Hydrochemistry

. At two caves Clamouse, S France and Ernesto, NE Italy , cave drip and pool waters were collected and sampled at intervals over a 2-3 year period. MgrCa and SrrCa concentration ratios, corrected for marine aerosols, are compared with those of bedrocks and, in some cases, aqueous leachates of soils and weathered bedrocks. Cave waters do not lie along mixing lines between calcite and dolomite of bedrock carbonate, but typically show enhanced and covarying MgrCa and SrrCa.

1] Isotopic analyses of dissolved molybdenum are presented for sediment pore waters from a reducing sedimentary basin and for fluids from a low-temperature ridge flank hydrothermal system. d 98/95 Mo in these fluids range from 0.8 to 3.5% (relative to a laboratory standard), demonstrating that marine sedimentary reactions significantly fractionate Mo isotopes. Within the upper 3 cm of sediment, manganese oxide dissolution produces an isotopically light fluid relative to seawater (mean of four analyses = 2.1 ± 0.1% versus seawater = 2.3 ± 0.1%). Below 6 cm depth, authigenic Mo uptake results in an isotopically heavier fluid (up to 3.5%) indicating that reducing sediments are likely to be a net sink for isotopically light dissolved Mo. In contrast, fluid circulation within a low-temperature ridge-flank hydrothermal system is a source of isotopically light Mo to the ocean having an end-member fluid of $0.8%.

In recent times, fish farming (aquaculture) has become a major source of income to many and a substitute for beef in many homes all over Nigeria because a kilogram of fish is cheaper especially the so call ice-fish compared to same kilogram of beef. As a result, many people have embraced fish farming and while some aquaculturist have recorded loss, only few got it right especially at the initial stage of the fish farming business. Some fish farm had average fish weighing a kilogram while others recorded less than half a kilogram due to many factors ranging from contamination of pond water from pile up of uneaten feeding stuff at bottom of the pond to the use of ground or surface water whose constituents or chemically controlled parameters have adverse effects on harvest in aquaculture. This study was carried out to ascertain the suitability of surface and groundwater from parts of northern Nigeria for fish farming. Thirty seven surface and groundwater samples were collected during the peak of dry season and analyzed for physicochemical parameters that could have adverse effects on fish farming using model V-2000 multi-analyte photometer, atomic absorption spectrophotometer, pH and conductivity meter. Whereas some of the measurements were carried out in-situ, the others were carried out in the laboratory. The result of the analysis indicated that the values obtained for most of the samples were within the range that can be used efficiently for aquaculture, only few were observed to have values that could have adverse effects on the intended use and these include pH, salinity, sodium contents and residual sodium carbonate which are closely related to the pH of water samples analyzed. The water samples analyzed are generally good for aquaculture.

Groundwater ecosystems comprising microorganisms and metazoans provide an important contribution to global biodiversity. Their complexity depends on geology, which determines the physical habitat available, and the chemical conditions within it. Despite this, methods of classifying groundwater habitats using geological data are not well established and researchers have called for higher resolution habitat frameworks. A novel habitat typology for England and Wales (UK) is proposed, which distinguishes 11 geological habitats (geo-habitats) on hydrogeological principles and maps their distribution. Hydrogeological and hydrochemical data are used to determine the characteristics of each geohabitat, and demonstrate their differences. Using these abiotic parameters, a new method to determine abiotic habitat quality is then developed. The geo-habitats had significantly different characteristics, validating the classification system. All geohabitats were highly heterogeneous, containing both high quality habitat patches that are likely to be suitable for fauna, and areas of low quality that may limit faunal distributions. Karstic and porous habitats generally were higher quality than fractured habitats. Overall, 70% of England and Wales are covered by lower quality fractured habitats, with only 13% covered by higher quality habitats. The main areas of high quality habitats occur in central England as north-south trending belts, possibly facilitating dispersal along this axis. They are separated by low quality geo-habitats that may prevent east-west dispersal of fauna. In south-west England and Wales suitable geo-habitats occur as small isolated patches. Overall, this paper provides a new national-scale typology that is adaptable for studies in other geographic areas.

Sulphate concentrations in speleothems identify major volcanic eruptions, provide useful information on soil and aquifer dynamics and, in similar fashion to the 14C bomb peak, its Anthropocene peak can be used to date recent cave formations. However, the transmission of S from the atmosphere to cave dripwater and its incorporation in speleothems is subjected to biogeochemical cycling and accurate studies of each cave site are needed in order to assess how the S atmospheric signal is modified and eventually encoded in speleothems. This study investigates the role of biogeochemical cycling and aquifer hydrology by utilising published and new dripwater and speleothem data from Grotta di Ernesto (ER) in northern Italy. Here we provide the first long-term record of sulphate concentration in cave dripwater based on over 20 years of measurements. Fast drip site st-ER1 is characterised by a continuous decrease in SO4 concentration from a high of 7.5 ±0.8 mg/l in 1993-1994 to a low of 2.2 ±0.2 mg/l in 2013-2014, and replicates with a delay of ~15 years the decline in the atmospheric SO2 emissions. The S-series of slow flow ER78 site is further delayed by ~4.5 years in relation to the S retention in the aquifer matrix. The dripwater data are used to extend the previously published S record (1810 – 1998 AD) of stalagmite ER78 and reconstruct the anthropogenic S-peak: this displays a delay of ~20 years with respect to the atmospheric S emission peak due to biogeochemical cycling and aquifer storage. However, sulphur recycling above the cave did not operate with the same degree of efficiency through time, which resulted in a variable time delay between S deposition and incorporation into the stalagmite. In the pre- Anthropocene era, and in particular during the cold Little Ice Age, biogeochemical cycling was far less efficient than today, and the fast transmission of the atmospheric signal allowed capture of S released during major volcanic eruptions by stalagmites.

A comprehensive chemical quality assessment of groundwater resources in the Talensi District has been conducted using conventional graphical methods and multivariate statistical techniques. e study sought to determine the main controls of groundwater chemistry and its suitability for domestic and irrigation purposes in the district. Silicate and carbonate mineral weathering were identified as the main controls on groundwater chemistry in the district, with reverse ion exchange also playing a role. High nitrate and lead levels observed have been associated with agrochemicals and wastewater from farms and homes. ree main flow regimes have been identified with Q-mode cluster analysis, in which mixed cation water types have been revealed, where areas designated as recharge zones are dominated by Na + + K +-Mg 2+-HCO 3 − fresh water types characterised by low mineralisation and pH, which evolve into Mg 2+-Na + + K +-HCO 3 − fresh water type with corresponding increased mineralisation of the groundwater. Based on the water quality index (WQI) technique modified for the district and an interpolation technique using ordinary kriging developed from a well-fitted exponential semivariogram for the estimated WQIs, the groundwater quality has been spatially classified as generally 'good' to 'excellent' for domestic purposes. Generally, the quality of groundwater for domestic usage deteriorates as one moves towards the north of the district, whereas waters in the east and west present the best quality. Classifications based on the United States Salinity Laboratory (USSL), Wilcox, and Doneen diagrams suggest that groundwater from the unconfined aquifers of the district is of excellent quality for irrigation purposes.

The paper deals with the major chemistry and stable isotopes (hydrogen, oxygen, carbon, sulfur, strontium) of waters and solutes from the Salar de Atacama basin (Rio Pedro, Honar Creek and Laguna Chaxa) and Andean Altiplano (Laguna Miñique and Laguna Miscanti). The water inflows of the Salar are chemically quite different, the Rio San Pedro being of Na-Cl type and the Honar Creek of Na-HCO3 type, in keeping with the sedimentary-evaporitic and volcanic nature of the catchment rocks respectively. The δ34S and δ18O values of sulfate and the 87Sr/86Sr ratio of strontium in the streams match those of drained rocks, whereas the δ13C values of dissolved carbonate are largely controlled by vegetation. The lagoons are evaporated meteoric water bodies, and the relative air humidity estimated from the slope of the isotopic evaporation line is in accordance with historical data on air humidity in the area. The Laguna Chaxa is Na-Cl rich, and its isotopic composition are consistent with a mixed sedimentary-volcanic provenance of sulfur and strontium solutes. The Laguna Miñique is Na-SO4 rich, and its sulfate δ34S is nearly identical to that of Laguna Chaxa. The δ13C(HCO3) values are quite different in the Laguna Chaxa and Laguna Miñique, with the former being notably enriched in 13C probably because of preferential uptake of 12C by the high biological productivity occurring in the lagoon. The limited set of new data is interpreted in the context of a much larger literature database. In particular, previous chemical data on inflows and brines in the Salar de Atacama were revisited, and compared with evaporation path models and mineral stability diagrams (boron, lithium and Mg-minerals) computed using updated software and thermodynamic databases. The modeling shows that the removal of boron and lithium from sulfate-rich brines possibly occurs, respectively, as ulexite and sulfate salts, and carnallite should be the final magnesium phase of the brine evolution.

The rapid underground dissolution of gypsum, and the evolution of the gypsum karst in Lithuania and England, results in subsidence problems which can make construction difficult. The natural dissolution yields sulphate-rich groundwater of poor quality and the karst is susceptible to the rapid transmission of pollutants.In the north of Lithuania gypsum karst is developed in Devonian gypsum. Here the towns of Birai, Pasvalys and the surrounding countryside suffer subsidence and some buildings have been damaged. The majority of the potable water in these areas is derived from groundwater extracted from sandstone sequences that underlie the gypsum. In Lithuania conservation measures have been introduced to control agriculture and prevent pollution of the gypsum karst. These measures include environmentally-friendly farming, restrictions on land use and exclusion zones around subsidence hollows.In England subsidence caused by the dissolution of Permian gypsum has caused severe problems in the vicinity of the town of Ripon. Numerous buildings have been damaged and new sites are difficult to develop. Here formal planning regulations have recently been introduced to help to protect against the worst effects of subsidence resulting from gypsum dissolution.

This paper presents the first shallow groundwater geochemical data from the Lut Desert (Dasht-e-Lut), one of the hottest places on the planet. The waters are Na-Cl brines that have undergone extensive evaporation, but they are unlike seawater derived brines in that the K + is low and the Ca 2+ > Mg 2+ and HCO 3 − > SO 4 2−. In addition to evapo-concentration, the most saline samples indicate that the dissolution of previously deposited salt also acts as a major control on the geochemistry of these waters. High concentrations of gypsum in surface soils along with the water geochemistry indicate the dissolution, precipitation, and reprecipitation of evaporite salts are very important to the overall chemistry of the near surface environment. As demonstrated by the high H 4 SiO 4 concentrations, the weathering of aluminosilicate minerals also contributes to the solutes present. Fixed nitrogen (NO 3 − + NO 2 −) concentrations suggest little to no denitrification is occurring in these waters. The processes controlling the geochemistry of the Lut waters are similar to those in other hyperarid regions of the Earth.

This research study focuses on hydro-geochemistry of Chanchaga area which forms an integral part of Minna North Central, Nigeria. The area is underlain by the Precambrian Basement Complex crystalline rocks such as Schist, Migmatite Gneiss and Granites. These rocks are dominantly structured in NE – SW and N – S directions. These structures have effect on both surface drainage pattern and influence the groundwater and surface water flow directions in the area. The Hydrogeological mapping entailed the measurement of groundwater table of hand-dug wells and subsequent sampling exercises. Twenty one (21) water samples were taken for physic-chemical analysis from both hand-dug wells and hand pump bore holes including one sample from Bosso dam for standard laboratory analysis at Federal Ministry of Agriculture, water quality laboratory in Minna, Niger State. The chemical analysis revealed the concentrations of hydrochemical parameters in the following range order: Temperature (28.1 – 31.3 °C), TDS (0.06 – 0.47ppm), Electrical conductivity (0.01 – 0.96 µs/cm), pH (5.55 – 7.2), salinity (1.1 – 1.9Mg/l), Turbidity (0.8 – 37NTU), Na + (19.74 – 92.8Mg/l), K + (0.94 – 54.4Mg/l), Ca 2+ (8.02 – 92.8Mg/l), Mg 2+ (0.49 – 55.6Mg/l), Cl-(11 – 156Mg/l), SO 4 (0 – 69Mg/l), HCO 3 (0 – 429Mg/l), CO 4 (0 – 98Mg/l), Cu 2+ (0 – 13.9Mg/l) and Fe 2+ (0 – 2.6Mg/l). From parametric comparism with WHO standards all the parameters under considerations fall below the maximum permissible limit except some very few parameters that reveal maximum concentration slightly higher to the recommended limits in some of the area. From correlation matrix Na + shows positive significant correlation between TDS, Cl-, and SO 4 (r = 0.542, 0.698, 0.594) respectively, which suggest that the aquifer chemistry is control by those elemental constituents. In the same vein Mg 2+ depict significant positive correlation between Cl-and SO 4 (r = 0.586 and 0.461). Piper diagram revealed three different facies which can be grouped into two zones: Earth alkali freshwater and area of alkali freshwater, it can be subdivided into bicarbonate type of water and sulphate type including sulphate-chloride type. The presence of bicarbonate in the water indicates that the twenty one wells were variously sunk in Calcium bearing granite gneiss while the Carbonates are the products of reaction between Carbon dioxide and rain water. Also some location has sulphate – Chloride type which might be the resultant influence of the pollution from municipal water and waste products.

Groundwater constitutes an important part of the available water resources in arid areas. Knowledge of the quantitative and qualitative status of groundwater is a key aspect in optimal groundwater management. The purpose of this study was to provide technical information on the groundwater in the sand aquifer of two neighboring areas in the United Arab Emirates to support stakeholders working towards sustainable groundwater development. The chemical characteristics of the groundwater have been used to identify the processes controlling groundwater chemistry and assess the suitability of the groundwater for agricultural purposes. Despite tapping into the same aquifer, considerable differences in groundwater quality were found between the two study areas. The area with a shallower water table showed clear indications of irrigation return flow deteriorating the groundwater quality. Using standard agricultural indices, the groundwater at both study areas is classified as unfit for agricultural purposes. However, considering that groundwater is the only available water source for irrigation, it will continue to be used for agriculture. This indicates the need for improved irrigation management and the development of new strategies for sustainable groundwater development in arid areas in the context of food security.

The developed strategy permits determination
in three steps of sixty-seven elements using inductively
coupled plasma mass spectrometry (ICP-MS). Sodium,
Mg, Si, S, Cl, K, and Ca are determined in a first step;
B, Al, P, Cr, Fe, Mn, Ni, Cu, Zn, As, Se, Ag, Cd, Sb, Ba,
Hg, and Pb are determined in a second step; and Li, Be,
Ti, V, Co, Ga, Ge, Br, Rb, Sr, Y, Zr, Nb, Mo, Sn, Te, I, Cs,
La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,
Hf, Ta, W, Pt, Au, Tl, Bi, Th, and U are analyzed in a third
step. The figures of merit obtained are adequate to carry
out water quality monitoring and other hydrochemical
studies, such those based in the application of hydrochemical
fingerprinting to water management.

Groundwater resources of Sohag, Egypt are currently threatened by contamination from agricultural and urbanization activities. Groundwater in Sohag area has a special significance where it is the second source for fresh water used for agricultural, domestic, and industrial purposes. Due to growing population, agriculture expansion, and urbanization, groundwater quality assessment needs more attention to cope with the increasing water demand in this arid zones and limited water resources. The aim of this paper is to address the integrated role of geochemical processes, agriculture and urbanization in evolution of groundwater composition, and their impact on groundwater quality to help in management and protection of groundwater resources of study area using geochemical modeling techniques and geographical information systems. Spatial variation of groundwater hydrochemical properties, rock–water interaction, ion exchange, and assessment of groundwater quality were investigated. Results indicated that groundwater properties are varied spatially and its evolution in the study area is generally controlled by the prevailed geochemical processes represented by leaching, dissolution, and precipitation of salts and minerals, ion exchange, in addition to human activities represented by agriculture and urbanization as well as climatic and poor drainage conditions. Management alternatives should be followed in the study area to avoid degradation of groundwater quality and provide sustainable development. تعتبر موارد المياه الجوفية فى منطقة سوهاج بمصر مهددة حالياً بالتلوث من الأنشطة الزراعية والتوسع الحضري. تحظى المياه الجوفية في منطقة سوهاج بأهمية خاصة حيث تعتبر ثاني مصدر للمياه العذبة المستخدمة في الزراعة والأغراض المنزلية والصناعية. ونظرا لتزايد عدد السكان ، والزراعة ، والتوسع الحضري، فان تقييم نوعية المياه الجوفية يحتاج الى مزيد من الاهتمام لمواجهة تزايد الطلب على المياه في هذه المناطق ذات الموارد المائية المحدودة. يهدف هذا البحث الى معالجة متكاملة لدور العمليات الجيوكيميائية، والزراعة ، والتوسع الحضري في نشوء وتكوين المياه الجوفية وتأثيرها على نوعية المياه للمساعدة في إدارة وحماية موارد المياه الجوفية فى منطقة الدراسة باستخدام تقنيات النمذجة الجيوكيميائية ونظم المعلومات الجغرافية. حيث تم دراسة التباين المكاني للخصائص الهيدروكيميائية للمياه الجوفية ، والتفاعل بين الصخور والمياه ، والتبادل الأيوني وكذلك تقييم نوعية المياه الجوفية. وقد بينت نتائج الدراسة ان الخصائص الهيدروكيميائية للمياه الجوفية بمنطقة الدراسة متغيره مكانياً وبصفة عامة يتحكم فى نشوئها وتكوينها العمليات الجيوكيميائية المتمثلة فى عمليات الغسيل والاذابة والترسيب للاملاح والمعادن والتبادل الأيوني والأنشطة البشرية المتمثلة فى الزراعة والتوسع الحضري بالاضافة الى العوامل المناخية وسوء حالة الصرف بالمنطقة. وقد اوصت الدراسة بضرورة اتباع بدائل للادارة لتجنب تدهور نوعية المياه الجوفية وتحقيق التنمية المستدامة.

Groundwater in the Van coastal aquifer is one of the main sources of potable, industrial and irrigational water in Van City, because of its semiarid climate. Groundwater extraction has been in excess of replenishment owing to increased agricultural and economic activities and a growing population during the last 20 years. A hydrochemical survey of the Van aquifer provided data on the groundwater chemistry patterns and the main mineralization processes. The main processes influencing the groundwater chemistry are salinisation from salt-water intrusion, silicate mineral dissolution, cation exchange and human activity. Deterioration in water quality has resulted from intrusion of the salt water of Lake Van along the coastal regions into the Van plain. At present, the mixing rate of salt water in the Van aquifer is between 1 and 5.5% and salt water has already invaded about 5 km inland in the iskele and the airport region.

Solute fluxes and transient carbon dioxide drawdown in a small glacierized basin investigated on Svalbard in 2002 are presented. It was a sample year within a period of significant climate warming in the Arctic. Discharge was recorded in the Scottbreen Basin (10.1 km 2 ), Bellsund Fjord, between July 8 and September 10, 2002. Specific runoff for this period was 0.784 m, 22% more than the mean for 1986-2001. The runoff for all of 2002 (i.e. the hydrologic year) was estimated by comparison with Bayelva, the only glacial river with longer records on Svalbard. The specific runoff for 2002 was $1.228 m, yielding crustal solute fluxes of 69.4 t km À2 yr À1 (25.8 m 3 km À2 yr À1 ). This rate is the highest chemical denudation rate reported from glacierized basins on Svalbard, and it may be underestimated because higher solute fluxes at the beginning of the melt season were not taken into account. Crustal fluxes in the fall may also have been higher because it is probable that crustal ion concentrations were increasing after recording stopped in September. The cation denudation rate was 1213 P meq + m À2 yr À1 and the mean annual crustal ion concentration derived from it amounted to 981 leq L À1 . Transient CO 2 drawdown in 2002 was 5242 kg C km À2 yr À1 . Most of the carbon dioxide was removed in the summer ablation waters, estimated CO 2 drawdown in the fall being only 13% of the total. Comparison with crustal solute fluxes (CSF) computed from specific conductivity in the 1980s and 1990s suggests that earlier fluxes may have been overestimated by around 19%. Comparing earlier data with the 2002 rates may confirm the influence of climate warming on increasing chemical denudation rates. It was also found that a globally derived equation relating specific conductivity to concentrations of dissolved limestone in water gave estimates of the crustal solute fluxes that were only 1.1% less than those obtained via comprehensive chemical analyses of waters and ion partitioning procedures. ª

Rapid economic expansion poses serious problems for groundwater resources in arid areas, which typically have high rates of groundwater depletion. In this study, integration of hydrochemical investigations involving chemical and statistical analyses are conducted to assess the factors controlling hydrochemistry and potential pollution in an arid region. Fifty-four groundwater samples were collected from the Dhurma aquifer in Saudi Arabia, and twenty-one physicochemical variables were examined for each sample. Spatial patterns of salinity and nitrate were mapped using fitted variograms. The nitrate spatial distribution shows that nitrate pollution is a persistent problem affecting a wide area of the aquifer. The hydrochemical investigations and cluster analysis reveal four significant clusters of groundwater zones. Five main factors were extracted, which explain >77% of the total data variance. These factors indicated that the chemical characteristics of the groundwater were influenced by rock ewater interactions and anthropogenic factors. The identified clusters and factors were validated with hydrochemical investigations. The geogenic factors include the dissolution of various minerals (calcite, aragonite, gypsum, anhydrite, halite and fluorite) and ion exchange processes. The anthropogenic factors include the impact of irrigation return flows and the application of potassium, nitrate, and phosphate fertilizers. Over time, these anthropogenic factors will most likely contribute to further declines in groundwater quality.

Assessment of redox state, pH, environmental isotope ratios (d18O, d2H) coupled with PHREEQC speciation modeling investigations were conducted to understand trace element geochemical controls in basement complex aquifer in Blantyre, Malawi. Groundwater in the area is typical Ca–Mg–Na–HCO3 type suggesting more of carbonate weathering and significance of carbon dioxide with dissolution of evaporites, silicate weathering and cation exchange being part of the processes contributing to groundwater mineralization. The significance of pH and redox status of groundwater was observed. The groundwater redox state was mostly O2-controlled with few exceptions where mixed (oxic–anoxic) O2–Mn(IV) and O2–Fe(III)/SO4 controlled redox states were modeled. More so, some of the main trace element species modeled with PHREEQC varied with respect to pH. For instance vanadium(III) and vanadium(IV) decreased with increase in field pH contrasting the trend observed for vanadium(V). The isotopic composition of the sampled groundwater varied between 5.89‰ and 3.32‰ for d18O and 36.98‰ and 20.42‰ for d2H. The d2H/d18O and d18O/Cl ratios revealed that groundwater is of meteoric origin through vertical recharge and mixing processes. The d-excess value approximated the y-intercept of GMWL of 10 (d-excess = 9.269, SD = 1.240) implying that influence of secondary evaporative processes on isotopic signature of the study area is minimal. Thus, there is evidence to suggest that groundwater chemistry in the studied aquifer is influenced by inherent processes with contribution from human activities and furthermore, the water originates from rainwater recharge. With such results, more studies are recommended to further constrain the processes involved in mineralization through isotopic fractionation investigations.

Uranium occurs naturally in groundwater and surface water. The objective of this study is to understand the causes for the occurrence of uranium and its spatio-temporal variation in groundwater in a part of Nalgonda district, Andhra Pradesh, south India. Uranium deposits occur in the southeastern part of this area. Groundwater samples were collected from 44 wells every two months from March 2008 to January 2009. The samples were analyzed for pH, ORP and uranium concentration. The uranium concentration in groundwater varies from 0.2 ppb to a maximum of 68 ppb with a mean of 18.5 ppb. About 21.6% of the samples were above the drinking water limit of 30 ppb set by USEPA. The uranium concentration varied with fluctuation in groundwater level, pH and ORP. Uranium concentration in groundwater changes depending on lithology, degree of weathering and rainfall recharge.

Editorial handling by R. Fuge a b s t r a c t Thirty-nine stream and river water samples were collected along a 120 km long transect through the Oslo Rift and the city of Oslo. All samples were analysed for 59 elements (4 ; SO 2À 4 ), and the additional parameters pH, alkalinity, colour, turbidity and electrical conductivity. The transect crosses four different lithologies, ranging from Precambrian gneisses, Cambro-Silurian sedimentary rocks (including black shales and limestones) to Permian syenites and granites. Parts of the transect are covered by glacial Drift or marine clays (especially in the south), others are Drift-free. Although varying forms of land-use occur throughout the transect, forestry is predominant in higher elevation, Drift-sparse areas, while agriculture and urban development are more characteristic of low lying areas with clayey Drift. Differences in stream water chemistry are likely to arise from the interrelationship between lithology, Drift cover, landscape, land-use and climate-related factors (different evaporation rates). It is possible to tentatively identify the impacts of marine influence, water-rock interaction, pH-related solubility and lithological influence (e.g. black shales). Even a city of the size of Oslo, which is a major diffuse source of contaminants in southern Norway, and intense agriculture have a limited influence on inorganic stream water quality. Nitrate, however, does appear to indicate human impacts, occurring in some streams in concentrations higher than can be explained by rainfall chemistry. Overall, ''natural" element sources and processes dominate surface water chemistry at a short distance from any point source of contamination.

The purpose of this research was to characterize the quality of groundwater for drinking and irrigation in Blantyre, Malawi as well as identify some geochemical processes governing mineralization of major and some minor elements. The aquifer studied is part of the extensive crystalline basement complex. The suitability and classification involved confirmatory analysis of the results with World Health Organization and Malawi Standards Board groundwater guideline values. The water samples were analyzed for major descriptors (pH, Temperature, turbidity, major ions, total dissolved solids and electrical conductivity (EC), using standard methods. Besides, arsenic, iron and fluoride were analyzed as well. Multivariate statistics (especially Hierarchical Cluster Analysis and Factor Analysis), hydrographical methods (i.e. Piper diagram) and geochemical modeling programs (AquaChem and PHREEQC) were used to characterize the quality and explain the sources and evolution of groundwater. Suitability of groundwater for irrigation was assessed using Wilcox method which identified BH01, BH16 and BH21 as high salinity areas. Incidentally, the three boreholes had relatively higher sulfate and nitrate concentrations than the rest. Nevertheless, the groundwater was found to be within acceptable limits for drinking quality except elevated concentrations of nitrate, fluoride and iron in some boreholes compared with WHO standards, despite meeting the national standards. Borehole BH01, BH02, BH07, BH13 and BH18 exhibited nitrate concentrations greater than national standards (45 mg/L) an indication of groundwater contamination. Furthermore, the groundwater is slightly acidic to slightly above neutral with total dissolved solids less than 500 mg/l. Generally, groundwater was undersaturated with respect to both calcite and dolomite while oversaturated with respect to halite, goethite and hematite. Silicate and carbonate weathering were identified as main mineral sources for major ions in groundwater. There is a dire need for more studies and monitoring of the groundwater in this area to safeguard the resource and human health.

The research on the Włocławek Reservoir (WR), situated on the Lower Vistula River (Poland), was carried out during two periods: between 1986 and 2002, hydrochemistry was studied, and between 1994 and 2000 – plankton. WR is 70 km2 in area, its capacity is 370 × 106 m3 and the retention time with the average flow rate (Q) amounts to 930 m3 s−1 – only 5 days (!). Until 2002, due to cyclic work of a hydroelectric power plant, considerable variability in the daily flow rate was recorded (from 600 to 1800 m3 s−1). Its specific hydrology and fluvial character mean that WR functions in a completely different way compared to dam reservoirs described in textbooks, with significantly longer retention time.WR significantly improves most of the water quality variables in the river. It reduces the concentration of suspended matter (on average by more than 50%), Ptot (by 16%), BOD5 (by 40%) and chlorophyll “a” (by 50–60%) (unpublished data).Phytoplankton is rich in species – altogether 441 taxa, with the count of 7.4 × 106 individuals per dm−3 and biomass of 16 mg dm−3. Throughout the research period, a significant reduction in the abundance of phytoplankton was recorded in WR, sometimes more than 60%. The total number of zooplankton taxa at the site upstream from WR and in the reservoir was almost identical (68 and 67), however in the reservoir itself, a small decrease in the number of Rotifera species and an increase in the number of Crustacea species was observed, as well as a significant, fourfold increase in the total zooplankton biomass. The aforementioned reduction of phytoplankton and enrichment of the river with Crustacea are one of the major biocenotic consequences of the functioning of the Włocławek Reservoir.

The present paper aimed at assessing the hydrochemistry and the water quality of the groundwater in the urban area of Baghdad. Sixty-six groundwater samples were collected from shallow tube wells and analyzed for pH, total dissolved solids (TDS), electrical conductivity (EC), calcium, magnesium, sodium, potassium, chloride, bicarbonate, carbonate, sulfate and nitrate. Groundwater suitability for drinking was evaluated based on the World Health Organization (WHO) and Iraqi standards, whereas suitability of groundwater for irrigation was evaluated based on various hydrochemical parameters and methods, such as sodium adsorption ratio (SAR), residual sodium carbonate (RSC), sodium percentage (%Na), United States salinity diagram, Wilcox's diagram and magnesium hazards (MH). Results showed that the urban area of Baghdad is highly affected by the anthropogenic sources. Based on Piper diagram, the groundwater in the study area are classified into two water types (NaCl and CaCl), indicating high-salinity water. Gibbs ratio indicates that the majority of the groundwater in the study area is affected by the evaporation process. Furthermore, the ion exchange process revealed that 85% of the groundwater samples indicate chloro-alkaline disequilibrium. Moreover, it was found that all the groundwater samples are unsuitable for both drinking and irrigation purposes.

Changes in soil water content, groundwater flow and a rise in pore water pressure are well-known causal or triggering factors for hillslope instability. Rainfall and snowmelt are generally assumed as the main sources of groundwater recharge. This assumption neglects the role of deep water inflow in highly tectonized areas, a factor that can influence long-term pore-pressure regimes and play a role on local slope instability.

12 springs from the northern Apennines of Italy were studied by means of a comprehensive hydrogeological investigation to unravel recharge processes taking place in a highly fractured slab of flysch rock hosting the corresponding aquifers. Several campaigns were carried out during the period 2005–2008 to gather springs’ discharge together with electrical conductivity and temperature data. Water samples were collected and allowed the determination of the major ions (Ca2+, Mg2+, Na+, K+, SO42−, HCO3−, Cl−) and the isotopic content (δ18O). Additionally, groundwater discharge from 3 selected springs was measured continuously using pressure-transducers. Over the same period, reference δ18O values for rainfall and snow-melt water were collected monthly by a rain-gauge. Results highlighted an aquifer-like behavior of this slab of flysch rock. The springs are characterized by a Ca–HCO3 hydro-facies and an increase of groundwater mineralization has been noticed moving toward the base of the slab; the mean discharges are between 0.3 and 0.7 l·s−1 and suffered a marked variability during the year; the total maximum yield is about 155,000 m3 while the total discharge volume is around 320,000 m3·y−1. By processing the δ18O isotope values from springs (mean annual values ranged from −9.67 and −10.42 ‰) and by combining them with rainfalls datasets, results show that the main aliquot of recharge occurs in the winter—spring months and it is principally related to the solid precipitations (snow-melt).

The GIS data of digital elevation model, topographic maps of different scales, satellite images and GPS were used to analyze the geometrical relations, bathometric properties and shape form of selected depressions on Al-Jirnaf valley. GIS was used to analyze the hydromorphometry and geometry of the depressions, these analyses explain the role of main valley's contribution to the hydrology of the valley, then, three locations for water storage were suggested. 2D and 3D models of the sites were given, the maximum level, volume, surface area, circumference, shape factor of three supposed reservoirs calculated for different hypothetical levels of water in the reservoir, and the optimal level were determined , the maximum suggested levels are 190, 185 and 180 m, the areas are 3.25, 7.97 and 20.47 km 2 , the volumes are 0.0096, 0.0334 and 0.1118 km 3 for the three locations respectively. This experimental procedure can be repeated in other depressions for the same purpose.

Analyses by inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS) and cold vapour atomic absorption (for Hg, CVAA) of a wide range of elements in some 300 surface water samples from the Salar de Uyuni and Salar de Coipasa catchments of the Bolivian Altiplano have been undertaken. Comparison of analyses of acidified aliquots of unfiltered sample water with water filtered at 0.45 Am reveals that the following elements are not affected significantly by filtration in this high-pH environment: B, Ca, Li, Mg, K, Si, Na, Sr, S. The following elements appear to experience significantly elevated concentrations in unfiltered samples, relative to filtered: Al, (As to a minor extent),

 Chemical data are used to clarify the hydrogeological regime in the Mafraq area in northern Jordan, as well as to determine the status of water quality in the area. Groundwater from the shallow aquifer in the Mafraq area can be divided into two major groups according to geographical locations and chemical compositions. Water in the basaltic eastern part of the study area is characterized by the dominance of chloride, sulfate, sodium, and potassium, whereas waters in the limestone aquifers in the west are dominated by the same cations but have higher concentrations of bicarbonate. Stable isotopes show that the shallow aquifers contain a single water type which originated in a distinct climatic regime. This water type deviates from the Global Meteoric Water Line (MWL), as well as from the eastern Mediterranean meteoric water line. The waters are poor in tritium, and thus can be considered generally older than 50 years. Chemical mass balance models suggest that water is moving from the west towards the north of the study area. This suggests that waters from the different basins are separated from each other. Degradation of water quality can be attributed to agricultural fertilizers in most cases, although the waste-water treatment plant at Khirbet es Samra is a contributor to pollution in the southwestern part of the study area.

The mercury concentration levels in the water of aquatic ecosystem of the Northern Dvina River delta are defined. The interrelations of mercury concentrations with physicochemical parameters of the water body, namely with pH, Eh, temperature, salinity, oxygen and organic matter content are studied. The dominant forms of mercury migration and its presence in the water are revealed. Regularities of changes and spatial variability of the mercury concentrations in the estuarine area of the river, peculiarities of mercury compound migration and transformation in the barrier zone of the Northern Dvina River-Dvina Bay of the White Sea are studied.

This article presents hydro-chemical and isotopic ( δ15 N-, δ18 O–NO 3 −, δ11 B ) data of water samples and potential nitrate sources from the Nyando river basin, a tributary of the Lake Victoria in Kenya. The data collection involved field sampling of water samples in 23 sampling stations spatially distributed in the basin during nine seasons from July/2016 to May/2018. The hydro-chemical data was generated from the Laboratory analysis of the water samples using the ion chromatogram. Samples for nitrate isotope ( δ15 N-, δ18 O–NO 3 −) analysis were prepared via the bacterial denitrification method and anal- ysed using Isotope Ratio Mass Spectrometer. The data, which is categorised in different land use zones and seasons, is im- portant for understanding the spatiotemporal variation in ni- trate and solute concentrations and the role of land use on the river water quality. In addition, the δ15 N-, δ18 O–NO 3 −and δ11 B values are key for elucidating nitrate pollution sources and potential biogeochemical processes for the management and control of nutrient pollution and eutrophication of the Lake Victoria. Furthermore, the dataset can be of great use in water quality models for understanding non-point pollution dynamics in tropical basins. This article is related to Nyilitya BK, Mureithi SM, Boeckx P. 2020. Land use controls Kenyan riverine nitrate discharge into Lake Victoria - Evidence from Nyando, Nzoia and Sondu Miriu river catchments. Isotopes in Environmental and Health Studies (GIEH). https://doi.org/10.1080/10256016.2020.1724999 Published online: 18 Feb 2020.

Groundwater dolocretes may exert an important geomorphic control on landscape evolution within sub-humid to arid regions. However, the geomorphic and hydrogeological settings of dolocrete remain poorly described. The hydrochemical conditions of dolomite precipitation in groundwater environments are also not well known. Classic models of dolocrete formation explain dolomite precipitation from highly evolved groundwaters at the terminus of major drainage but do not explain dolocrete distributed in regionally elevated landscapes, upgradient of major drainage. This study investigated the mineralogy, micromorphology and stable carbon and oxygen isotope compositions of three dolocrete profiles within a regionally elevated sub-basin of the Hamersley Ranges in the Pilbara region of northwest Australia. We sought to establish the environmental and hydrochemical conditions and present a model for dolocrete formation. We found that dolocrete formed within zones of emerging groundwater under salineevaporitic conditions within internally draining sub-basins, most likely during the Late Miocene and Pliocene. Saline-evaporitic conditions were indicated by: (i) the mineralogy, dominated by dolomite, palygorskite and smectite; (ii) desiccation features and the presence of phreatic and vadose cements, indicative of a shallow fluctuating water table, and; (iii) dolomite δ 18 O values (median =-5.88 ‰). Dolomite precipitation was promoted by evaporation and carbon dioxide degassing from shallow magnesium (Mg)-rich groundwater. These factors appear to have been the major drivers of dolocrete development without a requirement for significant down-dip hydrochemical modification. Primary dolomite precipitation was possible due to the presence of microbial extracellular polymeric substances (EPS). EPS provided negatively charged nucleation sites, which bound Mg 2+ , overcoming kinetic effects. High microbial activity within groundwater systems suggest these processes may be important for dolocrete formation worldwide and that groundwater dolocretes may be more pervasive in landscapes than currently recognized.

The geothermal field of Akropotamos produces fluids at temperatures up to 90oC. The waters from wells AKR-1, AKR-3, AKR-4, AKR-5 and AKR-6 at 30 86oC and TDS of 3.1-30.7 g/l are classified as Na-Cl type. The water from well AKR-2 at 46oC with TDS of 2.15 g/l belongs to Na-HCO3Cl type. The cold and sub-thermal waters (16.4- 27oC) in the area are considered as fresh or low salinity waters (TDS: 0.31-4.34 g/l) of various mixed types. The Na-Cl geothermal waters can be divided into two categories due to two different hot aquifers: (a) Τhe first shallow aquifer contains high salinity waters (TDS: 27.4 30.7 g/l) at 30-48oC located within sands, sandstones and gravels. (b) Τhe second deeper reservoir composed of calcareous conglomerates and sandstones contains lower salinity waters (TDS: 3.1-5.08 g/l) at 83-90οC. The contribution of seawater to the chemical composition of the thermal waters in the shallow aquifer system seems to be important. With the aid of chemical geothermomometers applied to the geothermal water from well AKR-1, the deep temperature has been estimated to be >120oC. Significant quantities of CO2 are encountered in wells AKR-1 and AKR-3.

Abstract Dal Lake (Lat. 340–6'N, 740-45'E, alt. 1583m) situated in the heart of Srinagar city, the summer capital of Jammu Kashmir State is under tremendous anthropogenic pressure. The myriad is ways in which people use the lake along with the numerous pollutant generating activities have stressed the lake ecosystem in diverse ways.

The term "geochemical barrier" (GCB) has been widely used in the Russian geochemical literature as a key concept of the distribution of elements and substances theory (incl. pollutions)although in the world research practice this term is not particularly represented. The assessment of the functional role of the geochemical barriers in relation to the properties and evolution of the geochemical systems (GCS)is demonstrated.The foundations of Haken synergy, the foundations of self-organization of systems and non-equilibrium (non-linear) thermodynamics of I. Prigogine and his school are used as a methodological framework. From the authors' point of view, GCB are considered as self-organizing components of GCS, in which physical and chemical processes are activated, leading to the transformation of atomic and molecular structures, chemical associations and individual chemical elements under the impact of active media (processes). They can be the defining phenomenon of the emergence and evolution of GCS. The concept of geochemical barriers is the foundation for technologies that are actively implemented for cleaning and protecting soils, groundwater and surface water, and the geological environment in general.

Groundwater plays an important role for urban and agricultural water supply in northern part of Peloponnesus. Despite increasing environmental awareness in this area, groundwater is a resource that is being stressed. Groundwater provides about 80% the total quantity of water supply. Distribution of water resources is nonhomogeneous in this region. In general the eastern part is semiarid, whereas the western part is supplied with abundant water. Surface water potential in North Peloponnesus estimated to be 0.9-1.2x10 9 m 3 y-1. Overexploitation of groundwater and the extensive agriculture has created environmental problems in some aquifers (sea water intrusion, nitrate pollution). Seawater intrusion occurs in some coastal aquifers, where negative water balance has been established. High percentage of the examined samples exceeded the maximum admissible nitrate concentration of 50 mg l-1 , set by EU for drinking water. Groundwater in urban areas has been contaminated to varying degrees. The water quality is classified into Ca-HCO 3 type (fresh water) and Na-HCO 3 or Na-Cl type (brackish waters) in the coastal part, due to seawater intrusion. Some recommendations are made in order to safeguard high water quality and to develop new ways of providing water source in the study area. Moreover, an integrated and comprehensive management scheme should be applied, aiming at sustainability of water resources and based on surface water and groundwater exploitation, simultaneously.

Due to the new modern life style in the Egyptian villages, a huge amount of water is used in domestic purposes. Because most of the villages are unsewered, the used water is artificially recharged to the subsurface causing water logging and groundwater pollution. Integration between water level, sedimentological setting, stable isotopes, subsurface temperature and hydrochemistry were used to investigate and evaluate the problem. Water level indicates that, water logging has been occurred due to the low hydraulic load of the surface clayey layer compared to the recharged amount of water. It is also estimated using the other criteria that, the sewage water polluted groundwater in the shallow and the intermediate zones. The pollution in the intermediate zone occurred where the second silty clay layer is missed. Draining the soil and constructing the sewage pipe net are the solutions to stop water logging and groundwater pollution.

  The Drama basin is a typical intermontane basin (2,300 km2) in northern Greece filled with detrital and lacustrine sediments containing peat/ lignite seams.In the southwestern part of the basin (Philippi sub-basin) peat accumulated practically until the present.Specific conductivity and pH, as well as contents  of major ions and trace elements have been determined  in 20 surface and shallow groundwater  samples collected across the basin. Water composition refiects the dominance of carbonate rocks in the whole basin.Peat oxidation and mineralization contribute to poor element enrichment of the Philippi sub-basin surface water derived from both the organic and inorganic peat fractions. Anthropogenic activities (waste water effiuents and rubbish dumps) increase Mn, P, B, and Br concentrations.Only Mn exceeds EC recommendations(50 ¡.g/l) in some places.There is also a slight in- crease in Na+  and Cl-  contents.Improving measures in the management of point pollution sources should be a priority  to warrant the sustainable ex- ploitation of water resources in the Drama basin.

 




  
    


   
 
 

 


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In southern Africa wetlands of different types are an integral part of the drainage network, yet evolve and are sensitive to different combinations of geologic, climatic, geomorphic, edaphic and hydrologic controls. Understanding of these controls can help in the interpretation of environmental and climatic records from different wetland types, given that wetland sensitivity to environmental and climatic changes may vary throughout their ‘life cycle’. The chapter discusses inland wetland records from dated sites in South Africa, in order to consider their significance for reconstructing lateglacial and Holocene climates; and the relationship of wetlands to preservation of the Pleistocene archaeological record. Wetlands are sensitive to degradation under contemporary environmental and climatic changes, which may impact on their hydrological and ecological function as well as the integrity of associated archaeological sites.