temporally constant, determined from lookup tables or calibration, and its spatiotemporal variability was never examined holistically at large scales. Here, we developed and analyzed a continental‐scale n dataset (along with alternative formulations) calculated from observed velocity, slope, and hydraulic radius in 200,000 surveys conducted over 5,000 U.S. sites. These large, diverse observations allowed training of a Random Forest (RF) model capable of predicting n (or alternative parameters) at high accuracy (Nash Sutcliffe model efficiency &gt;0.7) in space and time. We show that predictable time variability explains a large fraction (∼35%) of n variance compared to spatial variability (50%). While exceptions abound, n is generally lower and more stable under higher streamflow conditions. Other factorial influences on n including land cover, sinuosity, and particle sizes largely agree with conventional intuition. Accounting for temporal variability in n could lead to substantially larger (45% at the median site) estimated flow velocities under high‐flow conditions or lower (44%) velocities under low‐flow conditions. Habitual exclusion of n temporal dynamics means flood peaks could arrive days before model‐predicted flood waves, and peak magnitude estimation might also be erroneous. We therefore offer a model of great practical utility.

A Scientometric analysis and bibliometric review of IOEX as a treatment to remove pollutants

Pollutants in water bodies pose a serious threat to both the aquatic ecosystem and human health. Ion exchange is used as a chemical process to remove unwanted dissolved ions from water and wastewater. It is widely accepted in developing countries. This analysis provides a bibliometric examination to consider the status and trends of advanced ion exchange worldwide. This study was conducted using the Dimensions website to identify and collect the most important research papers. The retrieved manuscripts were organized through Microsoft Excel and then VOS viewer was used to analyze the data by reviewing previous studies related to ion exchange as a contaminant removal treatment. To create maps and find out which countries, universities, and journals have published research articles on topics related to ion exchange, as well as authors who have studied the topic of ion exchange and their research, cooperation. To benefit from these studies and learn the importance of ion exchange as a treatment for removing pollutants. The electro neutrality of the ion exchange (IOEX) process must always be maintained because it is a stoichiometric process. Search results for IOEX were exported from Dimensions to a CSV file, both coexistence, cooperation with affiliate countries and consortia were implemented on the full search results. Ion exchange treatment has proven effective in treating industrial wastewater and domestic wastewater. Professionals and practitioners in the field are provided with important information through this examination of ion exchange research. The analysts learned about leading academic and research institutions, the state of the exploration field, and the most controversial issues surrounding advanced ion exchange. In addition, this lesson will provide the opportunity to learn basic facts that will develop the extent of ion exchange knowledge. The bibliometric survey method can also be used to visualize the trend of research and study in various fields.

Investigating the impact of plasma plume length of atmospheric pressure plasma jet on ampicillin degradation efficiency and toxicity

Emerging pharmaceutical micropollutant: ampicillin-degradation in water using atmospheric pressure plasma jets (APPJs) is examined, and its environmental impact is evaluated. To this end, comprehensive plasma characterization techniques, including electrical and optical analyses, are used, to supplement existing research that primarily focused on degradation outcomes. The results of these techniques provide deeper insights into the degradation process. Additionally, the solution properties are assessed by examining the treated liquids and quantifying the corresponding hydrogen peroxide and nitrite concentrations, clarifying the role of reactive species in the degradation process. High-performance liquid chromatography analysis provides essential insights into degradation kinetics and rate constants. A comprehensive framework is developed for understanding the degradation of ampicillin by APPJs, combining plasma diagnostics, solution characterization, chemical assays, degradation kinetics, and toxicity analysis. Our study, grounded in these multidisciplinary approaches, contributes to both the fundamental understanding of plasma-based degradation and optimization of plasma plume length. Our findings highlight the potential of plasma jet technologies in addressing pharmaceutical pollution and promoting sustainable wastewater management practices. This research can advance efforts to enhance the efficiency of pharmaceutical waste treatment, ultimately safeguarding the health and well-being of aquatic ecosystems and human populations.

Utilizing cellulose nanofibers to enhance spent engine oil performance: A sustainable environmental solution

Spent engine oil is a major source of environmental pollution that affects the aquatic ecosystem and human health. Cellulose nanofibers (CNF) are natural nanomaterials that can be used as additives in spent engine oil to enhance its performance, especially at high temperatures and pressures. Utilizing sulfur-based unbleached rice straw pulping technique, the rice straw was grinded in a solution with 10 % sodium sulfite and 2 % sodium carbonate, that heated to 160 °C for 2 h. This produces unbleached sulfur pulp, which is then analyzed for ash, cellulose, and lignin content. A subsequent bleaching step at 80 °C with a sodium chlorite/acetic acid mix completes the process. This technique was adopted to produce CNF. In this study, preparation and characteriztion of CNF-additives to spent engine oil was performed using different techniquessuch as; IR spectra analysis, kinematic viscosity, and wear scar width. It was also evaluated on the oil adsorption, vibration, and noise reduction properties of the resulted additive oil. The results showed that CNF improved viscosity, lubrication, and anti-wear properties of the oil, and decreased its friction, vibration, and noise. The optimal concentration of CNF was 2.0 wt%, which increased the kinematic viscosity by 14.5 % and reduced the wear scar width by 31 % compared to the spent oil sample. Moreovere, CNF reduced the environmental impact of oil disposal and recycling. Overall, CNF are promising nanofillers for improving the performance of spent engine oil and lowering its environmental impact.

Potentially toxic elements contamination and ecological risk assessment in surface sediments of Moulouya Estuary (Northeastern, Morocco)

Potentially toxic elements (PTEs) in aquatic ecosystems are a major environmental concern posing serious risks to aquatic life and human health. Understanding their distribution, sources, and effects is crucial for effective environmental management and the protection of biodiversity and natural resources. This study assessed the variability, bioavailability, contamination degree, and ecological risks of PTEs in surface sediments of the Moulouya Estuary. The levels of PTEs were determined using an inductively coupled plasma-optical emission spectrometry (ICP-OES). The mean concentrations of PTEs can be classified in the following order: Zn > Cr > As > Pb >Cu > Cd. The highest values were found in sites (S2, S4, and S5) that receive metals from anthropogenic activities. The mineralogical study showed that the sediment studied is dominated by Ca, which influences the PTEs mobility and makes them bioavailable in the aquatic environment, which means aquatic organisms can easily assimilate them. The PTEs contamination degree was determined by several pollution indices (CF, CD, PLI, EF, Igeo), which indicate that surface sediment shows low to moderate contamination levels. However, the Potential Ecological Risk indicates a moderate to considerable risk in the study area. The multivariate analysis indicates that As, Zn, Cr, Pb, and Cu are derived from anthropogenic activities (urban wastewater, fertilizers, and fishing boats), while Cd could have mixed sources. The results highlight suggest that human activities pose an ecotoxicological risk in the Moulouya Estuary. To minimize these risks and protect the aquatic ecosystem and human health, periodic monitoring and management strategies should be continued. These measures will enable early detection of changes in PTE levels and the implementation of the necessary interventions to reduce their harmful effects.

Potential of nature-based solutions to reduce antibiotics, antimicrobial resistance, and pathogens in aquatic ecosystems. a critical review

This comprehensive scientific review evaluates the effectiveness of nature-based solutions (NBS) in reducing antibiotics (ABs), combating antimicrobial resistance (AMR), and controlling pathogens in various aquatic environments at different river catchment levels. It covers conventional and innovative treatment wetland configurations for wastewater treatment to reduce pollutant discharge into the aquatic ecosystems as well as exploring how river restoration and saltmarshes can enhance pollutant removal. Through the analysis of experimental studies and case examples, the review shows NBS's potential for providing sustainable and cost-effective solutions to improve the health of aquatic ecosystems. It also evaluates the use of diagnostic indicators to predict NBS effectiveness in removing specific pollutants such as ABs and AMR. The review concludes that NBS are feasible for addressing the new challenges stemming from human activities such as the presence of ABs, AMR and pathogens, contributing to a better understanding of NBS, highlighting success stories, addressing knowledge gaps, and providing recommendations for future research and implementation.

The effect of external flow on 3D orientation of a microscopic sessile suspension feeder, Vorticella convallaria.

Vorticella convallaria are microscopic sessile suspension feeders that live attached to substrates in aquatic environments. They feed using a self-generated current and help maintain the health of aquatic ecosystems and wastewater treatment facilities by consuming bacteria and detritus. Their environmental impact is mediated by their feeding rate. In ambient flow, feeding rates are highly dependent on an individual's orientation relative to the substrate and the flow. Here, we investigate how this orientation is impacted by flow speed. Furthermore, we examined whether individuals actively avoid orientations unfavorable for feeding. We exposed individuals to unidirectional laminar flow at shear rates of 0, 0.5, 1.0, and 1.5 s-1, and recorded their 3D orientation using a custom biplanar microscope. We determined that V. convallaria orientation became progressively tilted downstream as the shear rate increased, but individuals were still able to actively reorient. Additionally, at higher shear rates, individuals spent a larger fraction of their time in orientations with reduced feeding rates. Our shear rates correspond to freestream flows on the scale of mm s-1 to cm s-1 in natural environments.

Enhanced oxidation of parabens in an aqueous solution by air-assisted cold plasma

Various contaminants of emerging concern (CECs) including pharmaceuticals and personal care products (PPCPs) have been known to threaten the aquatic ecosystem and human health even at low levels in surface water. Among them, the wide variety use of parabens as preservatives may pose potential threat to human because parabens may present estrogenic activity. Various advanced oxidation processes have been attempted to reduce parabens, but challenges using cold plasma (CP) are very rare. CP is worth paying attention to in reducing parabens because it has the advantage of generating radical ions, including reactive oxygen/nitrogen species and various ions. Accordingly, this study demonstrates how CP can be utilized and how CP competes with other advanced oxidation processes in energy requirements. Quantified ethyl-, propyl-, and butyl-paraben indicate that CP can effectively degrade them up to 99.1% within 3 h. Regression reveals that the kinetic coefficients of degradation can be increased to as high as 0.0328 min−1, comparable to other advanced oxidation processes. Many by-products generated from the oxidation of parabens provide evidence of the potential degradation pathway through CP treatment. In addition, we found that the electrical energy consumption per order of CP (39–95 kWh/m3/order) is superior to other advanced oxidation processes (69∼31,716 kWh/m3/order). Overall, these results suggest that CP may be a viable option to prevent adverse health-related consequences associated with parabens in receiving water.