| 1. |
- Abiye, T. A., et al.
(författare)
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Arsenic concentration in groundwater : Archetypal study from South Africa
- 2019
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Ingår i: Groundwater for Sustainable Development. - : Elsevier. - 2352-801X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- South Africa does not have significant surface water resources, which is often easily affected by unpredictable and rapidly changing climatic variables, due to its location in the arid and semi-arid climatic setting. In large part of the country, groundwater from weathered and fractured crystalline rocks plays pivotal role in sustaining the livelihood, often it contains toxic metals released from the host rocks. The host rocks that are responsible for arsenic release in groundwater are primarily enriched due to metamorphism and igneous processes that resulted in the enrichment of economic minerals. Preliminary assessment indicates that the main arsenic containing minerals are arsenopyrite (FeAsS), arsenical oxide, sulpharsenide, arsenopyritical reefs, leucopyrite, löllingite (FeAs2) and scorodite (FeAsO4·2H2O). Owing to the release of arsenic from highly mineralized rocks that constitute the aquifers, arsenic concentration in the groundwater reaches up to 253 μg/L (Namaqualand), 6150 μg/L (west of Johannesburg), about 500 μg/L in the Karoo aquifers, considerably higher than the WHO guideline value of 10 μg/L. Acid mine drainage from coal and gold mining is also found to be an important source of arsenic and other toxic metals in groundwater.
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| 2. |
- Ahmad, Arslan, et al.
(författare)
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Environmental arsenic in a changing world
- 2019
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Ingår i: Groundwater for Sustainable Development. - : Elsevier. - 2352-801X. ; 8, s. 169-171
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Ali, S., et al.
(författare)
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Concentration of fluoride in groundwater of India : A systematic review, meta-analysis and risk assessment
- 2019
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Ingår i: Groundwater for Sustainable Development. - : Elsevier. - 2352-801X. ; 9
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Forskningsöversikt (refereegranskat)abstract
- It is a well-known fact that the Indian groundwater is polluted by fluoride. However, for the first time in India, non-carcinogenic risk assessments and meta-analysis of fluoride exposure to humans were carried out due to consumption of groundwater. In this context, we collected fluoride concentration data in groundwater across India by systematic searches conducted in various international search engines databases. Here, we demonstrated a detailed meta-analysis and meta-regression of fluoride and evaluated health risk assessment. For this purpose, meta-analysis of 63 studies on fluoride in groundwater in India, comprising 57381 samples are included. We found that 1.) The pooled concentration of fluoride in India is around 2.37 mg/L with 95% confident interval (1.46–3.28 mg/L) which is higher than WHO and national standards limit of 1.5 mg/L. 2) The meta-analysis of data suggests that in rural parts of the country, fluoride concentration is 1.85 times higher than urban areas. 3) The concentration of fluoride in groundwater decreased significantly (p < 0.05) with increase in rainfall and longitude. The risk assessment via oral and dermal route exposure reveals that the consumers in majority of the regions are at considerable non-carcinogenic risk and children are at higher risk than adults (Total hazard quotient > 1). The findings are helpful in identifying the affected areas of India and we recommend that the safer options of drinking water should be adopted.
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| 4. |
- Bhattacharjee, S., et al.
(författare)
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Groundwater governance in Bangladesh : Established practices and recent trends
- 2019
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Ingår i: Groundwater for Sustainable Development. - : Elsevier. - 2352-801X. ; 8, s. 69-81
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Tidskriftsartikel (refereegranskat)abstract
- Legal framework is very crucial to protect the vital resources, to provide rights to public and administration, to support national policy and to bring technological intervention to ensure equitable distribution, fair management, and effective decision making. In Bangladesh, groundwater is not directly priced (other than pumping costs), perhaps such issue is not surprising that users do not meter the volumes of water usage. Beside the industry, agricultural sector is by far the biggest groundwater consumer of this country, contributing significant amount of annual meter drop in the groundwater table to the annual decline of groundwater table. Additionally, the groundwater resources are severely affected by, pollution, encroachment and overexploitation. National Water Policy (1999) and Bangladesh Water Act (2013) are considered as country's pivotal legal framework but both of these lag behind to provide effective guidelines on permission, extraction limit, monitoring, protection of quality, water harvesting procedure, and recharge mechanism. Existing institutions suffer from consistent crisis, politics, corruption, absence of public participation and coordination of other institutions, mismanagement, and empirical assessment. This study evaluates the existing water related policies and functions of multidimensional institutions, and discusses the key challenges of effective groundwater management. The present paper also provides an overview of established practices around the world to cope with the common challenges.
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| 5. |
- Kimambo, Vivian, et al.
(författare)
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Fluoride occurrence in groundwater systems at global scale and status of defluoridation – State of the art
- 2019
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Ingår i: Groundwater for Sustainable Development. - : Elsevier. - 2352-801X. ; 9
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Forskningsöversikt (refereegranskat)abstract
- Occurrence of elevated concentrations of fluoride in the drinking water supply in many regions of the world has caused widespread dental and skeletal fluorosis. In this paper the studies available on the routes of fluoride exposure, regions with excess fluoride in water sources and various defluoridation techniques has been reviewed. It is evident from the literature survey that no single technique fits for diverse technical and socioeconomic situations and there is a pressing need to develop suitable defluoridation techniques for household and community level water supply system in order to prevent fluorosis.
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| 6. |
- Quino Lima, Israel, 1980-, et al.
(författare)
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Hydrochemical assessment with respect to arsenic and other trace elementsin the Lower Katari Basin, Bolivian Altiplano
- 2019
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Ingår i: Groundwater for Sustainable Development. - : Elsevier BV. - 2352-801X. ; 8, s. 281-293
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Hydrochemical investigations of groundwater and surface water were carried out to better understand the spatial distribution of As, major ions and trace elements.The study was carried out to evaluate the sources of dissolved species and elucidate the processes that govern the evolution of natural water in the Lower Katari Basin.The study area is close to the Titicaca Lake (Cohana Bay) formed by sediments of the Quaternary system, deposited in the fluvio-glacial to fluvio-lacustrineenvironment and geologic formations of the Devonian and Neogene system of volcanic origin. The study area has several environmental problems mainly caused bycontaminants such as heavy metals, nutrients, and bacteria. These problems are linked to the urban and industrial wastes, natural geologic conditions, and miningactivities carried out upstream of the Katari Basin, where rivers discharge into the Cohana Bay.A total of 37 water samples were collected during wet season, 31 groundwater samples including drinking water wells and six surface water samples. Thehierarchical cluster analysis and principal component analysis were applied to hydrochemical data. Results show high salinity in groundwater related to theevaporation causing serious problems for the groundwater quality and rendering it unsuitable for drinking. Dissolved As concentration ranges from 0.7 to 89.7 μg/L;the principal source of As could be the alteration of volcanic rocks, more than 48% of the shallow groundwater samples exceeded the WHO guideline value for As andmore than 22% for NO3-. Groundwater has neutral to slightly alkaline pH, and moderately oxidizing character. The groundwater chemistry reveals considerablevariability, ranging from Na-SO4,Cl type through mixed Na-HCO3 type and Ca,Na-HCO3,Cl type. The distribution of trace elements shows a large range of concentrations.Speciation of As indicates that the predominant oxidation state is As (V). The geochemical modelling indicates that As could be associated with ironoxides and hydroxides which are probably the most important mineral phases for the As adsorption. The spatial distribution and the variation of dissolved Asconcentration in groundwater is governed by the variability in geological characteristics of the region that raises a significant concern about drinking water quality.
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| 7. |
- Seddique, A. A., et al.
(författare)
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Hydrogeochemical and isotopic signatures for the identification of seawater intrusion in the paleobeach aquifer of Cox's Bazar city and its surrounding area, south-east Bangladesh
- 2019
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Ingår i: Groundwater for Sustainable Development. - : Elsevier B.V.. - 2352-801X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- In order to better understand the encroachment of seawater into the groundwater system a total 115 groundwater samples were collected in an area of ∼7 km 2 in Cox's Bazar paleobeach and its vicinity, from different types of tubewells, which included hand pump fitted bore wells (<50 m depth), moderately deep energized bore wells (50 m–100 m depth) and deep bore wells (>100 m depth) during June 2013. A combined hydro-geochemical indicators, selected trace elements (Sr and B) and in addition to δ 18 O and δ 2 H were used in this study. Results show that the high values of EC (202 μS/cm to 6730 μS/cm) and TDS (135 mg/L to 4509 mg/L) are found in groundwater of wells closer to the coast and few wells from the northern and central part of the study area. The cross plot of HCO 3 /Cl and TDS shows that groundwater along the paleobeach and some isolated areas are saline with TDS > 1000 mg/L, associated with high ratios of Cl/TDS (0.065). The groundwater facies generally evolves from freshwater (Ca-Mg-HCO 3 ) to saline water (Na- Cl) type with an intermediate Ca-Mg-Cl type indicating that the aquifer system interacts with seawater and undergoes cation exchange. Results also reveal that the area affected by marine water intrusion has ionic ratios of Br/Cl (0.0006–0.0021) similar to seawater (0.0015) with some higher values. Groundwaters along the paleobeach and some isolated areas, low ionic ratios of SO 4 /Cl (0.01–6.53) and Na/Cl (0.20–152.09), relative to marine ratios (0.05 and 0.86 respectively), are also observed. Groundwaters with Seawater Mixing Index >1.0 and TDS >1000 mg/L constitute about 20% of the studied groundwaters and have relatively high δ 18 O (>- 4.0‰) values and the linear relationships between TDS and most of the ions, including B and Sr, and the chemical signature of the saline plumes (e.g., marine SO 4 /Cl, Na/Cl and Br/Cl ratios) suggest that mixing processes control the chemical composition of the seawater within the aquifers. However, these geochemical variations also reveal that the quality of potable water has deteriorated to a large extent due to seawater intrusion along the paleobeach, migrating inland toward the heavily groundwater exploited areas from the coast line and may entail various future health hazards.
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| 8. |
- Shah, M., et al.
(författare)
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Assessment of geothermal water quality for industrial and irrigation purposes in the Unai geothermal field, Gujarat, India
- 2019
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Ingår i: Groundwater for Sustainable Development. - : Elsevier. - 2352-801X. ; 8, s. 59-68
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Tidskriftsartikel (refereegranskat)abstract
- Nowadays, a spotlight on the direct manipulation of water from the geothermal fields is laid for manifold applications. This manuscript discusses the utilization of water produced from geothermal wells for irrigation and industrial purposes. In order to identify the suitability of the water for the above mentioned uses, various hydrochemical parameters were evaluated. Samples were collected from three geothermal well sites from Unai village, a prominent geothermal field situated in Navsari district, Gujarat, India. The hydrochemistry of the samples collected from hot spring (depth 30–45 m) was studied and samples were examined by calculating different parameters. The complete study was done individually for both industrial and irrigational uses of geothermal water. The mean surface temperature of the water is 55 °C and average pH of the sample studied is 8.12. The key Water Quality Indices (WQI) such as Langelier Saturation Index (LSI), Ryznar Stability Index (RSI), Puckorius Scaling Index (PSI) and Larson-Skold Index (LS) were examined for industrial utilization and the key indices like Sodium Absorption Ratio (SAR), Sodium Percentage (SP), Kelly Ratio (KR) Residual Sodium Carbonate (RSC) and Permeability Index (PI) were examined for irrigational utilization of geothermal water. LSI and RSI values show that carbonate and bicarbonate concentration is in the desirable range, however, LS (15.09, 13.54) is very high which indicates higher Cl- content. High value of indices such as SAR, KR, and SP points out the increased concentration of Na+ in the water sample. The results of this study would help the end users to identify the necessary water-treatments before utilizing the water for industrial and irrigation purposes in the study area.
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| 9. |
- Yi, Lixin, et al.
(författare)
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Radium isotopes distribution and submarine groundwater discharge in the Bohai Sea
- 2019
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Ingår i: Groundwater for Sustainable Development. - : Elsevier BV. - 2352-801X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- In order to characterize the radium distribution and submarine groundwater discharge (SGD) in the Bohai Sea area, the three isotopes 223Ra, 224Ra and 228Ra in different water bodies were measured in a 4-year period with the radium-delayed coincidence counting (RaDeCC) system. The results indicated that radium activities take an order of groundwater > coastal seawater > river water > central seawater. The radium activities of groundwater were controlled by the lithology, human activities and salinity. Groundwater in aquifers with higher content of Th and U like igneous and metamorphic has higher radium activities, high salinity and oil exploitation which leads to groundwater contamination can also cause the higher radium activities. The radium isotopes of offshore waters were controlled by their respective onshore groundwater and SGD flux rates. The relative level of radium Ra isotope activity of coastal groundwater and nearshore seawater is determined by the interaction between groundwater and seawater. It is concluded that smaller radium mass transport from bottom sediments and the majority radium were supplied from landward groundwater from horizontal and vertical distribution of Ra isotope. The seasonal investigation showed that the seawater radium activities of 223Ra, 224Ra and 228Ra in autumn were higher than that in spring. Based on the seasonal variation of radium activities and the mass balance of radium, SGD of the Bohai Sea during rainy season were calculated to be 1.43 × 108 m3/d (3.73 × 10−3 m3/m2/d) in northern region and 2.84 × 107 (1.76 × 10−3 m3/m2/d) in western region by 228Ra.
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