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Environmental context We present a chemical characterisation of the seasonal snowpack sampled for four consecutive years at the Calderone, the southernmost glacier still surviving in peninsular Italy. This debris covered glacier recently split into two little ice bodies, whose evolution could be influenced by the snowpack properties. In particular the impact of long-range aerosol advections on concentrations of impurities in the snowpack over the local background is discussed. Rationale The Calderone Glacier (Central Apennine, Gran Sasso d’Italia mountain group) is the southernmost glacial apparatus in Europe, split into two glacierets (Upper and Lower Calderone) since the end of the last millennium. Because of its location and altitude, this site is mainly characterised by the long-range transport of air masses which arise from different Mediterranean source regions. Therefore, the seasonal snowpack’s chemistry is strongly affected by the dry and wet deposition of contaminants associated with anthropogenic and natural sources. Methodology In the present study, the seasonal snowpack stratified on the Calderone glacier has been characterised for four consecutive years (2017–2020) in the same monitoring site (2700 m asl), where a snow pit has been dug yearly, to observe the modification of chemical and physical properties depending on local and long-range atmospheric contributions. We determined the concentrations and fluxes of major inorganic ions (MIs) by ion chromatography and of 31 trace elements (TEs) by triple quadrupole ICP-MS. Results Major and trace element concentration profiles along the snowpack allowed to discriminate the snow layers contaminated by long range advections from the uncontaminated ones. The uncontaminated snow layers’ concentrations were used to calculate regional background values. The results have been compared to other remote sites to assess their robustness. Discussion Different source contributions have been recognised using enrichment factors for the trace elements, particularly crustal, marine and anthropogenic. Deposited atmospheric aerosols, found in the snowpack as distinct layers generated during intense air mass advections, have been correlated to these contributions.

Актуальность исследования обусловлена необходимостью контроля за гидрохимическими параметрами крупной пресной водной экосистемы для объективной оценки трансформации водоема, находящегося под антропогенным воздействием. Цель: изучить пространственно-временную динамику концентраций основных ионов в водах р. Ангары и Богучанском водохранилище. Объекты: р. Ангара до ее зарегулирования плотиной Богучанской ГЭС (2007 г.) и Богучанское водохранилище в период его заполнения (2013, 2014 гг.) и стабилизации уровня (2015, 2017 гг.). Методы. Химический анализ образцов воды проведен в Центре коллективного пользования «Изотопно-геохимических исследований» ИГХ СО РАН (г. Иркутск, Россия). Измерение концентрации Na+ и К+ в воде выполнено эмиссионным пламенно-фотометрическим методом, Са2+ и Мg2+ - методом атомно-абсорбционной спектрометрии, SO4 2- - турбидиметрическим методом, Cl- - меркуриметрическим методом, HCO3 - - титриметрическим методом. Результаты. В пространственно-временном аспекте изучены концентрации катионов (Ca2+, Mg2+, Na+, K+) и анионов (HCO3 -, SO4 2-, Cl-). Результаты исследования показали близкие значение TDS в воде мониторинговых станций р. Ангары (140,7-154,6 мг/л) и Богучанского водохранилища (139,1-172,3 мг/л). Однако увеличение уровня водоема приводит к изменению в соотношении концентраций главных ионов. По сравнению с р. Ангарой, в начальный период функционирования Богучанского водохранилища в воде увеличиваются концентрации SO4 2-, Cl-, Na+, Mg2+, уменьшаются концентрации HCO3- и Ca2+. Ионный состав вод Богучанского водохранилища определяется прежде всего вкладом из области, расположенной выше по потоку (сток из Усть-Илимского водохранилища). К антропогенным факторам относятся сточные воды и само создание водохранилища, оказывающие влияние на гидрохимию главных ионов. The relevance of the research is caused by the necessity of controlling hydrochemical parameters of large freshwater ecosystem for the objective estimation of waterbody transformation under the anthropogenic impact. The main aim of the research is to examine the spatial and temporal variability in major ion concentrations in Angara River water before regulating its flow by the Boguchany hydropower plants dam, as well as in Boguchany reservoir water during filling and water level stabilization. Objects of the research are the Angara River before regulating its flow by the Boguchany HPP dam (2007), and Boguchany reservoir during filling (2013, 2014) and water level stabilization (2015, 2017). Methods. Chemical analyses in the water samples were determined in the Centre for Collective Use «Isotope-Geochemical Research» of the IGC SB RAS (Irkutsk, Russia). Flame emission spectrophotometry was used in the analysis of Na+ and K+, atomic absorption spectrometry was applied to analyse Ca2+ and Mg2+, the turbidimetric method was used to measure SO4 2-, the titrimetric method was employed in the analysis of HCO3 - and the mercurimetric method was applied to study Cl-. Results. The spatial and temporal variability in the concentrations of cations (Ca2+, Mg2+, Na+, and K+) and anions (HCO3 -, SO4 2-, and Cl-) was examined. The results of the study show that the increase in the water level led to changes in the major ion concentration ratio. In comparison with the Angara River, in the Boguchany reservoir operation, SO4 2-, Cl-, Na+, and Mg2+ concentrations increased, while HCO3 - and Ca2+ concentrations decreased in the initial period of reservoir operation. The ionic composition of water in the Boguchany reservoir resulted primarily from the contribution from the area located upstream (runoff from the Ust-Ilimsk reservoir). Anthropogenic factors include wastewater and reservoir creation, which affect the hydrochemistry of major ions.

Municipal solid waste landfills leachate can cause serious environmental issues for groundwater quality. Therefore, the application of environmental tracing methods to identify groundwater contamination by municipal solid waste landfills leachate is significant. Hydrogeochemical evaluations to trace municipal solid waste landfills leachate are usually carried out. The study was carried out at a landfill in central Italy (Umbria). Samples of leachate and groundwater have been analyzed to evaluate the impact of leachates on groundwater through the comparison of their hydrogeochemical nature. Parameters like pH, Temperature (T), Electrical Conductivity (EC), redox potential (Eh) and Chemical Oxygen Demand (COD) were also measured in situ using digital instruments. Hydrogeochemical data (Na+, K+, Mg2+, Ca2+, SO42−, HCO3−, Cl−, NO3−), ionic ratios and geochemical correlations were used to confirm the processes that govern the chemistry of the spring water and to identify leachate contamination phenomena. In fact, the main geochemical diagrams (Langelier-Ludwig, Piper, Schoeller) confirm the leachate contamination in a groundwater sample. In particular, the Piper diagram shows that a sample is in Na+ – Cl- – HCO3- mixing zone, indicating a possible influence of the leachate on groundwater chemistry. As a matter of fact, some correlations between major elements, such as Cl- versus Na+ and Cl- versus HCO3-, confirm that the leachate in this study area is highly enriched in Cl- and HCO3- due to wastes dissolution and degradation processes. Further, the assessment of K+/Mg2+ ratio also confirms the presence of a sample heavily impacted from leachate contamination. These results indicate that also one basic hydrogeochemical study can be useful for fingerprinting the leachate pollution for groundwater samples.

Актуальность: изучение гидрохимического стока рек как одного из основных индикаторов экологического состояния водных объектов. Цель: получение новых знаний о гидрохимическом стоке рек юга Хабаровского края, которые необходимы для объективной оценки экологического состояния поверхностных вод края и проведения эффективных водоохранных мероприятий. Объекты: р. Амур и семь рек бассейна р. Уссури (одного из наиболее значимых притоков Амура): Бикин, Хор, Подхоренок, Бира, Кия, Малая Чирка и 2-ая Седьмая. Методы. Концентрации мaкро-aнионов (Cl{-}, SO[4]{2-}) измерялись методом ионно-обменной хромaтогрaфии; макро-катионов (Nа{+}, K{+}, Cа{2+}, Mg{2+}), микроэлементов и редкоземельных элементов ‒ методом ICP‒MS (Agilent, 7500с). В качестве концентрации гидрокарбонатного иона (HCO[3-]) принималась величина щелочности. Результаты. В июле 2011 г. проведены комплексные гидрохимические исследования в р. Амур и семи реках бассейна р. Уссури (одного из наиболее значимых притоков Амура): Бикин, Хор, Подхоренок, Бира, Кия, Малая Чирка и 2-ая Седьмая. В пробах речной воды были определены параметры основного солевого состава, микроэлементов и редкоземельных элементов. В период высокого расхода воды в высоко увлажненных южных районах Хабаровского края речные воды очень схожи по типу и величине минерализации: среди катионов доминирует Ca{2+}, основным противо-анионом является HCO3-; воды ультрапресные, [sigma]i не превышает 50 мг/л. В поверхностных водах всех исследованных рек обнаружены высокие концентрации растворенных форм Al, Fe и Pb. В р. Малая Чирка - высокие концентрации растворенных Co, Cu, Mn и экстремально высокие Cd, превышающие средние глобальные концентрации в 40 раз. Содержание остальных микроэлементов в исследуемых реках в целом соответствовало их средним глобальным концентрациям и является характеристикой природного регионального фона в период летних паводков. Установлен региональный уровень суммарных концентраций растворимых форм редкоземельных элементов (1,44-5,44 мкг/л). Величины концeнтрaций редкоземельных элементов в иccлeдуeмых реках укaзывaют нa однотипноcть иcточникa их поcтуплeния. Рассчитанные суммарные суточные потоки макро-ионов, микроэлементов и редкоземельных элементов, поставляемые реками Бира, Кия, Подхоренок, Бикин, Хор и Амур, равны 61894, 377 и 2,21 т/сут, соответственно. The relevance of the research consists in studying hydrochemical river discharge as one of the main indicators of the ecological state of water objects. The main aim of the research is to obtain new knowledge on hydrochemical discharge of the rivers at southern Khabarovsk region, which are required for objective assessment of the ecological status of the region and for carrying out effective water protection measures. Objects of the research are the Amur River and seven lesser streams: Bikin, Khor, Podkhorenok, Bira, Kiya, Malaya Chirka, 2-ya Sedmaya. Methods. Concentration of major anions (Cl{-}, SO4{2-}) wеrе аnаlyzеd by ion chromаtogrаphy (Shimаdzu LC‒10А); mаjor cаtions (Nа{+}, K{+}, Cа{2+}, Mg{2+}), trace elements and rare earth elements - with ICP-MS (Agilent, 7500с) method. The hydrocarbonate ion (HCO{3-}) concentration was taken as the total alkalinity. It wаs аnаlyzеd by dirеct titrаtion by Bruyеvich mеthod. Thе totаl minеrаlizаtion ([sigma]i) is thе sum of concеntrаtions of mаjor rivеr wаtеr еlеmеnts. Results. In July 2011 the Amur River and seven lesser streams (Bikin, Khor, Podkhorenok, Bira, Kiya, Malaya Chirka, 2-aya Sedmaya), located at southern part of Khabarovsk region, were sampled and analyzed for their major elements, trace elements and rare earth elements. During summer flood river waters are low-mineralizated, Results. In July 2011 the Amur River and seven lesser streams (Bikin, Khor, Podkhorenok, Bira, Kiya, Malaya Chirka, 2-aya Sedmaya), located at southern part of Khabarovsk region, were sampled and analyzed for their major elements, trace elements and rare earth elements. During summer flood river waters are low-mineralizated, [sigma]i does not exceed 50 mg/l. Ca{2+} is the predominant cation and HCO{3-} is the major counter-ion for cations in all samples. High concentrations of dissolved Al, Fe и Pb were found in the surface waters of all the rivers studied. In the Malaya Chirka River there are high concentrations of dissolved Co, Cu, Mn and extremely high Cd, exceeding the average global concentrations in 40 times. The concentration of the other trace elements in the studied rivers is in general corresponded to their average global concentrations and is a characteristic of the natural regional background during summer floods. A regional level of total concentrations of soluble forms of rare earth elements (1,44-5,44 [mu]g/l) was established. The distribution and level of rare earth elements concentrations in the studied river waters reflect the overall composition of the watershed rocks. The calculated total daily fluxes of major elements, trace elements and rare earth elements, supplied by the Bira, Kiya, Podhorenok, Bikin, Khor and Amur rivers, equal to 61894, 377 and 2,21 t/day, respectively.

The area studied in this thesis was assessed based on the analysis of a water sample collected from the exploratory well USU Camas-1. The water sample was characterized and compared to other water samples collected and analyzed during a previous phase of this project according to its water chemistry. Lithologic, geophysical, and temperature logs were also used to assess the study area. The depth sensitive data was analyzed to determine the characteristics of the formation as they relate to the favorable parameters of a geothermal resource, those being permeability of the subsurface, heat, and the presence of a clay seal. The analyses suggest that USU Camas-1 falls short of being a high-temperature resource capable of generating electricity efficiently. However, temperatures are high enough for the resource to be developed as a low-temperature asset that could be utilized to heat buildings in the area.

At present, the problem of climate change is becoming increasingly acute. This is especially pressing for Lake Baikal, a World Natural Heritage site. The Russian part of the Selenga watershed is a suitable site for climate change research. The study of changes in precipitation, runoff, and chemical runoff is important for sustainable water resources management. This study presents a trend analysis of precipitation and runoff at hydrological stations and weather stations in the Russian part of the Selenga River basin. A comparative analysis of the concentrations of major ions in the surface water of the Selenga River depending on water levels was also carried out. Analysis of the data series on precipitation revealed a slight negative trend at the Novoselenginsk, Ulan-Ude, and Kabansk stations, and a weak positive trend—at the Kyakhta station. Runoff analysis revealed negative trends at the two used stations (Novoselenginsk and Mostovoi). The hydrochemical regime of the Selenga River is characterized by an increase in major ions and salinity during winter low-water periods, and a decrease during high-water periods. Mineralization and major ion content are lower in the high-water period (2019–2021) than in the low-water period (2015–2017).

Groundwater plays an irreplaceable role in all aspects of the Loess Plateau. In this study, the loess phreatic water (LPW) and bedrock phreatic water (BPW) in the Ning County area (NCA) were sampled and analyzed, and the characteristics and controlling factors of groundwater were determined by using statistical analysis, hydrochemical methods, and hydrogeochemical simulation. The results indicated that the groundwater in the NCA was alkaline as a whole, and the average pH values of LPW and BPW were 8.1 and 7.8, respectively. The mean values of TDS concentrations of LPW and BPW were 314.9 mg/L and 675.3 mg/L, and the mean values of TH contents were 194.6 mg/L and 286.6 mg/L, respectively, which were mainly divided into hard fresh water. The Piper diagram illustrated that the hydrochemical type of groundwater in the NCA was mainly the HCO3·Ca type. The main recharge source of groundwater was atmospheric precipitation, and it was affected by evaporation to a certain extent. The linear relationships of δ18O and δ2H of LPW and BPW were δ2H = 6.998δ18O − 3.802 (R2 = 0.98) and δ2H = 6.283δ18O − 10.536 (R2 = 0.96), respectively. Hydrochemical analysis indicated that the groundwater in the NCA was mainly controlled by rock weathering and cation exchange. BPW was affected by the dissolution of gypsum. The possible mineral phases were identified on the basis of the main soluble minerals in the aquifer, and hydrogeochemical reverse simulations were performed. The dissolution of calcite, illite, and hornblende, and the precipitation of dolomite, plagioclase, and microcline occurred on both the LPW and BPW pathways.

Antarctica is a fundamental element of the global climate system. On the one hand, the ice masses of Antarctica are a unique climate archive that has steadily piled up over millennia. Analyses of stable water isotopes (δ18O and δ2H) and aerosols (including ions from sea salt and biogenic emissions), which serve as indirect indicators of climate in ice cores ("climate proxies"), make reconstructions of climate history possible. Gas inclusions in the ice even allow a direct study of the paleoatmosphere. On the other hand, Antarctica is strongly affected by global climate change. Rising temperatures cause a widespread mass loss in West Antarctica and a regional mass loss in East Antarctica. The whole Antarctic ice sheet may contribute to a global sea level rise of about 60 m if it melts entirely. This work provides important insights into both research aspects of glaciology – the look into the past and into the future. Particularly in areas that are logistically difficult to access, such as the East Antarctic Plateau, field data are scarce. However, these are essential both for studying the signal formation of climate proxies and for validating results from (satellite-based) remote sensing. The East Antarctic Plateau extends from 20°W to 45°E above an elevation of 2000 m asl. During the Antarctic summer of 2016/17, snow cores were sampled in that area on a traverse between Kohnen Station (0° 4’E, 75° 0’S) and the abandoned Plateau Station (40° 33’E, 79° 15’S). X-ray computed tomography was used to determine the density and stratigraphic properties of the snow. The cores were then cut into individual samples at 1 cm or 2 cm resolution under clean room conditions at -18°C, for which a special instrument was developed as part of this study. The distinct samples were analyzed for stable water isotopes as well as major ions. This approach of a multiparameter analysis allows a combined look at different individual parameters and thus better understand the snowpack history. Multiple snow cores per sampling location allow a more representative determination of the investigated parameters. The small-scale variability caused by stratigraphic noise or postdepositional processes can thus be filtered. The surface snow density is needed as a parameter to convert the elevation change of the ice sheet measured by satellites into a mass balance. Due to lack of large-scale data, this density is often modeled. The sampling approach allows us to obtain a representative surface snow density with a relative error of less than 1.5% at each sampling location. Along the traverse route, the mean surface snow density is 355 kg m-3 and shows a lower dependence on temperature and accumulation rate than assumed. The modeled values show a significant discrepancy of about -10% from the measured density. A simplified calculation shows that the modeled snow density underestimates the mass budget of the firn column on the East Antarctic Plateau by 3%. Parameterizations of surface snow density can be tuned with the presented data to reduce the uncertainty of the mass balance of East Antarctica. Crusts in polar snowpacks are a stratigraphic detail that has been used, for example, to characterize environmental conditions in remote regions of the ice sheets. In this work, the first dataset on the spatial distribution of crusts in polar snow is presented – not only with data from the East Antarctic Plateau, but also from Greenland. Contrary to the assumption of finding more crusts in locations with lower accumulation rates, the total number of crusts per meter decreases with decreasing accumulation rates. The results suggest a linear relationship between the number of crusts and the logarithmic accumulation rate. Also the use of crusts for seasonal dating is possible. They can be used as a stratigraphic element supporting the dating with chemical proxies. An effect of crusts on backscatter properties in remote sensing and on firn column ventilation could be future research topics. An exemplary combined study of stratigraphic and chemical properties of the snowpack allows a reconstruction of the continuous buildup of a dune by drifting snow. Whether the chemical signature is characteristic for this type of deposition, however, remains to be proven with further data. Measurements of δ18O and δ2H can be used to reconstruct paleoclimate from seasonal to millennial time scales because of their direct relationship to precipitation temperature. But on short time scales, mechanical (including redistribution by winds) and physical processes (including sublimation and diffusion) at the surface, especially in areas with low accumulation rates, complicate the temporal assignment of the measured signals. An increase in deuterium excess over the uppermost cm in the majority of the investigated snow cores suggest a strong sublimation effect. Samples over larger depth intervals show stronger correlation with temperature and elevation, as the uppermost snow layers can have a seasonal bias. Cycles in δ18O around Kohnen Station can still be interpreted as seasonal signals, but below an accumulation rate of 50 kg m-2a-1, however, they are overprinted by postdepositional diffusion and consequently no longer suitable for dating the snowpack on short time scales. A comparison with the atmospheric general circulation model ECHAM6-wiso validates the model trend along the traverse, but shows a constant offset in δ18O. Modeled snow profiles with precipitation values from ECHAM6-wiso and a diffusion model represent the measured profiles well at 1-2 m depth. However, from the surface to 1 m depth, redeposition and sublimation appear to contribute significantly to (postdepositionally) shaping of the δ18O signal. These processes need to be further quantified in the future to improve the interpretation of stable water isotopes as a proxy for temperature. On the one hand, the change in surface snow density between samples from 2005/06 and samples from this study can be attributed to different volume errors in sampling rather than to a change in climatic conditions. On the other hand, mean δ18O values over the recent decades show a trend of increasing δ18O (and thus increasing temperature) on the East Antarctic Plateau. While these values are within the range of natural variability, they may be early indications that climate proxies in the snow of the East Antarctic Plateau have already recorded the increase of the global temperature.

Long-term change and shorter-term variability in the atmospheric deposition of pollutants and 1 marine salts can have major effects on the biogeochemistry and ecology of soils and surface water 2 ecosystems. In the 1980s, at the time of peak acid deposition in the UK, deposition loads were highly 3 dependent on prevailing weather types, and it was postulated that future pollution recovery 4 trajectories would be partly dependent on any climate change-driven shifts in weather systems. 5 Following three decades of substantial acidic emission reductions, we used monitoring data collected 6 between 1992 and 2015 from four UK Environmental Change Network (ECN) sites in contrasting 7 parts of Great Britain to examine the trends in precipitation chemistry in relation to prevailing 8 weather conditions. Weather systems were classified on the basis of Lamb weather type (LWT) 9 groupings, while emissions inventories and clustering of air mass trajectories were used to interpret 10 the observed patterns. Concentrations of ions showed clear differences between cyclonic-westerly-11 dominated periods and others, reflecting higher marine and lower anthropogenic contributions in 12 Atlantic air masses. Westerlies were associated with higher rainfall, higher sea salt concentrations, 13 and lower pollutant concentrations at all sites, while air mass paths exerted additional controls. 14 Westerlies therefore have continued to favour higher sea salt fluxes, whereas emission reductions are 15 increasingly leading to positive correlations between westerlies and pollutant fluxes. Our results also 16 suggest a shift from the influence of anthropogenic emissions to natural emissions (e.g., sea salt) and 17 climate forcing as they are transported under relatively cleaner conditions to the UK. Westerlies have 18 been relatively frequent over the ECN monitoring period, but longer-term cyclicity in these weather 19 types suggests that current contributions to precipitation may not be sustained over coming years.

The aim of this work, conducted in the upper valley of the Khumbu on the southern part of Mount Everest, is to approach in parallel three topics: (i) the dynamics of the water geochemistry, major ions and trace elements; (ii) the stable water isotopes of precipitation and rivers; and (iii) the water uses by the inhabitants. As in most mountain environments, the Khumbu area is threatened by climate change, which impacts the cryosphere and consequently the people and the landscapes. Moreover, changes in water use are also related to new needs stemming from tourism, which strongly affect local livelihood. For the first two topics, new results are presented. They provide details on the global chemical quality of the river water and show how certain elements are seasonally influenced and how other elements allow us to distinguish the water origins within the study zone. Beside the use of stable isotopes to determine mainly the origin of the water flow in the rivers, the isotopic patterns confirm the double climatic influence of the westerly fluxes in the winter season and of the Asian monsoon in the summer season. Regarding water use, the study does not conclude on the potability of the water resource, because microbiologic and organic components have not been investigated; however it confirms that the chemical quality is good. In conclusion, we attempt to predict the future of the geochemistry patterns submitted to the double pressure of climate change and the surge in tourism.

"Background. Groundwater is a vital source of water for domestic and agricultural activities and the water of the Mocorito River Coastal Aquifer (MORCA), located in the agricultural valley of Culiacan, Sinaloa, Mexico, is not an exception. Goals. To assess MORCA's groundwater quality for drinking and irrigation purposes and the geochemical processes affecting its composition. Methods. Twenty-two well samples were collected during the dry and rainy seasons. Physical and chemical parameters, major ions, drinking quality (WQI and PHASECH water quality index), and irrigation suitability Richards (1954) and Wilcox diagrams) were studied. Results. Total Dissolved Solid (TDS) ranged from 1688 - 8762 mg L-1 for the dry season and 89-10016 mg L-1 for the rainy season. From inland to the coastal zone, MORCA's groundwater was considered hard and very hard, with non-dominant hydrochemical facies in the dry season and calcium, magnesium and sodium (cationic), and bicarbonate and chloride (anionic) types, in the rainy season. US Salinity Staff and Wilcox diagrams revealed that MORCA's groundwater is not suitable for use in irrigation. Further, the geochemical processes controlling the chemical composition of MORCA were evaporation and weathering. Conclusions. According to the TDS and water quality index (WQI and PHASECH) classifying just 4.5 % and over 50 % of the samples, respectively, MORCA water can be considered suitable for human consumption; only the groundwater from site EE-1, in the rainy season, was considered suitable for human consumption. US Salinity staff and Wilcox diagrams indicate that almost 50% of MORCA's groundwater is not suitable for irrigation use. MORCA's groundwater composition is dominated by evaporation and weathering of minerals such as anorthite, illite, and kaolinite."

Observed significant increase of migration properties of uranium from groundwater happens when pH rises above 9 - 10 against significant increases in the concentrations of major ions: Na+, K+, СО32-, NO2-, NO3-. Herewith, strongly alkaline reducing or transitional environment in groundwater is formed.

Concentrations of major ions in stream water from the Soft Plume River on Subantarctic Marion Island were measured. During the annual relief voyage, samples were collected daily over a 16-day period (21 April–6 May 2015) from three sites along the stream to better understand temporal and spatial variability of stream water chemistry on the island. The chemical composition of the stream is dominated by the sea salts Na+ and Cl−. Mean solute concentrations for Na+ and Cl− are 7 ± 0.58 and 12.5 ± 0.84 mg/L, respectively. The mean molar Na:Cl ratio for all samples is 0.86 ± 0.05, with a range from 0.71 to 0.99 (n = 47), and there is a strong, significant positive correlation between Na+ and Cl− concentrations (r = 0.80; p < 0.001). These values are consistent with previous studies from Marion Island and other Subantarctic islands. Temporal variation in ion concentrations was small. The largest detected change was a decrease in most solute concentrations that coincided with two precipitation events. This decrease was largest at the highest altitude and the shallowest site, suggesting that there was more rainfall at this location. These findings confirm the dominance of the surrounding ocean as the main source of the island’s stream water chemistry and illustrate spatiotemporal patterns that provide an insight into mechanisms affecting their composition on Subantarctic Marion Island.

We analysed δ13C of total carbon (TC) and δ15N of total nitrogen (TN) in submicron (PM1) and size segregated aerosol particles (PM0.056–2.5) collected during a cruise in the Baltic Sea from 9 to 17 November 2012. PM1 were characterized by the highest δ13C (–26.4‰) and lowest δ15N (–0.2 and 0.8‰) values when air masses arrived from the southwest direction (Poland). The obtained δ13C values indicated that combined emissions of coal and diesel/gasoline combustion were the most likely sources of TC. The depleted δ15N values indicated that TN originated mainly from liquid fuel combustion (road traffic, shipping) during this period. The lowest δ13C and highest δ15N values were determined in PM1 samples during the western airflow when the air masses had no recent contact with land. The highest δ15N values were probably associated with chemical aging of nitrogenous species during long-range transport, the lowest δ13C values could be related to emissions from diesel/gasoline combustion, potentially from ship traffic. The δ13C analysis of size-segregated aerosol particles PM0.056–2.5 revealed that the lowest δ13C values were observed in the size range from 0.056 to 0.18 µm and gradual 13C enrichment occurred in the size range from 0.18 to 2.5 µm due to different sources or formation mechanisms of the aerosols.

The environmental influence of the Three Gorges Reservoir (TGR) on the Changjiang River has been widely studied since the Three Gorges Dam (TGD) began operation in 2003. However, the changes in water chemistry in the reservoir in response to damming effect variations are poorly documented in the area of this large reservoir. The results suggest that in comparison to the water chemistry before the TGR operation, the inflow concentrations of Mg2+, K+, Na+ and Cl− increased in the TGR, and the abundance of Ca2+ and HCO3- decreased in the inflow in the period after the TGR filling as a result of climate change and human activities in the Changjiang River basin. The ionic composition in the TGR is primarily controlled by contributions from the upstream region of the Changjiang River but was modified by the interaction between water and rocks within the TGR. The concentrations of most major ions as well as the equivalent ratios of the major ions increased in the TGR after the operation of TGD. This change yielded a 6% increase in the major ion loading downstream of the TGD. The Three Gorges area strongly contributes to the increase in ion loading in the TGR due to enhanced water and rock interactions in comparison with the period before TGD operation., Biogeoscience; Hydrology; Geochemistry; Earth sciences; Three Gorges Reservoir; Major ions; Dissolved silicate; Changjiang River (Yangtze River)

Climate change and population growth around Mt. Meru experienced lower availability of water for domestic and agricultural uses. Reduction in quantity of water is compounded by lack of information on water quality which could lead to undesired health risks and agricultural effects when such water is used for irrigation. Thus, major ions from 54 different water types (springs, streams, dug wells, boreholes, and lakes) were used to assess hydrogeochemical characteristics and suitability of water for domestic and agricultural purposes. Results showed dominance of the major cation and anion in the order of Na+ > K+ > Ca2+ > Mg2+ and HCO3 − > CO3 2− > Cl− > SO4 2− > NO3 − > F−, respectively. It is revealed that Mt. Meru is the recharge zone. Geology, water–rock interaction time, and climatic conditions control water chemistry. Major freshwater aquifers were found to be fractured mafic volcanics, breccia, and tuff. Lahars, due to their susceptibility to weathering, were found to host groundwater of low quality. The suitability of water for domestic and irrigation purposes was moderate, in order of lakes

Rapid urbanization and industrial development in the Langat Basin has disturbed the groundwater quality. The populations’ reliance on groundwater sources may induce possible risks to human health such as cancer and endocrine dysfunction. This study aims to determine the groundwater quality of an urbanized basin through 24 studied hydrochemical parameters from 45 groundwater samples obtained from 15 different sampling stations by employing integrated multivariate analysis. The abundance of the major ions was in the following order: bicarbonate (HCO3−) &gt, chloride (Cl−) &gt, sodium (Na+) &gt, sulphate (SO42−) &gt, calcium (Ca2+) &gt, potassium (K+) &gt, magnesium (Mg2+). Heavy metal dominance was in the following order: Fe &gt, Mn &gt, Zn &gt, As &gt, Hg &gt, Pb &gt, Ni &gt, Cu &gt, Cd &gt, Se &gt, Sr. Classification of the groundwater facies indicated that the studied groundwater belongs to the Na-Cl with saline water type and Na-HCO3 with mix water type characteristics. The saline water type characteristics are derived from agricultural activities, while the mixed water types occur from water–rock interaction. Multivariate analysis performance suggests that industrial, agricultural, and weathering activities have contributed to groundwater contamination. The study will help in the understanding of the groundwater quality issue and serve as a reference for other basins with similar characteristics.

Rivers transport terrestrial matter into the ocean, constituting a fundamental channel between inland and oceanic ecosystem and affect global climate change. To reveal chemical weathering processes and environmental health risks during flood periods, water samples were collected in the upper reaches of Three Gorges Reservoir (TGR) in 2020. HCO3− and Ca2+ were the most abundant anions and cations of the river water, respectively. The range of HCO3− concentration was between 1.81 and 3.02 mmol/L, while the mean content of Ca2+ was 1.03 mmol/L. The results of the Piper diagram and element ratios revealed that the river solutes were mainly contributed by carbonate weathering and gypsum-rich evaporite dissolution. A mass balance model indicated that the contribution order of sources to cations in the main channel (Yibin-Luzhou) was evaporites &gt, carbonates &gt, atmospheric input &gt, silicates. The order in the Chongqing—Three Gorges Dam was carbonates &gt, evaporites &gt, silicates. These results showed a lithologic control on hydrochemical characteristics. Most sampling sites were suitable for agricultural irrigation according to the water quality assessment. However, indexes sodium adsorption ratio (SAR) and soluble sodium percentage (Na%) were higher than 1.0 in Yibin-Luzhou and 30% in Yibin–Chongqing, respectively, suggesting a potential sodium hazard. In addition, except Tuojiang River and Shennong River, the risk of sodium hazard in tributaries was relatively low. High Na+ concentration in irrigation water can damage soil structure and function and ultimately affect agricultural production. Water quality in the upstream of a Piper diagram should attract enough attention.

Salinization of freshwaters by human activities is of growing concern globally. Salt pollution can cause adverse effects to aquatic biodiversity, ecosystem function, ecosystem services, and human health. In many regions of the world, and in coal-mining-influenced streams of the temperate forests of Appalachia USA, specific conductance (SC), a surrogate measure for the dissolved major ions composing salinity, has been linked to decreased diversity of benthic macroinvertebrates. However, assessments used to reach this conclusion have generally not accounted for temporal variability of salinity, as most studies use "snapshot" SC data collected concurrently with biological data at a single point in time. Effective management of salinization requires tools to accurately monitor and predict salinity while accounting for temporal variability. To improve those tools, I conducted analyses of 4.5 years of salinity and benthic macroinvertebrate data from 25 forested headwater streams spanning a gradient of salinity where non-salinity stressors were minimized. My objectives were to: 1) model the annual pattern of salinity, 2) determine if salinity measures derived from continuous data are more precise than snapshot SC as predictors of aquatic biology, and 3) quantify response to salinity of the benthic macroinvertebrate community. A sinusoidal model of the annual cycle of SC using daily measurements for 4.5 years revealed that salinity naturally deviated ± 20% from annual mean levels, with minimum SC occurring in late winter and maximum SC occurring in late summer. The pattern was responsive to seasonal dilution as driven by catchment evapotranspiration dynamics. Alternative discrete sampling intervals can approximate the pattern revealed by continuous SC data if sampling intervals are ≤ 30 days. Continuous SC variables did not significantly improve precision for prediction of benthic macroinvertebrate metrics (p > 0.1) as compared to snapshot SC using generalized additive mixed models. Results suggest that snapshot SC is a capable predictor of benthic macroinvertebrate community structure if sampling is carefully timed. However, continuous SC data can quantify chronic salt exposure, which supports a hypothesis to explain how temporal variability of field-based observations of salt sensitivity of benthic macroinvertebrate taxa may be influenced by life stage. Benthic macroinvertebrate community structure diverged from reference condition as salinity increased, with stronger relationships in Spring than in Fall. Intra-seasonal variation in community structure was also revealed across sampling dates. Non-Baetidae Ephemeroptera were most sensitive to salinity, with richness and abundance lower than reference at SC > 200 =µS/cm in Spring based on snapshot SC. Equivalent effects were predicted by mean monthly SC of 250-300 µS/cm from the prior Fall. Continuous conductivity monitoring may improve assessment of salinity effects because they can describe life-cycle exposure, which may aid investigations of mechanisms driving field-based observations of benthic-macroinvertebrate community alteration. Ph. D.

The coastal atmosphere adjacent to large urban areas can be strongly affected by the emission of air pollutants, among them, major ions species. In this study, the chemical composition and sources of carboxylates and other water-soluble ions in fine and coarse aerosols as well as estimates of particle dry deposition fluxes were studied at a tropical coastal site affected by an urban environment. The mean concentrations of the total carboxylates were 78 ng m–3 in fine fraction and 81 ng m–3 in coarse fraction of particulate matter (PM). The corresponding values for the total inorganic ions were 2143 ng m–3 and 4880 ng m–3 respectively. Main sources for fine particles were: (i) photochemical formation of carboxylic acids in vapor phase and a posterior gas-to-particle conversion onto sea salt particles; (ii) emissions from anthropic sources with long range transportation processes; and (iii) the interchanging of volatile species among atmospheric phases. In turn, for coarse particles, the predominant sources were: (i) gas-phase species and ab/adsorbed onto pre-existing particles afterwards; (ii) primary emission of coarse particles from anthropogenic sources; and (iii) sea salt spray and/or soil resuspension. Finally, particle dry deposition was a very important mechanism representing air-to-sea fluxes of major species. A atmosfera de regiões costeiras adjacentes a regiões urbanas podem ser afetadas pela emissão de diferentes poluentes atmosféricos, dentre eles, os íons majoritários. Nesse estudo foram estudadas a composição química e as fontes de carboxilatos e íons solúveis em água em partículas finas e grossas bem como as estimativas de fluxo de deposição seca em um sítio em uma região costeira tropical afetada por uma Região Metropolitana. As concentrações médias de carboxilatos totais foram 78 ng m–3 na fração fina e 81 ng m–3 na fração grossa do material particulado (MP). Os valores correspondentes de concentração para os íons inorgânicos foram 2143 ng m–3 e 4880 ng m–3, respectivamente, para as frações fina e grossa. As principais fontes para as partículas finas foram: (i) formação fotoquímica de ácidos carboxílicos na fase vapor e posterior conversão gás-partícula sobre partículas de sal marinho, (ii) emissões de fontes antrópicas envolvendo processos de transporte de longas distâncias; e (iii) a interconversão de espécies voláteis entre fases atmosféricas. Por sua vez, as fontes predominantes para as partículas grossas foram: (i) espécies gasosas ab/adsorvidas em partículas pré-existentes, (ii) emissão primária de partículas grossas de fontes antrópicas, e (iii) spray marinho e/ou ressuspensão do solo. Finalmente, a deposição seca de partículas representa o fluxo de íons majoritários na interface ar-oceano.

The chemical composition of river water collected from the main stream of the Naqu and its tributaries was analyzed to reveal its hydrochemical characteristics and to evaluate the water quality for irrigation purposes. Based on 39 samples, the results revealed mildly alkaline pH values and total dissolved solids (TDS) values ranging from 115 to 676 mg/L, averaging 271 mg/L. Major ion concentrations based on mean values (mg/L) were in the order of Ca2+&gt, Na+&gt, Mg2+&gt, K+ for cations and HCO3-&gt, SO42-&gt, Cl-&gt, CO32- for anions. Most hydrochemical types were of the Ca&ndash, HCO3 (~74.36%) type. Cluster analysis (CA) suggested that the hydrochemical characteristics upstream of the main stream of the Naqu were obviously different from those from the middle and downstream of the main stream and its tributaries. The analysis shows that the Sangqu, Basuoqu, Mumuqu, Zongqingqu, Mugequ basin tributary, and the Gongqu basin tributary were mainly affected by carbonate weathering. Carbonate and silicate weathering commonly controlled the hydrochemistry upstream and downstream of the main Naqu, Chengqu, and Mugequ streams. The middle of the main stream of the Naqu was mainly affected by silicate weathering, and anhydrite/gypsum dissolution mainly affected the hydrochemistry of the main Gongqu stream. The quality of water samples was suitable for irrigation purposes, except for one sample from the main stream of the Mugequ.

In this research, the results of a hydro-chemical study of Lake Kopa in Kazakhstan are described, in thecontext of the regional geography and aggravating ecological problems of the lake. Besides analyzingthe concentrations of all major ions, heavy-metal ions and other pollutants, their vertical andhorizontal distribution were also assessed. Moreover, water pollution indices (WPI) were calculatedfor individual ions, classes of pollutants, and total pollution, revealing serious overload of human-induced pollution within the lake’s ecosystem. Concentrations of major ions and WPI were monitoredover 2009-2013 period, revealing a distinct seasonal pattern and a multi-year periodicity in respect tothe measured parameters. In addition, studying ion exchange between lake water and bottomsediment showed complex non-equilibrium processes besides leaching out Ca2+ and its exchange forNa+., Bu araştırmada, Kazakistan'ın Kopa Gölü'nde yapılan hidro-kimyasal çalışmanın sonuçları gölünbölgesel coğrafyası ve ciddileşen ekolojik sorunları bağlamında anlatılmıştır. Tüm majör iyonların, ağır-metal iyonlarının ve diğer kirleticilerin yoğunluklarının analiz edilmesi yanında, bunların dikey ve düşeydağılımları da irdelenmiştir. Bununla beraber, su kalitesi indisleri (water quality indices-WPI)kullanılarak her bir iyon, kirlilik sınıfları ve toplam kirlilik üzerinde yapılan hesaplamalar, gölekosisteminde insan-kaynaklı ciddi bir fazla yük kirliliği olduğu ortaya çıkarmıştır. Majör iyonlarınkonsantrasyonları ve su kalitesi indisleri (WPI) 2009-2013 periyotu boyunca izlenmiş ve ölçülenparametreler için belirgin bir mevsimsel desen ile çok yıllık periyodiklik olduğu açığa çıkmıştır. Ayrıca,göl suyu ve yatak sedimenti arasındaki iyon alış-verişinin araştırılması, Ca+2'un yıkanması ve Na+ iledeğişimi yanında karmaşık dengesizlik süreçleri de göstermiştir.

The present study investigates the chemical composition of wet atmospheric precipitation samples on a daily and an intra-event timescales in Opme, an experimental meteorological station located near Clermont-Ferrand, France. The samples have been collected from November 2005 to October 2007. A total of 217 rainwater samples, integrated for 24 h, were collected and analyzed for pH, conductivity, Na+, K+, Mg2+, NH 4 + , Ca2+, Cl−, NO 3 − , SO 4 2− , PO 4 3− and HCO 3 − . The composition of the rainwater collected appeared to be controlled by the following potential sources: neutralisation process (association among calcium, ammonium with nitrate and sulphate), marine and terrestrial sources. In order to determine the role of long-range transport, the integrated events were classified according to four origins of air-masses: (1) West, (2) North and East, (3) South including Iberian and Italian Peninsulae and (4) local. This analysis allows identifying the source areas of the different association of elements defined. Although calcium is always dominant, total content of rainfall is variable and neutralisation process can be more or less efficient and specific. Rainout (long-range transport) and washout (below-cloud scavenging) were investigated through intra-event measurements of chemical species. Four rain-events have been selected according to the four classes of origins of air-masses. It appears that the first fractions are responsible for an important part of the chemical content of the whole event. Terrestrial species, locally emitted, induce the neutralisation process of acid species. Local meteorological conditions, such as wind’s speed and direction, play an important role as they could provoke recharges of the below cloud air column during the event.

Systematic monitoring of subsurface hydrogeochemistry has been carried out for a period of one year in a humid tropical region along the Nethravati-Gurupur River. The major ion and stable isotope (delta O-18 and delta H-2) compositions are used to understand the hydrogeochemistry of groundwater and its interaction with surface water. In the study, it is observed that intense weathering of source rocks is the major source of chemical elements to the surface and subsurface waters. In addition, agricultural activities and atmospheric contributions also control the major ion chemistry of water in the study area. There is a clear seasonality in the groundwater chemistry, which is related to the recharge and discharge of the hydrological system. On a temporal scale, there is a decrease in major cation concentrations during the monsoon which is a result of dilution of sources from the weathering of rock minerals, and an increase in anion concentrations which is contributed by the atmosphere, accompanied by an increase in water level during the monsoon. The stable isotope composition indicates that groundwater in the basin is of meteoric origin and recharged directly from the local precipitation during the monsoonal season. Soon after the monsoon, groundwater and surface water mix in the subsurface region. The groundwater feeds the surface water during the lean river flow season.

The region of the investigated receptor is situated in the southern part of the Adriatic Sea in the Mediterranean. The measuring station is located on the seashore, which, being considered as a border area, is representative for the qualitative and quantitative estimation of the influence of marine and continental aerosols on the content of major ions in precipitation. In the sampling period, precipitation in the region of the investigated receptor was more abundant during the summer and autumn than during the winter and spring. The most frequent precipitation heights were up to 20 mm, while high precipitation came exclusively from the continental region. The results of the measurements of ions readily soluble in water were used for the differentiation of marine from continental contributions of primary and secondary aerosols to their content in the precipitation. Using PCA, it was shown that main contribution of Cl-, Na+ and Mg2+ came from primary marine aerosols, while the contribution from continental sources was dominant for the content of SO42-, NO3-, NH4+ and Ca2+ in the precipitation. The continental origin of Ca2+ was from a primary source, while SO42-, NO3- and NH4+ were representatives of secondary aerosols produced by reactions between acid oxides and alkaline species in the atmosphere, but SO2- and NO3- also exist in the precipitation as free acids. The origin of the trace elements Cd, Cu, Pb and Zn in the precipitation came from anthropogenic emission sources. The results obtained in this work are based on experimental data from 609 samples collected during the period 1995-2000. (c) 2006 Elsevier B.V. All rights reserved.

In this study, the major chemical compositions of 159 shallow groundwater samples incorporated saturation index (SI) and Principal Component Analysis (PCA) were employed to evaluate the mainly geochemical processes that control the hydrogeochemical evolution of groundwater in a typical karst area, Bijie city, Guizhou Province. The groundwater samples in this study area were dominated of HCO3-Ca, HCO3-Ca-Mg, and HCO3-SO4-Ca types. The PCA suggested that four principal components could explain 88.85% of the total variance of 10 parameters, indicating that the hydrogeochemical evolution of groundwater was mainly controlled by the dissolution/precipitation of carbonates, gypsum, and halite minerals, cation exchange, and anthropogenic activities. To be specific, the enrichment of Ca2+, Mg2+, HCO3− and SO42− in groundwater were primarily affected by the dissolution of dolomite and gypsum minerals, and the role of calcite dissolution was relatively weaker because most groundwater samples were saturated with respect to calcite. Besides, cation exchange was another factor that may affect the concentration of Ca2+ and Mg2+ in groundwater, and the concentration of SO42− can also be influenced by coal mining activity. In addition, the concentrations of Na+ and Cl− in groundwater were likely influenced by the dissolution of halite, cation exchange, and human activities.

The present study deals with the characterization of Mazzoccolo karst spring which feeds the most important water supply network in southern part of Latium region, in Central Italy. During sample collections from 2006 to 2008, a series of in situ measurements were conducted for pH, electrical conductivity (EC), total dissolved solids (TDS) and temperature. The environmental isotopic and hydrochemical measurements were carried out for the vulnerability assessment and geochemical modeling with the aim of achieving (i) proper management and protection of this important resource, (ii) hydrochemical processes controlling the evolution of groundwater and (iii) identification of recharge areas. All sampled spring waters are characterized as Ca-HCO3 type waters reflecting the main rock types in the area investigated, where limestones and Pliocene conglomerates are the most dominant formations. The electrical conductivity (EC) and TDS values of water samples from springs varies from with a maximum value of 341 µS/cm and 268 mg/l and minimum value of 28 µS/cm and 104 mg/l, respectively. The pH values of spring samples range from 7.4 to 9 indicating alkaline nature. The anion composition is quite stable showing HCO3 −>Cl−>SO4 2− (in mg/l), while calcium is the dominant cation, followed by magnesium, sodium and potassium. The comparison of δ18O and δ2H values of spring water samples with meteoric water lines shows that most of the samples fall to the Local Meteoric Water Line suggesting input to local rain-fall derives from the Mediterranean Sea. The elevation of the recharge areas range between 600 and 800 m a.s.l confirming the Aurunci karst aquifer is feeding Mazzoccolo spring.