Water Salinization Research Articles

Salinity causes widespread restriction of methane emissions from small inland waters

Inland waters are one of the largest natural sources of methane (CH4), a potent greenhouse gas, but emissions models and estimates were developed for solute-poor ecosystems and may not apply to salt-rich inland waters. Here we combine field surveys and eddy covariance measurements to show that salinity constrains microbial CH4 cycling through complex mechanisms, restricting aquatic emissions from one of the largest global hardwater regions (the Canadian Prairies). Existing models overestimated CH4 emissions from ponds and wetlands by up to several orders of magnitude, with discrepancies linked to salinity. While not significant for rivers and larger lakes, salinity interacted with organic matter availability to shape CH4 patterns in small lentic habitats. We estimate that excluding salinity leads to overestimation of emissions from small Canadian Prairie waterbodies by at least 81% ( ~ 1 Tg yr−1 CO2 equivalent), a quantity comparable to other major national emissions sources. Our findings are consistent with patterns in other hardwater landscapes, likely leading to an overestimation of global lentic CH4 emissions. Widespread salinization of inland waters may impact CH4 cycling and should be considered in future projections of aquatic emissions.

Growth and Oxidative Stress of Clownfish Amphiprion ocellaris Reared at Different Salinities

Aquaculture of ornamental marine fish is often conducted in recirculating aquaculture systems (RAS) using artificial seawater. Considering the cost of salts to produce artificial seawater (salinity 35‰), we investigated the effect of different salinities (5, 15, 25, and 35‰) on survival, growth, and oxidative stress responses of juvenile clownfish Amphiprion ocellaris. All fish died when reared at salinity 5‰, but at all other salinities survival was ≥95% in the other treatment groups. There was no influence of salinity on growth and oxidative stress responses of clownfish reared at salinities 15, 25, and 35‰, except for the activity of glutathione S-transferase (GST) of fish reared at 25‰, which was significantly lower compared to those reared in salinity 35‰. The salinity of home aquariums is usually 35‰, so even though clownfish can be reared in brackish water, they need to be transferred to full strength seawater (35‰) in order to be commercialized. Therefore, we also evaluated the responses of acute transference of fish reared at 15 to salinity 35‰. There were no mortalities associated with acute salinity transference and no oxidative damage was observed either. The total capacity against peroxyl radicals (ACAP) was immediately increased after fish were placed in salinity 35‰, and remained high after 168 h (7 days), helping fish to deal with oxidative threats. In conclusion, it is possible to rear juvenile clownfish at 15‰ without harming growth or inducing oxidative stress, possibly reducing costs of water salinization. They can be transferred from brackish water to salinity 35‰ immediately before going to the retail market, with no mortality or oxidative damage.

Ecology of Saline Watersheds: An Investigation of the Functional Communities and Drivers of Benthic Fauna in Typical Water Bodies of the Irtysh River Basin.

In this study, we investigated how changes in salinity affect biodiversity and function in 11 typical water bodies in the Altai region. The salinity of the freshwater bodies ranged from 0 to 5, the brackish water salinities ranged from 5 to 20, and the hypersaline environments had salinities > 20. We identified 11 orders, 34 families, and 55 genera in 3061 benthic samples and classified them into 10 traits and 32 categories. Subsequently, we conducted Mantel tests and canonical correlation analysis (CCA) and calculated biodiversity and functional diversity indices for each sampling site. The results indicated that biodiversity and the proportion of functional traits were greater in freshwater environments than in saline environments and decreased gradually with increasing salinity. Noticeable shifts in species distribution were observed in high-salinity environments and were accompanied by specific functional traits such as swimming ability, smaller body sizes, and air-breathing adaptations. The diversity indices revealed that the species were more evenly distributed in high-diversity environments under the influence of salinity. In contrast, in high-salinity environments, only a few species dominated. The results suggested that increasing salinity accelerated the evolution of benthic communities, leading to reduced species diversity and functional homogenization. We recommend enhancing the monitoring of saline water resources and implementing sustainable water resource management to mitigate the impact of salinity stress on aquatic communities in response to climate-induced soil and water salinization.

Synthesis and performance of water absorbing polymer with salt isolation and anti-leakage functions

The northwest of China is experiencing a severe water deficit and salinization of the land. Pentaerythritol diacrylate (PEDA) was developed as a new cross-linking agent, and Polyacrylic acid/ Pentaerythritol diacrylate (PAA/PEDA) was created by free radical polymerization utilizing acrylic acid as the monomer, to enhance the water retention and salt isolation qualities of soil. Infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis were used to determine the structure, morphology, and thermal stability of the improved SPA. Under ideal synthesis circumstances, the water absorbency of SPA in deionized water, tap water, and NaCl solution (0.9 wt%) was 501 g/g, 150 g/g, and 58 g/g, respectively. The water retention, reswelling, fertilizer retentio, anti-leakage, and salt isolation properties of PAA/PEDA at different temperatures under optimal conditions were investigated. The results showed that the PAA/PEDA material had the best water retention at room temperature; the addition of 0.8% PAA/PEDA material reduced the water infiltration rate by 86% compared with the blank control group; The addition of 0.4% PAA/PEDA material showed a lower salinity trend than the control, and the PAA/PEDA material had a hindering effect on the upward movement of salts in the soil.

The tradeoff between water savings and salinization prevention in dryland irrigation

Soil salinization is a global phenomenon that affects large tracts of arid farmland worldwide. It contributes to the loss of soil fertility, declining yields, and – in the most severe cases – land unsuitability for cultivation. Irrigation water applications are both the main cause of and the solution to, anthropogenic (or ‘secondary’) salinization because salt typically enters the soil column as dissolved in irrigation water and leaves it through excess water applications (e.g., leaching). Excess leaching, which places additional water costs in areas affected by water scarcity, can be achieved with different irrigation techniques and practices. Here, by complementing a process-based crop water model with a salt balance of the shallow soil, we investigate the tradeoff between root zone salinization and water conservation to limit withdrawals from the water source. We evaluate how such a tradeoff is achieved under different irrigation technology and excess leaching practices. Considering as a case study the cultivation of tomatoes in Egypt, we find that drip and furrow irrigation allows for better control of salt accumulation, thus preventing crop exposure to salt stress. Drip irrigation achieves this goal with minimal water applications because it maintains the soil wetter. Thus, the (rare) rainfall events find more suitable conditions to drain the excess moisture. Conversely, by using more irrigation water (and ‘less efficiently’), furrow irrigation allows for higher rates of soil drainage and salt leaching. The irrigation schedule typically adopted with sprinkler irrigation allows for soil drying, thus limiting the ability of rainfall events to drain the soil and leach its salts. Collectively, these results highlight the key role of irrigation technology and practices in the management of secondary salinity in dryland agriculture. Specifically, there is a tradeoff between minimizing water use and preventing salt accumulation in the root zone. Drip irrigation exhibits the co-benefit of achieving both goals, while furrow irrigation limits soil salinity at the cost of requiring greater volumes of applied irrigation water.

Species Diversity of Zooplankton of Small Steppe Lakes of the Northern Part of Kazakhstan

The inland waters of Northern Kazakhstan are important components of the ecosystems of this region and have unique characteristics. Endorheic steppe lakes are important ecosystems with significant ecological value. They play an important role in maintaining biodiversity, they provide water resources for living organisms, they serve as breeding and migration sites for various animal species, and their zooplankton communities have a key role in the trophic web of these waters. Therefore, the purpose of this work is to study the diversity of zooplankton communities in some small steppe lakes in the northern part of Kazakhstan (Pavlodar, Kostanay, North Kazakhstan, and Akmola regions), which have different environmental conditions. Sampling to study the species diversity of zooplankton in the steppe water bodies of Northern Kazakhstan was carried out from 13 areas, 12 of which are plain lakes, and 1 of which is a reservoir, and sampling was performed in 2021 and 2022 during in the spring, summer, and autumn periods. Within the research period of 2021–2022, between 6 and 36 species of zooplankton were found in small steppe lakes. A total of 92 taxa were found. Rotifers (46 taxa) were found to have the richest number of species representatives. Cladocera were represented by 21 taxa, and Copepods by 25 taxa. All studied steppe lakes in the northern part of Kazakhstan are characterized by high specificity in terms of taxonomic composition, since the similarity indices did not exceed 0.632. According to cluster analysis, the studied samples of water bodies are divided into five clusters, in which lakes with a relatively similar taxonomic composition are combined. The halophile species (e.g., Arctodiaptomus salinarus) indicate water salinization. Our results confirm the applicability of the use of zooplankton in assessing water quality and the current ecological state of aquatic ecosystems.

Mental health and socio-psychological manifestations of cyclone-induced water insecurity in the Indian Sundarban delta

Advancements in early warning, efficient evacuation, and previous experience with cyclones have largely restricted disaster casualties in the Sundarban delta in India and Bangladesh. Despite the limited loss of life, post-cyclone soil, inland water salinity, and loss of agriculture productivity remain among the impeding factors affecting people's lives. Two severe cyclones, cyclone Amphan, which hit on May 20, 2020, and cyclone Yaas, which hit the delta on May 28, 2021, caused significant damage to the life and livelihood of the local people. In this paper, we inquired into the mental health and socio-psychological aspects of cyclone Amphan and Yaas-induced water insecurity in the Indian Sundarban delta using both qualitative and quantitative research methods. The empirically derived data from Focus Group Discussions (N = 17; Number of participants = 157) and household surveys (N = 121) were subjected to various qualitative and quantitative analyses to understand the key determinants of post-cyclone water-induced mental health and well-being. Results suggest varying levels of stress and anxiety among the respondents, which include indecisiveness, general anxiety, fear of waterlessness, irritation, loss of self-esteem, and multiple other mental health issues. The FGD participants pointed out the severe impacts of the cyclones including increased seawater inundation, salinization of agricultural lands, flooding of the freshwater sources and increased water prices. Among all these impacts, seawater inundation and salinization of water and soil have the most long-lasting impact on the life and livelihood of local people. In the quantitative analysis, we observed that the perceived lack of fresh water, including both quality and quantity, alongside, the experience of water-borne diseases, loss of social relations, and loss of livelihood are the key determinants of the self-reported emotional stress of the respondents. In the lieu of existing knowledge gap on disaster-induced water insecurity and its impact on the mental health of affected people, the present research findings emphasize the need for resilient water structures on one side and socio-psychological counselling at the community level on the other side to ensure a sound recovery of the damaged resources as well as make the community a part of the recovery process that can improve their mental health.

Public perceptions of environmental degradation in the Arab World: evidence from surveys about water, air, and sanitation

ABSTRACT Many Arab countries are struggling to combat a range of environmental problems from air pollution to water salinization to overflowing garbage. Yet little is known about how people in this region perceive these environmental problems and the factors that influence their perceptions. This article analyzes surveys conducted by the Arab Barometer with 13,850 people across 12 Arab countries in 2018–19. The focus is on public perceptions about water pollution, air pollution, and trash. About 91% of respondents said that water pollution is a very serious or serious problem. About 89% and 73% feel the same way about trash and air pollution, respectively. Perceptions about environmental quality are mainly shaped by a person’s age, educational background, financial status, and how they view the current economic situation. Although perceptions about water and trash are directly connected to a national environmental quality measure, they are unconnected to specific measurements of clean water access and sanitation quality. Furthermore, perceptions about air quality are unconnected to any general or specific (national- or local-level) measurements. Instead, a person’s age, gender, educational background, financial status, and minority status are better predictors of how much they view air quality to be a problem. These findings shed light on the topic of environmental concern in a comparatively understudied area of the world, highlighting the ways that individual, local, and national factors shape how the average person evaluates environmental problems.

Combined effects of salinization and temperature on microbial-mediated oak decomposition and invertebrate consumption

Water salinization is a recognized growing threat to freshwaters, whose consequences on streams’ function, per se or concomitantly with other stressors, are still far from clear. This microcosm study evaluated the combined effect of salinization (0 and 4 g/l NaCl) and temperature (5, 15, and 20 °C) on microbial-mediated oak leaf litter decomposition, with fungal biomass, sporulation, and microbial respiration as microbial descriptors. Invertebrate consumption was also assessed using the common shredder Sericostoma vittatum (Trichoptera, Sericostomatidae). Mass loss was affected by temperature and interaction between salinity and temperature. Under salt conditions, mass loss was higher at 15 °C and reduced (~ 10%) at 20 °C. Microbial activity was lower at 5 °C and higher at 15 and 20 °C, irrespective of salinity. Fungal biomass was affected by both temperature (5 < 20 < 15 °C) and salinity (4 < 0 g/l NaCl), although the interaction between both was not significant. The interaction of both variables affected the production of spores: salt addition strongly reduced sporulation rates at all temperatures despite a significant increase in conidial production with temperature. Invertebrate leaf consumption was significantly reduced only by salinization. Overall, our results seem to indicate that temperature may modulate the effect of salinization (at least at ≥ 4 g/l NaCl) on stream leaf decomposition. While stronger salinization effects may be observed at higher temperatures, a consistent strong inhibition of shredders’ feeding behavior promoted by salt, regardless of temperature, may anticipate important repercussions on streams’ secondary production throughout the year.

Synergistic Effects of Climate Change and Alien Fish Invasions in Freshwater Ecosystems: A Review

The interaction between climate warming and alien fish invasions could have severe consequences in inland waters, which represent isolated environments with high biodiversity richness. Due to the current climatic trend, increasing water temperatures and salinization, shorter ice cover period, and altered flow regimes are predicted for these environments. The aim of this review is to offer a comprehensive analysis at a global scale of the recent studies available in the literature, focused on the responses of invasive freshwater fish to the effects of climate change in both lotic and lentic environments. To achieve this purpose, we selected 34 relevant papers, using the Scopus and Google Scholar database. New alien species establishment, distribution range expansion of species already introduced, and exacerbating impacts on freshwater ecosystems and the native fish communities they host were included in the topics covered by the analyzed papers. Despite the uncertainties related to the unpredictability with which the effects of global warming will occur, the findings of the selected studies served as a support to evaluate conservation and management implications, with particular reference to possible mitigation strategies.

Characterization of subsurface pathways contributing to freshwater salinization of urban streams using electrical and electromagnetic imaging techniques

Salinization of inland fresh surface waters in temperate climates is a growing concern due to increasing salt inputs from sources including chloride (Cl)-containing road salt de-icers, industrial waste, and landfill leachate. Groundwater pathways play an important role in the year-round delivery of Cl to streams, but quantifying this pathway, including spatiotemporal variability and amount of Cl mass stored in the subsurface, is challenging. The objective of this study was to demonstrate, evaluate, and compare the potential applications of the geoelectrical techniques – electromagnetics (EM) and direct current (DC) resistivity – for mapping salt contamination in shallow urban groundwater and characterizing the groundwater pathways delivering Cl to urban streams. EM and DC surveys were conducted (3D mapping and 2D time-lapse) across a 20 m salt-impacted stream section and surrounding riparian zone that is located near an arterial road and parking lot. Groundwater samples and soil cores were also collected to validate the geoelectrical results. Both the EM and DC surveys detected high salt concentrations in the shallow subsurface (up to 3 m depth) near the road, parking lot, and stream; however, DC more accurately represented groundwater Cl concentrations. DC results were used to calculate the total Cl mass in the subsurface, with the spatial mass distribution used to infer the temporal variability in the subsurface salt plume. Finally, time-lapse DC showed that the highest groundwater salt concentrations existed near the stream between June and October – this is expected to contribute to the elevated salt concentrations in the stream during summer months. This study has shown that EM and DC can be useful for identifying groundwater salt concentration, storage, and transport in a non-intrusive and efficient manner, making them valuable field tools for characterizing and quantifying groundwater salt pathways to urban streams.

Study of Salinity in Market Garden Production on the Togolese Coast

Agriculture accounts for over 40% of Togo's GDP, and employs almost 65% of its working population. Market gardening, one of its sub-sectors, remains an important source of income and food self-sufficiency for rural and peri-urban populations. Among the peri-urban production zones, the coastline, by virtue of its geographical position, is sensitive to the salinisation of water and soil, as well as to sea spray. Salinity has a negative impact on market garden production. This study was therefore carried out to investigate the salinity of water and soil used in market garden production on the Togolese coast. To do this, measurements were taken of the electrical conductivity (EC) and pH of irrigation water and soil sampled in the Ablogamé and Agodéké districts, two production areas on the coastal strip. In each of these areas, water and soil samples were taken at three sites, with three samples per site, giving a total of six sites for analysis. At Ablogamé, the values for irrigation water ranged from 1113.67±3.06 µS/cm, 1971.67±9.24 µS/cm, to 1926.33±6.51 µS/cm and for Agodéké, they ranged from 756.67 ± 1.53, 1016.00 ± 1.00 to 1178.33 ± 0.58 µS/cm. This shows that, according to CIRAD and WHO standards, the water analysed is classified as "salty", with a variability of EC within the same production zone, the exception being one of the Agodeke sites, which has soft water according to WHO standards. The FAO, for its part, classifies all the waters as having slight to moderate restrictions for irrigation. Furthermore, the EC values obtained are moderately and slightly high. In addition, those of the Agodéké sites, located at around 83 to 108 m from the sea, in the erosive zone, are generally lower than those of the Ablogamé sites located in the accumulation zone, at around 288 m to 406 m from the sea. The pH of the water is slightly alkaline. As for the soil, the EC values are below the norms at all the sites studied, thus demonstrating the non-saline nature of the market-garden production areas on the Togolese coastal strip. The soil pH is neutral to slightly alkaline. There is therefore a dynamism in the Togolese coastal aquifers that requires further studies to improve the performance of vegetable production on this coast.

Epidemiological evidence on drinking water salinity and blood pressure: a scoping review

In addition to diet, drinking water can be an important contributor to the total body burden of salts. Water salinity (defined as the amount of dissolved salts in a body of water) has been associated with adverse health effects. We mapped the current research on drinking water salinity and its effects on blood pressure (BP). We aimed to identify knowledge gaps in the methodology and tools used in the epidemiological literature to address water salinity effects on BP. We performed a scoping review of epidemiological studies by searching PubMed and Web of Science databases from 1980 to 2022. Reviews, study comparisons, meta-analyses, commentaries, viewpoints, correspondence, protocols, studies in clinical settings, animal or in vitro studies, or not in English, were excluded. Epidemiologic studies including systolic/diastolic BP and/or the risk of hypertension as the main health outcome and drinking water salts (sodium, potassium, calcium, magnesium, including electrical conductivity and total dissolved solids) as the main exposures were included. After screening 246 articles, 29 articles were retained. Most studies were conducted in Bangladesh and USA (n = 9 and n = 9, respectively). The majority of studies were cross-sectional (n = 18; 62%). The study populations were adults (55%) or children (35%) or both (10%). Only eight (28%) studies did not collect urine samples and only three studies (10%) did not record participant BP. About half of the studies (n = 15, 52%) reported a positive significant (p < 0.05) association between salts in drinking water and higher BP and/or risk of hypertension; while 24% and 24% reported non-significant (p > 0.05) and significant (p < 0.05) negative associations (with lower BP mainly attributed to higher Mg, Ca, and K (rather than Na) levels in drinking water). More longitudinal studies are warranted to investigate the impact of drinking water salinization on cardiovascular health and risk of hypertension. Under a changing climate, this may be particularly important for coastal populations, as sea level rise in combination with the overexploitation of groundwater would differentially perturb the salinity of their drinking water supplies.

Hydrogeochemical and isotopic assessment for characterizing groundwater quality in the Mitidja plain (northern Algeria).

Coastal aquifer overexploitation represents a concerning trigger for water salinization around the world and especially in arid and semi-arid regions along with urban growth and urbanization, as well as land use human-induced changes. This study aims to assess the groundwater quality in the Mitidja alluvial aquifer (northern Algeria) along with its suitability for domestic and agricultural utilizations. A hydrogeochemical approach, based on the interpretation of groundwater physiochemical parameters (EC, pH, dry residue, Ca2+, Mg2+, Na+, K+, Cl-, SO42-, HCO3-, and NO3-) collected during the wet and dry periods for the years 2005 and 2017 along with an isotopic characterization, including stable isotopes to identify the recharge sources for the samples collected in October 2017, has been proposed. The results show the presence of three dominant hydrochemical facies: (i) calcium chloride, (ii) sodium chloride, and (iii) calcium bicarbonate. Groundwater mineralization and salinization are so ascribable carbonates and evaporitic dissolution, especially during the dry periods, and to the presence of seawater. Ion exchange significantly affects groundwater chemistry along with human activities which directly or indirectly contribute in raising groundwater salts concentration. Specifically, NO3- concentrations are very high in the eastern portion of the study area which is exposed to fertilizers pollution where also the Richards classification pointed out the necessity of limit water utilization for agricultural use. The δ2H = f(δ18O) diagram indicates that the recharge origin for this aquifer is mainly due to the oceanic meteoric rainwater from the Atlantic and the Mediterranean Sea. The methodology proposed in this study can be applied in the similar worldwide coastal areas in order to contribute and sustainable water resource management in these regions.

Effect of feeding frequency and water salinization on early development of Pyrrhulina brevis, an Amazonian ornamental fish

ABSTRACT Pyrrhulina brevis is an endemic fish from the Amazon basin that is valued in the ornamental fish market. In larviculture, fish are very sensitive to stressors and have a high mortality rate. Salinized water may provide more energy to overcome stress and feeding frequency is an important strategy to improve productive performance. Therefore, the aim of this study was to evaluate the best feeding frequency and the best level of water salinization for larval development of P. brevis. A total of 360 post-larvae of P. brevis (5.26 ± 1.65 mg, 5.57 ± 0.68 mm) were randomly distributed in 36 aquariums (1 L) in a 3x4 factorial scheme, to evaluate three concentrations of salt in water (0, 1 and 2 g L-1) and four feeding frequencies (once, twice, three and four times a day). We offered 150 Artemia nauplii per day and per post-larvae during 15 days. The fish kept at 1 g L-1 salinized water, and those fed 3 and 4 times a day presented significantly greater final length and weight, weight gain, and specific growth rate for length and weight. An interaction between salinized water and feeding frequency was observed for survival rate. We conclude that, during the initial rearing phase of P. brevis, feeding frequency of three times a day and salinized water at 1 g L-1 is recommended.

Groundwater salinity in the Horn of Africa: Spatial prediction modeling and estimated people at risk

BackgroundChanges in climate and anthropogenic activities have made water salinization a significant threat worldwide, affecting biodiversity, crop productivity and contributing to water insecurity. The Horn of Africa, which includes eastern Ethiopia, northeast Kenya, Eritrea, Djibouti, and Somalia, has natural characteristics that favor high groundwater salinity. Excess salinity has been linked to infrastructure and health problems, including increased infant mortality. This region has suffered successive droughts that have limited the availability of safe drinking water resources, leading to a humanitarian crisis for which little spatially explicit information about groundwater salinity is available. MethodsMachine learning (random forest) is used to make spatial predictions of salinity levels at three electrical conductivity (EC) thresholds using data from 8646 boreholes and wells along with environmental predictor variables. Attention is paid to understanding the input data, balancing classes, performing many iterations, specifying cut-off values, employing spatial cross-validation, and identifying spatial uncertainties. ResultsEstimates are made for this transboundary region of the population potentially exposed to hazardous salinity levels. The findings indicate that about 11.6 million people (∼7% of the total population), including 400,000 infants and half a million pregnant women, rely on groundwater for drinking and live in areas of high groundwater salinity (EC > 1500 µS/cm). Somalia is the most affected and has the largest number of people potentially exposed. Around 50% of the Somali population (5 million people) may be exposed to unsafe salinity levels in their drinking water. In only five of Somalia's 18 regions are less than 50% of infants potentially exposed to unsafe salinity levels. The main drivers of high salinity include precipitation, groundwater recharge, evaporation, ocean proximity, and fractured rocks. The combined overall accuracy and area under the curve of multiple runs is ∼ 82%. ConclusionsThe modelled groundwater salinity maps for three different salinity thresholds in the Horn of Africa highlight the uneven spatial distribution of salinity in the studied countries and the large area affected, which is mainly arid flat lowlands. The results of this study provide the first detailed mapping of groundwater salinity in the region, providing essential information for water and health scientists along with decision-makers to identify and prioritize areas and populations in need of assistance.

HORIZONTAL CIRCULAR PUMPING WELLS TO MINIMIZE SALINE WATER UPCONING: WATER RESOURCE DEVELOPMENT MEASURE FOR TROPICAL SAVANNA CLIMATIC NINH THUAN AREA, VIETNAM

Link for citation: Nguyen Van Hoang, Trinh Hoai Thu, Shakirov R.B., Syrbu N.S., Tran Thi Thuy Huong, Lee N.S. Horizontal circular pumping wells to minimize saline water upconing: water resource development measure for tropical savanna climatic Ninh Thuan area, Vietnam. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 4, рр.209-220. In Rus.&#x0D; The relevance. The Southern central region of Vietnam, including Ninh Thuan province, has a tropical savanna climate and has been heavily suffering from drought and water salinization. Ninh Thuan province has faced severe droughts in recent years because of the increase of the frequency and intensity of extreme weather conditions, the water scarcity, and the salinity of the groundwater. The distribution of fresh and saline groundwater in Ninh Thuan plain has three zones: 1) zone of entire profile with fresh groundwater; 2) zone of the upper profile's with fresh groundwater and of the lower profile's with saline groundwater, and 3) zone of entire profile with saline groundwater. The groundwater abstraction facilities in the first zone are vulnerable to salinization from surrounding saline water, while in the second zone are vulnerable to the upconing saline water from below. The aim: to determine the optimal groundwater pumping in respect to given water level drawdown, to show that the horizontal circular wells are the best for minimization of saline water upconing, to determine the relationship between the saline water upconing height and the radii of the horizontal circular wells. Objects: tropical savanna climate, coastal plain, fresh and saline groundwater, aquifer with fresh water in the upper profile and saline water in the lower profile, circular groundwater wells, saline water upconing. Methods: finite element method, dynamic programming, Dagan–Bear model of saline water upconing, superimposition principle in dealing with multiple pumping points for identification of overall saline water upconing. Results. Different schemes of pumping fields with either vertical wells or horizontal circular wells with different radii were analyzed for saline water upconing. The time of saline upconing height in all the alternative schemes were determined. A very well regression curve of the relationship between the time saline water upconing to the horizontal circular wells and the circular well radii was obtained. The analysis results are extremely useful supporting well design in terms of minimization of saline water upconing.

Five decades of freshwater salinization in the Amu Darya River basin

Study regionThe Amu Darya River (ADR) basin in Central Asia. Study focusTo understand the spatiotemporal patterns and underlying driving mechanisms of river salinization in arid environments, this study gathered 50 years (1970–2019) of water chemistry data from 12 locations along the ADR. The variations in discharge and salinity were assessed by a linear regression model and violin plot. The salinity-discharge relationships were evaluated by a general hyperbolic model and Spearman’s rank correlation coefficient. Random forest models were also constructed to identify the predominant drivers of river water salinization. Finally, a conceptual model of river water salinization was constructed. New hydrological insights for the regionThe water salinity (S) in the upper stream of the ADR was 541–635 mg/L. Salinity showed an increasing trend along the river course, reaching 751–1560 mg/L downstream. In the downstream, the river salinity before the 1990 s (751–1128 mg/L) was slightly lower than that after the 1990 s (983–1560 mg/L). Generally, water salinity was notably correlated with river discharge (Q) in upstream, exhibiting a relationship of S= 17,497Q−0.62, p < 0.05, before the 1990 s. Interannual variation in river salinity is mainly controlled by secondary salinization, and intra-annual variation is controlled by river flow. From upstream to downstream, the controlling salinization process changes from primary salinization to secondary salinization. Specifically, secondary salinization has accelerated due to intensified agricultural activities in recent years.

A Qualitative Assessment of Natural and Anthropogenic Drivers of Risk to Sustainable Livelihoods in the Indian Sundarban

In the Indian Sundarban, multiple attributes and interactions of natural hazards, exposure, and vulnerability pose severe threats to lives and livelihoods. Understanding the cause-and-effect relationships contributing to the risk of loss of sustainable livelihoods has become imperative but has not yet been holistically explored in a single study that provides a broader picture of all possible complex interactions. This study used the impact chain tool to holistically understand the risk that manifests as a result of interactions of hazards, exposure, and vulnerability. The secondary literature and authors’ observations helped us structure the first draft of the impact chain, which was further developed and validated through fourteen gender-disaggregated interviews with key informants and delta dwellers. This validation process identified the complex interconnections contributing to risk as experienced by experts and delta dwellers, which is seldom reflected through exclusively quantitative data. A quantitative analysis of the qualitative data strongly indicated that tropical cyclones, rainfall variability, and storms are the dominant hazards that affect social–ecological vulnerability manifested through mangrove degradation, land loss due to erosion, and embankment breaching. Social vulnerability is caused by processes and factors that are either directly or indirectly influenced by natural hazards and social–ecological factors. Processes such as increasing seasonal male migration, uncertain agricultural income, and a lack of hazard-resistant housing exacerbates social vulnerability. Embankment breaching, the salinization of land and water, land loss due to erosion, mangrove degradation, land conversion, and groundwater abstraction were identified as the fundamental threats that can lead to a loss of sustainable livelihoods of the people if left unaddressed.

A Hydrochemical Study of Groundwater Salinization in Qinzhou Bay, Guangxi, Southern China

AbstractThe salinity of groundwater in Qinzhou Bay has been increasing since 2013. This phenomenon affects livelihoods and the local agricultural economy, specifically in the Longmengang area. In this work, we investigate the causes of water salinization to provide evidence for effectively managing the local water resources and improving water quality. We collected 110 samples of water from spatially distributed local wells, rivers, reservoirs, and the sea, and conducted a hydrochemical study complemented by numerical modeling. We found that water pumping and mariculture practices are the principal contributors to seawater intrusion into the groundwater table, which leads to increased water salinization.