Assessment of groundwater quality in a part of Mhlathuze catchment of Empangeni and Richards Bay, KwaZulu-Natal, South Africa

Abstract
The study area comprises of a part of Mhlathuze catchment of Empangeni and Richards bay, KwaZulu Natal. This study has revealed the significance of hydrogeochemical studies in understanding the groundwater quality for drinking and irrigation purposes. The study also identified the hydrogeochemical processes and the probable source of toxic metals in the groundwater. About 40 and 33 groundwater samples were collected in the year 2015 and 2016 respectively and they were analysed. The groundwater ranges from acidic to alkaline in nature. The parameters of drinking water quality such as pH, EC, Na, K, Ca, Mg, Cl, HCO3 and SO4 exceeds the permissible limits of WHO standard. The USSL salinity classification revealed that the groundwater samples of the study area are unsuitable for irrigation as high salinity and high alkalinity hazards are observed. The hydrogeochemistry of the major ions in the groundwater are in the order of dominance of Na > K > Ca > Mg and Cl > HCO3 > SO4 in 2015 and Na > Ca> Mg >K and Cl > SO4 > HCO3 in the year 2016. Ca-Mg-Na, Cl-SO4-HCO3, Ca-Mg-Cl, and Na-Cl are the dominant hydrochemical facies. The hydrogeochemical processes that have strong influence on groundwater quality are the rock water interaction, ion exchange, and reverse ion exchange, carbonate and silicate weathering processes and evaporation. PI values specified that the quality of groundwater is good for irrigation purposes. The abundance of metals exhibited the sequence in increasing order as follows: Mn < Si < Fe < B < Cu < Zn < Pb < Al < Li < Co < Ni < Cd < Cr and Si < B < Zn < Ag < Li < Pb < Mn < Al < Cr < Fe < Cd < Co. The water quality analysis clearly revealed that the toxic heavy metals such as Mn, Fe, Pb, Al, Ni, Cd and Cr exceeded the permissible limit of WHO and USEPA drinking water standard. Spatial variation of heavy metals also revealed that the overall part of the study area are extremely hazardous and polluted by landfill site, industrial effluents, mining and associated activities, fertilizers and anthropogenic sources in and around the study area. Consumption of groundwater by the public may cause severe health issues. Generally, the study concludes that the high level of contamination is contemporary in the Empangeni and Richard Bay area. The study also suggests that utilising this baseline informations, reconciliation strategies should be formulated to improve and protect the groundwater quality in the study region. .
Description
A dissertation submitted to the Faculty of Science and Agriculture in partial fulfillment of the requirements for the Degree of Masters Of Science (MSc) in the Department of Hydrology at the University Of Zululand, 2018
Keywords
hydeogeochemical processes --rock water interaction --landfill --evaporation --KwaZulu-Natal
Citation
Collections