High Water Turbidity Research Articles

Novel cationic and amphoteric starch-modified coagulants for efficient treatment of relatively high turbidity and large organic matter source waters: Performance, predictive modeling and mechanism analysis

Finding alternative solutions of water source containing short-term relative high turbidity and large organic content is a pressing need in view of the inherent limitations of traditional inorganic coagulants. Requirement of significant dosage increase for conventional iron and aluminum salt coagulants can create several challenges including dose adjustment, suboptimal performance and high concentration of residual metal ions. In this study, acrylamide monomer (AM) and methacryloyloxyethyltrimethylammonium chloride (DMC) were grafted onto starch and carboxymethyl starch to obtain novel cationic and amphoteric starch-modified coagulants. Concurrently, the obtained coagulants were comprehensively evaluated under varying simulated water quality conditions to analyze their turbidity and organic matter removal efficiencies. Polymerized aluminium chloride (PACl) was used as the reference coagulant to evaluate the roles of polymer charge density, total charge, and molecular chain length in the coagulation mechanism for further illustration of their efficacy. In comparison to the traditional coagulant PACl, the modified coagulant was found to be more effective in enhancing flocculation and aggregation behavior, lowering of energy barriers, and enhancing adsorption energy by using the Density Functional Theory (DFT) calculations and Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory based investigation of the mechanism. Moreover, these behaviors were mainly attributed to significant exchange of charge density between coagulant and the pollutants. Additionally, in order to facilitate accurate and efficient treatment of water having diverse qualities, quadratic polynomial equation based mathematical model was constructed for quantitative analysis and model prediction. Findings of this study point towards an effective and precise approach to coagulation technology and thereby enabling sustainable and efficient purification of turbid source water containing large organic matter.

Multivariate Analysis of Water Quality in the Seybouse River: Implications for Pollution Management

ABSTRACTHeavy metal contamination in water bodies is a pervasive and persistent environmental challenge in many parts of the world, especially in developing countries. This study investigates the use of multivariate analysis methods for monitoring variations in water quality along a spatial gradient and for the interpretation of pollution levels at different sampling sites. We assessed the water quality of the Seybouse River and identified possible sources of pollution using three complementary multivariate analysis techniques (PCA, NMDS, and K‐means clustering). The results indicate a longitudinal gradient in water quality associated with industrial and agricultural activities in the middle and lower Seybouse River. Physico‐chemical and heavy metal analyses show high water turbidity with elevated concentrations of iron and chromium. We show that the contamination stems from four different sources, which can be categorized into different pollution levels. Our results suggest that complementary multivariate methods are a robust approach to identifying and categorizing significant sources of pollution in rivers, enabling the development of future successful water quality management strategies based on water pollution levels. This study highlights the importance of monitoring water quality and taking effective measures to control and mitigate pollution from various sources to ensure the safety of the environment and human health.

Effects of pre-chlorination on ultrafiltration process in directly treating seasonal high-turbidity surface water: Membrane fouling control and shock load resisting

The seasonal high turbidity in the surface water is posing great challenges to the feasibility of direct ultrafiltration (UF) due to the severe membrane fouling. In this study, a direct UF process was employed to treat the high-turbidity surface water. With the conventional operational protocols, severe membrane fouling encountered. Model fitting indicated that membrane fouling, resulting from the UF of high turbidity water, was predominantly associated with the complete obstruction of pores on the surface of the membrane and the subsequent formation of a cake layer. A pre-disinfection process using sodium hypochlorite was developed in this study, and the membrane fouling was significantly mitigated during long-term (885 h) filtration. The optimized chlorine dosage was 1.5 mg/L in treating the 800 NTU surface water, and enabled the transmembrane pressure (TMP) stabilization of UF process at a low level (<10 kpa). Pre-disinfection can effectively inactivate microorganisms and diminish the presence of microbial extracellular polymeric substances (EPS). This results in a transition from complex and viscous fouling to inorganic fouling on the cake layer caused by high turbidity water. With pre-chlorination, the adhesion force of the cake layer attached on the membrane reduced significantly to make the fouling more easily detach and be removed from on the membrane surface by the shear stress caused by the hydraulic backwash. These findings are expected to develop new insights into the membrane fouling control of UF in directly treating the seasonal high-turbidity surface water.

Production and characterization of efficient bioflocculant in high-turbidity drinking water treatment: Identification of flocculation-related genes

Bioflocculants are eco-friendly water treatment agents produced by bioflocculant-producing strains that are valuable in drinking water turbidity removal. The major challenges in the application of bioflocculants include low flocculation efficiency, high production costs, and unclear flocculation-related genes. In this study, Pseudomonas sp. ZC-41 a highly efficient bioflocculant-producing strain, was isolated from activated sludge to produce polysaccharide-based bioflocculant MBF-ZC with 94.12% flocculation efficiency under more economical culture conditions, which can solve the problem of low flocculation efficiency. Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed MBF-ZC contained hydroxyl, carboxyl, and amine groups, crucial for flocculation via adsorption bridging effects as the main flocculation mechanism. The 2393 differentially expressed genes (DEGs) in the transcriptome of strain ZC-41 were classified into five co-expression modules, and the turquoise module was associated with flocculation efficiency and bioflocculant yield. Nineteen flocculation-related genes were identified by combining functional pathways related to sugars. In addition, response surface methodology was optimized to achieve the efficiency of 93.57% for turbidity removal from high-turbidity water by bioflocculant. The results not only provide a solid theoretical foundation to solve the challenges of bioflocculants, but also enrich strategies for high-turbidity drinking water treatment.

Symbiodiniaceae diversity in Pocillopora corals in different environments of the Colombian Eastern Pacific: symbiont specificity in spite of coral-host flexibility

Reef-building corals live in close mutualism with dinoflagellate algae (family Symbiodiniaceae), which play key roles in coral physiological performance and survival. Association patterns between host species and endosymbiont algae and their significance are still not fully understood, but they seem to affect the ability of hosts to inhabit different environments and their resilience to climate change. In this work, we used next-generation sequencing of the Internal Transcribed Spacer 2 region of ribosomal DNA to determine the diversity and composition of the Symbiodiniaceae community in Pocillopora corals from Colombia, in the Eastern Tropical Pacific (ETP). We sampled 243 colonies from four localities characterized by distinct sea surface temperature, turbidity, and proximity to the coast. Two genera of Symbiodiniaceae, Durusdinium and Cladocopium were found associated with Pocillopora mitochondrial Open Reading Frame (mtORF) types. Cladocopium latusorum was highly specific to Pocillopora mtORF type 1, while C. pacificum was found exclusively associated with Pocillopora mtORF type 3. In contrast, Durusdinium glynnii was found in both Pocillopora mtORF types. Furthermore, a Cladocopium-dominated symbiont community occurred in cooler and less turbid localities, while a Durusdinium- dominated community was found in localities with high sea surface temperature and high water turbidity, irrespective of mtORF type. These results suggest that Pocillopora mtORF lineages associate with different Symbiodiniaceae genera in response to local environmental conditions. The ability to associate with a different partner under particular environmental conditions (Pocillopora-Durusdinium combination), and also maintain a specific partnership (Cladocopium species and Pocillopora mtORF types) may be key to understanding the resilience of the genus Pocillopora on ETP coral reefs.

Impact of variable hydrostatic pressure and intermittent operation on filtration performance and biofouling layer in gravity-driven membrane system for practical decentralized water supply

The gravity-driven membrane (GDM) systems offer a promising solution for decentralized drinking water supply due to its low maintenance and energy consumption. However, research on the practical application of GDM under variable hydrostatic pressure (variable load) and intermittent operation conditions, particularly in response to high-turbidity water, remains limited. This study investigates the long-term performance and characteristics of the biofouling layer of GDM under ultra-low variable hydrostatic pressure (20–60 mbar) and intermittent operation (8–12 h) conditions in practical decentralized water supply. The results indicate that the membrane flux (1.9–6.0 L∙m−2∙h−1, LMH) remained relatively stable despite variations in gravity-driven pressure (ΔP). Long-term operation of GDM can stably remove turbidity and potential pathogens from raw water. The total protein/polysaccharide ratios of extracellular polymeric substances (EPS) in the biofouling layer were below 0.50, reducing contaminant adhesion on the membrane surface. The 0.2–0.4 μm transparent exopolymer particles (TEP) fraction might be crucial for biofouling layer formation. The key species, belong to Proteobacteria and Patescibacteria, significantly alleviated membrane fouling by degrading polysaccharide and proteins in biofouling layer. Comammox Nitrospira were significantly enriched, contributing to efficient nitrification. GDM with variable load maintained a stable flux of 2.2–5.2 LMH under high-turbidity water conditions (300–1200 NTU), and simple forward flushing combined with sludge discharge can quickly restore ΔP. Overall, the variable load GDM system effectively manages membrane fouling and maintains stable filtration performance through the combined effects of variable load and intermittent operation, ensuring long-term and low-maintenance operation for decentralized water supply.

A Framework for Characterizing Spatio-Temporal Variation of Turbidity and Drivers in the Navigable and Turbid River: A Case Study of Xitiaoxi River

Turbidity, as a key indicator of water quality linked to underwater light attenuation, is crucial for evaluating water quality. Control in high-turbidity water environments plays a critical role in navigable rivers. For this purpose, our study proposed a framework for analyzing the spatio-temporal variation of turbidity and its driving factors in a navigable and turbid river using in situ measurement data, satellite data, socioeconomic data, a power index function model, and correlation analysis. The results show that the proposed model is feasible for quantitative turbidity monitoring of the Xitiaoxi River. Its upstream turbidity is lower than downstream, with seasonal averages for spring, summer, autumn, and winter of 93.9, 111.3, 113.5, and 120.9 NTU, respectively. Furthermore, the turbidity in the middle and lower reaches of the Xitiaoxi River continuously increased before 2005 and began to decline after 2005 due to the policy of mining moratorium. This trend is especially noticeable at monitoring points along the main stream of the Xitiaoxi River, such as downstream of the Xitiaoxi River (S1), Gangkou station (S2), middle reaches of the Xitiaoxi River (S4), Hengtangcun station (S6), upper stream of the Xitiaoxi River (S7), and Huxi River (S8). Mining and shipping have significantly contributed to the turbidity of the target river. This framework offers a practical approach for assessing the environmental impacts of both natural and anthropogenic factors, thereby providing valuable insights for river management practices.

Self-Assembly of Three-Dimensional Hyperbranched Magnetic Composites and Application in High-Turbidity Water Treatment.

In order to improve dispersibility, polymerization characteristics, chemical stability, and magnetic flocculation performance, magnetic Fe3O4 is often assembled with multifarious polymers to realize a functionalization process. Herein, a typical three-dimensional configuration of hyperbranched amino acid polymer (HAAP) was employed to assemble it with Fe3O4, in which we obtained three-dimensional hyperbranched magnetic amino acid composites (Fe3O4@HAAP). The characterization of the Fe3O4@HAAP composites was analyzed, for instance, their size, morphology, structure, configuration, chemical composition, charged characteristics, and magnetic properties. The magnetic flocculation of kaolin suspensions was conducted under different Fe3O4@HAAP dosages, pHs, and kaolin concentrations. The embedded assembly of HAAP with Fe3O4 was constructed by the N-O bond according to an X-ray photoelectron energy spectrum (XPS) analysis. The characteristic peaks of -OH (3420 cm-1), C=O (1728 cm-1), Fe-O (563 cm-1), and N-H (1622 cm-1) were observed in the Fourier transform infrared spectrometer (FTIR) spectra of Fe3O4@HAAP successfully. In a field emission scanning electron microscope (FE-SEM) observation, Fe3O4@HAAP exhibited a lotus-leaf-like morphological structure. A vibrating sample magnetometer (VSM) showed that Fe3O4@HAAP had a relatively low magnetization (Ms) and magnetic induction (Mr); nevertheless, the ferromagnetic Fe3O4@HAAP could also quickly respond to an external magnetic field. The isoelectric point of Fe3O4@HAAP was at 8.5. Fe3O4@HAAP could not only achieve a 98.5% removal efficiency of kaolin suspensions, but could also overcome the obstacles induced by high-concentration suspensions (4500 NTU), high pHs, and low fields. The results showed that the magnetic flocculation of kaolin with Fe3O4@HAAP was a rapid process with a 91.96% removal efficiency at 0.25 h. In an interaction energy analysis, both the UDLVO and UEDLVO showed electrostatic repulsion between the kaolin particles in the condition of a flocculation distance of <30 nm, and this changed to electrostatic attraction when the separation distance was >30 nm. As Fe3O4@ HAAP was employed, kaolin particles could cross the energy barrier more easily; thus, the fine flocs and particles were destabilized and aggregated further. Rapid magnetic separation was realized under the action of an external magnetic field.

Machine learning-based understanding of aquatic animal behaviour in high-turbidity waters

Inspired by the ambitions envisioned in the Fourth Industrial Revolution for aquaculture, also known as Aquaculture 4.0, the aquaculture (marine animal farming) industry is seeking to adopt data-driven Artificial Intelligence (AI) to help significantly improve business operations. One of the major barriers is the manual annotation of animal behaviour data, which is a time-consuming task that demands high levels of concentration from biologists. To address this challenge, this paper proposes novel automatic animal behaviour monitoring tailored for industrial scenarios. Our approach introduces a real-time machine-learning-based instance segmentation system that is specialised for underwater environments, where large groups of shrimp are farmed. The implemented system achieves an accuracy rate of 89% at 30 frames per second (fps) and can accurately detect shrimp in high-density areas under poor lighting conditions and high turbidity waters, despite the challenges of occlusion and overlapping. A key innovation of our method is the implementation of a new density cluster algorithm for time series and video analysis. This approach provides a more efficient and accurate way of monitoring animal behaviour, significantly saving time and effort for biologists and advancing the capabilities of automated aquaculture systems.

Suspended sediment exchange between the Changjiang Estuary and Hangzhou Bay and their key driving mechanisms

Nowadays estuarine deltas are threatened by factors such as insufficient terrigenous sediment supply and rising sea levels. The Changjiang Estuary is adjacent to Hangzhou Bay, characterized by high turbidity waters, and the suspended sediment exchange between the two will inevitably affect the erosion and deposition of subaqueous delta in the future. Based on in situ observation data and numerical model, we found that suspended sediment is transported from the Changjiang Estuary into Hangzhou Bay during spring tides, while from Hangzhou Bay into the Changjiang Estuary during neap tides. The key driving mechanisms for the difference during spring-neap tides were expounded by momentum analysis and numerical sensitivity experiments. The barotropic pressure gradient force during spring tides is the key force that drives the suspended sediment from the Changjiang Estuary into Hangzhou Bay. Conversely, the baroclinic pressure gradient force during neap tides is the key force that drives the suspended sediment from Hangzhou Bay into the Changjiang Estuary. This study can provide valuable scientific evidence for erosion and deposition in estuaries and adjacent seas, as well as the sustainable utilization of regional coastal sediment resources.

Use of an acrylamide-based anionic polymer for the concentration and removal of Giardia duodenalis cysts from high-turbidity water samples

The increasing investigation into environmental contamination by Giardia spp. cysts and its impact on public health has spurred interest in developing more sensitive methods for detecting these protozoa, particularly in water. However, these methods remain complex and costly. This study evaluated the concentration and removal efficiency of Giardia duodenalis cysts using an acrylamide-based anionic flocculant polymer (AFP) in filter backwash water samples from a water treatment plant (WTP) located in Blumenau City, southern Brazil, and compared them with the calcium carbonate flocculation technique (CCF), which is routinely used for water matrices with high turbidity. The average recovery rates of G. duodenalis cysts using CCF and AFP were 33.33% and 43.33%, respectively, with an average turbidity reduction of 98.39% and 98.78%. The use of an anionic flocculant polymer proved to be an efficient alternative for the concentration and removal of protozoan cysts in water samples with high turbidity. It is important to highlight that the development and application of new studies and strategies aimed at increasing the efficiency of the removal of these organisms from complex environmental matrices would bring benefits to public health and promote a One Health perspective. Keywords: cyst recovery, high turbidity, water.

Spatiotemporal Expansion of Algal Blooms in Coastal China Seas.

The coastal seas of China are increasingly threatened by algal blooms, yet their comprehensive spatiotemporal mapping and understanding of underlying drivers remain challenging due to high turbidity and heterogeneous water conditions. We developed a singular value decomposition-based algorithm to map these blooms using two decades of MODIS-Aqua satellite data, spanning from 2003 to 2022. Our findings indicate significant algal activity along the Chinese coastline, impacting an average annual area of approximately 1.8 × 105 km2. The blooms exhibit peak intensity in August, while the maximum affected area occurs in September, featuring multifrequency outbreaks in spring, and pronounced large-scale events in summer and autumn. Notably, our analysis demonstrates a robust 67% increase in bloom occurrences over the study period. This expansion is primarily attributed to increased nutrient inflow from terrestrial sources linked to human activity and precipitation, compounded by rising global sea surface temperatures. These spatiotemporal insights are critical for devising effective management strategies and policies to mitigate the impacts of algal blooms.

Analysis of the efficiency of different Oleaginous seeds and shells for use as natural coagulants

The research problem is to reduce the use of chemical coagulants by seeking more sustainable alternatives to water treatment. The use of Moringa oleifera (MO) is a good alternative coagulant agent, indicated in the water treatment system, in its clarification process, in addition to being biodegradable, but there is a need to look for other seeds that also have potential for be used as natural coagulants, in this context, it is justified to study other typical seeds from Portugal, where this study was carried out, to be used as an alternative natural coagulant. The hypothesis of this project is: among the typically European seeds selected for evaluation, seeds with high potential for use as a natural coagulant for use in water treatment will be found. This project aims to identify seeds, typical of Portugal, with similar potential to Moringa oleifera Lam to be used as a natural coagulant. The project was carried out in partnership with UFS, IFS and ISEP, where experiments were carried out with synthetic water with turbidity ranging from 40 to 350 NTU. The seeds used were four different types of European chestnuts, American and Portuguese nuts, plantain and Moringa oleifera, in addition to chestnut and walnut shells. From the results found, the Spanish chestnuts stand out with a turbidity removal efficiency of up to 69.8% in high turbidity water, in addition to the MO with a removal efficiency of 89.8% in high turbidity water.

Underwater light source changes microecosystem constructed by Vallisneria spinulosa Yan for water restoration: Efficiency of water purification, characteristics of growth, and rhizosphere

Submerged macrophytes are effective in ecological restoration of water bodies polluted by nitrogen and phosphorus, and its restoration capacity depends on underwater illumination condition. This study explored the influencing mechanism of illumination on Vallisneria spinulosa Yan (V. spinulosa Yan) for water restoration. Addition of underwater light source increased the total nitrogen, ammonia nitrogen, total phosphorus, and phosphate removal loads of the V. spinulosa Yan growth system by 61.5, 39.2, 8.5, and 5.0 mg m−2 d-1, respectively. Meanwhile, the growth of V. spinulosa Yan was obviously promoted, even with high water turbidity. Although the biological nitrogen removal processes were inhibited by adding underwater light source, the growth of V. spinulosa Yan can be significantly improved, thus enhancing the efficiency of water purification via the absorption of nitrogen and phosphorus by V. spinulosa Yan. This study provides a theoretical foundation and technical support for application of submerged macrophytes in ecological water restoration.

Water quality in a shallow eutrophic lake is unaffected by extensive thinning of planktivorous and benthivorous fish species

Ambitious to fulfill the European Water Framework Directive obligations, the European governments support projects to rehabilitate lakes with poor water quality. However, most lake restorations having relied on biomanipulation by fish thinning have failed to improve or even maintain water quality. Previous attempts removed all target fish species simultaneously, thus making it impossible to assess the specific impact of each feeding group on water chemistry. Lake Bromme was selected for extensive, time-selective fish biomanipulation to improve water clarity and promote submerged macrophytes and piscivorous fish stocks over a three-year monitoring period. Thinning of adult benthivorous bream (Abramis brama) and tench (Tinca tinca) was conducted throughout year one while thinning in years two and three targeted planktivorous roach (Rutilus rutilus), juvenile bream, and small perch (Perca fluviatilis). Yearly fish surveys assessed changes in fish population structure and biomass. Water quality parameters were monitored continually, and the cover of submerged macrophytes was surveyed annually via sonar. We found no improvement in water clarity or reductions of nutrients, organic particles, chlorophyll concentrations, or watercolor, despite a 6-fold thinning of total estimated fish biomass, from 112 to 19 kg ha−1. Over the period, the macrophyte cover increased from 0.8 to 13.5 %, but no recruitment of large piscivorous fish (perch and pike (Esox lucius) > 10 cm) was detected. We found higher correlations of particle concentration and water clarity to water temperature than to wind speed, which indicates sediment particle resuspension by the remaining fish community (mostly carp Cyprinus carpio) that forage on benthos in shallow lakes. Further system-ecological research in Lake Bromme should evaluate whether thinning the stock of carp and increasing plant cover may improve water quality and test which optical properties sustain high water turbidity and prevent shallow, eutrophic lakes like Lake Bromme from responding to intense fish thinning.

Interactive effects of sedimentary turbidity and elevated water temperature on the Pugnose Shiner (Miniellus anogenus), a threatened freshwater fish.

High turbidity and elevated water temperature are environmental stressors that can co-occur in freshwater ecosystems such as when deforestation increases solar radiation and sedimentary runoff. However, we have limited knowledge about their combined impacts on fish behaviour and physiology. We explored independent and interactive effects of sedimentary turbidity and temperature on the swimming activity and both thermal and hypoxia tolerance of the Pugnose Shiner (Miniellus anogenus, formerly Notropis anogenus), a small leuciscid fish listed as Threatened under Canada's Species at Risk Act (SARA). Fish underwent a 15-week acclimation to two temperatures (16°C or 25°C) crossed with two turbidities (~0 NTU or 8.5 NTU). Swimming activity was measured during the first 8weeks of acclimation. Fish in warm water were more active compared to those in cold water, but turbidity had no effect on activity. Behavioural response to hypoxia was measured after 12weeks of acclimation, as the oxygen level at which fish used aquatic surface respiration (ASR). Fish in warm water engaged in ASR behaviour at higher oxygen thresholds, indicating less tolerance to hypoxia. Turbidity had no effect on ASR thresholds. Finally, thermal tolerance was measured as the critical thermal maximum (CTmax) after 13-15weeks of acclimation. Acclimation to warm water increased fish CTmax and Tag (agitation temperature) but reduced the agitation window (°C difference between Tag and CTmax) and thermal safety margin (°C difference between the acclimation temperature and CTmax). Furthermore, fish in warm, turbid water had a lower CTmax and smaller thermal safety margin than fish in warm, clear water, indicating an interaction between turbidity and temperature. This reduced thermal tolerance observed in Pugnose Shiner in warm, turbid water highlights the importance of quantifying independent and interactive effects of multiple stressors when evaluating habitat suitability and conservation strategies for imperilled species.

Cross-habitat utilization of fish in a tropical deltaic system as a function of climate variability and body size: Are mangroves fish nurseries in a tropical delta?

The temporal variability of fish habitat utilization is poorly understood in tropical deltaic systems due to high water turbidity, which limits visual censuses, and to the lack of long-term data incorporating climate variability events. We aimed to assess the influence of body size and El Niño Southern Oscillation (ENSO) variability on the cross-habitat utilization rate of 14 fish species of commercial relevance in the Ciénaga Grande de Santa Marta (CGSM). We estimated the utilization of mangroves and coastal lagoons based on relative catch frequencies from encircling gillnets used within a long-term catch monitoring program, and then tested for significant changes in each species' habitat utilization as a function of body size and climate variability. Six species showed a high dependence on mangroves and four on coastal lagoons for most body size classes (including juveniles) and ENSO conditions. One species (Elops smithi) showed a high utilization of mangroves in some ENSO phases and body size classes, while three species showed a high utilization of both mangroves and coastal lagoons. Mangrove utilization by six species (Megalops atlanticus, E. smithi, Centropomus undecimalis, Mugil incilis, Mugil liza, and Ariopsis canteri) increased in larger body sizes at low depths, which usually occurs under dry ENSO conditions, when predatory risk is higher in coastal lagoons. Another species (Caquetaia kraussi) increased its mangrove utilization from the body size at which its feeding habits change. Mangroves and coastal lagoons are important nurseries and habitats for adults of the main commercial fish species in the CGSM. Seascape habitats and fringe/riverine mangroves must be conserved in tropical deltas to promote not only nurseries but also fish lifecycles.

2003–2021年呼伦湖藻华数据集

The presence of cyanobacteria blooms is an intuitive visual indicator of the eutrophication levels in lakes. It is of great importance to precisely assess the extent, coverage, location and other pertinent details of algal blooms and to monitor the eutrophication degree of water in real time, which is essential for ecological restoration and human life quality protection. Using MODIS Aqua satellite image as the primary data source, in the dataset we eliminated the influence of cloud, flare, aquatic vegetation, high turbidity water and other potential factors of interference in the extraction of algal blooms, calculated the algal bloom coverage at the individual pixel level, and finally obtained the data algal blooms in Hulun Lake spanning 19 years, from 2003 to 2021. The accuracy verification process generally met the stipulated requirements. The format of this dataset is * tif, which is compatible with GIS professional software for reading and editing. The dataset can provide data reference for professionals in the field, offering valuable data support for the ecological environment monitoring of Hulun Lake.

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The biodiversity of benthic foraminifera around the coral communities and the concentration of heavy elements (e.g., Mn, Fe, Cr, Cu, Ni, Pb, Zn, Cd, and Co) in Miskan Island and Al-Khiran coastline of Kuwait are used as an ecological indicator for the environmental and anthropogenic stresses occurred from February 2018 to February 2019. The study resulted in identifying 19 families, 6 orders, 29 genera, and 94 species. Using R-mode cluster analysis results in four assemblages and using Q-mode principal component analysis (PCA) distinguished three groups depending on the deep. The three main assemblages refer to different depths, Group A from 20 cm to 1 m depth; Group B from 1.5 to 2 m depth, Group C from 6 to 8 m depth. Al-Khiran coastline is characterized by anoxic conditions, confirmed by the existence of pyrite. Additionally, high water turbidity because of anthropogenic effects. The low number of benthic foraminifera on Miskan Island is due to the dissolution and calcification of foraminifera shells. The Island characterized by freshwater runoff from Iraq meets saltwater in the gulf, affecting the salinity. The turbidity is caused by sediment runoff and eutrophication. Both sites were considered relatively unpolluted compared with the nearest Iranian coast. However, the relatively high potentially toxic elements in some locations are due to the semi-restricted geographic characteristic and high anthropogenic activity. There is no clear abnormality in the identified species showing normal aperture, coiling, shape, and size.

Drowning incidents in urban rivers: An underestimated issue with future challenges in need of an interdisciplinary database to characterise its epidemiology

In recent decades, the recreational use of urban rivers has become popular, and public access to riverbanks has improved. However, in the context of global warming, the risk of drowning in urban rivers may increase. The objective of this study is to examine drownings in the Rhone and Saone rivers in Lyon (France) and to identify risk factors, hot spots and high-risk moments using an environmental database.A total of 386 fatal and non-fatal drownings occurred in Lyon on the Rhone and Saone rivers between 2015 and 2021. The analyses identify that, universally, most drowning victims are men (68 %) and young adults (37 %). More drownings occur in the summer period (45 %). There are also hot spots near the city centre and in urban river parks. Three types of drownings are characterised by using principal component analysis (PCA) and hierarchical clustering on principal components (HCPC) methods. These groups are distinguished by hydrological and meteorological conditions, as well as by the seasonality and circumstances of the incident. The first group (G1) corresponds to drownings that occur on cold winter days, with high water flows and turbidity. The second group (G2) corresponds to drownings that resulted from bridge jumping in a festive context or a challenge between friends. These drownings occur on autumn days with interesting hydrological conditions (low flow and clear water). The last group (G3) groups together drownings that occurred while a victim is swimming in an unsupervised area. These drownings occur during the summer on very hot days. Finally, a multiple logistic regression method showed that the average daily outdoor temperature was positively correlated with the occurrence of drowning in Lyon (p < 0.05) and that daily rainfall was negatively correlated with the occurrence of drowning (p < 0.05).