Major Ion Chemistry Research Articles

Seasonal Variations in Groundwater Quality and Hydrogeochemistry in the Endemic Areas of Chronic Kidney Disease of Unknown Etiology (CKDu) in Sri Lanka

Groundwater quality and geochemical processes were investigated in the endemic areas of chronic kidney disease of unknown etiology (CKDu) in Sri Lanka. Representative groundwater samples (n = 60) were collected from 30 dug wells located in the Anuradhapura district, over the dry and wet seasons. The samples were analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), alkalinity, major cations and major anions. Calcium-magnesium-bicarbonate ion combinations are predominant in this groundwater, and the simultaneous occurrence of high hardness (382–394 mg/L as CaCO3), alkalinity (364–379 mg/L as CaCO3) and ionicity is a salient characteristic. Alkalinity, TDS, hardness, and magnesium exceeded the safe limits for drinking in over half of the samples, regardless of the season. The major ion chemistry (Ca2+, Mg2+, Na+ and HCO3−) is primarily governed by the weathering of carbonate and silicate minerals, ion exchange, and evaporation which is accelerated by the semi-arid climate. Fluoride and chloride inputs are regulated by dissolution of fluoride-bearing minerals and anthropogenic causes, respectively. Saturation indices suggested supersaturation of carbonates and silicates, and undersaturation of evaporites and fluorite. Persistent high ionicity, and hardness of groundwater that is seldom impacted by seasonal variations might be playing a vital role in the genesis of CKDu.

Hydrogeochemical characteristics of the Indus river water system

ABSTRACT The Indus River is the most prominent freshwater source of the northwestern part of the Indian subcontinent. Glacier/snow melting during the summer season is the main source of water. Here, we are presenting the major ion chemistry of the Indus river water, its tributary rivers, including small streams (nallahs), mainly in the territory of India, to know the overall quality of water, and geochemical processes controlling the solute acquisition and sources of elements in the catchment region. The analytical results indicate that the water samples are mildly acidic to alkaline in nature and have Ca2+ and Mg2+ dominance in cationic and HCO3 - and Cl- in anionic composition. Overall, alkaline-earth elements (Ca2+ + Mg2+) dominate over alkalis (Na+ + K+), and weak acids (HCO3 -) exceed strong acids (SO4 2- + Cl-) in the river/stream water samples. The hydrogeochemical diagrams, molar ratios, and statistical analysis suggest that carbonate and silicates minerals’ weathering mainly control the solute acquisition process with negligible contribution from marine or anthropogenic sources. Most of the surface water samples are fit for drinking and domestic uses except the hot spring and saline lake waters.

Major ion chemistry and hydrochemical processes controlling water composition of Teesta River catchment, Sikkim Himalaya, India

ABSTRACT The study determines the major ion chemistry of the Teesta River catchment in the Eastern Himalayan region and evaluates hydrochemical processes controlling water composition of the catchment area. Water of the Teesta River basin was in neutral to alkaline condition. HCO3 −, Ca2+, Na+, Mg2+ and SO4 2- were identified as the dominant ionic species in the Teesta catchment water composition and Ca-Mg-HCO3 as the dominant hydrochemical facies. Higher contribution of (Ca2++Mg2+) and HCO3 − towards the TZ+ and TZ−, high ionic ratios of (Ca2++Mg2+)/(Na++K+), HCO3 −/(Cl−+SO4 2-) and low (Na++K+)/TZ+ ratio suggest carbonate weathering as a major contributor of dissolved ions in the Teesta basin water. Under-saturation with respect to both carbonate and sulphate phase minerals suggests that water can dissolve these minerals during water-rock interaction. Concentration of the analysed water quality parameters were well below the specified drinking and irrigation water limits.

Major-Ion Chemistry and Quality of Water in Rivers of Northern West Siberia

This study reports a synthesis of years-long hydrogeochemical monitoring in northern West Siberia, performed by the Russian Meteorological Service (Rosgidromet) and several academic institutions. Natural factors and intensive human economic activity lead to the disruption of the ecosystems of the northern territories of Western Siberia. The aim of this study is to estimate the background water chemistry parameters in the rivers of northern West Siberia in the beginning of the 21st century. The mean values hydrochemical and geochemical indicators were determined with STATISTICA software, which can be used as background values in assessing the actual and allowable anthropogenic impact on water bodies. We revealed four water chemistry provinces: western Ob Gulf and Ob estuary catchments (I); eastern Ob Gulf and Taz Gulf catchments, except for the Taz River and its tributaries (II); Taz River catchments (III); Yenisei River catchments, right bank (IV). The major-ion chemistry of the sampled river waters records a combination of geological, geomorphological, and hydrological conditions in the four provinces. The features typical of the northern West Siberian Plain are especially prominent in province II, which has the lowest average total of major ions (Σmi), the highest chemical oxygen demand (potassium dichromate COD), and the highest contents of Fe and phosphates. The Σmi value is the highest in province IV. The river waters from four provinces share similarity in quite high organic contents (both potassium dichromate and permanganate COD), as well as high NH4+ and Fe. The long-term average Σmi of the waters is predicted not to change much in the coming one or two decades, though it may decrease slightly in the winter season but increase in the fall and spring time.

Machine Learning Can Assign Geologic Basin to Produced Water Samples Using Major Ion Geochemistry

Understanding the geochemistry of waters produced during petroleum extraction is essential to informing the best treatment and reuse options, which can potentially be optimized for a given geologic basin. Here, we used the US Geological Survey’s National Produced Waters Geochemical Database (PWGD) to determine if major ion chemistry could be used to classify accurately a produced water sample to a given geologic basin based on similarities to a given training dataset. Two datasets were derived from the PWGD: one with seven features but more samples (PWGD7), and another with nine features but fewer samples (PWGD9). The seven-feature dataset, prior to randomly generating a training and testing (i.e., validation) dataset, had 58,541 samples, 20 basins, and was classified based on total dissolved solids (TDS), bicarbonate (HCO3), Ca, Na, Cl, Mg, and sulfate (SO4). The nine-feature dataset, prior to randomly splitting into a training and testing (i.e., validation) dataset, contained 33,271 samples, 19 basins, and was classified based on TDS, HCO3, Ca, Na, Cl, Mg, SO4, pH, and specific gravity. Three supervised machine learning algorithms—Random Forest, k-Nearest Neighbors, and Naïve Bayes—were used to develop multi-class classification models to predict a basin of origin for produced waters using major ion chemistry. After training, the models were tested on three different datasets: Validation7, Validation9, and one based on data absent from the PWGD. Prediction accuracies across the models ranged from 23.5 to 73.5% when tested on the two PWGD-based datasets. A model using the Random Forest algorithm predicted most accurately compared to all other models tested. The models generally predicted basin of origin more accurately on the PWGD7-based dataset than on the PWGD9-based dataset. An additional dataset, which contained data not in the PWGD, was used to test the most accurate model; results suggest that some basins may lack geochemical diversity or may not be well described, while others may be geochemically diverse or are well described. A compelling result of this work is that a produced water basin of origin can be determined using major ions alone and, therefore, deep basinal fluid compositions may not be as variable within a given basin as previously thought. Applications include predicting the geochemistry of produced fluid prior to drilling at different intervals and assigning historical produced water data to a producing basin.

Evaluation of strontium isotope tracers of produced water sources from multiple stacked reservoirs in Appalachian, Williston and Permian basins

Both unconventional and conventional oil and gas production have led to instances of brine contamination of near-surface environments from spills of saline produced waters. Strontium isotope ratios (87Sr/86Sr) have been used as a sensitive tracer of sources of brine contamination in surface waters and shallow aquifers in areas where oil and gas production are limited to only a few reservoirs and produced water sources are well-defined. Recent expansion of conventional and unconventional oil and gas production to additional tight formations within sedimentary basins has resulted in production of formation waters from multiple oil and gas reservoirs that may have similar chemical and isotopic ratios, including 87Sr/86Sr. This study evaluates the utility of 87Sr/86Sr, the most widely available tracer dataset beyond major ion chemistry and water stable isotopes, as a tracer of brine contamination related to conventional and unconventional oil and gas production in the Williston, Appalachian and Permian basins. Multiple stacked oil and gas reservoirs within each basin have overlapping formation water 87Sr/86Sr, based on a non-parametric statistical test. For example, in the Appalachian Basin, produced waters from unconventional gas production in the Middle Devonian Marcellus and Upper Ordovician Utica shales have overlapping 87Sr/86Sr. In the Permian Basin, produced waters from the unconventional Pennsylvanian-Permian Wolfcamp Shale and conventional and unconventional Pennsylvanian Cisco/Canyon/Strawn formations have similar 87Sr/86Sr. In the Williston Basin produced waters from Late Devonian to Early Mississippian Bakken Formation unconventional oil production have overlapping 87Sr/86Sr with produced waters associated with minor production of conventional oil from the Middle Devonian Winnipegosis. Improved spatial characterization of 87Sr/86Sr and other isotopic signatures of produced waters from various oil/gas reservoirs are needed to constrain geographic and depth variability of produced waters in hydrocarbon producing regions. This is particularly important, as unconventional oil and gas production expands in areas of existing conventional oil and gas production, where delineating sources of saline produced waters in cases of accidental surface spills or subsurface leakage will become a greater challenge. Sr isotopes alone may not be able to distinguish produced waters in areas with overlapping production from reservoirs with similar isotopic signatures.

Unveiling the extent of salinization to delineate the potential submarine groundwater discharge zones along the North-western coast of India

The North-West coast of India was notable for the urbanization and semiarid climate, particularly the Gujarat coastal region which was facing water crises and aquifer salinization issue. Under the light of these critical issues, the present study investigates the sources of aquifer salinization and probable location of submarine groundwater discharge (SGD) using an integrated approach of major ion chemistry, statistical techniques, and isotopic signature of groundwater (GW). The evolution of GW reveals that water facies changes from Ca2+-Mg2+-Cl− to Na+-Cl type from the south Gujarat towards the Gulf of Khambhat. Log-normal distribution of Cl− and NO3− divulges that different pollution sources influence the GW quality. Statistical findings supplemented with Isotopic signatures, ionic ratios and cross plots identified four classes of GW, which varies with degree of anthropogenic and seawater influences. Results suggested that seawater intrusion heavily influences 42% of the total GW samples, whereas 58% samples showed the probability of SGD. The study recommends the feasible locations of check dams as a remedial measure for controlling the salinization of coastal aquifer.

An Age Scale for the First Shallow (Sub-)Antarctic Ice Core from Young Island, Northwest Ross Sea

The climate of the sub-Antarctic is important in understanding the environmental conditions of Antarctica and the Southern Ocean. However, regional climate proxy records from this region are scarce. In this study, we present the stable water isotopes, major ion chemistry, and dust records from the first ice core from the (sub-)Antarctic Young Island. We present and discuss various dating approaches based on commonly used ice core proxies, such as stable water isotopes and seasonally deposited ions, together with site-specific characteristics such as melt layers. The dating approaches are compared with estimated precipitation rates from reanalysis data (ERA5) and volcanic cryptotephra shards likely presenting an absolute tie point from a 2001 CE eruption on neighboring Sturge Island. The resulting ice core age scale spans the period 2016 to 1995, with an uncertainty of ±2 years.

Expounding major ions chemistry of groundwater with significant controlling factors in a suburban district of Uttar Pradesh, India

Expounding major ions chemistry of groundwater with significant controlling factors in a suburban district of Uttar Pradesh, India

Changes in sediment, nutrients and major ions in the world largest reservoir: Effects of damming and reservoir operation

River damming and reservoir operation alter hydrological process, raising concerns over far-reaching influence on fluvial water, biogeochemistry and sediment fluxes due to the common occurrence of fragmented river landscapes around the world. Here, we investigated carbon, nutrients, and geochemical conditions in the world's largest reservoir, the Three Gorge Reservoir (TGR) in China, under three different dam operations. We also analyzed long-term trends of sediment and geochemistry in response to the reservoir building and operation. We found a drastically reduced average sediment load of 32 ± 29 Mt/y during the post -TGR, which accounts for only 6.4% of the average annual sediment load (501 Mt/y) during the period, of 1950–2000. Cumulatively, over 2004–2018, sediment inflow to the TGR totaled 2090 Mt and sediment outflow (i.e. downstream of the TGR) was 480 Mt, resulting in a total of 1610 Mt (or 77%) sediment trapped in the Reservoir, equivalent to 107 Mt/y. The reservoir water is geochemically dominated by Ca2+ and HCO3− with low-moderate mineralization and excess nutrients. Concentrations of carbon, nutrients and major ions differ notably in response to reservoir operations with the highest nitrogen level under the sluicing period (SP). Major cations concentrations are low in the low water level period (LWLP), while major cations and Cl− and SO42− concentrations reach high in the SP. Concentrations of Cl−, SO42−, and Na++K+ increase 2-3-fold, increasing their relative abundance by a factor of 1.5–2. Nutrients show overall increases with considerable alteration of dominance for dissolved and particular species due to damming and anthropogenic inputs. Furthermore, dissolved inorganic nitrogen increases 8-fold during the last 50 years. The findings imply great effects of river damming and reservoir regulation on sediment transport, nutrient levels and major ion chemistry.

Hydrochemistry and fluoride contamination in Ndali-Kasenda crater lakes, Albertine Graben: Assessment based on multivariate statistical approach and human health risk

Hydrochemistry of crater lakes (n = 15) in the Ndali-Kasenda cluster was deciphered using standard methods of the American Public Health Association to understand the major ion chemistry; spatial distribution, occurrence, and non-carcinogenic health risks due to exposure to fluoride levels in the lakes in Ndali- Kasenda cluster, Albertine Graben. Numerous economic activities take place in and around the crater lakes which serve as major sources of domestic water whose origin of potential contaminants is ambiguous. In this study, WHO (2017)regulatory limit exceedance included F−, pH, Ca2+, Fe2+, Mn2+, and TDS. A strong positive correlation was observed between F− and TDS; F− and pH; F− and EC; F− and HCO3−. However, concerning hydrogeochemical signature, the lakes are mainly of Ca–HCO3 type and low in Na–K–HCO3 type due to rock water interaction in the geology of the area. Principal component analysis (PCA) performed on Ndali-Kasenda hydrogeochemical data resulted in six principal components (PCs) explaining 88.6% of the total variance. The PCs represented the primary processes that control the crater lake hydrogeochemistry in the Ndali-Kasenda area which include; weathering of rocks reactions, ion exchange, and evaporation processes. The hazard quotient (HQ) for non-carcinogenic health risks associated with exposure to Ndali- Kasenda fluoride levels via ingestion revealed that HQ for infants surpassed the acceptable HQ limit for all the lakes studied, while 86.67 % of the sampled lakes exceeded the HQ value for children via ingestion. Based on the hydrogeochemical parameters analyzed, aside from L. Murigamire and L. Wankenzi, water from the other studied lakes is chemically not acceptable for drinking purposes. An urgent need to take ameliorative action in this area to protect the inhabitants from exposure to excess fluoride in drinking water was recommended.

Hydrogeochemical evidence for fluoride behavior in groundwater and the associated risk to human health for a large irrigation plain in the Yellow River Basin

A hydrochemical analysis of groundwater (GW) was conducted to investigate the factors controlling GW fluoride (F) in a large irrigation plain in the Yellow River Basin, Guanzhong Plain, China. Area-dependent variations in F were observed in the study region. The F concentrations of 93% of samples on the south bank of the Weihe River and the western part of the Qishui River were <1 mg L−1, whereas those of 73% of GW samples for the eastern part of the Qishui River exceeded the national limit. A forward model based on mass budget equations identified carbonate weathering as the dominant factor regulating hydrochemistry in low-F GW, whereas the factors in the high-F zone were evaporate dissolution and evaporation. The high-F GW displayed a distinctive major ion chemistry, which could be attributed to a high pH, low Ca2+, and high HCO3− and Na+ concentrations. An analysis of the correlation between F/Cl and F concentrations and fluid-mineral equilibria indicated distinct forces driving the behavior of F in the subparts of the high-F GW zone, including irrigation-induced F dilution, F enrichment through Na-Ca exchange, and adsorption of F on clay minerals. The order of vulnerable segments of the population in terms of risk posed by F in GW was: infants > children > adults. These results can enhance the understanding of F behaviors in GW and provide insights into the effect of irrigation practices on GW F concentration.

Groundwater quality assessment of domestic shallow dug wells in parts of Tanah Merah district, Malaysia

Groundwater resources have become an important fresh water supply due to its increasing demandsfor agricultural, drinking and industrial uses. Groundwater is often contaminated by the process ofindustrial development and suburbanization that has gradually advanced over time without anyconcern for environmental consequences. The objective of this study is to analyse the groundwaterquality of shallow dug wells in parts of Tanah Merah district by conducting quality assessment ofgroundwater using WHO and MHO guide lines. Groundwater samples were collected from dugwells uniformly spread out across the study area to investigate the major ion chemistry of thegroundwater as well as physical parameter. The major ion being investigated are sodium,magnesium, calcium, potassium, sulphate, nitrate, chloride and bicarbonates. Various methods havebeen were employed to determine the major ions concentration in the samples such as atomicabsorption spectrophotometer for cations, gravimetric method for sulphates, titration method forchloride and bicarbonates and colorimetric method for nitrate ion. From the analysed data’s, mostwells are safe for drinking purpose although quite a small amount of ion concentration has surpassedthe permissible limit set by WHO and MOH. The graphical presentation of major ion chemistryaids in identifying two types of groundwater. Ionic species such as Na-K-HCO3 and mixed typewaters are likely to occur in the groundwater system. The analysed major ions concentrationsindicates that majority of the shallow dug wells reported adequate or lower values compared topermissible limit which are safe and can be utilized for various domestic purposes includingdrinking. Several recommendations has been suggested to proliferate the groundwater quality suchas strictly monitoring and supervising the dissipation of waste such as pesticides, industrial effluentand domestic sewage into the aquifer.

Arsenic fate in upper Indus river basin (UIRB) aquifers: Controls of hydrochemical processes, provenances and water-aquifer matrix interaction

Major river basins of the Himalayas contain a significant amount of arsenic (As) in the geological matrix, which tends to contaminate the groundwater at a local and regional scale. Although As enrichment in Quaternary deposits has been linked to primary provenances (Himalayan orogeny), limited studies have reported As enrichment in bedrock aquifers. In the present study, the hard rock and groundwater samples were collected across the upper Indus river basin (UIRB), Ladakh to assess the hydrogeochemical processes and environments responsible for As mobilization and release. The higher As concentrations were found in Khardung volcanics followed by Ophiolitic melange, Dras volcanics, Nindam sandstone, and Nindam Shale. The variability in As concentration among different rock samples is largely governed by the presence of felsic minerals and the type of magmatic setting. The groundwater is less mineralized, with moderate electrical conductivity (EC), and weakly acidic to alkaline in nature. The results indicated that mineral weathering, dissolution, and active cation exchange reactions have a strong influence on the major ion chemistry of the groundwater. Redox-sensitive processes are influencing the As mobilization and release under reducing environmental conditions. As in groundwater poses a serious threat to human health hence awareness is urgent towards achieving sustainable As mitigation globally. The study provided a significant dataset to better understand the processes and environmental conditions responsible for hydrogeochemical evolution, sources of solutes, and As mobilization and release in groundwater which will help in sustainable water resource management policies and ecosystem restoration across the Himalayas.

Paleoclimate Signals and Groundwater Age Distributions From 39 Public Water Works in the Netherlands; Insights From Noble Gases and Carbon, Hydrogen and Oxygen Isotope Tracers

AbstractKnowing the age distribution of water abstracted from public water supply wells helps to ensure customer trust in drinking water sources and underpin predictions of water quality evolution. We sampled the mixed water of 39 large public supply well fields for major ion chemistry, 3H, 3He, 18O, 2H, 14CDIC, 13CDIC and noble gases and determined the Noble Gas Temperature (NGT). We used a discrete travel time distribution model to quantify the age distributions using 3H, 4He, 14C apparent age and NGT as the 4 distinctive tracers. Helium‐4 and NGT provided information on the older part of the age distributions and showed that the 14C apparent ages are often the result of mixing of waters ranging between 2,000 and 35,000 years old, instead of being discrete ages with a limited variance as previously assumed. The results reveal a large range of age distributions, comprising vulnerable well fields with &gt;60% young water (&lt;100 years) and well fields with &gt;30% paleo groundwater (&gt;25,000 years) and all forms of intermediate distributions. The age distributions match the hydrogeological setting; well fields with age distributions skewed towards older ages appear in the Roer Valley Graben structure, where fluvial and marine aquitards and sealed faults provide protection from recent recharge. Waters from this graben exhibit paleoclimate signals, with a clear relation between NGT (range 3.2–9.3 °C), 4He (up to 3.3 × 10−6 ccSTP/g) and δ18O (range −8.5‰ to −5.9‰VSMOW). Moreover, 3He/4He ratios of these graben waters suggest a certain influx of He from mantle origin.

Hyporheic zone geochemistry of a multi-aquifer system used for managed aquifer recharge in Beijing, China

Hyporheic groundwater geochemistry evolution depends on the interactions of surface water and groundwater (SW–GW). Hydrodynamic variations driven by the long-term managed aquifer recharge (MAR) practice could change hyporheic geochemical processes, which requires a better understanding for groundwater management. In this work, a geochemical survey was conducted in a multi-aquifer MAR system. The results showed great impact of the MAR practice on the hydrodynamics and major ion chemistry of groundwater in the hyporheic zone compared to natural recharge. Besides, related geochemical processes including rock weathering and ion exchange showed increased effect on hyporheic hydrochemistry with aquifer depth, depending on hydrogeological conditions in addition to river water infiltration. Combined with hydrochemical indicators and the end-member mixing model, the relative contribution of precipitation to groundwater was estimated to be 5% for the 30-m aquifer, 16% for the 50-m aquifer, and 64% for the 80-m aquifer. However, precipitation made small contributions (<5%) to the major ions of groundwater regardless of depth. Conversely, the relative contributions of river water infiltration decreased with aquifer depth (95%→84%→36%), and its proportional contributions to major ions showed a similar trend (90%→84%→39%), which suggests reduced SW–GW interaction intensity with depth in the hyporheic zone. The major ion compositions of hyporheic groundwater tend towards river water after the long-term MAR practice, reflecting comprehensive effect of mixing and related geochemical processes. This study demonstrates the relevance of detailed studies at regional scale to understand anthropogenic effects from projects such as MAR on groundwater geochemistry especially in multi-aquifer systems.

Hydrochemical, isotopic, and dissolved gas characterization of groundwater in Gariz aquifer, Southwest of Yazd Province, central Iran

Here we discussed the results of the first geochemical investigation of the fluids (groundwater and the associated gases) emerging in the southwest of Yazd Province. We carried out two surveys, one in July 2019 and the second in September 2019s, in the region of the Gariz aquifer (central Iran). We focused our attention to 1) the chemistry of the water (major and minor constituents coupled to the stable isotopes of oxygen and hydrogen), 2) the chemical composition of dissolved gases in water together with 3) the isotopic composition of Helium (3He/4He) and 4) the dissolved carbon in water (δ13CTDIC). Hydrogen and oxygen isotope values of groundwater display a fairly narrow range and indicate that the waters are of meteoric origin. On the base of the major ions chemistry, the bulk of the water samples are classified as Ca-HCO3, CaCl and NaCl types. The groundwater chemistry is mainly influenced by the interaction with CO2-rich fluids, leakage of chlorinated saline water into the alluvial aquifer, and silicate dissolution. High dissolved carbon contents, mainly as bicarbonate ion, reflect the noticeable interaction of the groundwater with CO2-rich fluids. CO2 is the dominant gaseous component in most samples and its amount is always greater with respect to a water in equilibrium with the atmosphere (Air Saturated Water, ASW). Such excess of CO2 contents (more than 730 cc/l STP) dissolved in groundwater also supports the presence of a deep source of CO2-rich gas. The computed δ13C(CO2) in equilibrium with the groundwater highlight a mixing in different proportion between an inorganic deep sourced CO2 (13C-enriched) and organic CO2 (13C-depleted). We also used the helium isotopes as a tools to figure out the origin of helium in the aquifer (air vs. mantle, and crust). The collected samples show a contribution of mantle-derived He in the Gariz aquifer up to (~45%) and the crust suggesting that at regional scale the tectonic discontinuities had a connection with the mantle or magmatic intrusions migrated through the crust transporting mantle volatiles to shallow crustal layers. However, we cannot infer the timing of this possible magmatism at depth in the complex tectonic evolution of the area.

Assessment of non-point source of pollution using chemical mass balance approach: a case study of River Alaknanda, a tributary of River Ganga, India.

The low ionic concentration meltwaters of the rivers originating from the Himalayan glaciers play a significant role in diluting the high solute load emanating from Ganga plain catchments. Hence, any change in the qualitative and quantitative characteristics of the Himalayan tributaries of River Ganga under the changing climatic scenario will impact the hydrochemical parameters of River Ganga as well. Hydrochemical investigations have been carried out in the River Alaknanda, a tributary of River Ganga during the period September 2016-May 2018 and revealed that TSS and COD values were observed above the prescribed criteria limit of 10mg/L for drinking purpose for river as prescribed by CPCB. The anions for all sampling sites and seasons were observed to be in decreasing order of HCO3- > SO42- > Cl- > NO3- and cations Ca2+ > Mg2+ > Na+ > K+. The weathering of rock forming minerals of drainage basin is responsible for the chemical composition of river water. HCO3- being the dominant anion in the study area accounts for its presence due to carbonate and silicate weathering. Ion exchange process controls the major ion chemistry of the river water. The assessment and management of non-point sources (NPS) pollution are difficult by any deterministic method and require a vast amount of data to compensate for their extent of contamination, in the account of their prevailing nature in response to hydrological processes and land use patterns. In the present investigation, the application of a simple chemical mass balance approach based on law of conservation of mass/matter has been applied on River Alaknanda, a tributary of River Ganga for measuring the chemical mass loadings of some selected water quality constituents, viz., major cations (sodium, potassium, calcium, magnesium, and ammonium) and major anions (chloride, sulfate, nitrate, and phosphate) at upstream and downstream of different point source locations for examining the contribution made by non-point sources of pollution to the river. Time series analysis of various ion concentrations at point source sites and upstream/downstream sites inferred that the fluvial variations pertaining to ion concentration and flux are strongly dependent on the seasonal changes. More contribution (> 30-50%) for almost all constituents from uncharacterized sources was observed in the months of November to February, which may be attributed to intensified agricultural activities during the winter months particularly cereals and vegetables.

Evaluation of groundwater quality in Jampali coal mine, Raigarh, Chhattisgarh, India

AbstractGroundwater is the main source of water for drinking, industrial, and irrigation uses for most nations. Groundwater quality deterioration occurs due to urban, agricultural, mining, and industrial expansions. This research deals with the assessment of groundwater quality index, correlation, clustering analysis, and major ions chemistry around Jampali opencast coal mine of Raigarh district, Chhattisgarh, India, where groundwater is the main source of drinking water. A total of 28 groundwater samples were collected from the different stations in the month of April 2019 and 11 physicochemical parameters were examined. The results of the physicochemical analysis showed that cation abundance follows the order Na+ &gt; K+ &gt; Mg2+ &gt; Ca2+ in the groundwater, while anion abundance follows the order Cl− &gt; NO3− &gt; SO42− &gt; F−. A strong positive correlation is observed between TDS–EC, TDS–Mg2+, TDS–Na+, TDS–Cl−, TDS–SO42− (r = 0.999, 0.871, 0.872, 0.846, and 0.801) and EC–Mg2+, EC–Na+, EC–Cl−, EC–SO42− (r = 0.871, 0.873, 0.846, 0.802). The two clusters demonstrate a blended genesis connected to anthropogenic and geogenic measures. Based on calculated water quality index (WQI) values, groundwater falls under two classes: excellent and good water. WQI values of the study region depict that 85.72% of samples come under the excellent category and 14.28% in the good category.

Major ion chemistry in the headwater region of the Yellow River: impact of land covers

Major ion chemistry in the headwater region of the Yellow River: impact of land covers