scholarly journals Spatial analysis of hydrogen and oxygen stable isotopes (“isoscapes”) in ground water and tap water across South Africa

2014 ◽  
Vol 145 ◽  
pp. 213-222 ◽  
Author(s):  
A.G. West ◽  
E.C. February ◽  
G.J. Bowen
Author(s):  
J. BERRY, ◽  
C. COOK, ◽  
T.F. DOMINGUES, ◽  
J. EHLERINGER, ◽  
L. FLANAGAN, ◽  
...  

2020 ◽  
Vol 4 (2) ◽  
pp. 100-111
Author(s):  
Adebola Adebayo Adekunle ◽  
Igba Uvieoghene Tobit ◽  
Ogunrinola Oluwaseyi Gbemiga

: Landfill liners are underlying materials with low permeability whose main function is to mitigate the infiltration of toxic contents into ground water lying beneath. Landfill liners are primarily made of bentonite clay. Bentonite has a very low hydraulic conductivity, that might not be readily accessible, unlike kaolin which is found to have a lower hydraulic conductivity compared to that of bentonite and can be extensively obtained from numerous different sources. Explored, for the purposes of the present research paper, were various ratios of bentonite and kaolin and their hydraulic conductivity, in particular ratios of 90:10 kaolin to bentonite, 80:20 kaolin to bentonite, 70:30 kaolin to bentonite, 60:40 kaolin to bentonite and 50:50 kaolin to bentonite in an effort to achieve an acceptable barrier suitable as a liner / where tap water and ammonium solution were used as permeants. It was concluded that the ratios not lower than 20% bentonite (80:20, 70:30, 60:40 and 50:50) all had their hydraulic conductivity value reduced compared to the 100% kaolin.


Geology ◽  
2021 ◽  
Author(s):  
Haoyang Zhou ◽  
Robert B. Trumbull ◽  
Ilya V. Veksler ◽  
Ilya N. Bindeman ◽  
Johannes Glodny ◽  
...  

There is abundant evidence for significant H2O in evolved melts from the platinum-rich UG2 chromitite and the Merensky Reef of the Bushveld Complex (South Africa), but there is no consensus about the source of H2O. We report triple-oxygen and hydrogen isotope ratios of interstitial, late-magmatic phlogopite from three localities of the UG2 layer. The phlogopite yielded δD values of –43‰ to –23‰, which is >30‰ higher than previously known from Bushveld rocks and far above the mantle values of ~–75‰. The phlogopite triple-oxygen isotope ratios are the first to be reported for Bushveld rocks, with values of Δ′17O0.5305 (17O excess relative to the reference line 0.5305) from –0.069‰ to –0.044‰ (δ18O 5.2‰–6.2‰). The oxygen data support existing models of as much as 30%–40% contamination of mantlederived magmas in the lower to middle crust. However, the high δ values require a second step of contamination, which we attribute to brines from the marine sediments in the Transvaal Basin at the emplacement level.


2020 ◽  
Author(s):  
Francis Hamwiinga ◽  
Chisala D. Meki ◽  
Patricia Mubita ◽  
Hikabasa Halwiindi

Abstract Background: One of the factors impeding access to safe water is water pollution. Of particular concern is heavy metal contamination of water bodies. This study was aimed at determining the levels of heavy metals in drinking water sources of Chingola District of Zambia. Methods: A cross sectional study was employed. A total of 60 water samples were collected. Thirsty (30) samples were collected in the dry season in the month of October 2016 and another 30 in the wet season in the months of February and March, 2017. For each season 10 water samples were collected from each of the three water sources. i.e. Tap water, Urban ground water sources and Rural ground water sources. Heavy metal analysis was done using Atomic Absorption Spectrophotometer (AAS).Results: This study revealed that the concentrations of Iron, Manganese, Lead, Nickel and Arsenic were beyond maximum permissible levels in various water sources. Combined averages for both dry and wet seasons were as follows: Iron: 2.3, Copper: 0.63, Cobalt: 0.02, Manganese: 0.36, Lead: 0.04, Zinc:3.2, Nickel: 0.03, Arsenic: 0.05. Chromium and Cadmium were below detection limit in all water samples. The median concentrations of iron, arsenic, copper, manganese in drinking water from the Tap, rural and urban ground water sources were different, and this difference was statistically significant (p<0.05). The median concentrations of arsenic, nickel, manganese and cobalt were different between dry and wet season, and this difference was statistically significant (p<0.05).Conclusions: Sources of heavy metals in water seems to be both natural and from human activities. The concentration of heavy metals in different water sources in this study was found to be above the recommended levels. This calls for improvement in water monitoring to protect the health of the public. Therefore, there is need for continuous monitoring of heavy metals in drinking water sources by regulatory authorities.


2021 ◽  
Author(s):  
Louis Honegger ◽  
Thierry Adatte ◽  
Jorge E. Spangenberg ◽  
Miquel Poyatos-Moré ◽  
Alexandre Ortiz ◽  
...  

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