Hydrochemistry Of Surface Water Research Articles

Assessment of Some Trace Elements in Surface Water and Soil near Al-Ahdab Oil Field, Wasit Governorate, Iraq

The main objective of this munscript is to spot light on the negative consequences of oil emissions from Al-Ahdab oil field on the water and soil surrounding the oil field at Wasit Governorate. To obtain this objective, seven sediment samples were collected from the surfacre soil, in addition to five water samples from the Tigris River near Al-Ahdab oil field within Al-Kut Wasit governorate. The more effective eight trace elements were chosen to detect the limitations of their occurrence in the soil and water of the study area, these are Fe, Cd, Cu, Cr, Ni, Pb, Zn, and Zr. The Zr is used as a background for the specific equations applied. Samples of sediments and water were collected in October 2022. The standardization of the Enrichment Factor (EF), geo-accumulation index (I-geo), and contamination factor (CF) in addition to the pollution load index (PLI) were applied to detect the extent of soil pollution. In contrast, the hydrochemistry of water samples was determined by comparing the results of the analysis with the standards of WHO, 2018, and IQS, 2009. The enrichment factor value (EF) Cadmium value (Cd) in soil samples is 6.6, which reflects a significant impact of air emissions, the cobalt (Co) value is 1.77m this value reflects minimum Enrichment factor while the EF has a rather moderate enrichment factor. By applying the I-geo equation, the oitput results indicate unpolluted soil for Co, and Ni metals, while it is moderately polluted for Cu, Cr, Zn, and Pb metals. According to the PLI index, the soil of the study area is ordered as moderately contaminated for these metals. As for the hydrochemistry of surface water of the Tigris River near the study area, the water samples are classified as not contaminated by (Ni, Cd, Pb, Zn, Cr, and Cu).

Evaluation of Ground and Surface Water Hydrochemistry for Irrigation Suitability in Borneo: Insights from Brunei Darussalam

Water for irrigation use plays a critical role in agriculture via supporting crop growth and maintaining food production worldwide. Irrigation water quality evaluations provide useful information for sustainable water practices in many agricultural regions. In Brunei Darussalam, the quality of irrigation water is still poorly understood. The present study aims to investigate the hydrochemical characteristics of water resources in Brunei Darussalam and evaluate their quality and suitability for irrigation use. A total of fifteen sampling locations were chosen from selected ground and surface water sources found in all four Brunei districts. The water samples’ physicochemical properties, including pH, EC, and major cations and anions, were measured and compared with FAO standards. Hydrochemical classification based on the Piper diagram revealed that water mainly belongs to the calcium-, magnesium-, and bicarbonate-type, or Type IV water class. The evaluation of heavy metals (Fe, Zn, Cu, Cr, As, and Cd) showed concentrations within the FAO’s permissible limits. In this regard, iron showed the highest concentration among the investigated metals. Established water quality indices such as SAR, Na%, RSC, MAR, KR, PS, and IWQI were used to evaluate and classify the water’s suitability for irrigation use. Overall, our findings revealed that almost all of the analysed water samples in the study area have low salinity and sodicity risks. However, only 27% of the samples passed the magnesium hazard assessment, and one sample showed a very poor IWQI result. Thus, additional testing and treatment are recommended for these cases. This study provides valuable insights on water quality for present and future utilisation, aiming to contribute to the protection of water resources in Brunei Darussalam.

Monitoring the dynamics of acid mine drainage affected stream surface water hydrochemistry at Jaintia Hills, Meghalaya, India.

Streams are pristine natural life-thriving water sources for people living in the mountainous proximity of NE India, where water scarcity is a common occurrence in most villages and towns. In the last few decades, factors like coal mining had drastically reduced the usability of stream water in the region; as such, an attempt has been made to assess the spatiotemporal variation of stream water chemistry affected by acid mine drainage (AMD) at Jaintia Hills, Meghalaya. The water variables were subjected to a multivariate statistical technique of principal component analysis (PCA) to understand their condition at each sampling point while comprehensive pollution index (CPI) and water quality index (WQI) was incorporated to assess the quality status. Maximum WQI was recorded in S4 (541.14) during summer, while minimum value was estimated in winter at S1 (14.65). Throughout the seasons, the WQI revealed "Good" quality in S1 (unimpacted stream), while the impacted streams (S2, S3, and S4) exhibited a "Very poor" to "Water unsuitable for drinking" status. Similarly, in S1, the CPI showed a ranged value of 0.20 to 0.37, presenting a water quality status of "Clean to Sub-Clean," whereas, CPI of the impacted streams indicated "Severely polluted" status. In addition, PCA bi-plot presented higher affinity of free CO2, Pb, SO42-, EC, Fe, and Zn in AMD-impacted streams than in unimpacted streams. The result demonstrates the environmental issues induced by coal mine waste and in particular, stream water being severely affected by AMD in mining areas of Jaintia Hills. Thus, measures to stabilized the mine repercussions and cumulative effects on the water bodies need to be formulated by the government, as stream water will remain the primary water source for the tribal communities in this region.

Hydrochemistry of surface waters in a permafrost headwater catchment in the Northeastern Tibetan Plateau

The permafrost headwater catchments in the Tibetan Plateau (TP) have experienced extensive permafrost degradation, which may cause major changes in riverine solutes. However, surface water hydrochemistry and its influencing factors in such catchments are poorly understood. Hydrochemistry data for different surface waters were obtained for the Yakou catchment in the Northeastern TP. The results indicate that the ionic and organic concentrations of frozen soil seeps (FSS) were higher on the north-facing slope compared to the south-facing slope, and that FSS may be involved in streamflow generation processes and in determining the spatial pattern of riverine solutes. The north-facing slope of the catchment has a thin active layer and wet moisture conditions compared to the south-facing slope; hence supra-permafrost water, with high ionic concentrations, can drain to the ground surface as FSS in the riparian zone and then recharge the surface ponding water and the main stream water. The high ionic concentrations of the supra-permafrost water and FSS can be attributed to intense rock weathering and evaporative effect, together with the high mobility of elements and the transport of organic matter. The tributaries, with low ionic concentrations, comprise a mixture of infiltrating precipitation and diluted supra-permafrost water. Carbonate weathering is the dominant weathering type within the catchment, but the weathering of evaporite and silicate is more important on the north-facing and south-facing slopes, respectively, and chemical weathering on the north-facing slope may be enhanced by strong physical erosion during repeated freeze–thaw cycles due to the wet conditions. The results indicate that the surface water hydrochemistry is heterogeneous on the different hillslope units, and that a thicker active layer under climate change may lead to a shift of hydrological and hydrochemical pathways, and thus a decrease in water and solute flux from the hillslopes, with underlying permafrost, to the river channel.

Evaluation of seasonal dynamics of the surface water hydrochemistry using multivariate statistical techniques and aquatic macrophyte productivity in a mountainous lake, Northeast India.

The present work elucidates the effective application of multivariate statistics in understanding the probable relations between surface water hydrochemistry and aquatic macrophyte productivity and their underlying seasonal dynamics in a remote mountainous lake of northeast India. The result of hierarchical cluster analysis revealed three distinct clusters corresponding to the pre-monsoon (35.42%), post-monsoon (52.08%), and monsoon (12.50%) seasons. The factor analysis yielded three principal components suggesting the sediment flux, farming discharge, domestic waste, bacterial oxidation of sulfur compounds, and dissolution of plant matters associated with dissolved feldspar minerals as the influential factors. The lake hydrochemistry also varied significantly, both spatially and temporally implying geogenic weathering processes from rock-soil-water interactions. Overall, sixteen aquatic macrophytes were identified, and their monthly and daily net primary productivity varied considerably in different seasons. Regression analysis highlighted the effect of temperature, total dissolved solids, electrical conductivity, and turbidity on the seasonal fluctuations in macrophyte productivity. Overall, the study provides insights into seasonal variation in the lake water chemistry and highlights the role of statistical tools in understanding the fragile aquatic ecosystems over cost-, labor-, and time-intensive inventory studies.

Hydrochemistry and Quality Assessment of Surface Water in Oba Dam, Ogbomoso, Southwestern Nigeria

Hydrochemistry of the surface water in Oba Dam, Ogbomoso was investigated to determine the chemical characteristic and evaluate the water quality for drinking, domestic and agricultural usage. Twenty selected water samples collected at different points within the reservoir were analysed for pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Hardness (TH) and major ions (Na+, K+, Mg2+, Ca2+, Cl-, NO3-, SO42-, HCO3). The pH values (6.5-7.9) of the samples suggest circumneutral to weakly alkaline nature of the water in Oba Dam. The cations are dominantly Na+ and K+, while the anions are mainly NO3-, Cl- and SO42-. The plot of the chemical data in Piper diagram revealed the water samples as Na-K-Cl water facie suggesting that the water chemistry is being controlled mainly by anthropogenic inputs. Comparing the analysed water samples with WHO and Nigerian water quality standards shows that all the chemical parameters were within the desirable limits for drinking purpose. Similarly, the computed water quality index (WQI) values (15-21) for the studied water samples suggest excellent quality for drinking and domestic purposes. Calculated parameters like sodium adsorption ratio (SAR), percent sodium (%Na) and Keller index (K1) reveal that most of the analysed water samples are suitable for irrigation usage. However, higher Na+ content of few samples restrict the suitability for irrigation purposes. Therefore, this calls for regular monitoring of sodium contents to ascertain suitability for agricultural irrigation.

Towards Standardization for Determining Dissolution Kinetics of Nanomaterials in Natural Aquatic Environments: Continuous Flow Dissolution of Ag Nanoparticles.

The dissolution of metal-based engineered nanomaterials (ENMs) in aquatic environments is an important mechanism governing the release of toxic dissolved metals. For the registration of ENMs at regulatory bodies such as REACH, their dissolution behavior must therefore be assessed using standardized experimental approaches. To date, there are no standardized procedures for dissolution testing of ENMs in environmentally relevant aquatic media, and the Organisation for Economic Co-operation and Development (OECD) strongly encourages their development into test guidelines. According to a survey of surface water hydrochemistry, we propose to use media with low concentrations of Ca2+ and Mg2+ for a better simulation of the ionic background of surface waters, at pH values representing acidic (5 < pH < 6) and near-neutral/alkaline (7 < pH < 8) waters. We evaluated a continuous flow setup adapted to expose small amounts of ENMs to aqueous media, to mimic ENMs in surface waters. For this purpose, silver nanoparticles (Ag NPs) were used as model for soluble metal-bearing ENMs. Ag NPs were deposited onto a 10 kg.mol−1 membrane through the injection of 500 µL of a 5 mg.L−1 or 20 mg.L−1 Ag NP dispersion, in order to expose only a few micrograms of Ag NPs to the aqueous media. The dissolution rate of Ag NPs in 10 mM NaNO3 was more than two times higher for ~2 µg compared with ~8 µg of Ag NPs deposited onto the membrane, emphasizing the importance of evaluating the dissolution of ENMs at low concentrations in order to keep a realistic scenario. Dissolution rates of Ag NPs in artificial waters (2 mM Ca(NO3)2, 0.5 mM MgSO4, 0–5 mM NaHCO3) were also determined, proving the feasibility of the test using environmentally relevant media. In view of the current lack of harmonized methods, this work encourages the standardization of continuous flow dissolution methods toward OECD guidelines focused on natural aquatic environments, for systematic comparisons of nanomaterials and adapted risk assessments.

SPATIOTEMPORALDYNAMICITY OF ENVIRONMENTAL VARIABLES AND WATER QUALITY INDEX IN AQUIFERS AND GROUNDWATER OF BLUE CITY USING MULTIVARIATE STATISTICAL TECHNIQUE

Thecurrent research investigates the quality of ten different surface water sites in and around Jodhpur using water quality ratings. This paper gives insight into water pollution's qualitative and quantitative extent. The water quality index (WQI)is usedfor assessing and comparing water quality. In each study region, a five-point grading scale was adopted to classify water quality as a single understandable value. Twelveparameters were employed for determining the WQI of different sites: turbidity, TSS, TDS, conductivity, alkalinity, hardness, calcium, magnesium, chloride, fluoride, and nitrate. Multivariate analysis of the samplesrevealed that most of the individual parameters are not in harmony with the standard values prescribed by the regulating authorities. According to the study, seasonal fluctuations play a significant effect in the hydrochemistry of surface water, indicating a change in WQI. Thesamples showed less pollution in the pre-monsoonseason as compared to post-monsoon. Overall, this paper lays forth a strategy for proper utilization and protection, as well as assesses the quality of surface water to determine its suitability for various uses and its impact on groundwater quality.

Spatial variations and controls on the hydrochemistry of surface waters across the Ili-Balkhash Basin, arid Central Asia

Climate variability influences both water quantity and quality in lakes and rivers, e.g., shifts in salinity caused by changes in the evaporation/precipitation ratio. However, knowledge about climate and human influences on water quality in some regions is scarce, which causes uncertainty when evaluating water resources and developing water management plans. We measured the chemical composition and stable isotope values (δD and δ18O) in water samples from the Ili-Balkhash Basin, arid Central Asia, to investigate factors that control hydrologic processes in the area, and explore how the arid environment influences local hydrochemistry and water resources. Isotope values in lake waters (−24.1‰ [δD] and −1.5‰ [δ18O]) are enriched relative to river waters (−84.6‰ [δD] and −12.4‰ [δ18O]), indicating that lake waters experience intense evaporation. In the upstream Ili River, waters with lowest δD and δ18O values are supplied mainly by glacial ice and snow melt, whereas lower reaches of the river are affected increasingly by evaporation and human water extraction. Waters of the Ili River and other small rivers that drain to Lake Balkhash are chemically similar, and of the Ca-HCO3 type. Gibbs diagrams indicate that mineral weathering is the key process that controls river water chemistry. On average, carbonate and silicate weathering contribute 55.1% and 26.7%, respectively, to the total dissolved ion load in the river waters, illustrating the strong control that regional geology exerts on streamwater chemistry. In contrast, lake waters are characterized as Na-Cl type, which results mainly from evaporation and some evaporite dissolution. Weathering in the area is controlled by climate, i.e. precipitation and temperature. Moreover, a negative correlation between lake water total dissolved solids and d-excess, and a systematic increase in chemical concentrations and stable isotope values downstream in the Ili River, reflect the fact that arid climate conditions promote evaporation and affect water quality. PCA analysis and mass balance calculation of water chemistry suggests that humans contribute only 6.6% of the major ion load to waters, which display increasing concentrations in the middle and downstream regions. There, effects of human-mediated weathering and transport of salts from agricultural irrigation are reinforced by higher temperatures and evaporation.

Hydrogeochemical Characteristics and Quality Assessment of Surface Water in an Agricultural Area in Equatorial Africa: The Mungo River Basin, South West Cameroon, Central Africa

The Mungo River and its tributaries represent the major sources of water supply for agriculture and drinking purposes for the Douala city and the south western agricultural region of Cameroon. In this study, the surface water hydrochemistry was investigated at 12 locations to determine the hydrochemical and heavy metals characteristics and to assess the suitability for drinking and irrigational purposes. Results of water samples collected along the main channel and tributaries showed that the major ions were dominated by Ca2+ > Na+ > Mg2+ > K+ > NH4+ and > HCO3- > SO42- > Cl- > F- > PO43- , with concentrations varying between 0 to 60 mg/l. Heavy metal concentrations were relatively weak, dominated by Fe > Mn > As > Cd > Zn > Se. The main hydrochemical facies types revealed primarily 52% Ca-Na-HCO3 and 48% Ca-Mg-HCO3. Base on Gibbs diagram and relative ion ratios, the hydrochemical characteristics are derived from weathering of silicate rocks and atmospheric source. The influence of anthropogenic factors including agro-industrial activities on the hydrochemical characteristics was less marked. The chemical composition of the water samples was compared with the drinking water standards and only the concentration of Fe was above the WHO guide limits in a single sample at Passi. The evaluation of the water quality for irrigation showed that 95% of water samples are suitable for irrigation in almost all soil types. According to the water quality index (HPI, HEI and Cd), this water is considered of excellent quality for consumption. The results provide a preliminary database for sustainable management of water resource in the Mungo River basin.

Hydrochemical Characteristics and Possible Controls of the Surface Water in Ranwu Lake Basin

To study the chemistry of surface water and potential control measures in the Ranwu Lake basin, 19 samples were collected from Ranwu Lake in 2019. Conventional hydrochemical techniques and statistical analysis methods (descriptive statistics, the Gibbs figure, ion ratio, Piper triangular diagrams) were applied to better understand the solute geochemistry and surface water hydrochemistry in the Ranwu Lake catchment. Surface water in the Ranwu catchment is slightly alkaline (pH of the samples ranged from 7.54 to 8.48 with an average value of 8.06). The concentrations of total dissolved solids (TDS) in the water range from 59.89 to 96.75 mg ·L-1 with an average of 79.98 mg ·L-1, the total dissolved solids of all samples are less than 100 mg ·L-1 and belong to fresh water. The TDS are dominated by Ca2+, Mg2+, HCO3-, and SO42- in the Ranwu Lake. The ion concentrations in the lake water samples are in the order of Ca2+ > Mg2+ > Na+ > K+. The concentrations of Na+and K+are very low. Ranging from 0.5 to 1.21 mg ·L-1, with an average value of 0.58 mg ·L-1, the equivalent concentration of Ca2+ accounts for 63.3% to 76.2% of total cations with an average value of 67.2%. The equivalent concentration of Mg2+ accounts for 23.4% to 36.2% of total cations with an average value of 31.4%. Ca2+ and Mg2+ account for 98.5% of total cations. The main anions were HCO3- and SO42-. The equivalent concentration of HCO3- accounts for 74.31% to 84.29% of total anions with an average value of 78.21%. The equivalent concentration of SO42- accounts for 9.59% to 19.37% of total anions with an average value of 15.34%. HCO3- and SO42- together account for 93.55% of total anions on average. All the water samples fall in the water-rock interaction field, which suggests that the weathering of rocks primarily controls the major ion chemistry of groundwater in this area. Solutes are mainly derived from carbonate weathering and silicate weathering. The role of cation exchange in the geochemical process of the lake and the influence of human activities on the lake are found to be weak.

Examination of Surface Water Along River-Rima Floodplain in Wamakko, Sokoto State, Nigeria

This study examined the hydrochemistry of surface water along the River-Rima floodplain area. Five sampling locations were purposively selected, and, in each point, three samples were taken from surface water (river).The sampling was repeated after 20 days. Thus, a total of 30 samples werecollected. Water samples obtained were subjected to laboratory tests. Results revealed that BOD, TDS, Mg2+, and Fe3+ are above the World HealthOrganization (WHO) and Standard Organization of Nigeria (SON) reference guidelines for drinking water quality. Isolates detected from the coliform bacteriological analysis include Enterobacter aerogene, Escherichiacoli, and Citrobacter freundii with most of the samples showing coliform bacteria growth above the SON standard for drinking water. Hence, the water in the River-Rima floodplain of the Wamakko area is of low quality and unsafe for drinking. Results of principal component analysis (PCA)revealed external influences such as pollutant wash off and rock weatheringas controls on hydrochemistry of surface water. There is some indication of anthropogenic inputs (Cl- , NO3- , and PO4 2-) based on hierarchical cluster analysis. Elements including Cl-, NO3-, and PO42- are increasingly added into surface water from human activities, mainly agriculture, and municipal sewage.

Hydrochemical characteristics and irrigation suitability of surface water in the Syr Darya River, Kazakhstan

The surface water hydrochemistry of the Syr Darya River in Kazakhstan was investigated at 39 locations to analyze regional hydrochemical characteristics and evaluate the irrigation suitability of the studied regions. The cations in the surface water are mainly Na+, Ca2+, and Mg2+, while the anions are mainly SO42−. The main hydrochemical type is Ca-Mg-SO4-Cl. From the perspective of natural factors, the hydrochemical characteristics in the study area are derived from the dual effects of rock weathering and evaporation-concentration; however, the influence of anthropogenic factors include industrial and agricultural production near the river and the inflow of urban domestic sewage on the hydrochemical characteristic is also present. The irrigation suitability evaluation of the surface water based on SAR, Na% and KI showed that the majority of the water is suitable for irrigation, and from the TDS content analysis, 71.43% of the samples are in a critical state, indicating that the influence of TDS concentration on irrigation suitability cannot be ignored. The results have practical significance for maintaining the sustainable use of water resources in the Syr Darya River.

Hydrochemistry of pit lakes in the Portuguese sector of the Iberian Pyrite Belt

The Iberian Pyrite Belt (IPB) is a world-class metallogenic province with volcanogenic massive sulphide ore deposits. Most ore exploitation occurred since pre-Roman time, creating extensive galleries, wells, waste-dumps and pit lakes. These last structures are a concern for their potential environmental impact because they accumulate large volumes of mine water affected acid mine drainage. The present work classifies the pit lakes based on the surface water hydrochemistry. Using the Ficklin diagram for classification, pit lake waters vary from acid, high-metal to high-acid, extreme-metal and exhibit similarities with other pit lakes from the Spanish sector of the IPB.

Impact of snow deposition on major and trace element concentrations and elementary fluxes in surface waters of the Western Siberian Lowland across a 1700 km latitudinal gradient

Abstract. In order to better understand the chemical composition of snow and its impact on surface water hydrochemistry in the poorly studied Western Siberia Lowland (WSL), the surface layer of snow was sampled in February 2014 across a 1700 km latitudinal gradient (ca. 56.5 to 68° N). We aimed at assessing the latitudinal effect on both dissolved and particulate forms of elements in snow and quantifying the impact of atmospheric input to element storage and export fluxes in inland waters of the WSL. The concentration of dissolved+colloidal (&lt; 0.45 µm) Fe, Co, Cu, As and La increased by a factor of 2 to 5 north of 63° N compared to southern regions. The pH and dissolved Ca, Mg, Sr, Mo and U in snow water increased with the rise in concentrations of particulate fraction (PF). Principal component analyses of major and trace element concentrations in both dissolved and particulate fractions revealed two factors not linked to the latitude. A hierarchical cluster analysis yielded several groups of elements that originated from alumino-silicate mineral matrix, carbonate minerals and marine aerosols or belonging to volatile atmospheric heavy metals, labile elements from weatherable minerals and nutrients. The main sources of mineral components in PF are desert and semi-desert regions of central Asia. The snow water concentrations of DIC, Cl, SO4, Mg, Ca, Cr, Co, Ni, Cu, Mo, Cd, Sb, Cs, W, Pb and U exceeded or were comparable with springtime concentrations in thermokarst lakes of the permafrost-affected WSL zone. The springtime river fluxes of DIC, Cl, SO4, Na, Mg, Ca, Rb, Cs, metals (Cr, Co, Ni, Cu, Zn, Cd, Pb), metalloids (As, Sb), Mo and U in the discontinuous to continuous permafrost zone (64–68° N) can be explained solely by melting of accumulated snow. The impact of snow deposition on riverine fluxes of elements strongly increased northward, in discontinuous and continuous permafrost zones of frozen peat bogs. This was consistent with the decrease in the impact of rock lithology on river chemical composition in the permafrost zone of the WSL, relative to the permafrost-free regions. Therefore, the present study demonstrates significant and previously underestimated atmospheric input of many major and trace elements to their riverine fluxes during spring floods. A broader impact of this result is that current estimations of river water fluxes response to climate warming in high latitudes may be unwarranted without detailed analysis of winter precipitation.

Mechanisms linking active rock glaciers and impounded surface water formation in high‐mountain areas

AbstractRock glaciers are slowly flowing mixtures of debris and ice occurring in mountains. They can represent a reservoir of water, and melting ice inside them can affect surface water hydrochemistry. Investigating the interactions between rock glaciers and water bodies is therefore necessary to better understand these mechanisms. With this goal, we elucidate the hydrology and structural setting of a rock glacier–marginal pond system, providing new insights into the mechanisms linking active rock glaciers and impounded surface waters. This was achieved through the integration of waterborne geophysical techniques (ground penetrating radar, electrical resistivity tomography and self‐potentials) and heat tracing. Results of these surveys showed that rock glacier advance has progressively filled the valley depression where the pond is located, creating a dam that could have modified the level of impounded water. A sub‐surface hydrological window connecting the rock glacier to the pond was also detected, where an inflow of cold and mineralised underground waters from the rock glacier was observed. Here, greater water contribution from the rock glacier occurred following intense precipitation events during the ice‐free season, with concomitant increasing electrical conductivity values. The outflowing dynamic of the pond is dominated by a sub‐surface seepage where a minor fault zone in bedrock was found, characterised by altered and highly‐fractured rocks. The applied approach is evaluated here as a suitable technique for investigating logistically‐complex hydrological settings which could be possibly transferred to wider scales of investigation. Copyright © 2017 John Wiley &amp; Sons, Ltd.

Characteristics of stable isotope and hydrochemistry of surface water, and their significance on the Huaibei plain, China

Eighteen river- and two ground- water samples were collected on Huaibei plain. The major ions, and hydrogen and oxygen isotope concentrations were determined, and statistical and other analyses carried out. The results showed that all of the waters are alkaline, with high Total Dissolved Solids (TDS) concentrations. Na+ + K+, and SO42− + HCO3− are the dominant anionic and cationic species, respectively, and the waters are mainly Na·K-SO4 and Na·K-HCO3 types. The δD and δ18O in river waters ranged from −53.07‰ to −22.07‰ and −6.97‰ to −1.23‰, with average values of −38.30‰ and −4.09‰, respectively. The δD and δ18O concentrations in groundwater were lower than in the river water samples. The correlation between δD and δ18O concentrations in the river water can be described by the formula δD = 5.32*δ18O − 16.54, which can also be considered the local evaporation line. The ionic content and character of the river water is mainly controlled by precipitation, evaporation and carbonate weathering, as deduced from the Gibbs diagram and principal component analyses.

Using inverse modeling and hierarchical cluster analysis for hydrochemical characterization of springs and Talkhab River in Tang-Bijar oilfield, Iran

Hierarchical cluster analysis (HCA) and inverse modeling (PH REdox EQuilibrium (in C language) (PHREEQC)) were simultaneously useful approaches in interpreting surface water hydrochemistry within Talkhab River in the Tang-Bijar oilfield, Iran, where large uncertainties exist in the understanding of the water quality system. Q-mode HCA applied to the data revealed three major surface water associations distinguished on the basis of the major causes of variation in the hydrochemistry. The three water groups were classified as upstream waters (group 1: Ca–SO4), intermediate waters (group 2: Ca–SO4–Cl), and downstream waters (group 3: Na–Cl). Geochemical reaction models were constructed using PHREEQC to establish the reactions associated with the different mineral phases through inverse modeling. The hydrochemical compositions of the water groups and the mass balance calculations indicate that the dominant processes and reactions responsible for the hydrochemical evolution in the system are (1) dissolution of evaporites, (2) precipitation of carbonate minerals, (3) silicate weathering reactions, (4) limited mixing with saline water, and (5) ion exchange.

Hydrochemical assessment of surface water in watersheds near the Uranium Mining and Milling Facilities of Caldas, Brazil

Sited in the Pocos de Caldas Plateau, in south-eastern Brazil, the Uranium Mining and Milling Facilities (UMMF) of Caldas are in the process of decommissioning. The main environmental problem in this site is the generation of acid mine drainage (AMD) in the tailings dam, open pit and waste rock piles. The aim of this work is to evaluate, by hydrochemical studies, the influence of acidic effluents from the Caldas UMMF, on the hydrochemistry of surface water along three watersheds: Consulta Brook, Soberbo Creek and Taquari River. Twelve sampling stations were established to carry out the investigation. Two of them were located at effluent retention ponds. Sampling was performed in the rainy and dry seasons of 2011, and the measured parameters were Eh, pH, EC (electrical conductivity), SO42−, HCO3−, Cl−, Na+, K+, Ca2+, Mg2+ and Fe. The results have shown that iron is not a main constituent of the ionic composition of the local AMD. It could also be observed that acidic effluents were being discharged from retention ponds into the watercourses, causing a pronounced increase of the sulfate and calcium concentrations downstream. To trace the AMD migration the (SO42−/HCO3−)/(Na+ + K+/Ca2+) ratio was used. A detailed investigation of the near-surface groundwater is recommended downstream of the effluent ponds sites to evaluate the need for mitigating actions such as constructing hydraulic barriers. The present article shows that using simple techniques, such as Eh–pH and Piper diagrams, it is possible to depict the AMD fluvial migration pattern, which is an important information both to the authority responsible incumbent upon the remediation of the site, and to the affected interested parties who inhabit the impacted region.

Hydrochemistry of surface water and groundwater in the shale bedrock, Cross River Basin and Niger Delta Region, Nigeria

Water chemistry in the shale bedrock of the Cretaceous-Tertiary of the Cross River and Niger Delta hydrological basins has been investigated using major ions. To carry out a characterization of the water bearing units, 30 and 16 representatives surface and groundwater samples were collected. The evolution of the water is characterized by enhanced content of sodium, calcium and sulphate as a result of leaching of shale rock. The spatial changes in groundwater quality of the area shows an anomalous concentrations of ions in the central parts, while lower values characterize the eastern part of the basin covering Ogoja, Ikom and Odukpani areas. The values of total dissolved solids (TDS) and ions increases down gradient in the direction of groundwater flow. The dissolution of halite and gypsum explains part of the contained Na+, Ca2+, Cl− and SO42−, but other processes such as ion exchange, silicate weathering and pyrite oxidation also contribute to water composition. The assessment with contamination indicators such as TDS, hardness, chloride, nitrate and sulphate indicates that the water in area is suitable for human consumption in some locations. Modelling using MINTEQA2 program shows that the water from all the shale water bearing units are under saturated with respect to gypsum.