Water Types Research Articles

COMPOSITES BASED ON OYMASH SALT

In recent years, an urgent task is to find materials of domestic origin and create on their basis affordable and cheap, easy-to-use, reliable composite compositions for the preparation of well killing fluid. Nowadays, the need for process fluids that help preserve and restore reservoir properties always remains. Available and inexpensive natural salt from the Oimash deposit (Mangistau region) can create the required density in the well killing fluid and be its main component. The aim of the work is to develop compositions based on Oimash salt for the preparation of well killing fluids, which include all necessary additives. Methodology: The physicochemical characteristics of the composite compositions for the preparation of well killing fluid (bulk density, mass fraction of insoluble substances in water, mass fraction of moisture, solubility) and using standard methods corrosion activity studied. Results. The physicochemical parameters of Oimash salt showed that the salt is not prone to caking, the proportion of insoluble substances in sea water is 0.45%, and in waste water - 0.54%. The solubility of the developed compositions depending on the types of water was studied. All compositions are soluble in various types of water. The solubility of all compositions in seawater is 96.64-97.56%, and in wastewater from 95.59% to 95.97%. The optimal composition of the salt composition is the composition of sample No. 1 with the percentage content of components TPPF: NTF: PAA = 0.5: 0.5: 0.1:30, with a bulk density of 0.7055 t/m3, a mass fraction of insoluble substances in water - 1.4334%, well soluble in sea and waste water 97.56 and 95.66%. As the results of samples No. 1 showed, the corrosive environment is slightly aggressive in terms of aggressiveness.

Highly efficient radium removal from mine wastewater with fly ash NaP1 zeolite

This study investigates the application of NaP1 zeolite, synthesized hydrothermally from F-class fly ash, for treating radium-contaminated mine water. The objective was to assess the efficiency of NaP1 zeolite in removing radium ions from real mine water samples. Three samples with high concentrations of 226Ra and 228Ra and total dissolved cation contents ranging from 48.9 to 89.0 g/L were treated using sequential batch and fixed bed experiments. The NaP1 zeolite demonstrated high treatment efficiency for radium-sulfate and radium-strontium water, with removal rates of 97 % and 82 % for the 1st liter, and 54 % for the 53th and 9th liters, respectively. However, for radium-barium water, the maximum treatment efficiency was 45 % for the 1st liter, dropping to 0 % after 4th liter. This decline was attributed to the competitive adsorption of barium ions, which reduced the radium removal efficiency more rapidly than in the other water types. An additional experiment with synthetic barium water confirmed that 10 g of NaP1 zeolite adsorbed 1 g of Ba from one liter of distilled water. These results highlight the potential of NaP1 zeolite for radium removal in certain contexts, although its efficiency may be hindered by the presence of competing ions such as barium.

Geochemical Correlation of Volcanic Rocks and Groundwater Quality in the Todoko-Ranu Complex, Sahu District, West Halmahera, North Maluku, Indonesia

The research area is located in the Mount Todoko-ranu complex and its surroundings, Sahu District, West Halmahera Regency, North Maluku, Indonesia. This area geologically consists of Quaternary volcanic rocks with various petrochemical composition. On the other hand, natural water found in the research area generally physically appears turbid, while people who take water from this sites actually need clean water. As it is known, groundwater quality is influenced by the geochemistry of the aquifer through which it flows, therefore it is important to conduct a study on the geochemical correlation of volcanic rocks and groundwater quality in the research area. Thus, the aim of this research is to examine the geochemical characteristics of Mount Todoko-Ranu complex volcanic rocks, to analyze groundwater quality, and to study the correlation between the geochemical characteristics of rocks and the quality of groundwater in this volcanic complex. Methodology applied in this study was geological mapping, rock samples testing to determine the mineralogy chemical composition, groundwater, and surface water samples testing to identify their quality, and then correlation analysis. The results show that andesitic and basaltic-andesite of calc-alcaline volcanic rock complex is correlative to no dominant cation, but bicarbonate anion, or mixing type of natural water.

Hydro-Geochemistry and Water Quality Index Assessment in the Dakhla Oasis, Egypt

Water quality is crucial to the environmental system and thus its chemistry is important, and can be directly related to the water’s source, the climate, and the geology of the region. This study focuses on analyzing the hydrochemistry of specific locations within the Dakhla Oasis in Egypt. A total of thirty-nine groundwater samples representing the Nubian Sandstone Aquifer (NSSA) and seven surface water samples from wastewater lakes and canals were collected for analysis. Key parameters such as pH, electrical conductivity (EC), and total dissolved solids (TDS) were measured on-site, while major ions and trace elements (Fe+2 and Mn+2) were analyzed in the laboratory. The water quality index (WQI) method was employed to assess the overall water quality. Hydro-chemical facies were investigated using Piper’s, Scholler’s, and Stiff diagrams, revealing sodium as the dominant cation and chloride, followed by bicarbonate as the dominant anion. The hydro-chemical composition indicates that Na–Cl constitutes the primary water type in this study. This points to the dissolution of evaporates and salt enrichment due to intense evaporation resulting from the region’s hyper-aridity. In groundwater samples, the order of hydro-chemical facies is HCO3− > Cl− > SO4−2 > Na+ > Ca+2 > K+ > Mg+2, while in wastewater samples, it is Cl− > Na+ > SO4−2 > HCO3− > Ca+2 > Mg+2 > K+. When considering iron and manganese parameters, the water quality index (WQI) values suggest that most groundwater samples exhibit excellent to good quality but become poor or very poor when these elements are included. This study could prove valuable for water resource management in the Dakhla Oasis.

Failure mechanism of loess landslide induced by water stagnation on the combined surface

In order to reveal the destructive mechanism of loess landslide induced by stagnant water on the combined surface, and to clarify the influence of the main control factors, this paper takes a typical loess landslide in northern Shaanxi as the research object, analyzes the structure of the rock and soil body, and the excavation and filling construction through the geohazard survey, and analyzes the process of traction sliding caused by the stagnant water on the combined surface at the different stages of the project by combining with the calculation of the stability of the slope body. Further the article analyses the process of traction sliding caused by water on the combined area due to construction by means of a discrete element model, and delves into the mechanism of strength reduction of saturated loess. The results show that: 1) the combined surface stagnant water type loess landslide has the characteristics of sudden sliding and rapid evolution, which is highly hazardous and difficult to prevent and control; 2) the slope destabilization is controlled by the engineering geological conditions, and the slope excavation changes the original mechanical equilibrium conditions of the slope, which provides the dynamic conditions for the traction sliding of the slope; 3) the change of the hydrogeological environment results in the obstruction of the natural drainage channel, which leads to the formation of continuous sliding surface due to stagnant water on the combined surface, and the formation of a continuous sliding surface due to stagnant water on the combined surface. Surface stagnant water to form a continuous slippery surface, inducing the overall destabilization of the slope damage; 4) loess strength index with the increase of saturation and the exponential function form of reduction, and when the saturation degree reaches more than 80%, the strength index of the soil body to reach the basic stability. The article expanding the ideas of landslide control and analysis, and the research results will provide a theoretical basis for the design of junction landslide management in the loess areas of northern Shaanxi.

GROUNDWATER POLLUTION SOURCE USING PRINCIPAL COMPONENT ANALYSIS IN GUELMA PLAIN, NORTHEAST ALGERIA

This study was conducted in the agricultural region of Guelma, located in northeastern Algeria, where groundwater is the main source of water for human consumption, agriculture, and industry. The objective was to characterize groundwater quality and identify potential pollution sources using multivariate statistical methods, including Principal Component Analysis (PCA), correlation matrix, and the Piper diagram. The analyses revealed strong correlations between certain ions, such as sodium and chloride, suggesting carbonate dissolution processes, such as calcite and dolomite, leading to increased water hardness. The Piper diagram allowed for the classification of water types based on the relative concentrations of major cations (Ca²⁺, Mg²⁺, Na⁺+K⁺) and anions (Cl⁻, SO₄²⁻, CO₃²⁻+HCO₃⁻), showing a predominance of mixed hydrochemical types influenced by both natural and anthropogenic processes.PCA then simplified the interpretation by identifying the most influential variables that could serve as key indicators for the continuous monitoring of water quality. Overall, the results indicate that groundwater chemistry in this region is strongly influenced by human activities and local geological conditions, highlighting the need for sustainable management and continuous monitoring to protect this vital resource.

Water quality assessment of Upper Ganga and Yamuna river systems during COVID-19 pandemic-induced lockdown: imprints of river rejuvenation.

Clean river water is an essential and life-sustaining asset for all living organisms. The upper Ganga and Yamuna river system has shown signs of rejuvenation and tremendous improvement in the water quality following the nationwide lockdown due to the coronavirus pandemic. All the industrial and commercial activity was shut down, and there was negligible wastewater discharge from the industries. This article addresses the water quality assessment from the study area, which is based on the original data of physical parameters, major and trace elements, and stable isotopes (hydrogen and oxygen) systematics during the nationwide lockdown. The impact of the lockdown could be seen in terms of an increase in dissolved oxygen (DO). Water samples were collected from the Upper Ganga and Yamuna river basins (Alaknanda, Bhagirathi, and Tons rivers) during an eight-week lockdown in Uttarakhand, India. We discussed the signs of rejuvenation of riverine based on physical parameters, major ions, trace elements, isotopic ratios, and water pollution index (WPI). Results reveal that the water quality of the entire upper basins of the Ganga has significantly improved by 93%, reflecting the signs of self-rejuvenation of the rivers. Multivariate analysis suggests a negative factor loading for an anthropogenic element ( ), implying that they contribute little to the river water during the lockdown. Further, bicarbonate ( ) is a dominant element in both river basins. The geochemical facies are mainly characterized by the ( ) type of water, suggesting that silicate rock weathering dominates with little influence from carbonate weathering in the area. The positive factor loadings of some cations, like , , and reflect their strong association with the source of origin in the lockdown phases. Stable isotopic reveals that the glaciated region contributed the most to the river basin, as evidenced by the low d-excess in riverine water compared to anthropogenic contributions. Rivers can self-rejuvenate if issues of human influence and anthropogenic activities are adequately resolved and underline our responsibility for purifying the ecosystem. We observed that this improvement in the river water quality will take a shorter time, and quality will deteriorate again when commercial and industrial activity resumes.

Synthetic Microplastics in UK tap and bottled water; Implications for human exposure

There is increasing concern for public health over inadvertent human exposure to MPs due to potential adverse health effects linked to MPs polymeric composition, toxic chemical additives, and/or harmful microorganisms adsorbing onto their surfaces. While numerous studies have reported MPs occurrence and risk in the freshwater aquatic environment and drinking water sources (e.g., rivers, lakes, and reservoirs), the current state-of-knowledge on MPs pollution in drinking water (i.e., tap water and bottled water) remains limited at a global level. This paper provides the first comprehensive study of the occurrence, concentrations, size distribution, shape, and polymer type of MPs in 177 tap water samples from 13 cities in the United Kingdom, as well as 85 samples of bottled water from 17 popular brands, with various packaging materials, on the UK market.MPs were detected in all tap water samples (range 6–100 MP/L) and bottled water samples (range 12–62 MP/L). Average MPs concentration in tap water (40 ± 16 MP/L) was statistically indistinguishable from that in bottled water (37 ± 11 MP/L). However, the average MPs particle size in tap water (32.4 μm) exceeded significantly (p < 0.05) that in bottled water (26.5 μm), indicating the various purification processes applied to bottled water may help remove larger MPs, but raises concern over the potential adverse health effects from exposure to smaller MPs. The most frequently detected polymer types were: polypropylene (PP), polyethylene (PE), and polyvinyl chloride (PVC) in tap water, and PE, PP and polyethylene terephthalate (PET) in bottled water. A strong correlation was observed (r = 0.68, P = 0.049) between the plastic cap material (PE) and the predominant polymer type in the bottled water. In terms of morphology, fragments and fibres were the most abundant MPs, together constituting 92 % and 96 % of MPs detected in tap and bottled water samples, respectively.Using EFSA (European Food Safety Authority) recommended daily water intakes, the corresponding exposures to MPs in different UK age groups were estimated. On a body weight (BW) basis, infants and toddlers were exposed (4 MP/kg BW/day) at a higher level than adults (1 MP/kg BW/day). This raises concern, given the former's incompletely developed immune/nervous systems rendering them at higher risk of adverse health effects from such exposure.

Workability, mechanical, durability, and microstructural investigation of sustainable concrete utilizing secondary treated wastewater, fly ash, and sodium nitrite

ABSTRACT This study explored the use of secondary treated wastewater (STW) from three secondary-level wastewater treatment plants, along with fly ash (FA) and sodium nitrite (SN), to produce sustainable concrete, comparing it to concrete made with tap water. Key properties examined included workability (slump cone), strength (compressive, split tensile, and flexural), and durability (rapid chloride permeability and efflorescence). Scanning electron microscopy (SEM) analysis was performed to investigate the concrete's microstructure. The results indicated that FA and SN content had a notable influence on the workability, mechanical strength, and durability of the concrete mixtures. However, the type of water (STW or tap water) used in the concrete preparation showed no significant impact. Durability tests revealed that the penetrability of the mixtures ranged from low to moderate, signifying good quality, and no efflorescence was observed. Ultimately, the study concluded that concrete made with STW, when supplemented with 10% FA and 2% SN, demonstrated comparable performance to that made with tap water across key properties, offering a viable option for sustainable concrete production.

Natural High Strontium Mineral Water Might Reduce Liver Protein Synthesis: A Non-Targeted Metabolomics Study in Rats.

Strontium-rich mineral water (strontium > 0.20mg/L) is the second largest type of mineral water on commercial drinking water market. Exposure to high levels of strontium through drinking water or soil may interfere with calcium metabolism and increase the risk of cardiovascular and skeletal diseases, but no in-depth mechanism has been disclosed to date. Data on liver metabolic alterations in rats resulted from drinking natural high strontium mineral water (strontium 26.06mg/L, SrHW) or tap water (filtered by activated carbon, strontium 0.49mg/L, TW) for 3months were obtained and analyzed with non-targeted metabolomics strategy. Compared with rats drinking TW, those drinking SrHW showed a significant change in 36 liver metabolites. Among them, 33 liver metabolites (including 14 amino acids, 6 carbohydrates, 4 short-chain fatty acids, 4 organic acids, 2 phenylpropanoic acids, 1 fatty acid, 1 peptide, and 1 bile acid) were down-regulated, and 3 (hydroxyphenyllactic acid, propionylcarnitine and S-adenosine homocysteine) were up-regulated. Metabolic pathway analysis showed that aminoacyl-tRNA biosynthesis, valine, leucine and isoleucine biosynthesis, and alanine, aspartate and glutamate metabolism are most impacted. Furthermore, the serum prealbumin content also significantly decreased in rats drinking SrHW. Therefore, changes in liver metabolites and serum protein levels suggested that high concentration of strontium in water was associated with decreased liver protein synthesis; changes in liver metabolites suggested that high strontium was associated with decreased lipid levels. In conclusion, high strontium in water may exert a negative effect on protein synthesis, and further study on the dose-response relationship is necessary.

DNA-based marine benthic assessment methods can perform as morphological ones, but an intercalibration is needed

There is an increasing need for legislation worldwide to monitor and assess the ecological status of marine ecosystems, due to increasing pressures from human activities. The costs and time of traditional analyses are high, while methods based on molecular analysis could reduce these costs and shorten evaluation times significantly. Some biotic indices used to assess the status need reference conditions to be applied. Hence, our objective here is to develop reference conditions for a molecular-based benthic index (M−gAMBI), which can be compared with a morphological one (M−AMBI). Using 6 years of data from estuaries and coasts, we have been able to set reference conditions for five water types, including richness, diversity and AMBI. However, one problem is the absence of the whole human pressure gradient in all water types, making difficult to validate the reference conditions. Based on the results of this research, the M−gAMBI index could be considered suitable for ecological status assessment since it meets most of the criteria for considering a genomics-based index suitable. However, it is considered necessary to advance in (i) improving the detection of errors in genomic methods and similarity with morphological methods, and (ii) an intercalibration exercise, allowing adjusting quality class boundaries and determining the ecological status in an equivalent manner using both methods.

Groundwater quality assessment using revised classical diagrams and compositional data analysis (CoDa): Case study of Wadi Ranyah, Saudi Arabia

This research aims to assess the status and chemical properties of groundwater in the shallow aquifer of the Wadi Ranyah region, Saudi Arabia, using robust statistical methods (CoDA) that take into account the unique characteristics of chemical analysis data from forty-five (45) groundwater samples collected in the Wadi Ranyah valley. A centered logarithmic transformation (clr) approach and isometric logarithmic transformation (ilr) plots for compositional data were utilized to determine the different water types and to understand the hydrogeochemical processes influencing groundwater chemistry in the region. The results of principal component analysis and K-means clustering reveal the existence of three groundwater groupings: (i) The first group occupies the recharge region with a relationship between trace metal elements (F, Pb, Mn, Zn), pH, and TDS, indicating the effect of alteration of igneous and metamorphic rock minerals. (ii) The second group characterizes the downstream part of the Al-Hujrah area with a relationship between calcium and nitrates, indicating the influence of agricultural activities. (iii) The third group, located in the Ranyah area, shows a relationship between major ions (Na+, SO42−, Mg2+, HCO3–, Cl−, K+), which explains water mineralization influenced by silicate weathering and evaporation phenomena. According to the modified Piper diagram (ilr Piper), two hydrochemical facies are identified. The upstream region is categorized as Ca-HCO3– while the downstream region is classified as Na-K-HCO3–. Calculated water quality index (WQI) values indicate that all Wadi Ranyah groundwater samples are of very poor quality (WQI > 300). This is due to higher concentrations of polluting elements (Pb, Mn and F), in particular the high lead concentrations which vary between 0.24 and 0.4 mg/L, and are well above the WHO limit (0.01 mg/L) for consumption of drinking water. The application of CoDA for the first time in the study region has provided a more detailed and reliable assessment of the mechanisms governing groundwater quality, permitting suggestions for the management of groundwater resources and defining future research needs.

Research on the Compressive Strength of Saltwater Mixing and Curing Cement Mortar Incorporating Blast Furnace Slag

In this study, the blast furnace slag (BFS) was used to replace 30% cement (weight replacement), freshwater, and saltwater (half, same, and twice the concentration of seawater) used to produce the cement mortar. Then, these four types of mixing water were used to cure the mortar till the test ages (7 days and 28 days). The test results show that, at 7 days, the compressive strength of saltwater (half concentration) mixing and curing mortar incorporating BFS is the highest (78 MPa). The freshwater mixing and curing control mortar has the lowest compressive strength (36.2 MPa). At 28 days, the compressive strength of saltwater (twice concentration) mixing and saltwater (half concentration) curing mortar incorporating BFS is the highest (90.2MPa). The strength of the control mortar is 53.0MPa under the same curing water, which is still relatively low. It can be seen from this that the mixing and curing of saltwater are beneficial to improving the compressive strength of cement mortar. The freshwater mixing and saltwater (twice concentration) curing cement mortar incorporating 30% BFS can have a higher strength at 28 days.

Asphaltene-Silica Interactions in Salinity Water and Their Ion Dependence

Summary The adsorption of asphaltene on the pore surface not only forms a dense adsorption film but also induces a transition in sandstone wettability to more hydrophobic, which poses challenges to oil displacement, especially in unconventional reservoirs. The asphaltene adsorption exhibits a strong ion dependence, especially toward high ion concentration and high-valence cations, and the mechanism is not yet entirely understood. In this work, atomic force microscopy (AFM), coreflooding experiments, and the self-priming rate method were used to investigate the impacts of ion concentration and types in connate water on the adsorption of asphaltene. Enhanced asphaltene adsorption is observed in the presence of ions, leading to a more pronounced hydrophobic character in the cores saturated by high-salinity water. Then, we proceed with a consideration of the attraction force law between asphaltene and rock. The attraction showed an exponential decay with respect to distance and is in accordance with the hydrated ion bridge interaction. Furthermore, the attraction intensified notably in CaCl2 solution compared to that in NaCl solution and was enhanced progressively with increasing ionic concentration. Therefore, the adsorption amount of asphaltene and ultimately the wettability of the rock are affected by ion concentration and valence in formation water. Our findings hold significant implications for enhancing oil recovery in unconventional reservoirs under high-salinity conditions.

Assessment of Shallow Wells of Public Importance in Selected Areas of Ekiti State Capital City, Ado Ekiti, Nigeria

ABSTRACTGroundwater is one of the main sources of public water supply all over the world. This study assessed hand‐dug wells of economic importance in selected areas of Ado Ekiti in relation to terrain characteristics. A total of 15 wells were randomly sampled with replicates from 5 densely populated parts of the study area. Water samples collected were processed and analyzed in the laboratory using established scientific methods. Results showed that physicochemical characteristics of the sampled groundwater compared favorably with the standard for drinking water, except for phosphate (PO43−) concentration, which was above the permissible limit of 0.1 mg/L. Moreover, while lead (Pb2+) was within the acceptable limits of 0.001 mg/L, cadmium (Cd2+) and iron (Fe2+) mean values of 0.01 and 16.723 mg/L were above the permissible limits of 0.003 and 0.03 mg/L, respectively. All the samples analyzed were found to contain total coliforms. Piper diagram indicates prevalence of chloride anion facies and a small portion of sulfate with no carbonate ions. There was no dominant water type among the cations. The chemical makeup mainly showed the prevalence of strong acids (Cl−) and slightly alkaline earth elements (Ca2+). The Schoeller plot suggests the dominance of calcium and elevated chloride concentrations in comparison to other ions. The water quality index indicated widespread pollution in most of the sampled water, showing that the shallow wells are not suitable for drinking purposes except in Adebayo and Erifun axis as expected. The study revealed terrain's influence and unprofessional construction of wells. A holistic water safety plan is imperative in the area and thus recommended.

Performance investigation of UOWC system based on OAM beams for various Jerlov water types

This paper introduces a novel high-speed underwater optical wireless communication (UOWC) system employing three distinct orbital angular momentum (OAM) beams. A single green laser source operating at 532 nm generates these beams: LG0,0,LG0,20,andLG0,50, each transmitting data at 10 Gbps. The paper provides a comprehensive analysis of absorption and scattering coefficients for five Jerlov water types: I (JI), IA (JIA), IB (JIB), II (JII), and III (JIII). Simulation results demonstrate the system ability to transmit multiple data streams simultaneously using distinct OAM modes, achieving an overall capacity of 30 Gbps. The longest underwater (UW) transmission distance of 22 m is achieved in JI water as it exhibits the lowest attenuation. This range decreases by 9.09 %, 31.82 %, 59.09 %, and 80.91 % in JIA, JIB, JII, and JIII, respectively, due to increased attenuation in these water types. These results are obtained with a log (BER) below −5 and a Q-factor above 4, indicating successful data reception. The findings highlight the potential of OAM multiplexing for enhancing data capacity in challenging underwater environments.

Biochar Weakens the Efficiency of Nitrification Inhibitors and Urease Inhibitors in Mitigating Greenhouse Gas Emissions from Soil Irrigated with Alternative Water Resources

While previous studies have suggested that biochar, nitrification inhibitors, and urease inhibitors may reduce soil greenhouse gas emissions, their effectiveness in soils irrigated with alternative water resources remains unclear. To compensate for this, reclaimed water and livestock wastewater were utilized as alternative water resources alongside groundwater control. Nitrapyrin and N-(n-butyl) thiophosphoric triamide and biochar were applied to the soil either individually or in combination, and a no-substance treatment (NS) was included for comparison. The results revealed that reclaimed water and livestock wastewater irrigation exacerbated the global warming potential. Compared to the NS, all exogenous substance treatments suppressed nitrous oxide (N2O) emissions while increasing carbon dioxide (CO2) emissions, and affecting methane (CH4) emissions varied across treatments irrespective of the water types. Interestingly, the additional biochar reduced the inhibitory effect of the inhibitors on the greenhouse effect. Using nitrification inhibitors reduced the global warming potential by 48.3% and 50.1% under reclaimed water and livestock wastewater irrigation, respectively. However, when nitrification inhibitors were applied in combination with biochar, the global warming potential was increased by 52.1–83.4% compared to nitrification inhibitors alone, and a similar trend was also observed in the scenario of urease inhibitors, with increases ranging from 8.8 to 35.1%. Therefore, the combined application of biochar and inhibitors should be approached cautiously, considering the potential for increased greenhouse gas emissions.

Baseline survey of environmental parameters, radiation, and drip water hydrochemistry in Niah Caves (Sarawak, Malaysia)

Relict caves in fenglin karst may typically have numerous entrances and openings. Hence, they host a variety of environments in which parameters such as light, airflow, humidity, and temperature may vary significantly over short distances. Similarly, drip water hydrochemistry, including isotopic values, may vary due to different contributions of various sources and residence time in the karst. This study investigated environmental parameters, including radiation, using hand-held instruments, along a transect within several major caves in the Niah karst of Sarawak (Malaysia). This has led to a baseline data set which showed an inverse relationship between humidity and temperature, gamma radiation levels that are about 25% of that in surrounding non-karst region, and high percentages of twilight zones in the studied caves. Airflow was found to be variable, with high values of 530 m3/s in Painted Cave and 122 m2/s in parts of Gan Kira passage, with flow towards the southeast at the time of the study. The hydrochemistry of the drip water and surface water was also analyzed and found to be dominantly Ca–Mg–Cl water type which indicates dissolution of minerals through water–rock interaction. In addition, the cave environment, particularly air temperature, humidity, and ventilation, also influences the drip water composition and isotopic values. Three different origins (precipitation, evaporation, and paleo-recharge) of drip water have been identified through the δ18O-δ2H diagram. Enriched isotopic values were observed in the cave entrance due to increased evaporation caused by lower humidity and higher air temperature. Factor analysis identifies the key geochemical processes responsible for the drip water chemistry. The outcome of this study provides the first baseline environmental data for the Niah caves, which could support future initiatives for sustainable management of this famous archeological site in southeast Asia.

Application of major ions and Sr isotopes to indicate the evolution of river water and shallow groundwater chemistry in a typical endorheic watershed, northwestern China

Studying the hydrochemical evolution of river water and groundwater is vital for comprehending complex regional hydrological cycles and managing water resources. An investigation of hydrochemical evolution mechanism of river water and groundwater was executed in an arid and semi-arid endorheic watershed located in the eastern edge of Qaidam Basin, northwest China, by analyzing major ions and strontium isotopic compositions with the combination of hydrogeochemical methods, PMF model and Pearson correlation analysis. From upstream to downstream, the major ions, 87Sr/86Sr values and hydrochemical types of river water and groundwater show spatial variations. Major ions and 87Sr/86Sr analysis reveal that the hydrochmical compositions of river water and groundwater are primarily attributed to silicate weathering, carbonate weathering, evaporite weathering, and agricultural activity. The contribution of four factors affecting the hydrochemical evolution show obvious spatial variations along the flow path. The hydrochemical compositions of river water from the upstream to downstream are mainly contributed by carbonate and silicate weathering as well as weak evaporite weathering (<25%), which are affected by agricultural activity with a great contribution (>25%) in the middle and lower reaches. The contribution to the hydrochemical compositions of groundwater is relatively small (<25%) for carbonate, silicate and evaporite weathering, but great (>25%) for agricultural activity. This study provides implications for understanding the formation and evolution of water and better watershed water management in that typical endorheic watershed basin and even at larger scales.

Studying the effect of irrigation water quality (fresh water, treated water and wastewater) on some soil physical and chemical proper-ties and the protein content in the paulownia leaves.

Samples of soil irrigated with three types of water: Fresh water (F), wastewater (W), fresh water and wastewater (F1W1, alternative irrigation) were collected at two depths (0-15 cm and 15-30 cm) for two consecutive years. The bulk density, true density, soil total porosity, electrical conductivity, pH, percentage of organic matter, and concentration of phosphorus and potassium were measured. In addition, the length and circumference of paulownia tree trunk were measured, and the protein content of dry and green leaves was estimated. The results showed the differences in the apparent density values, as wastewater irrigation decreases the apparent density and increased the soil total porosity. The results also indicated that there were significant differences in the soil PH between the three treatments, as treated water irrigation decreased the pH and insignificantly increased the soil electrical conductivity. However, there were significant differences when irrigating with wastewater, as the electrical conductivity and organic matter content increased in the soil irrigated with wastewater compared to soil irrigated with fresh water at two depths (0-15cm and 15-30cm). Moreover, the concentrations of phosphorus and potassium increased in the soil irrigated with wastewater and treated water compared to fresh water. Furthermore, there were significant differences in the height of paulownia tree and its trunk circumference when irrigating with treated water compared to wastewater and fresh water. As for the protein content in paulownia leaves, it was observed that there were significant differences when irrigating with wastewater compared to treated water and fresh water. There was high protein content in the dry and green leaves when irrigating with the three types of water, but the highest protein content was for wastewater irrigation.