Natural Surface Water Research Articles

Water disinfection using hydrogen peroxide with fixed bed hematite catalyst - kinetic and activity studies.

A lab-scale reactor with a fixed-bed hematite catalyst for the effective decomposition of H2O2 and bacteria inactivation was designed. The bactericidal effect is the largest at a low initial bacterial count of 2·103CFU/L, which is typical for natural surface waters. When using a 5mM H2O2 solution and a residence time of 104min, the reduction in the number of E. coli bacteria is about 3.5-log. At a higher initial bacterial count of 1-2·104CFU/L, a 5mM H2O2 solution reduces the bacteria number by about 4-log. The H2O2 decomposition follows the log-linear kinetics of a first-order reaction while the bacterial inactivation does not. The kinetics of bacterial inactivation was described using the Weibull model in the modified form: log10(N0/N) =b · tn. The values of the non-linearity parameter n were found to be lower than 1, indicating that bacterial inactivation slows down over time. With increasing initial H2O2 concentration, the rate parameter b increases while the non-linearity parameter n decreases. With increasing temperature, both parameters increase. The stability of the catalyst has been proved by XRD, FTIR, SEM, and ICP-OES. The concentration of iron leaching into water during disinfection is much lower than the limit declared by WHO for iron in drinking water. The results show that technical-grade hematite is a promising Fenton-like catalyst for water disinfection. The fixed-bed reactor can be the basis of the mobile installations for water purification in emergencies.

The Physical and Chemical Properties of Natural Drinking Water in Phonexay District, Lao PDR

This study aims to determine the physical, chemical and biological properties and capacity of the commercial purifier (TerraClear ceramic water purifier) of natural drinking water. The present study was conducted in three villages of Phonexay district, Luang Prabang province, Lao PDR where the purifiers were provided for the target households. The surface water was collected before and after purifications. The collected samples were sent to the laboratory of the Water Supply Company for the analysis of physical, chemical and biological compositions. The result showed that: The compositions of physical. pH, Conductivity (uS/cm), Turbidity (NTU), Color (TCU) before purifications were 7.56, 261.00, 6.38, 5.66 The values after purifications were 7.50, 239.00, 0.45, 0.66 The compositions of chemical. Fluoride (mg/L), Nitrate (mg/L), Nitrite (mg/L), Total Hardness (CaCo3: mg/L), Arsenic (mg/L), Iron (mg/L), Manganese (mg/L) before purifications were 0.15, 1.13, 0.01, 132.00, 0.00, 0.05, 0.01 The values after purifications were 0.02, 0.36, 0.002, 18.00, 0.00, 0.02, 0.01 The compositions of biological. Coliform bacteria (100ml), E-Coli (100ml) before purifications were 53.33, 2.33 The values after purifications were 0.00, 0.00, respectively. The natural surface water in the northern province of Lao PDR is not seriously harmful in some areas as well as in the remote areas in terms of biological, physical and chemical contaminations. Moreover, this study confirmed that using the TerraClear ceramic water purifier was safe for drinking water for people and its exceeded chemical compositions which could be harmful to human health were also purified. Further research is recommended to classify more details and varies of other related biological and chemical contaminations.

Sukhareva O.Yu., Kushtan S.M., Sukharev S.M. SCREENING OF CONTENT OF BIOAVAILABLE FORMS OF FLUORIDE IN SURFACE AND GROUNDWATER OF THE TISA RIVER BASIN

Fluorine, as a essential trace element, plays an important role in maintaining human health, but an excess of fluorides causes various diseases. The main way fluoride enters the human is drinking water, the source of which is natural surface and underground water. In surface and groundwater, fluorides can exist in bound (compounds with aluminum, iron, calcium and magnesium) and free (bioavailable) forms, therefore, when monitoring natural waters, it is important to distinguish between the total content of fluorides and the content of bioavailable forms. This work presents a screening of the content of bioavailable forms of fluorides in surface (river) and underground (well) waters of the Tisza River basin. The study was carried out in the summer (June-August) period of 2023. The screening results showed that river waters have a lower concentration of bioavailable forms of fluorides (2.9-8.3 μg×L-1) than groundwater (7.5-14.4 μg×L-1). It was established that the content of bioavailable forms of fluorides in natural waters is determined, first of all, by the geology of the territories (the lowest content in mountainous areas, and the highest in lowland areas), and for surface waters also by the morphologys of the river. For river waters, the general pattern of fluoride content distribution is complicated and ambiguous. In general, the content of bioavailable forms of fluorides in the surface and underground waters of the Tisza River basin is small, which causes a risk to the human dental health of the region.
 Keywords: monitoring of natural waters; indirect spectrophotometry; liquid-liquid microextraction; human health risk.

Coupling pretreatment of ultraviolet/ferrate (UV/Fe(vi)) for improving the ultrafiltration of natural surface water.

Ultrafiltration (UF) is a high-potential technology for purifying natural surface water; however, the problem of membrane fouling has limited its widespread application. Herein, ultraviolet (UV)-activated ferrate (Fe(vi)) was used to purify natural surface water and improve the performance of the UF membrane. The combination of UV and Fe(vi) could generate active species (Fe(v), Fe(iv), ˙OH and O2˙-) to degrade pollutants, while the in situ produced Fe(iii) had the effect of coagulation. With the above action, pollutants were removed, and the pollution load of natural surface water was reduced. After treatment with the UV/Fe(vi) system, dissolved organic carbon was reduced by 49.38%, while UV254 was reduced by 45.00%. The removal rate was further increased to 54.88% and 51.67% after UF treatment. In addition, the fluorescent organics were reduced by 44.22%, and the molecular weight of the organics became smaller. In the stage of UF, the terminal J/J0 was increased from 0.61 to 0.92, and the membrane fouling resistance was decreased by 85.94%. The analysis of the membrane fouling mechanism indicates that the role of cake filtration was weakened among all the mechanisms. Fourier transform infrared spectroscopy showed that less pollutants were accumulated on the membrane surface, and scanning electron microscopy revealed that the membrane pore blockage was relieved. In summary, the UV/Fe(vi) co-treatment process proposed in this study can significantly improve the purification efficiency of the UF systems in natural surface water treatment.

Effect of nano Fe3O4-(CMC-Na)-PFS coagulant on coagulation–ultrafiltration process for treatment of algae -rich water

A novel composite flocculant (PCNF) was prepared using nano Fe3O4 as the condensed core, sodium carboxymethyl cellulose (CMC-Na) as the binder, and polyferric sulfate (PFS). The results indicate that the mass ratio of Fe3O4 to PFS is the key factor determining the flocculation effect of PCNF. When the mass ratio of Fe3O4 to PFS is 1:3, the Zeta potential value is approximately − 1.5 mV, indicating better removal of algae through adsorption electroneutralization. The resulting floc, characterized by negative charge and a loose structure, forms a filter cake layer that is easily backwashed on the surface of the ultrafiltration membrane. This floc also creates strong electrostatic repulsion with the membrane surface. Experimental results demonstrate that the specific flux decreased to 0.69, the total relative pollution was 0.33, and the proportion of irreversible pollution was only 34.65%, all of which were superior to traditional flocculant like PACl. Through microinterface mechanism analysis, it is concluded that the new PCNF flocculant, in combination with algal matter, forms a floc structure critical for mitigating ultrafiltration membrane pollution caused by high algal content in natural surface water.

Enrichment of Water Bodies with Phenolic Compounds Released from Betula and Pinus Pollen in Surface Water.

Betula and Pinus pollen, which are dispersed in natural surface waters, release biologically active compounds into the water bodies. This study aims to evaluate variations in the distribution and composition of phenolic compounds in suspended particles in natural water bodies during pollen spreading. Samples taken from water bodies of different trophic levels were analyzed by microscopy, UV/VIS spectroscopy, HPTLC, and HPLC/DAD. The study revealed that the total phenolic content in water-suspended particles varied from 3.0 mg/g to 11.0 mg/g during Betula and Pinus pollen spreading. It was also observed that the surface water of dystrophic natural lakes had a higher content of phenolic compounds than the eutrophic, hypereutrophic, and mesotrophic water bodies. Chlorogenic, trans-ferulic, vanillin, and 3,4-dihydroxybenzoic acids were frequently detected in the surface water samples. Experimental measurements have shown variations in the release of phenolic compounds from Betula pollen into water (p < 0.05). After the exhibition of pollen, the distilled water predominantly contained bioactive chlorogenic acid. Further in situ investigations are necessary to gain a more comprehensive understanding of the function of phenolic compounds in aquatic ecosystems. The exploration of the release of bioactive compounds from pollen could provide valuable insights into the potential nutritional value of pollen as a nutrient source for aquaculture.

Impact of wildfire ash on bacterioplankton abundance and community composition in a coastal embayment (Ría de Vigo, NW Spain)

Wildfire ash can have an impact on coastal prokaryotic plankton. To understand the extent to which community composition and abundance of coastal prokaryotes are affected by ash, two ash addition experiments were performed. Ash from a massive wildfire that took place in the Ría de Vigo watershed in October 2017 was added to natural surface water samples collected in the middle sector of the ría during the summer of 2019 and winter of 2020, and incubated for 72 h, under natural water temperature and irradiance conditions. Plankton responses were assessed through chlorophyll a and bacterial abundance measurements. Prokaryotic DNA was analyzed using 16S rRNA gene partial sequencing. In summer, when nutrient concentrations were low in the ría, the addition of ash led to an increase in phytoplankton and bacterial abundance, increasing the proportions of Alteromonadales, Flavobacteriales, and the potentially pathogenic Vibrio, among other taxa. After the winter runoff events, nutrient concentrations in the Ría de Vigo were high, and only minor changes in bacterial abundance were detected. Our findings suggest that the compounds associated with wildfire ash can alter the composition of bacterioplanktonic communities, which is relevant information for the management of coastal ecosystems in fire-prone areas.

Enhancing nanofiltration membrane selectivity between mineral salts and organic pollutants by sulfonic acid functionalization for drinking water treatment

Efficient removal of natural organic matter (NOM) and organic micropollutants (OMPs) while preserving essential mineral salts is a critical goal of high-quality drinking water production, which has not been satisfyingly achieved by available nanofiltration (NF) membranes. In this study, a facile modification strategy was developed to enhance membrane salt/organics selectivity, purposely utilizing the advantages of sulfonic acid groups including high hydrophilicity, strong acidity and low complexation propensity for divalent cations. The post-treatment using a heated alkaline solution of taurine endowed the membrane with reduced active layer thickness, properly enlarged pore size and more favorable surface characteristics inheriting from grafted sulfonic acid groups. Compared to the control one, the optimal modified membrane exhibited a more than doubled water permeance and significantly reduced rejections of Ca2+ and Mg2+, while maintaining a high removal capacity for OMPs. The membrane superiority in the rejection selectivity between mineral salts and NOM was further demonstrated for natural surface water treatment, which outperformed a variety of commercial NF membranes. Improved dual resistance to Ca2+-involved organic fouling and scaling was also achieved by the sulfonic acid functionalized membrane with a higher passage of Ca2+. This study provides insights on the fit-for-purpose enhancement of membrane performance for more efficient water treatment.

Event‐Based Recession Analysis for Estimation of Basin‐Wide Characteristic Drainage Timescale and Groundwater Storage Trends

AbstractIn the absence of precipitation or any other recharge source, baseflow sustains natural surface water bodies like streams and rivers. It also indicates the quality and quantity of storage in the aquifers underlying the basin. Thus, identifying and extracting baseflow is critical for most hydrological studies, for example, estimating water budget, watershed characteristics, and groundwater surface‐water interactions. Most approaches for baseflow separation are based on recession hydrographs obtained solely from streamflow observations. A few studies have used the absence of precipitation as a filter for extracting baseflows for recession analysis, but not for estimating changes in groundwater storage. We demonstrate that an accurate estimation of drainage characteristic recession timescale 𝐾 for a linear storage‐discharge relationship should be based on carefully selected individual baseflow events extracted from streamflow observations complemented with precipitation observations. The drainage/recession timescale varies with time, even for a single basin, and hence, should not be generalized to a specific range for a wide range of basins. Estimations of groundwater storage trends and aquifer characteristics from streamflow and lumped analysis can be misleading. Event‐based recession analysis yields large variations in characteristic drainage timescales for a given catchment, which appears a more realistic representation of basin‐wide aquifer characteristics that are known to vary with antecedent climate. In the Rock River basin, we find contrasting trends in the estimated groundwater storages in two selected periods, which are then attributed to the contrasting trends in annual rainfall and evapotranspiration. The approach presented here would be beneficial in investigating aquifer characteristics and storage trends.

Application of Green Technology in Clean Water Treatment Installation: A Case Study of Batuah Village

Access to clean water is a fundamental human right, critical to life and health, especially in many rural regions such as Batuah Village. However, several obstacles, including the geographic layout, absence of natural rivers or surface water, and lack of a comprehensive public water supply network, have made the provision of clean water to these communities exceedingly challenging. This study, titled "The Application of Green Technology in Clean Water Treatment Installation: A Case Study of Batuah Village," is concentrated on employing environmentally-friendly technology in water purification. The objective is to ascertain its impact on the efficiency and effectiveness of water treatment processes. Through the deployment of sustainable water treatment systems, the research aspires to evaluate the performance of such technologies in enhancing water quality, accessibility, and sustainability. This research delves into the strengths and weaknesses of the existing system, proposes potential improvements, and assesses the implications of adopting these green technologies on the socio-economic fabric of the village. The insights derived could be beneficial for other similar contexts striving to ensure clean water availability in challenging environments. This research applied a collaborative strategic planning method, involving Batuah Village Government, Samarinda State Polytechnic, and the community in planning the Pamsimas program. The Pamsimas Water Treatment Installation (IPA Pamsimas) Karya Makmur, a community-managed system guided by government, educational institutions, and BSSR, demonstrated this synergistic approach. The study aimed to implement, sustain, and assess the clean water program's effectiveness using observations, interviews, and tests in the Batuah village area.

Tuning nanofiltration membrane performance: OH–MoS2 nanosheet engineering and divalent cation influence on fouling and organic removal

Natural organic matter (NOM) present in surface water causes severe organic fouling of nanofiltration (NF) membranes employed for the production of potable water. Calcium (Ca2+) and magnesium (Mg2+) are alkaline earth metals present in natural surface water and severely exacerbate organic fouling owing to their ability to cause charge neutralization, complexation, and bridging of NOM and the membrane surface. Hence, it is of practical significance to engineer membranes with properties suitable for addressing organic fouling in the presence of these cations. This study employed OH-functionalized molybdenum disulphide (OH–MoS2) nanosheets as nanofillers via the interfacial polymerization reaction to engineer NF membranes for enhanced removal of NOM and fouling mitigation performance. At an optimized concentration of 0.010 wt.% of OH–MoS2 nanosheet, the membrane was endowed with higher hydrophilicity, negative charge and rougher membrane morphology which enhanced the pure water permeance by 46.33% from 11.2 to 16.39 L m−2 h−1 bar−1 while bridging the trade-off between permeance and salt selectivity. The fouling performance was evaluated using humic acid (HA) and sodium alginate (SA), which represent the hydrophobic and hydrophilic components of NOM in the presence of 0, 0.5, and 1 mM Ca2+ and Mg2+, respectively, and the performance was benchmarked with control and commercial membranes. The modified membrane exhibited normalized fluxes of 95.09% and 93.26% for HA and SA, respectively, at the end of the 6 h filtration experiments, compared to the control membrane at 89.71% and 74.25%, respectively. This study also revealed that Ca2+ has a more detrimental effect than Mg2+ on organic fouling and NOM removal. The engineered membrane outperformed the commercial and the pristine membranes during fouling tests in the presence of 1 mM Ca2+ and Mg2+ in the feed solution. In summary, this study has shown that incorporating OH–MoS2 nanosheets into membranes is a promising strategy for producing potable water from alternative water sources with high salt and NOM contents.

A comprehensive and systematic study of geothermal energy-based desalination systems for sustainable development

ContextGeothermal energy is one of the most promising renewable energy sources as it is a power source that produces electricity with minimal environmental impact. It has been proven that among renewable energy sources, it is the most reliable, safe, and clean, and therefore it is used for power production, heating, and cooling. The importance of geothermal desalination is beneficial in areas lacking natural groundwater or surface water supplies. Over time, water reuse desalination can solve water scarcity and, in some countries, provides over 90 % of the total water supply. The novelty of the workThis research presents an in-depth analysis of the desalination of seawater utilizing geothermal energy as the primary resource. It will also evaluate the risks and market possibilities of the system and the constraints on further development. MethodologyThe method of geothermal desalination has also been briefly covered, along with the most common cycles of thermal desalination. These cycles include multi-effect distillation, multistage flash distillation, and vapor compression. Main results and related interpretationsGeothermal desalination technologies address worldwide water scarcity sustainably and effectively. Geothermal energy can make desalination more sustainable and environmentally friendly. Compared to conventional fossil fuel-based systems, desalination using geothermal energy can result in lower overall energy usage and CO2 emissions.

Carbon-based nanomaterials mediated adsorption and photodegradation of typical organic contaminants in aqueous fulvic acid solution.

In this work, the formation of carbon-based nanomaterials-fulvic acid (CNMs-FA) composites and their capacities for the adsorption and photodegradation of typical organic contaminants in aqueous solutions were investigated. The results suggested that the formation of CNMs-FA composites was dominated by adsorbing FA on CNMs via the physisorption process, which fit the pseudo-first-order kinetic model and the Langmuir isotherm model. The formed CNMs-FA composites were characterized by using the Brunauer-Emmett-Teller, scanning electron microscopy, and infrared spectroscopy techniques and further applied for examining their effects on the adsorption and photodegradation of selected organic contaminants in aqueous solutions. The adsorption of organic contaminants on CNMs-FA composites is mainly involved in hydrogen bonding and electrostatic interactions between organic contaminants and FA species adhering to CNMs. In addition, the CNMs-FA composites are able to promote the photosensitive degradation of organic contaminants due to the photogenerated reactive species including ROS and CNMs-3FA* under sunlight irradiation. This study provided a deeper and more comprehensive understanding of the environmental behavior of CNMs in real natural surface water and clarified the underlying mechanisms.

O.6.2-7 “Virtual Surf Booth”: assessment of a novel tool and data collection process to measure the impact of a 6-week surf programme on wellbeing

Abstract Purpose Practicing physical activity in blue space (i.e. forms of natural and manmade surface water) is shown to be associated with an improvement in wellbeing. Surfing is a popular blue space activity with surf therapy increasingly used as a health intervention. However, the mechanisms through which surfing leads to an improvement in wellbeing remain unclear. One reason for this is the challenges with collecting data related to acute and chronic wellbeing outcomes. The purpose of this study was to evaluate the usability of an online digital tool to measure wellbeing outcomes, and the usefulness of the data collected. Methods Participants of a 6-week surf programme, delivered at The Wave Bristol, were invited to partake. Each participant was asked to complete the online digital tool on weeks 1, 2, 4 and 6. Qualitative (video recording and word association) and quantitative (Short Warwick-Edinburgh Mental Well-Being scale) responses were collected. Usability and acceptability of the tool were evaluated through focus groups with participants and engagement data. Descriptive analysis and paired samples t-tests were used to assess differences in wellbeing during the surf programme. A reflexive thematic analysis was used to assess video and word association responses. Results Participants (n = 15, 100% female, age=43.0±5 years) perceived the tool as easy to use due to the short completion time, range of tool functionalities, and useful because it provided time for reflection. Aspects such as increasing privacy when using the tool, accessibility of the tool, and incentivisation with completing the questions were seen as aspects that can increase future engagement. From a research perspective, the data collected allowed for the assessment of acute and chronic wellbeing, and demonstrated a positive relationship between surfing and wellbeing. Conclusions The study provides support that the tool can be a usable and useful process of collecting wellbeing data within surfing. Such a tool may allow us to understand the mechanisms through which surfing and other activities impact wellbeing. However this area of research is still new and more work needs to be done to assess the reliability and validity of the tool. Funding Source University of Bristol Grant Capture Fund.

Effect on growth and development of common toad (Rhinella arenarum) tadpoles in environment related to fluorite mine

Fluorite mining activities have been scarcely evaluated so far and the potential effect of this activity on larval stages is poorly known. Thus, studies addressing the effect of contaminants present in water bodies on the health of amphibian larvae are crucial information for their conservation and constitute a warning sign of environmental modification. This study aims to evaluate the effects of natural and artificial surface waters associated with a fluorite mine on the early life stages of Rhinella arenarum. Using microcosms, we assessed four sites with different degrees of disturbance by the fluorine mine: Vallecitos stream (undisturbed); Cerros Negros upstream of mining camp (low disturbance); Cerros Negro downstream of mining camp (medium disturbance); Decantation Ponds (high disturbance). For 65 days we measured different endpoints at different periods of tadpole development. The highest mortality of tadpoles was observed in the Decantation Ponds. In the same way, larval body condition was lower at Decantation Ponds throughout the study, due mainly to the lower weight. A significant decrease in growth and development was observed in Cerros Negro downstream of the mining camp and Decantation Ponds. No significant differences in growth, development and mortality were observed for the other two sites. At the metamorphic climax we observe a lower body condition and a reduced recruitment of individuals in Decantation Ponds. This study allowed us to assess the effect on larvae of R. arenarum of fluorite mining wastewater compared with other near-natural sites. Given the potentially negative synergic effects of mixed water pollutants on tadpoles, this study suggests that chronic exposure to fluorite mining water may significantly impact the adult amphibian population structure, thus altering population viability. Therefore, we propose to monitor the correct functioning of the mine and especially of Decantation Ponds to avoid discharges into the natural streams.

Photocatalytic membrane coated with α-Fe2O3/Fe3O4 for enhanced filtration performance and antifouling property in surface water treatment

A photocatalytic membrane coated with α-Fe2O3/Fe3O4 nanoparticles has been developed to address the challenges of membrane fouling and organic removal in the treatment of natural surface water. The photocatalytic and filtration properties of the membranes were investigated through a variety of methods. The successful preparation of iron oxide was confirmed by UV–vis diffuse reflectance spectra and X-ray diffractometry, with α-Fe2O3 identified as the primary photocatalytic agent. A commercial ultrafiltration (UF) membrane was employed as a comparison to evaluate the photocatalytic performance and filtration properties of the modified membrane. Results showed that the photocatalytic membrane achieved better removal rates for UV254 (22.0%) and specific fluorescent organic compounds, such as component 2 (19.38%) and component 3 (16.89%), compared to the control group. Furthermore, both irreversible and reversible fouling resistances of the prepared membranes were significantly lower than that of the control group, with reductions of 39.4% and 50.2%, respectively. The membrane coated with α-Fe2O3/Fe3O4 nanoparticles exhibited moderate removal of protein-like and terrestrially derived humic-like fluorescent organics while controlling membrane fouling. Although the α-Fe2O3/Fe3O4 nanoparticles-coated photocatalytic membrane demonstrated good anti-fouling properties, the removals of organic matters were not as effective as anticipated due to the shorter hydraulic retention time. This study provides valuable insights for enhancing pollutant degradation and anti-fouling properties of membranes through the utilization of solar photocatalytic α-Fe2O3/Fe3O4 surface-modified membranes in the treatment of natural surface water.

Activation of peroxymonosulfate with biochar-supported CuO (CuO@BC) for natural organic matter removal and membrane fouling control

To achieve excellent activation efficiency of peroxymonosulfate (PMS), this work prepared a biochar-supported CuO (CuO@BC) catalyst, and the CuO@BC/PMS system was proposed to remove the organic matter in natural surface water and reduce the fouling of ultrafiltration membrane. The successful synthesis of CuO@BC was demonstrated through characterization of its microscopic morphology and chemical composition by various techniques. The prepared heterogeneous catalyst showed a strong catalytic effect on PMS, which significantly removed natural organic matter through the production of active substances (•OH, SO4•−, O2•− and 1O2) from water. With respective degradation rates of 39.4% and 59.4%, the concentrations of DOC and UV254 dropped to 1.702 mg/L and 0.026 cm−1, respectively. Additionally, the CuO@BC/PMS oxidation displayed potent oxidation capabilities for contaminants and fluorescent organics with various molecular weights. The system effectively decreased the amount of organic matter that caused reversible and irreversible fouling of polyethersulfone membranes in natural water by 85.8% and 56.3%, respectively. The main fouling mechanisms changed as well, with standard and complete blocking dominating the entire filtration process. The results demonstrated the capacity of the CuO@BC/PMS system to remove contaminants in natural water and mitigate membrane fouling.

Non-Equilibrium Bedload Transport Model Applied to Erosive Overtopping Dambreach

Bedload sediment transport is an ubiquitous process in natural surface water flows (rivers, dams, coast, etc), but it also plays a key role in catastrophic events such as dyke erosion or dam breach collapse. The bedload transport mechanism can be under equilibrium state, where solid rate and flow carry capacity are balanced, or under non-equilibrium (non-capacity) conditions. Extremely transient surface flows, such as dam/dyke erosive collapses, are systems which always change in space and time, hence absolute equilibrium states in the coupled fluid/solid transport rarely exist. Intuitively, assuming non-equilibrium conditions in transient flows should allow to estimate correctly the bedload transport rates and the bed level evolution. To get insight into this topic, a 2D Finite Volume model for bedload transport based on the non-capacity approach is proposed in this work. This non-equilibrium model considers that the actual bedload sediment discharge can be delayed, spatial and temporally, from the instantaneous solid carry capacity of the flow. Furthermore, the actual solid rate and the adaptation length/time is governed by the temporal evolution of the bedload transport layer and the vertical exchange solid flux. The model is tested for the simulation of overtopping dyke erosion and dambreach opening cases. Numerical results seems to support that considering non-equilibrium conditions for the bedload transport improves the general agreement between the computed results and measured data in both benchmarking cases.

The Effect of Supplemental Irrigation on a Dry-Farmed Vitis vinifera L. cv. Zinfandel Vineyard as a Function of Vine Age

With natural rainfall and surface water availability becoming scarce, prolonged droughts are expected to become more frequent, thereby creating issues for agriculture. In viticulture, a lack of rainfall is often supplemented with irrigation during the growing season and/or dormancy. However, with surface and groundwater resources declining in addition to current changes in rainfall patterns, it is unlikely that supplemental irrigation will continue to be an available tool for most growers. As such, this study aims to evaluate the effect of dry farming and supplemental irrigation during the growing season on vine performance and fruit composition as a function of vine age in Zinfandel grapevines. A historically dry-farmed vineyard block with interplanted vines of varying ages was evaluated during the 2021 growing season. Treatments included young vines (5–12 years old), control vines (2:1 ratio of old to young vines representative of the block), and old vines (40–60 years old); each age designation included irrigated and dry-farmed vines. Based on age-specific ETc and to replenish 95% of crop evapotranspiration (ETc), irrigation was manually applied to the irrigated treatment vines at véraison and véraison + 4 weeks. Results indicated no significant changes in phenological progression, leaf senescence, or physical berry analysis when irrigation was added to dry-farmed vines, as most differences were driven by vine age in most parameters measured. Irrigated vines were slightly more advanced in phenological growth and senescence progression compared to dry-farmed vines. Results suggest that the practice of applying supplemental irrigation during the growing season, provided winter rainfall or additional winter irrigation is sufficient, does not have significant impacts on vine performance. Thus, dry farming during the growing season is a reasonable alternative practice in Zinfandel, even in periods of drought.

In situ sea urchin carbonates analysis by LA-MC-ICP-MS to identify lead isotopic signatures: A case study at Trindade Island (South Atlantic Ocean versus anthropogenic)

Isotope ratios of lead (Pb) are increasingly applied to trace pollution sources in marine settings, using mostly carbonate remains of living organisms. However, this data has never been acquired in sea urchin carbonates. Sea urchins are widely distributed in marine settings and have been recognized for their ability to bioaccumulate heavy metals and their skill to track environmental changes. Thus, this work intends to perform, for the first time in-situ analysis of Pb isotope ratios using LA-ICP-MC-MS in sea urchin spines collected on the beaches from Trindade Island (SE Brazil). Trindade Island is a protected environmental area, almost uninhabited, located in a remote region of the South Atlantic Ocean (1200 km from the mainland). The results obtained in sea urchins spines collected on the beaches from Trindade Island varied from: 1.03 to 1.30 (mean 1.18 ± 0.06) for 206Pb/207Pb; 1.44 to 2.23 (mean 2.10 ± 0.07) for 208Pb/206Pb and 2.22 to 2.87 (mean 2.48 ± 0.15) for 208Pb/207Pb. The biplot of 208Pb/206Pb versus 206Pb/207Pb ratios show greater dispersion of isotopic values in the sea urchin spines than in the geogenic data of the Vitória-Trindade Ridge (VTR; used as reference) and the surface water from the Tropical Atlantic Ocean. While the Pb isotope ratios of rocks and sediments of the VTR are quite similar and present intermediate values, a significant variation of the isotopic signature in the sea urchin spines was observed. The comparison of the sea urchin spines 206Pb/207Pb ratios with data published in the literature from several materials suggests the presence of anthropogenic contamination on Trindade Island caused using fossil fuels. The range of variation of Pb isotopes analyzed in sea urchin spines suggests mixing between the natural source (the rocks and sediments of the Vitória-Trindade Ridge) and surface water masses of the Tropical South Atlantic and anthropogenic sources.