ORCID Profile
0000-0002-3696-7227
Current Organisations
University of South Australia
,
University of the Western Cape Faculty of Natural Science
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Publisher: Academy of Science of South Africa
Date: 24-08-2010
Publisher: African Journals Online (AJOL)
Date: 11-11-2004
Publisher: Elsevier BV
Date: 07-2020
Publisher: CRC Press
Date: 23-09-2008
Publisher: Elsevier BV
Date: 12-2017
Publisher: Wiley
Date: 15-10-2004
Abstract: Nitrate is a stable nitrogen (N) species under certain natural conditions and forms highly soluble compounds. These are peculiar features that allow nitrate ion to be transported in some groundwater systems to environments where it can be converted into other nitrogen species that either promote surface water eutrophication or are hazardous to humans, livestock, and the environment. Nitrate test results are usually expressed in milligrams per liter as either nitrogen (NO 3 ‐N, sometimes written as plain N) or as nitrate (NO 3 ). The occurrence of high nitrate concentrations in groundwater is widespread, particularly from agricultural usage of fertilizers and animal manure or land disposal of domestic waste and wastewaters. Much research has been conducted to determine the amounts of nitrates in drinking water wells as well as in foods. Exposure to high doses of nitrate is generally perceived to be associated with adverse health effects in humans and other species. These range from infant methemoglobinemia, cancers, the ‘hot dog headache,’ and hypertension, to other adverse effects such as birth defects (congenital malformations) and spontaneous abortions. Most reported cases of infantile methemoglobinemia have been associated with the use of water containing more than 10 mg/L NO 3 ‐N.
Publisher: Wiley
Date: 15-10-2004
Abstract: Water is essential for life and health and has both cultural and religious significance. Water plays a vital role in transmitting infectious diseases, and 80% of diseases reported are directly or indirectly water‐related. Scarce and unclean water supplies are critical public health problems in many parts of the world. These have been identified as leading factors that will limit economic development in the near future. Based on projected population growth, the amount of water available for use per person per year is expected to drop annually. Apart from the pressure of population growth on water resources, the supply of freshwater available to humanity is shrinking, in effect, because of increasing pollution. On the whole both water scarcity and water pollution pose serious health problems. Unclean water is by far the largest environmental killer around the world. Water shortages, polluted water, and unsanitary living conditions claim millions of lives annually via various water‐related diseases. About 60% of all infant mortality is linked to infectious and parasitic diseases most are waterrelated, and a large percentage of these diseases is attributable to inadequate water supply and sanitation.
Publisher: Elsevier BV
Date: 09-2018
Publisher: Wiley
Date: 15-10-2004
Abstract: In the last three to four decades, environmental isotopes have contributed immensely to studies and investigations in hydrogeology, complementing physical and chemical hydrogeology. Many hydrogeologic studies use stable isotopes of the water molecule to determine groundwater quality, origin, recharge mechanism, and rock–water interaction. A goodly number of the applications of environmental isotopes in hydrogeology have been in the arid and semiarid areas of the world, where water scarcity is most acute and poses constraints on economic development. A substantial amount of basic data and results of applied field investigations have already been published on applications of different isotopes for hydrologic purposes. Environmental isotopes provide indications of groundwater age and serve as natural traces for groundwater provenance. Stable isotopes of carbon, boron, nitrogen, and sulphur (i.e., 13 C/ 12 C, 11 B/ 10 B, 15 N/ 14 N, and 34 S/ 32 S) can give valuable information about reactions involving these elements and can also serve as pollution tracers. On the other hand, radioactive isotopes of some of these elements decay, providing us with a measure of the circulation time and, invariably, groundwater renewability. The most common of the radioisotopes, carbon‐14, is used to estimate groundwater residence time. Isotopes of the uranium series ( 234 U, 238 U, 226 Ra, and 222 Rn) are also useful tracers in isotope hydrogeology but are often not precise enough to establish the age of groundwater due to mineral–water interactions.
Publisher: Springer Science and Business Media LLC
Date: 23-06-2009
DOI: 10.1007/S10653-009-9271-4
Abstract: The 500,000 inhabitants of Mayo Tsanaga River Basin are vulnerable to a "silent" fluorosis from groundwater consumption. For the first time, the groundwater is investigated for the purpose of identifying the provenance of fluoride and estimating an optimal dose of fluoride in the study area. Based on the fluoride content of groundwater, fluorine and major oxides abundances in rocks from the study area, mean annual atmospheric temperature, and on-site diagnosis of fluorosis in children, the following results and conclusions are obtained: Fluoride concentration in groundwater ranges from 0.19 to 15.2 mg/l. S les with fluoride content of 1.5 mg/l show a tendency towards Na-HCO(3) type. Fluor-apatite and micas in the granites were identified as the main provenance of fluoride in the groundwater through water-rock interactions in an alkaline medium. The optimal fluoride dose in drinking water of the study area should be 0.7 mg/l, and could be adjusted downward to a level of 0.6 mg/l due to the high consumption rate of groundwater, especially during drier periods.
Publisher: Taylor & Francis
Date: 23-09-2008
Publisher: Springer Science and Business Media LLC
Date: 25-04-2015
DOI: 10.1007/S10661-015-4509-3
Abstract: This study uses a multidisciplinary approach to simulate the spatial and temporal patterns of hydrodynamics and water quality in a thermally stratified reservoir in the southern side of the Mediterranean Sea in response to water withdrawal elevation using the 2D water quality and laterally averaged hydrodynamic model CE-QUAL-W2. The withdrawal elevation controls largely the transfer of heat and constituents in the dam in particular during thermal stratification. Fifteen scenarios of withdrawal elevation are possible. To identify the most effective scenarios, a hierarchical clustering technique was performed and only four scenarios were clustered. Deep withdrawals deepen the hypoxia, increase the thickness of the metalimnion, and weaken the stratification stability, which facilitate the vertical transfer of heat and dissolved oxygen mainly. Surface withdrawals, however, shrink the metalimnion and tend to strengthen the stratification, resulting in less transfer of matter from the epilimnion to the hypolimnion. Most of the bottom sediment is overlaid by the hypolimnion. The oxygen depletes significantly and waters become anoxic at a few meters depth. For all scenarios, the reservoir experiences a summer hypolimnetic anoxia, which lasts from 42 to 80 days and seems to decrease as withdrawal elevation increases. At the end of stratification, waters below the withdrawal elevation showed a noticeable release of iron, nutrients, and suspended sediments that increases with depth and near-bottom turbulence. Attention should be drawn to shallower withdrawals because they accumulate nutrients and silts continuously in the reservoir, which may deteriorate water quality. Based on these results, a withdrawal elevation rule is presented. This rule may be adjusted to optimize water withdrawal elevation for dams in the region with similar geometry.
Publisher: Taylor & Francis
Date: 04-10-2006
Publisher: Wiley
Date: 15-10-2004
DOI: 10.1002/047147844X.GW1141
Abstract: The word contaminant is a general term to describe dissolved constituents, nonaqueous phase liquids (NAPLs), or industrial solvents which, when added to water as a result of human activities, impair groundwater quality. To an important extent, the complexity of a groundwater contamination problem can be determined by whether or not NAPLs are present. Obviously, contaminants related to anthropogenic activities are one of the major threats facing groundwater resources today. Groundwater contamination can have a significant impact on the present and future use of groundwater resources as a source of drinking water for an increasing population living in cities and rural areas.
Publisher: Wiley
Date: 12-08-2014
DOI: 10.1002/HYP.10281
Publisher: Springer Netherlands
Date: 2011
Publisher: Taylor & Francis
Date: 04-10-2006
Location: Australia
Location: South Africa
Start Date: 2016
End Date: 2016
Funder: Agriculture Victoria
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