Concentrations Of Major Cations Research Articles

Salt-resistant hierarchically porous wood sponge coated with graphene flake/polyaniline nanocomposite for interfacial solar steam production and wastewater treatment

This research presents an innovative approach for developing a flexible wood sponge (WS) with a hierarchically porous structure. This unique structure is achieved through a sequential process involving balsa wood delignification, freeze-drying, and subsequent coating with graphene flake (GF)/polyaniline (PANI) nanocomposite. The resulting GF/PANI nanocomposite significantly reduces electron transfer resistivity, thereby enhancing heat generation for water evaporation. This results in self-cleaning photoabsorber, benefiting from GF’s salt-rejecting properties, PANI’s ionic network, and the WS’s porous structure. The photoabsorber demonstrates improved mechanical strength, reduced thermal conductivity, and a single water route design atop a drilled insulator foam, effectively minimizing heat loss during solar desalination. Under 1 sun (1 sun = 1 kW m−2) illumination, the photoabsorber achieves an impressive evaporation flux of 1.49 kg m−2h−1 and a high solar to thermal efficiency of 95.51 %. Importantly, continuous 10-cycle testing under 1 sun illumination reveals no salt deposition on the surface. Furthermore, the photoabsorber demonstrates promising applications in wastewater treatment, effectively purifying dye-contaminated seawater and desalinating both acidic and alkaline seawater. The investigation into the GF/PANI nanocomposite’s effect on steam generation, conducted through electrochemical impedance spectroscopy in a 0.5 M Na2SO4 electrolyte, reveals enhanced interfacial charge transfer, surpassing both PANI and GF due to reduced electrochemical resistance. Evaluation of desalinated seawater and purified wastewater demonstrates a significant decrease in major cation concentrations, meeting WHO and EPA drinking water standards. These findings underscore the potential of the GF/PANI nanocomposite in superior steam generation applications.

Influence of clay minerals on pH and major cation concentrations in acid-leached sands: Column experiments and reactive-transport modeling

A series of laboratory experiments are conducted to simulate the acidification and subsequent recovery of a sand aquifer exploited by in situ recovery (ISR) mining. A sulfuric acid solution (pH 2) is first injected into a column packed with sand from the Zoovch Ovoo uranium roll front deposit (Mongolia). Solutions representative of local groundwater or enriched in cations (Na+, Mg2+) are then circulated through the column to simulate the inflow of aquifer water. pH and major ion concentrations (Na+, Cl−, SO42−, Ca2+, Mg2+, K+) measured at the column outlet reproduce the overall evolution of porewater chemistry observed in the field. The presence of minor quantities of swelling clay minerals (≈6 wt% smectite) is shown to exert an important influence on the behavior of inorganic cations, particularly H+, via ion-exchange reactions. Numerical models that consider ion-exchange on smectite as the sole solid-solution interaction are able to reproduce variations in pH and cation concentrations in the column experiments. This highlights the importance of clay minerals in controlling H+ mobility and demonstrates that sand from the studied aquifer can be described to a first order as an ion-exchanger. The present study confirms the key role of clay minerals in controlling water chemistry in acidic environments through ion-exchange processes. In a context of managing the long-term environmental footprint of industrial and mining activities (ISR, acid mine drainage…), this work will bring insights for modeling choices and identification of key parameters to help operators to define their production and/or remediation strategies.

How do major ions and fulvic acid affect dissolved inorganic phosphorus adsorption onto suspended particulate matter in estuarine environment?

The adsorption and desorption of Dissolved Inorganic Phosphorus (DIP) onto Suspended Particulate Matter (SPM) are of key importance for the biogeochemistry in estuarine system. These processes are susceptible to changes in environmental factors, especially the inherent changes in levels of major ions, fulvic acids and salinity. As anthropogenic organic contamination in estuaries increases, aniline was chosen to investigate the influence of anthropogenic organic matter on DIP adsorption The influence of these factors on adsorption and desorption of phosphate onto SPM in estuarine aquatic system was examined using batch experiments in single and combined systems. The study showed that the adsorption of DIP onto SPM in estuaries was mainly controlled by salinity, especially the concentration of calcium (Ca2+), magnesium (Mg2+), sulfate (SO42−) and bicarbonate (HCO3−). Increased concentrations of major cations (Ca2+ and Mg2+) enhance DIP adsorption, while increased concentrations of major anions (SO42− and HCO3−) reduce adsorption. The amount of DIP adsorbed to SPM was mainly governed by the concentration of Ca2+, while the effect of differences in salinity was mainly dictated by the concentration of major anions. The facilitating effect of fulvic acid on DIP adsorption was generally negatively affected by increased salinity, as the fulvic acid increasingly reduced the enhancing effect of Ca2+ on DIP adsorption by forming stable complexes. Fulvic acids had no significant influence on the effect of Mg2+ and HCO3− on DIP adsorption to SPM. Aniline slightly inhibited DIP adsorption by competing with DIP for active sites on SPM. Aniline had no significant influence on the effect of cations on DIP adsorption to SPM, while slightly increasing inhibitory influence on anions.

Hydrogeochemical processes and nitrate contamination of shallow groundwater in the Gareb-Bouareg region, northeastern Morocco

In semiarid regions, groundwater faces considerable challenges due to both natural and human-induced contaminants, including nitrate contamination. These issues impact the availability of groundwater, a vital resource. Therefore, it is crucial to identify the sources and mechanisms contributing to salinization and nitrate contamination. In this study, we examined the hydrogeochemical characteristics of shallow groundwater in the Gareb-Bouareg region, northeast Morocco. The aim was to determine and understand the key processes that govern its chemical composition and assess nitrate contamination. A total of 50 groundwater samples were collected from existing wells and analysed for major cation and anion concentrations. The results showed that the dissolution of evaporite minerals, cation exchange and evaporation are the predominant processes of groundwater mineralization. In 72% of the samples, nitrate concentrations surpassed the anthropogenic origin threshold value of 10 mg/L, while 16% of the samples exceeded the drinking water standard of 50 mg/L. The highest values were found in the rural and urban areas, at 122 mg/L and 84.24 mg/L, respectively. Nitrate levels and the depth to the water table reveal the impacts of surface contamination sources. The spatial distribution and interrelationship between nitrate and other parameters suggest possible distinct origins of dissolved nitrates associated with various anthropogenic activities.

Assessment of groundwater suitability for sustainable irrigation: A comprehensive study using indexical, statistical, and machine learning approaches

Groundwater quality for irrigation purposes varies across regions, countries, and specific locations, primarily due to factors such as groundwater extraction and utilization methods, the intensity of rainfall, and the subsequent recharge of aquifers. The present study aimed to evaluate seasonal groundwater suitability for irrigation purposes using indexical approaches, statistical computing, graphical plotting, and machine learning algorithms. Groundwater samples were collected from intensively cultivated areas before and after the monsoon season and were analysed for different physicochemical parameters. The results revealed that the cation concentration of groundwater during pre-monsoon season followed the order of Na+ (59.9 %) > Ca2+(21.9%) > Mg2+ (17.1 %) > K+ (1.2%), whereas, anion chemistry followed the order of Cl−(50.9%) > HCO3− (43.6%) > SO42− (4.0 %) > CO32− (1.4%). A significant increase in the concentrations of major cations (Ca2+ and Na+) and anions (Cl− and HCO3−) was observed during the post-monsoon season. Various irrigation suitability indices expressed that 98.9, 73.5, 99.5, 56.12, and 97.9 % of groundwater samples were found suitable for irrigation based on electrical conductivity (EC), residual sodium carbonate (RSC), sodium adsorption ratio (SAR), percentage sodium (Na%) and water quality index (WQI), respectively. The factor and cluster analyses revealed that salinity, natural processes, and anthropogenic factors are the key determining factors affecting the correlations among water quality parameters. In the purview of predicting groundwater quality, multiple linear regression (MLR) and artificial neural network (ANN) models excelled, with ANN consistently outperforming MLR. Thus, it can be concluded that seasonal shifts in groundwater quality for irrigation are influenced by monsoon dynamics, demonstrating notable changes in cation and anion chemistry, with ANN models displaying superior predictive capabilities of irrigation suitability.

Groundwater contamination & health risk assessment with special reference to As in different tehsils of Bhakkar district

The present study was conducted to evaluate the concentration of arsenic in groundwater in Bhakkar district, Western Punjab Province, Pakistan. To analyze hydrochemical characteristics, 68 groundwater samples from various water schemes in four tehsils were taken. While most of the samples' concentrations of major cations and anions were within the WHO's maximum allowed range, almost 44% had higher arsenic levels than what was considered acceptable for drinking water. Gibbs diagrams were used to show how groundwater chemistry is affected by the dominance of rocks and evaporation crystallization. An investigation of the Indus River's lateral distribution and upstream to downstream locations' arsenic concentrations showed variability. According to the Health Risk Assessment (HRA), samples from Bhakkar tehsil (73.3%), Darya Khan tehsil (60%), and Kalur Kot tehsil (13.3%) all surpassed the hazard quotient level of “1,” whereas all samples from Mankera tehsil were within acceptable bounds. The hazard quotient numbers displayed a range of 0.038–5.127, with an average of 1.149 – suggesting that a considerable portion of people consuming water laden with high levels of arsenic may suffer from non-cancerous health complications. Moreover, the carcinogenic risk values were as high as 2.31 × 10−3, implying a heightened danger of cancer over the long term due to arsenic-contaminated water. It was determined that Bhakkar tehsil had the highest quantity of arsenic among the tehsils in the Bhakkar district, making the groundwater unfit for drinking.

Potential environmental pollution study by leachate generation and health risk assessment in the vicinity of bandhwari landfill disposal site, National Capital Region, India

Effects of fast urbanization and development in metropolitan cities is the production of massive amounts of waste from households and industries. Dumping of waste at an unengineered landfill site creates environmental issues. Generated leachate from such landfill is having potential to pollute the surrounding environment including groundwater. To understand the groundwater pollution by the effect of landfill leachate and health risk assessment for humans, four leachate samples and thirty-six groundwater samples were collected from different sources of groundwater from close proximity of Bandhwari Landfill site located in National Capital Region, Delhi. EC and SO42− values of Leachate samples i. e L-1 and L-2 are 42.5 mS/cm and 55.4 mS/cm; 1916.4 mg/l and 1931 mg/l respectively. Leachate pollution Index (LPI) values signifies that landfill leachate is having moderate potential for contamination. The dominance of average ionic species concentration of major cations in groundwater is given as Ca2+>Na+>Mg2+>K+ and major anion as HCO3− > Cl− > SO42− > NO3− > F−. As per Water Quality Index (WQI), 67% of samples lies in excellent category, 17% of samples falling in good category, whereas around 6% of groundwater samples lies in poor category, very poor category and unsuitable category. Landfill leachate and groundwater sample from North East direction are having high concentration of tritium i.e. 8.11 ± 0.40 TU and 3.03 ± 0.29 TU, respectively. Leachate samples from leachate pond-1 and leachate pond-2 are showing quite high Cl−/Br− ratio i. e 342 and 320. 86 respectively. But groundwater samples are exhibiting Cl−/Br− ratio in the range of 173.68 to 108.75. This represents leaching of salts from solid decomposed waste from landfill. Both non-carcinogenic and carcinogenic risk (CRing) were calculated for children and adult. Hazard Index (HI) values are higher than reference value i. e > 1 in the children (in 23% samples) as compare to the adult. These are mainly associated with Co, Cd and Pb. CRing of groundwater sample due to the presence of As, Ni, Cr and Cd falling in the range of 10−6 and 10−4 showing high risk to cancer per 10, 00, 000 million people by ingestion. However there is no significant cancer risk by dermal exposure by all metals in all groundwater samples. Groundwater pollution appears to be limited to the close vicinity in South and North-East direction.

Effects of Douglas fir cultivation in German forests on soil seepage water quantity and quality

Norway spruce (Picea abies L.) has been a key tree species and timber source in European forests the last centuries and is increasingly suffering from drought and bark beetle infestations due to climate warming. Current management options include replacing of Norway spruce monocultures with pure and mixed stands of European beech (Fagus sylvatica) that is the naturally dominating tree species in Central Europe. Additionally, Douglas fir (Psudotsuga menziesii), a tree species with high water use efficiency and drought tolerance, is being increasingly cultivated to increase the resilience of European forests and meet the future demand of conifer timber in a warming climate. We studied the seepage water quantity and quality with a particular focus on the nitrate (NO3–) concentration and N leaching under pure and mixed stands of Douglas fir, Norway spruce, and European beech at seven sites in Germany. Additionally, we investigated seepage water concentrations of SO4-S, Ca, Mg, K, Al and hydrological variables (interception, canopy throughfall, transpiration). Looking at the seepage water quantity and quality, the best management option is the cultivation of pure beech stands. However, this is associated with the well-known risk of monocultures concerning ecosystem disturbance. Beech stands showed the highest seepage water quantities and the lowest seepage water concentrations of major cations and anions, including NO3–. Seepage water quantity was the smallest under pure Douglas fir compared to spruce and beech stands. The composition effects of stand tree species on seepage water quality and nutrient leaching were site-dependent. At N-rich sites, pure Douglas fir stands showed higher seepage water NO3– concentrations than spruce and beech stands, whereas the tree species effects were small at N-poor sites. With respect to seepage water quantity and quality, cultivation of mixed Douglas fir–beech stands is a promising option for producing conifer timber and at the same time avoiding increased disturbance risks of mono-species forests under a warmer climate. Our results support the recommendation of mixed Douglas fir–beech stands based on soil quality, ecosystem resilience, and forest economic studies.

Geochemical Signatures of Bara Basin Aquifers, Kordofan State, Sudan

Purpose: In this paper, geochemical investigation has been carried out to study the concentrations of major cations; Sodium (Na+), Potassium (K+), Magnesium (Mg2+), and Calcium (Ca2+), and major anions; Chloride (Cl-), Bicarbonate (HCO3-), Nitrate (NO3-) and Sulphate (SO42-), other parameters such as (pH), Electric conductivity and T.D.S were also studied in all water samples taken from wells in Bara basin.
 Methodology: Forty five (45) water samples have been collected from wells. Lab works were done at Groundwater and Wadis Directorate (GWD), Khartoum State according to Sudanese Standards and Metrology Organization, (2002), to study the major cations and major anions.
 Findings: The results revealed that the average value of pH was (7.9) E.C values were (843.4 μS/cm) and T.D.S values were (59 mg/l). The average concentrations of the major cations obtained were; Na+ (126.3), K+ (5.22), Mg2+ (28.30), Ca2+(66.41) and the major anions (mg/l) were; Cl- (159.00), HCO3- (165.30), NO3- (156.70) and SO42- (164.70). The (Na/Cl) ratio is (2.47) is also high which reflects the abundance of (Na+) ions relative to the Chloride (Cl-) ions which confirmed the light-salty nature of groundwater. Geochemical mass balance calculations indicate that upper aquifer is mainly affected by the dissolution and dolomitization processes of major anions.
 Unique Contribution to Theory, Policy and Practice: This process is highly developed in the central west part of the basin due to the abundance of Sulphate (SO42-), Bicarbonate (HCO3-), Magnesium (Mg2+), and Calcium (Ca2+) ions. High values of E.C, T.D.S, Ca2+, and SO42- are mainly presents as a saline water resource in some villages. Two types of water are classified here these are : i). Na-HCO3 type and ii). Ca- Cl -SO4 type. The study concluded that water samples from Almakser, Hamdan-2, Um-Zeeraga-2, and Al-Zareeba-2 villages have very high concentrations of E.C, T.D.S Ca2-, Cl-, NO3- and SO42-, which may suggest that water samples are not fit for human consumption, according to guidelins by W.H.O (1984). This paper recommends further study on water quality.

Mobility of arsenic and vanadium in waterlogged calcareous soils due to addition of zeolite and manganese oxide amendments.

Addition of manganese(IV) oxides (MnO2 ) and zeolite can affect the mobility of As and V in soils due to geochemical changes that have not been studied well in calcareous, flooded soils. This study evaluated the mobility of As and V in flooded soils surface-amended with MnO2 or zeolite. A simulated summer flooding study was conducted for 8 weeks using intact soil columns from four calcareous soils. Redox potential was measured in soils, whereas pH, major cations, and As and V concentrations were measured biweekly in pore water and floodwater. Aqueous As and V species were modeled at 0, 4, and 8 weeks after flooding (WAF) using Visual MINTEQ modeling software with input parameters of redox potential, temperature, pH, total alkalinity, and concentrations of major cations and anions. Aqueous As concentrations were below the critical thresholds (<100μgL-1 ), whereas aqueous V concentrations exceeded the threshold for sensitive aquatic species (2-80μgL-1 ). MnO2 -amended soils were reduced to sub-oxic levels, whereas zeolite-amended and unamended soils were reduced to anoxic levels by 8 WAF. MnO2 decreased As and V mobilities, whereas zeolite had no effect on As but increased V mobility, compared to unamended soils. Arsenic mobility increased under anoxic conditions, and V mobility increased under oxic and alkaline pH conditions. Conversion of As(V) to As(III) and V(V) to V(IV) was regulated by MnO2 in flooded soils. MnO2 can be used as an amendment in immobilizing As and V, whereas the use of zeolite in flooded calcareous soils should be done cautiously.

Hydrogeochemical processes of critical zone developed in Tégulines Clay, Paris Basin: Hydrogeochemical and multi-isotopic approach (δ13C, δD, δ18O, 87Sr/86Sr and 14C)

Water transfers and processes governing the chemistry of groundwaters and clay pore waters were investigated in the critical zone developed in Tégulines Clay in the area of Brienne-Le-chateau, at east of the Aube alluvium plain (France). A pit-digging campaign along two-stepped west-facing hillslopes along the Brevonne valley and the Aube/Brevonne paleo-valley gives evidence of a thin Quaternary clay silty and carbonate-free loams overlying Tégulines Clay, mobile regolith along the slopes and the presence of a carbonate alluvium layer in pits of the Brevonne valley. Groundwaters at the first ridgetop attest of a temporary perched water table, while groundwaters at top of Tégulines Clay along the first west-facing steep slope toward the Brevonne River provide evidence of lateral groundwater transfers and runoff of waters toward the valley which is a discharge zone belonging to the present-day Aube alluvium plain. Groundwaters have low concentrations of Total Dissolved Solids (TDS < 600 mg/L) and are calcic-carbonate waters. Their δ18O and δD of groundwaters are consistent with local meteoric values. An 18O and D enrichment in groundwaters at the bottom of the second hillslope and in waters from reservoirs indicates evaporation processes. The δ13CCO2 of dissolved inorganic carbone in groundwaters is essentially due to degradation of organic matter. The composition of the pore waters from Tégulines Clay in boreholes are chemically heterogeneous and different from groundwaters. They are Ca-Mg-SO4-rich and show a large range of TDS concentrations (592–6457 mg/L). The highest values are measured in the most intensely weathered clay developed in the first 10–15 m under the first ridge top and the low east-facing slope of the Aube/Brevonne paleo-valley. This latter seems to represent a large intermediate discharge zone between the coarse ridgetops (recharge zones) and the current Aube alluvium plain. The δ18O and δD of pore waters are alined along the local meteoric water line, indicating that meteoric waters have diffused through the clay formation during post-depositional history and replaced original connate seawater. On contrary the 87Sr/86Sr ratios of pore waters remain almost similar to that of Lower Cretaceous seawater, suggesting a limited diffusion of Sr since the formation deposition. Toward the top of the formation in the Aube/Brevonne paleovalley, major cation and anion concentrations, 18O and D enrichment and a slight increase of the 87Sr/86Sr ratios suggest the diffusion of evaporated waters. The δ13C, δ18O,87Sr/86Sr ratios and 14C activity of concretions at top of Tégulines Clay show that they precipitated from evaporated old groundwaters, the oldest one at ∼ 34 ky in the TPH2-1 pit at the ridgetop of the second hillslope and a younger age of ∼ 8 ky in the TV4-1 pit.

Examining spatial variation in soil solutes and flowpaths in a semi-arid, montane catchment

Biogeochemical properties of soils play a crucial role in soil and stream chemistry throughout a watershed. How water interacts with soils during subsurface flow can have impacts on water quality, thus, it is fundamental to understand where and how certain soil water chemical processes occur within a catchment. In this study, ~200 soil samples were evaluated throughout a small catchment in the Front Range of Colorado, USA to examine spatial and vertical patterns in major soil solutes among different landscape units: riparian areas, alluvial/colluvial fans, and steep hillslopes. Solutes were extracted from the soil samples in the laboratory and analyzed for major cation (Li, K, Mg, Br, and Ca) and anion (F, Cl, NO2, NO3, PO4, and SO4) concentrations using ion chromatography. Concentrations of most solutes were greater in near surface soils (10 cm) than in deeper soils (100 cm) across all landscape units, except for F which increased with depth, suggestive of surface accumulation processes such as dust deposition or enrichment due to biotic cycling. Potassium had the highest variation between depths, ranging from 1.04 mg/l (100 cm) to 3.13 mg/l (10 cm) sampled from riparian landscape units. Nearly every solute was found to be enriched in riparian areas where vegetation was visibly denser, with higher mean concentrations than the hillslopes and fans, except for NO3 which had higher concentrations in the fans. Br, NO2, and PO4 concentrations were often below the detectable limit, and Li and Na were not variable between depths or landscape units. Ratioed stream water concentrations (K:Na, Ca:Mg, and NO3:Cl) vs. discharge relationships compared to the soil solute ratios indicated a hydraulic disconnection between the shallow soils (&amp;lt;100 cm) and the stream. Based on the comparisons among depths and landscape units, our findings suggest that K, Ca, F, and NO3 solutes may serve as valuable tracers to identify subsurface flowpaths as they are distinct among landscape units and depth within this catchment. However, interflow and/or shallow groundwater flow likely have little direct connection to streamflow generation.

Hydrochemistry and an appraisal of surface water and groundwater quality for domestic and irrigation use in parts of Southern Benue Trough, Nigeria.

This research attempts to assess the hydrochemistry of major ions, the quality of surface and subsurface water, as well as its suitability for domestic and agricultural uses, in parts of the Southern Benue Trough. A total of thirty water samples were collected and analyzed in the laboratory using standard practices. Results revealed that the concentration of major cations for both surface and groundwater is in the order: Na+ > Ca2+ > Mg2+ > K+, while major anionic constituents are, respectively, present in the order: Cl− > HCO3− > CO32− > NO3− > SO42− and HCO3− > CI− > CO32− > NO3− > SO42− for surface and groundwater. The water quality index (WQI) model revealed that 100% of the surface water is of good quality for domestic and other uses, while 29.17% and 70.83% of the groundwater are of excellent and good quality, respectively. Three water types were identified, namely Na–Cl, Ca–Mg–HCO3, and Na–HCO3. Lastly agricultural indices (total hardness, TH, percent sodium, %Na, sodium absorption ratio, SAR, residual sodium carbonate, RSC, permeability index, PI and magnesium hazard, MH) computed along with various plots, revealed that the analyzed surface and subsurface water are suitable for irrigation purposes. The application of plots, tables, and models based on the major ionic constituents, gives fast and effective visualization of the quality and chemistry of surface water and groundwater.

Phosphorus Release and Speciation in Manganese(IV) Oxide and Zeolite-Amended Flooded Soils.

Phosphorus (P) losses from flooded soils and subsequent transport to waterways contribute to eutrophication of surface waters. This study evaluated the effectiveness of MnO2 and a zeolite Y amendment in reducing P release from flooded soils and explored the underlying mechanisms controlling P release. Unamended and amended (MnO2 or zeolite, surface-amended at 5 Mg ha-1) soil monoliths from four clayey-alkaline soils were flooded at 22 ± 2 °C for 56 days. Soil redox potential and dissolved reactive P (DRP), pH, and concentrations of major cations and anions in porewater and floodwater were analyzed periodically. Soil P speciation was simulated using Visual MINTEQ at 1, 28, and 56 days after flooding (DAF) and P K-edge X-ray absorption near-edge structure spectroscopy and sequential fractionation at 56 DAF. Porewater DRP increased with DAF and correlated negatively with pe+pH and positively with dissolved Fe. Reductive dissolution of Fe-associated P was the dominant mechanism of flooding-induced P release. The MnO2 amendment reduced porewater DRP by 30%-50% by favoring calcium phosphates (Ca-P) precipitation and delaying the reductive dissolution reactions. In three soils, the zeolite amendment at some DAF increased porewater and/or floodwater DRP through dissolution of Ca-P and thus was not effective in reducing P release from flooded soils.

Polyhumous Dystrophic Pit Lakes: Hydrographic and Hydrochemical Characteristics on the Example of Reservoirs in the Włoszczowska Basin, Central Poland

The article presents the hydrographic and hydrochemical characteristics of post-exploitation reservoirs formed in peat excavations. Two natural bog lakes were selected as the control objects for the study. The research indicated that both the waters of post-exploitation peat reservoirs and natural bog lakes show low electrolytic conductivity (&lt;100 µS/cm) and acidic water reaction (pH &lt; 5.5). The concentration of major cations and anions is also very low. The concentration of calcium and magnesium does not exceed a few mg/L. Hydrochemically, all post-exploitation peat reservoirs are bi-ionic sulphate–calcium (SO42−-Ca2+). This distinguishes post-exploitation peat reservoirs from natural bog lakes in which multi-ion waters were found, for example, sulphate–chloride–calcium (SO42−-Cl−-Ca2+) and sulphate–calcium–sodium (SO42−-Ca2+-Na+). The calculated water humic state index (HSI) allowed the classifying of the examined reservoirs as polyhumous. The value of this index, in all reservoirs, was &gt;50. Based on the calculated hydrochemical dystrophy index (HDI), it was found that all post-exploitation peat reservoirs are dystrophic. So far, no such hydrochemical type has been found in other post-exploitation peat reservoirs. Therefore, the examined objects should be classified as unique post-exploitation peat reservoirs.

Groundwater quality evaluation: a case study of Igando waste dumpsite, southwestern Nigeria

The quality of groundwater samples around Igando area, Lagos State, Nigeria was investigated with the aim of detecting possible influence of dumpsites on nearby aquifers. Thirty-seven (37) groundwater samples were evaluated for their suitability in drinking and agricultural purposes. Physical parameters were determined in situ using portable multi-meter. Flame absorption was used to determine the concentrations of major cations while ion chromatography and titrimetry was used for anions’ concentration. Bacteriological test was conducted using multiple tube technique. Results of in-situ physical parameters revealed pH range of 7.01–7.79, EC range of 20–880 μS/cm while TDS range from 13–590 mg/L. Laboratory analyses showed Ca2+ concentration ranging 1.60–72.80 mg/L and HCO3− ranging 19.52–204.96 mg/L as the dominant ions. None of the ions’ concentrations exceed the WHO drinking limit. Water Quality Index (WQI) classification showed that all samples fall within good to excellent water categories. The majority of the samples are suitable for irrigation using indices such as Sodium Adsorption Ratio (SAR), Kelly’s ratio (KR), and Magnesium Hazard (MH). Bacteriological analyses revealed low total bacterial count and E-coli absence making the samples safe for drinking. Piper diagram indicated two main water-facies (Ca–HCO3 and the Mixed Ca–Mg–Cl). Gibbs’s plots showed that the samples are primarily influenced by rock weathering, while precipitation also contributed. Chloro-Alkaline Index confirmed direct ion-exchange process. Cluster analyses revealed four groups: the first revealed influence of groundwater by anthropogenic activities in the study area, the second and third revealed lithological origin of ions in the water while group 4 indicated pH low influence on the dissolved ions in the waters. The groundwater quality can be said to be fair-good, thus suggestive of minimal interactions between the dumpsites and the groundwater in the area at the time of testing.

Irrigation Water Quality Assessment and Hydrochemical Facie of Oguta Lake, Southeastern Nigeria

The quality of water for irrigation is important for maintaining soil properties and improving yields. This study assessed the quality of Oguta Lake for irrigation using irrigation indices of SAR, %Na, PI, KI, and MH. Twenty (20) water samples were collected in the study area over two seasons and analyzed using standard methods. The results indicate that the water is excellent for irrigation with values of SAR, %Na, PI, KI, and MH ranging between 0-0.007, 0-0.18, 213-329, 0.0006-0.0022, and 0.06-13 in the dry season and 0.001-0.154, 0-3.57, 212-328, 0.008-0.0477 and 4.46-13.21 in the rainy season respectively. Piper and Durov diagrams were used to determine the hydrochemical facie of the water and both plots indicate that the water type is dominantly Ca2+ - Mg2+ - HCO3- and this water type is typical of fresh water. The piper plot also shows that weak acid exceeds strong acids and alkaline earth (dominant metal ions) exceeds alkalis. The concentration of major cations and anions follows the trend, Ca2+ &gt; K+ &gt; Mg2+ &gt; Na+ and HCO3 &gt; SO42- &gt; CO3- &gt; Cl-, respectively.

The Sensitivity of a Unionid Mussel (Lampsilis Siliquoidea) to a Permitted Effluent and Elevated Potassium in the Effluent.

Freshwater mussels are one of the most imperiled groups of animals in the world and are among the most sensitive species to a variety of chemicals. However, little is known about the sensitivity of freshwater mussels to wastewater effluents. The objectives of the present study were to (1) assess the toxicity of a permitted effluent, which entered the Deep Fork River, Oklahoma (USA), to a unionid mussel (Lampsilis siliquoidea) and to two standard test species (cladoceran Ceriodaphnia dubia; and fathead minnow Pimephales promelas) in short-term 7-day effluent tests; (2) evaluate the relative sensitivities of the three species to potassium (K), an elevated major ion in the effluent, using 7-day toxicity tests with KCl spiked into a Deep Fork River upstream reference water; (3) determine the potential influences of background water characteristics on the acute K toxicity to the mussel (96-h exposures) and cladoceran (48-h exposure) in four reconstituted waters that mimicked the hardness and ionic composition ranges of the Deep Fork River; and (4) determine the potential influence of temperature on acute K toxicity to the mussel. The effluent was found to be toxic to mussels and cladocerans, and it contained elevated concentrations of major cations and anions relative to the upstream Deep Fork River reference water. The K concentration in the effluent was 48-fold greater than in the upstream water. Compared with the standard species, the mussel was more than 4-fold more sensitive to the effluent in the 7-day effluent tests and more than 8-fold more sensitive to K in the 7-day K toxicity tests. The acute K toxicity to the mussel decreased by a factor of 2 when the water hardness was increased from soft (42 mg/L as CaCO3 ) to very hard (314 mg/L as CaCO3 ), whereas the acute K toxicity to the cladoceran remained almost the same as hardness increased from 84 to 307 mg/L as CaCO3 . Acute K toxicity to the mussel at 23 °C was similar to the toxicity at an elevated temperature of 28 °C. The overall results indicate that the two standard test species may not represent the sensitivity of the tested mussel to both the effluent and K, and the toxicity of K was influenced by the hardness in test waters, but by a limited magnitude. Environ Toxicol Chem 2021;40:3410-3420. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.

Assessment of surface and groundwater quality for irrigation purposes in the Danube-Tisa-Danube hydrosystem area (Serbia).

The study evaluates irrigation water quality in the Danube-Tisa-Danube hydrosystem area (Vojvodina, northern Serbia). The area is dominantly a plain with about 75% arable land, suitable for agricultural production and irrigation. Use of water of inadequate quality can have long-term effects on irrigated land and affect the yield of cultivated crops. The analyses included data from 40 surface water and 23 groundwater quality monitoring locations, observed during the period 2013-2018. The average annual values of the concentrations of major cations and anions and of electrical conductivity in surface and groundwater were comparatively analyzed. These values were statistically significantly higher (by p < 0.05) in groundwater bodies with most of the analyzed parameters. Hydrochemical classification of water types shows that 95% of surface and 87% of groundwater locations belong to the Ca·Mg-HCO3 water type. Water suitability for irrigation was assessed using specific parameters and indices (sodium adsorption ratio, Na%, residual sodium carbonate, magnesium hazard, permeability index, and Kelly's index). The results showed that surface and groundwater resources are generally of good quality and suitable for irrigation, with sporadic deviations at several locations. The principal component analysis (PCA) was used to identify the most important variables affecting the chemical composition of the analyzed waters and group the monitoring locations by their chemical characteristics. The spatial variation of the analyzed water quality indices was shown on thematic maps.

Chemical weathering and carbon dioxide consumption in a small tropical river catchment, southwestern India

Studies done on small tropical west-flowing river catchments located in the Western Ghats in southwestern India have suggested very intense chemical weathering rates and associated CO2 consumption. Very less studies are reported from these catchments notwithstanding their importance as potential sinks of atmospheric CO2 at the global scale. A total of 156 samples were collected from a small river catchment in the southwestern India, the Payaswini–Chandragiri river Basin, during pre-monsoon, monsoon and post-monsoon seasons in 2016 and 2017, respectively. This river system comprises two small rivers originating at an elevation of 1350 m in the Western Ghats in peninsular India. The catchment area is dominated by biotite sillimanite gneiss. Sodium is the dominant cation, contributing ~ 50% of the total cations, whereas HCO3− contributes ~ 75% of total anions. The average anion concentration in the samples varied in the range HCO3− > Cl− > SO42− > NO3− > F−, whereas major cation concentration varied in the range Na+ > Ca2+ > Mg2+ > K+. The average silicate weathering rate (SWR) was 42 t km−2 y−1 in the year 2016 and 36 t km−2 y−1 in 2017. The average annual carbon dioxide consumption rate (CCR) due to silicate rock weathering was 9.6 × 105 mol km−2y−1 and 8.3 × 105 mol km−2 y−1 for 2016 and 2017, respectively. The CCR in the study area is higher than other large tropical river catchments like Amazon, Congo-Zaire, Orinoco, Parana and Indus because of its unique topography, hot and humid climate and intense rainfall.