Laguna de Bay, the largest lake in the Philippines and third in Southeast Asia, is constantly challenged by anthropogenic activities. Hydrochemistry was investigated to understand its spatial and seasonal dynamics in terms of anthropogenic and natural influences. Water sampling campaigns were done during dry and wet seasons from the western, southern, and eastern parts of the bay representing residential and industrial areas, agricultural and residential areas, and agricultural area in the catchment, respectively. Sites include crucial waterbody spots such as important tributaries, i.e., rivers and lakeshores. Major ions, Cl−, Na+, Ca2+, Mg2+, K+, and NO3−, were analyzed. Using Canonical Correspondence Analysis (CCA) and ion molar ratios assessments, water origin was traced using the major ions, land cover, and geological characteristics. In general, results showed that in terms of concentration the dominance of the ions is as follows: Cl− > Na+ > Ca2+ > Mg2+ > K+ > NO3− whether wet or dry season. However, this varies when looking at the individual river. In terms of the total ion concentrations at each site, the highest contributors were the tributaries in the western part and the lakeshore in the southern part. In general, all the measured major ions are influenced by the anthropogenic origins mainly by built-up at the same time geogenic sources were identified, Cl−, Ca2+, Mg2+ are inclined to the Pliocene Quaternary volcanic area whereas Cl−, K+ and Na+ are associated from seawater discharges. In terms of tendencies, south and east bays showed vulnerability to both anthropogenic and magmatic influences. West bay showed the dominance of anthropogenic influence. The results presented the geogenic and anthropogenic origins of Laguna de Bay’s hydrochemistry that can help in coming up with better management programs to improve the water quality.

Microplastics (MPs) are increasingly detected in aquatic environments and are a growing concern due to their persistence, mobility, and potential risks to ecosystems and human health. This study aims to investigate the presence of MPs (>20 μm) across the urban water cycle of Geneva (Switzerland). The scope of the assessment includes large water volumes (50-2000 L) of raw water sources (groundwater and surface water), drinking water treatment, water supply network, and effluents of three wastewater treatment plants. MPs concentrations, size distributions, and chemical compositions were determined across these interconnected systems. Sampling and analysis followed a strict quality assurance protocol aligned with current MP analysis guidelines and standards. Fourier-transform infrared spectroscopy (FTIR) was used to characterise MPs. Geneva's main conventional drinking water treatment plant (serving approximately 500,000 consumers) showed high removal efficiency, reducing MPs concentrations from 640 ± 292 MP/m3 in raw water to 10 ± 6 MP/m3 after treatment (including coagulation, sand filtration, ozonation and granular activated carbon filtration), demonstrating a removal efficiency of 97 ± 3 %. Groundwater samples showed low concentration of MPs (8 ± 7 MP/m3). However, the drinking water supply network (DWSN) contributed to an increase of MPs concentration, with values equal to 27 ± 37 MP/m3 in the eastern section and 23 ± 19 MP/m3 in the western section. Effluents from wastewater treatment plants (WWTPs) exhibited the highest concentrations, averaging 5829 ± 5108 MP/m3. This study highlights the importance of full-cycle monitoring and supports the need for improved mitigation strategies across all stages of the urban water cycle.

Because he thought the nanoparticles I drew for him were too small, too large, too elongated, I ended up drawing a fiber and telling him that the nanoparticles he wanted were inside, which lit up his face.

This study provides a detailed assessment of groundwater salinization in the Quaternary aquifer of the Samba Dia region, Senegal, using an integrated approach that combines hydrochemical, stable isotopic (δ2H, δ18O), and electrical resistivity tomography (ERT) techniques. Fourteen high-resolution ERT profiles, along with comprehensive chemical and isotopic analyses, were performed to identify the main causes of salinity and their spatial distribution. Results show that groundwater salinization in the area is primarily driven by three mechanisms: seawater intrusion, surface salt leaching, and ion exchange. Hydrochemical facies evolution diagrams, ionic ratios, and isotopic signatures helped differentiate marine-influenced zones from inland salinization areas. ERT imaging also mapped the three-dimensional extent and geometry of saline interfaces, confirming zone-specific mixing of seawater and freshwater. The findings indicate that salinization of the coastal aquifer has worsened over the past twenty years, mainly due to human activities and climate variability. This study recommends a sustainable monitoring strategy to support aquifer management, focusing on accurately identifying vulnerable zones and enabling adaptive resource planning in semi-arid Senegal.

Under varying flow rate conditions, the transport and retention of polydisperse microplastics (MPls), with an average particle size of 16 ± 6 µm, were investigated in saturated porous media. First-order reversible and irreversible kinetic sorption models were used to describe the sorption kinetics. Sensitivity analyses provided insight into the effects of each sorption parameter. Both numerical modeling and experimental measurements were utilized to evaluate the retention rates of sand filters. The influence of flow rate on sorption was reflected in variations in the distribution coefficient (Kd), the mass transfer coefficient (β), and the irreversible sorption rate (K1). Lower flow rates were associated with higher Kd and β values, indicating increased sorption and reduced mass transfer rates. An increase in Kd resulted in a more gradual sorption process, with a decrease in peak concentration, whereas changes in β had a comparatively smaller impact on sorption rate and peak concentration. Lower K1 values were linked to higher peak concentrations and decreased retention efficiency. Numerical modeling revealed retention rates of 28 ± 1% at a flow rate of 31 mL min−1 and 17 ± 1% at 65 mL min−1. The introduction of MPls into saturated sand environments modifies the transport dynamics within the medium. Consequently, these alterations affect the hydrological characteristics of porous media, impacting groundwater quality and agricultural output. The mean absolute error (MAE) of 6% between the modeled and observed retention rates indicated a high level of accuracy. This study underscores the importance of examining retention efficiency and the accuracy of numerical models in understanding MPl transport in porous media.

This study concerns the transport and retention of polydisperse micron-sized (16 ± 6 µm) of microplastics (MPls) in porous media under varying flow rate conditions. Sorption kinetics were modeled using first-order reversible and irreversible kinetic sorption models, with sensitivity analyses providing insights into each sorption parameter's effect. Both numerical modeling and experimental measurements were employed to assess sand filter retention rates. The impact of flow rate on sorption reveals variations in distribution coefficient (Kd), mass transfer coefficient (β), and irreversible sorption rate (K1). Lower flow rates are correlated with higher Kd and β values, indicating an increase in sorption and diminished mass transfer rates. The findings revealed that an increase in Kd resulted in a more gradual sorption process with a decrease in peak concentration, whereas changes in β influenced the rate of sorption and peak concentration to a lesser extent compared to Kd. Lower K1 values are associated with higher peak concentrations and decreased retention efficiency. Retention rates were evaluated by a numerical model and found as 28 ± 1% at a flow rate of 31 ml min⁻¹ and 17 ± 1% at 65 ml min⁻¹. The introduction of MPls into soil environments has been noted to modify transport dynamics into soil. As a result, these alterations effects hydrological characteristics of soil, thereby impacting quality of groundwater and agricultural output. The mean absolute error (MAE) of 6% between modeled and observed retention rates suggests minor discrepancies. This study highlights the importance of examining retention efficiency and the accuracy of numerical models in porous media during MPl transport.

A wastewater treatment plant (WWTP) prototype coupled with Moringa oleifera seeds (MOSs) was developed to evaluate its effectiveness to reduce metallic trace elements (MTEs) in domestic wastewater. The WWTP is composed of a septic tank (F0) where wastewater is treated by biological processes under anaerobic conditions, followed by a bacterial filter (F1) where wastewater is filtered under aerobic conditions, followed by an infiltration well (F2), which provides additional filtration of wastewater before discharge into the soil. MTEs present in waters can bind with humic substances contained in colloid particles and then be eliminated by coagulation–flocculation with a cationic polyelectrolyte. MOSs contain positively charged cationic polymers that can neutralize the colloids contained in waters, which are negatively charged. Based on this observation, 300 mg·L−1 of MOS was added into F0, 50 mg·L−1 into F1, and 50 mg·L−1 into F2 mg·L−1. MOS activation in samples was performed by stirring rapidly for 1.5 min, followed by 5 min of gentle stirring and 3 h of settling. The data analysis shows that wastewater samples had significant concentrations of MTEs, particularly for Cu, Ni, Sr, and Ti, and sediment samples had high amounts of Cr, Cu, Ni, Sr, Ti, and V. The addition of MOS to F0, F1, and F2 samples resulted in reductions in MTE concentration of up to 36%, 71%, 71%, 29%, 93%, 81%, 13%, 52%, and 67% for Co, Cr, Cu, Ni, Pb, Se, Sr, Ti, and V, respectively. The quantified MTEs (As, Co, Cr, Cu, Ni, Pb, Se and V) in treated samples were reported to be lower than UN-EP standards for a safe reuse for irrigation and MOS proved to be as effective as chemical coagulants such as lime and ferric iron for the removal of MTEs contained in wastewater. These results highlight the potential of MOSs as natural coagulants for reducing MTE content in domestic wastewater. This study could be the first to evaluate the effectiveness of MOS in reducing 10 MTEs, including As, Co, Se, Sr, Ti, and V, which are currently understudied. It could also provide a better understanding of the origin of MTEs found in domestic wastewaters and how an effective treatment process can result in high-quality treated wastewaters that can be reused for irrigation without posing health or environmental risks. However, more research on MOSs is needed to determine the type and composition of the coagulant substance found in the seeds, as well as the many mechanisms involved in the decrease in MTEs by MOSs, which is currently understudied. A better understanding of MOS structure is required to determine the optimum alternative for ensuring the optimal effect of MOS paired with WWTP in removing MTEs from domestic wastewaters.

In this transdisciplinary study, we investigated, using genomic tools and physico-chemical parameters, the effect of Moringa oleifera seed (MOS) on the removal of microorganisms and pharmaceutic residues (antibiotics), and also the development of antibiotic-resistant genes (ARGs) in water samples from a domestic wastewater treatment plant (WWTP) prototype. Water samples were analyzed with and without the addition of powder of MOS. The results showed that MOS addition reduced the total bacterial load from 1.73 × 1010 ± 3.21 × 109 to 6.67 × 106 ± 5.77 × 106 CFU/L, while fecal coliforms and Escherichia coli were removed with efficiencies of 99

Information about the influence of surface charges on nanoplastics (NPLs) transport in porous media, the influence of NPL concentrations on porous media retention capacities, and changes in porous media adsorption capacities in the presence of natural water components are still scarce. In this study, laboratory column experiments are conducted to investigate the transport behavior of positively charged amidine polystyrene (PS) latex NPLs and negatively charged sulfate PS latex NPLs in quartz sand columns saturated with ultrapure water and Geneva Lake water, respectively. Results obtained for ultrapure water show that amidine PS latex NPLs have more affinity for negatively charged sand surfaces than sulfate PS latex NPLs because of the presence of attractive electrical forces. As for the Geneva Lake water, under natural conditions, both NPL types and sand are negatively charged. Therefore, the presence of repulsion forces reduces NPL’s affinity for sand surfaces. The calculated adsorption capacities of sand grains for the removal of both types of NPLs from both types of water are oscillating around 0.008 and 0.004 mg g−1 for NPL concentrations of 100 and 500 mg L−1, respectively. SEM micrography shows individual NPLs or aggregates attached to the sand and confirms the limited role of the adsorption process in NPL retention. The important NPL retention, especially in the case of negatively charged NPLs, in Geneva Lake water-saturated columns is related to heteroaggregate formation and their further straining inside narrow pores. The presence of DOM and metal cations is then crucial to trigger the aggregation process and NPL retention.

Groundwater has been the main resource used for drinking, domestic and agricultural activities in West central Senegal for the past few decades. Thus, this study investigates the quality of groundwater and assesses its suitability for drinking and irrigation purposes. To this end, 42 samples were collected and analyzed for various chemical parameters (major ions, fluoride, pH, total dissolved solids (TDS)). Chemical data were interpreted using water quality indexes, Wilcox and USSL salinity diagrams, bivariate plots, ionic ratios and by comparing with the WHO standards. Results indicated that the groundwater is neutral to slightly alkaline with pH values between 7.1 and 8.2. Piper diagram shows that mixte-Ca-Na-Mg-HCO3 is the dominant hydrochemical facies. TDS and water quality index (WQI) values indicated respectively that 69% and 64.3% of samples were suitable for drinking. Moreover, major ions concentrations were found below the desirable limits in most of groundwater samples. However, for fluoride, 69% of samples exceed the WHO guideline, limiting their use for drinking. The computed index of irrigation water quality and Wilcox diagram reveal that 87% and 78% of samples belong, respectively, to excellent to good category and excellent to good and good to permissible. Similarly, according to the US salinity classification, the majority of samples were acceptable for irrigation. Gibbs plots illustrate that water-rocks interaction with some extent evaporation is the main hydrochemical process controlling groundwater chemistry while bivariate plots and ionic ratios indicate that mineral dissolution and ion exchange play important role in groundwater chemistry.

The efficiency of sand filtration was investigated in terms of the behavior of the nanoplastics (NPLs) with different surface functionalities. The initial condition concentrations of NPLs were varied, and their effects on retention and transport were investigated under a constant flow rate in saturated porous media. The behavior of NPLs in this porous system was discussed by considering Z- average size and zeta (ζ) potential measurements of each effluent. The retention efficiencies of NPLs were ranked as functionalized with amidine [A-PS]+ > with sulfate [S-PS]− > with surfactant-coated amidine [SDS-A-PS]−. The reversibility of the adsorption process was revealed by introducing surfactant into the sand filter system containing adsorbed [A-PS]+ at three different initial state concentration conditions. The deposition behavior on sand grain showed that positively charged NPLs were attached to the quartz surface, and negatively charged NPLs were attached to the edge of the clay minerals, which can be caused by electrical heterogeneities. The homoaggregates made of positively charged NPLs were more compact than those made of negatively charged NPLs and surfactant-coated NPLs. An anti-correlation was revealed, suggesting a connection between the fractal dimension (Df) of NPL aggregates and retention efficiencies. Increased Df values are associated with decreased retention efficiencies.The findings underscore the crucial influence of NPL surface properties in terms of retention efficiency and reversible adsorption in the presence of surfactants in sand filtration systems.

Since the first plastic production at an industrial scale in the 1950s, the importance of plastics in our lives and their production have continued to increase daily. Most of the studies focused on plastic debris accumulation in the marine environment. However, terrestrial environments significantly contribute to the plastic waste abundance of marine and freshwater environments. While investigating the accumulation in these environments, the land-based contamination sources, pathways, and transport mechanisms of plastic debris need to be accounted for to clarify the budget for global plastic contamination. Evaluation of the studies based on the mobility of microplastics (<5 mm) from terrestrial to the aquatic environment is the main concern of this review. Understanding the transport process into soil and soil to the surface and underground freshwater environments is important to emphasize the scale of plastic pollution. Microplastic contamination in the water directly bounds the organism and human health. The importance of microplastic contamination was highlighted by the experimental results of studies in the literature modeling microplastic transport from soil to aquatic environments using different methods. The results showed that salinity has effects on transportation. The maximum penetration depth was found to be 7.5 cm. At last, the retention and aggregation effects on transport were revealed.

One of the most serious problems affecting coastal aquifers is seawater intrusion. Senegal is currently facing an increased demand for freshwater resources due to population growth and economic development in coastal areas. In areas affected by saltwater contamination, chloride concentrations as high as 8880 mg/L were measured in groundwater samples taken from wells near the coastal zone, indicating deterioration in water quality. Our study aims to identify the zones of degradation of the water quality by determining the chemical composition of groundwater and the geochemical processes controlling the chemical patterns. Hydrogeochemical (Piper and Chadha diagrams, chloroalkaline indices, normalized bivariate plots) and multivariate statistical (Hierarchical cluster analyses) techniques were used. Forty-two groundwater samples were collected and analyzed for concentrations of major and some minor ions, electrical conductivity (EC), total dissolved solids (TDS), temperature, and pH. From samples we were able to establish a diagnosis of the very heterogeneous quality of the groundwater in this area. The average pH of the groundwater is 7.6 and about 80% of the groundwater samples have a TDS below 1000 mg/L. On the other hand, the EC values are very heterogeneous with very high conductivities in coastal areas. Approximately, 80% of the groundwater samples have a TDS less than 1000 mg/L and EC values are very heterogeneous. The dominant water types in the study area are Na-Cl water type (less than 10% of the samples) characteristic of the spatial evolution of groundwater salinization from west to east, mixed Ca-Mg-Cl due to fresh water/salt water contact and Ca-Mg-HCO 3 water-type (nearly 56% of the samples) to the east. A hydrogeochemical zonation of the aquifer, based on the presence of different water families allows us to visualize the highly degraded (west), mixed (center) and healthy (east) zones. Chloroalkaline indices and normalized bivariate plots show that the chemistry of groundwater is controlled mainly by water-rock interaction and evaporation processes. As water-rock interaction processes, dissolution of carbonate and evaporite, weathering of silicate, ions exchange regulates major ion chemistry.

Plastics are widely used in every part of life. Microplastics (MPs) are classified as emerging contaminants in nature. Yet, microplastic transportation parameters in groundwater are not characterized well. In this study, microplastic transport in saturated homogeneous media was investigated. For this purpose, one-dimensional column tests were performed using the fluorescent and microplastic tracers to figure out the hydrodynamic conditions for the microplastic transport. Large silica, small silica, sand, and coarse gravel were the tested media. The hydrodynamic transport parameters were calculated by inverse solution methodology using the experimental and the analytical solution results. Only the coarse gravel medium with a minimum 1 mm and maximum 20 mm (5 mm of median) pore sizes and kinematic porosity 40.2% were found to be suitable for the transport of the used polyethylene (PE) whose particle size was between 200 and 500 µm. It is not possible to transport PE particles of selected size from fine-grained media. Transportation occurred in coarse-grained media such as coarse gravel. The calculated dispersivity values for the coarse gravel were 2.58 and 3.02 cm by using fluorescent and PE tracers, respectively. The experiments showed that the used PE particles cannot be transported if the mean flow velocity is lower than 2.02 cm/min in the coarse gravel medium. The microplastic accumulation might be an issue for an actual aquifer rather than the transportation of it considering the actual groundwater flow velocity is generally much lower.

For the last few decades, many efforts have been made in developing cell culture methods in order to overcome the biological limitations of the conventional two-dimensional culture. This paradigm shift is driven by a large amount of new hydrogel-based systems for three-dimensional culture, among other systems, since they are known to mimic some living tissue properties. One class of hydrogel precursors has received interest in the field of biomaterials, low-molecular-weight gelators (LMWGs). In comparison to polymer gels, LMWG gels are formed by weak interactions upon an external trigger between the molecular subunits, giving them the ability to reverse the gelation, thus showing potential for many applications of practical interest. This study presents the use of the nucleoside derivative subclass of LMWGs, which are glyco-nucleo-bola-amphiphiles, as a proof of concept of a 3D cell culture scaffold. Physicochemical characterization was performed in order to reach the optimal features to fulfill the requirements of the cell culture microenvironment, in terms of the mechanical properties, architecture, molecular diffusion, porosity, and experimental practicality. The retained conditions were tested by culturing glioblastoma cells for over a month. The cell viability, proliferation, and spatial organization showed during the experiments demonstrate the proof of concept of nucleoside-derived LMWGs as a soft 3D cell culture scaffold. One of the hydrogels tested permits cell proliferation and spheroidal organization over the entire culture time. These systems offer many advantages as they consume very few matters within the optimal range of viscoelasticity for cell culture, and the thermoreversibility of these hydrogels permits their use with few instruments. The LMWG-based scaffold for the 3D cell culture presented in this study unlocked the ability to grow spheroids from patient cells to reach personalized therapies by dramatically reducing the variability of the lattice used.

Developing countries are confronted with general issues of municipal wastewater management and treatment. Untreated wastewater and faecal sludge from septic tanks and traditional toilets are often discharged into rivers and used for urban agriculture without any treatment to minimize potential biorisks. Such practices result in potential environmental and public health risks. In this study, a wastewater treatment plant prototype coupled with Moringa oleifera seeds treatment was developed to evaluate their effectiveness for the reduction of faecal indicator bacteria and antibiotic-resistant bacteria in domestic wastewater. We demonstrated that that the proposed wastewater treatment plant prototype reduces bacteria by 99.34%. A high removal of the bacteria load was obtained after the addition of Moringa oleifera seeds into waters, with removal rates of 36.6–78.8% for E. coli, 28.3–84.6% for faecal coliform, 35.3–95.6% for Vibrio cholera and 32.1–92.4% for total flora. A similar effect of Moringa oleifera seeds was noted for the removal of antibiotic-resistant bacteria, extended-spectrum beta-lactamases and carbapenem-resistant Enterobacteriaceae, with a removal rate of up to 98% for E. coli and faecal coliform, 100% for Vibrio cholera and 91.96% for total flora. This study demonstrated the high removal efficiency pathogens and antibiotic-resistant bacteria from domestic wastewater using Moringa oleifera seeds.

The presence of NPs in drinking water resources raises a global concern on their potential risk for human health, and whether or not drinking water treatment plants are able to effectively remove NPs to prevent their ingestion by humans. In this study, we investigate the efficiency of granular activated carbon (GAC), commonly used in conventional municipal water treatment processes, for the removal of CeO2 NPs. In ultrapure water, NPs are found to have a good affinity for GAC and results indicate an increase in the adsorption capacity from 0.62 ± 0.10 to 5.05 ± 0.51 mg/g, and removal efficiency from 35 % ± 4 to 54 % ± 5 with increasing NPs concentration. Kinetic studies reveal that intraparticle diffusion is not the only rate controlling step indicating that mass transfer effect is also playing a role. Adsorption mechanisms are mainly controlled by the electrostatic attractions between the positively charged NPs and negatively charged GAC. Although electrostatic conditions in Lake Geneva water are less favorable for NPs adsorption, the adsorption capacity and removal efficiency are higher than in ultrapure water with values raising from 0.41 ± 0.17 to 7.13 ± 1.13 mg/g and 26 % ± 8 to 75 % ± 11, respectively. Furthermore, the external mass transfer process onto GAC surface is more important than for ultrapure water. NPs adsorption mechanism is explained by the presence of divalent cations and natural organic matter (NOM) which promote the formation of CeO2 NPs-NOM-divalent cation heteroaggregates increasing both adsorption and removal efficiency by cation bridging.