scholarly journals Depth–Sequential Investigation of Major Ions, δ18o, δ2h and δ13C in Fractured Aquifers of the St. Lawrence Lowlands (Quebec, Canada) Using Passive Samplers

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1806
Author(s):  
Guillaume Meyzonnat ◽  
Florent Barbecot ◽  
José Corcho Alvarado ◽  
Daniele Luigi Pinti ◽  
Jean-Marc Lauzon ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Major Ions ◽  
Anthropogenic Activities ◽  
Carbon Sources ◽  
Passive Samplers ◽  
Flow Paths ◽  
Aquifer Heterogeneity ◽  
Fractured Aquifers ◽  
Fractured Carbonate ◽  
Observation Wells

General and isotopic geochemistry of groundwater is an essential tool to decipher hydrogeological contexts and flow paths. Different hydrogeochemical patterns may result from the inherent physical aquifer heterogeneity, which may go unnoticed without detailed investigations gathered from multilevel or multiple observation wells. An alternative to overcome the frequent unavailability of multiple wellbores at sites is to perform a detailed investigation on the single wellbore available. In this perspective, the aim of this study is to use passive samplers to sequentially collect groundwater at depths in long–screened wellbores. Such investigation is carried out for major ions and stable isotopes compositions (δ2H, δ18O, δ13C) at ten sites in the context of fractured carbonate aquifers of the St. Lawrence Lowlands (Quebec, Canada). The information gathered from the calco–carbonic system, major ions and stable isotopes report poorly stratified and evolved groundwater bodies. Contribution of water impacted by anthropogenic activities, such as road salts pollution and carbon sources from C4 vegetation, when they occur, are even observed at the greatest depths. Such observations suggest quick flow paths and efficient mixing conditions, which leads to significant contributions of contemporary groundwater bodies in the fractured aquifers investigated down to depths of about 100 m. Although physical aquifer investigation reported few and heterogeneously distributed fractures per wellbore, hydrogeochemical findings point to at overall well interconnected fracture networks in the aquifer and high vulnerability of groundwater, even at significant depths.

scholarly journals Water Quality and Hydrogeochemical Characteristics of Some Karst Water Sources in Apuseni Mountains, Romania

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 857
Author(s):  
Maria-Alexandra Hoaghia ◽  
Ana Moldovan ◽  
Eniko Kovacs ◽  
Ionut Cornel Mirea ◽  
Marius Kenesz ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Chemistry ◽  
Major Ions ◽  
Anthropogenic Activities ◽  
Water Sources ◽  
Main Process ◽  
Karst Water ◽  
Rock Interaction ◽  
Apuseni Mountains ◽  
Karst Waters

Human activities and natural factors determine the hydrogeochemical characteristics of karst groundwaters and their use as drinking water. This study assesses the hydrogeochemical characteristics of 14 karst water sources in the Apuseni Mountains (NW Romania) and their potential use as drinking water sources. As shown by the Durov and by the Piper diagrams, the chemical composition of the waters is typical of karst waters as it is dominated by HCO3− and Ca2+, having a circumneutral to alkaline pH and total dissolved solids ranging between 131 and 1092 mg L−1. The relation between the major ions revealed that dissolution is the main process contributing to the water chemistry. Limestone and dolostone are the main Ca and Mg sources, while halite is the main Na and Cl source. The Gibbs diagram confirmed the rock dominance of the water chemistry. The groundwater quality index (GWQI) showed that the waters are of excellent quality, except for two waters that displayed medium and good quality status. The quality of the studied karst waters is influenced by the geological characteristics, mainly by the water–rock interaction and, to a more limited extent, by anthropogenic activities. The investigated karst waters could be exploited as drinking water resources in the study area. The results of the present study highlight the importance of karst waters in the context of good-quality water shortage but also the vulnerability of this resource to anthropogenic influences.

scholarly journals Natural and human-induced factors controlling the phreatic groundwater geochemistry of the Longgang River basin, South China

2020 ◽  
Vol 12 (1) ◽  
pp. 203-219
Author(s):  
Wei Li ◽  
Xiaohong Chen ◽  
Linshen Xie ◽  
Gong Cheng ◽  
Zhao Liu ◽  
...  
Keyword(s):  
Groundwater Quality ◽  
Chemical Evolution ◽  
South China ◽  
Major Ions ◽  
Negative Impact ◽  
Flow Direction ◽  
Anthropogenic Activities ◽  
Ionic Composition ◽  
Primary Source ◽  
Ammonia Concentration

AbstractGroundwater chemical evolution is the key to ensuring the sustainability of local society and economy development. In this study, four river sections and 59 groundwater wells are investigated in the Longgang River (L.R.) basin in South China. Comprehensive hydrochemical analysis methods are adopted to determine the dominant factors controlling the chemical evolution of the local phreatic groundwater and the potential impact of human activities on groundwater quality. The results indicate that the ionic composition of the local phreatic groundwater is dominated by Ca2+ (0.9–144.0 mg/L), HCO3− (4.4–280.0 mg/L), and SO42− (1.0–199.0 mg/L). Ca–Mg–HCO3, Ca–Na–HCO3, and Na–Ca–HCO3 are the major groundwater hydrochemical facies. Water–rock interactions, such as the dissolution of calcite and dolomite, are the primary source of the major ions in the local groundwater. Cation-exchange reaction has its effects on the contents of Ca2+, Mg2+, and Na+. Ammonia concentration of the sampling sections in the L.R. increases from 0.03 to 2.01 mg/L along the flow direction. Groundwater nitrate in the regions of the farmland is attributed to the lowest level of the groundwater quality standards of China, while the same test results are obtained for heavy metals in the industrial park and landfill, suggesting a negative impact of the anthropogenic activities on the local phreatic groundwater quality.

scholarly journals Scale dependency of fractional flow dimension in a fractured formation

2011 ◽  
Vol 15 (7) ◽  
pp. 2165-2178 ◽  
Author(s):  
Y.-C. Chang ◽  
H.-D. Yeh ◽  
K.-F. Liang ◽  
M.-C. T. Kuo
Keyword(s):  
Field Data ◽  
Geothermal Field ◽  
Fractured Media ◽  
Fractional Flow ◽  
Hydraulic Test ◽  
Flow Paths ◽  
Flow Dimension ◽  
Flow Geometry ◽  
Flow Dimensions ◽  
Observation Wells

Abstract. The flow dimensions of fractured media were usually predefined before the determination of the hydraulic parameters from the analysis of field data in the past. However, it would be improper to make assumption about the flow geometry of fractured media before site characterization because the hydraulic structures and flow paths are complex in the fractured media. An appropriate way to investigate the hydrodynamic behavior of a fracture system is to determine the flow dimension and aquifer parameters simultaneously. The objective of this study is to analyze a set of field data obtained from four observation wells during an 11-day hydraulic test at Chingshui geothermal field (CGF) in Taiwan in determining the hydrogeologic properties of the fractured formation. Based on the generalized radial flow (GRF) model and the optimization scheme, simulated annealing, an approach is therefore developed for the data analyses. The GRF model allows the flow dimension to be integer or fractional. We found that the fractional flow dimension of CGF increases near linearly with the distance between the pumping well and observation well, i.e. the flow dimension of CGF exhibits scale-dependent phenomenon. This study provides insights into interpretation of fracture flow at CGF and gives a reference for characterizing the hydrogeologic properties of fractured media.

scholarly journals Suspended Particular Matter drives the spatial segregation of nitrogen turnover along the hyper-turbid Ems estuary

2021 ◽  
Author(s):  
Gesa Schulz ◽  
Tina Sanders ◽  
Justus E. E. van Beusekom ◽  
Yoana G. Voynova ◽  
Andreas Schöl ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Nitrous Oxide ◽  
Water Column ◽  
Anthropogenic Activities ◽  
Inorganic Nitrogen ◽  
Nitrate Removal ◽  
Tidal River ◽  
Nutrient Loads ◽  
Ems Estuary ◽  
Nitrogen Turnover

Abstract. Estuaries are nutrient filters and change riverine nutrient loads before they reach coastal oceans. They have been extensively changed by anthropogenic activities like draining, deepening, and dredging to meet economic and social demand, causing significant regime changes like tidal amplifications and in some cases to hyper-turbid conditions. Furthermore, increased nutrient loads, especially nitrogen, mainly by agriculture cause coastal eutrophication. Estuaries can either act as a sink or as a source of nitrate, depending on environmental and geomorphological conditions. These factors vary along an estuary, and change nitrogen turnover in the system. Here, we investigate the factors controlling nitrogen turnover in the hyper-turbid Ems estuary (Northern Germany) that has been strongly impacted by human activities. During two research cruises in August 2014 and June 2020, we measured water column properties, dissolved inorganic nitrogen, dual stable isotopes of nitrate and dissolved nitrous oxide concentration along the estuary. Overall, the Ems estuary acts as a nitrate sink in both years. However, three distinct biogeochemical zones exist along the estuary. A strong fractionation (~ 26 ‰) of nitrate stable isotopes points towards nitrate removal via water column denitrification in the hyper-turbid Tidal River, driven by anoxic conditions in deeper water layers. In the Middle Reaches of the estuary nitrification gains in importance turning this section into a net nitrate source. The Outer Reaches are dominated by mixing with nitrate uptake in 2020. We find that the overarching control on biogeochemical nitrogen cycling, zonation and nitrous oxide production in the Ems estuary is exerted by suspended particulate matter concentrations and the linked oxygen deficits.

scholarly journals Inconsistent relationships between major ions and water stable isotopes in Antarctic snow under different accumulation environments

Polar Science ◽  
2016 ◽  
Vol 10 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Yu Hoshina ◽  
Koji Fujita ◽  
Yoshinori Iizuka ◽  
Hideaki Motoyama
Keyword(s):  
Stable Isotopes ◽  
Major Ions ◽  
Antarctic Snow

The monogenean Paradiplozoon ichthyoxanthon behaves like a micropredator on two of its hosts, as indicated by stable isotopes

2018 ◽  
Vol 93 (1) ◽  
pp. 71-75 ◽  
Author(s):  
B. Sures ◽  
M. Nachev ◽  
B.M. Gilbert ◽  
Q.M. Dos Santos ◽  
M.A. Jochmann ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Trophic Level ◽  
Trophic Interactions ◽  
Carbon Sources ◽  
Food Sources ◽  
Carbon And Nitrogen ◽  
Blood Sucking ◽  
Vaal Dam ◽  
Living Organisms ◽  
Host Fishes

AbstractThe analysis of stable isotopes of carbon and nitrogen has been used as a fingerprint for understanding the trophic interactions of organisms. Most of these studies have been applied to free-living organisms, while parasites have largely been neglected. Studies dealing with parasites so far have assessed the carbon and nitrogen signatures in endoparasites or ectoparasites of different hosts, without showing general trends concerning the nutritional relationships within host–parasite associations. Moreover, in most cases such systems involved a single host and parasite species. The present study is therefore the first to detail the trophic interactions of a freshwater monogenean–host model using δ13C and δ15N, where a single monogenean species infects two distinctly different hosts. Host fishes, Labeobarbus aeneus and Labeobarbus kimberleyensis from the Vaal Dam, South Africa, were assessed for the monogenean parasite Paradiplozoon ichthyoxanthon, individuals of which were removed from the gills of the hosts. The parasites and host muscle samples were analysed for signatures of δ13C and δ15N using an elemental analyser connected to an isotope ratio mass spectrometer. Host fish appear to use partly different food sources, with L. aeneus having slightly elevated δ13C signatures compared to L. kimberleyensis, and showed only small differences with regard to their nitrogen signatures, suggesting that both species range on the same trophic level. Carbon and nitrogen signatures in P. ichthyoxanthon showed that the parasites mirrored the small differences in dietary carbon sources of the host but, according to δ15N signatures, the parasite ranged on a higher trophic level than the hosts. This relationship resembles predator–prey relationships and therefore suggests that P. ichthyoxanthon might act as a micropredator, similar to blood-sucking arthropods such as mites and fleas.

scholarly journals Nitrate stable isotopes and major ions in snow and ice samples from four Svalbard sites

2015 ◽  
Vol 34 (1) ◽  
pp. 23246 ◽  
Author(s):  
Carmen P. Vega ◽  
Mats P. Björkman ◽  
Veijo A. Pohjola ◽  
Elisabeth Isaksson ◽  
Rickard Pettersson ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Major Ions ◽  
Snow And Ice

scholarly journals Hydrochemistry of the Lhasa River, Tibetan Plateau: Spatiotemporal Variations of Major Ions Compositions and Controlling Factors Using Multivariate Statistical Approaches

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3660
Author(s):  
Meizhuang Zhu ◽  
Xingxing Kuang ◽  
Yuqing Feng ◽  
Yinlei Hao ◽  
Qiule He ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
River Water ◽  
Major Ions ◽  
Anthropogenic Activities ◽  
Controlling Factors ◽  
Anthropogenic Activity ◽  
Chemical Compositions ◽  
Spatiotemporal Variations ◽  
Southern Tibetan Plateau ◽  
Lhasa River

Spatiotemporal variations of the hydrochemical major ions compositions and their controlling factors are essential features of a river basin. However, similar studies in the southern Tibetan Plateau are relatively limited. This study focuses on the chemical compositions of the dissolved loads in the Lhasa River (LR) in the southern Tibetan Plateau. Two sampling campaigns were conducted during the rainy and dry seasons across the LR basin to systematically investigate the spatiotemporal variations of water chemistry and sources of the dissolved loads. The results show that the river water possesses slight alkalinity with an average pH of 8.05 ± 0.04. Total dissolved solids (TDS) and oxidation-reduction potential (ORP) range widely from 39.8 mg/L to 582.6 mg/L with an average value of 165.6 ± 7.7 mg/L and from −9.4 mV to 295 mV with a mean value of 153.7 ± 6.9 mV, respectively. The major cations follow the decreasing order of Ca2+, Mg2+, Na+, and K+ while HCO3−, SO42−, Cl−, and NO3− for anions. Ca2+ and Mg2+ account for 87.8% of the total cations, while HCO3− and SO42− accounts for 93.9% of the total anions. All the major ions show higher concentrations in the dry season. NO3−, HCO3−, and Mg2+ show significant spatial variations due to the influence of basin lithology and anthropogenic activity. Multi-variables statistical analysis reveals that the mechanisms controlling the LR hydrochemistry are mainly carbonate weathering followed by silicate weathering. Geothermal springs and anthropogenic activities also play crucial roles in altering river water ions composition in the middle stream and downstream. The relatively high NO3− value (3 ± 0.2 mg/L) suggests water quality will be under the threat of pollution with the increase of anthropogenic activities.

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