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North-West University (2013)

Evaluation of microbiological and physico-chemical quality of water from aquifers in the North West Province, South Africa

Carstens, Alewyn Johannes

Titre : Evaluation of microbiological and physico-chemical quality of water from aquifers in the North West Province, South Africa.

Auteur : Carstens, Alewyn Johannes

Université de soutenance : North-West University

Grade : MSc (Environmental Sciences) 2013

Résumé partiel
Contamination of groundwater that is suitable for drinking is of growing concern as the water supply of South Africa is becoming increasingly limited. This is especially the case in the North West province, with its semi – arid climate and variable rainfall patterns. The aim of the study was to evaluate the microbiological and physico – chemical qualities of groundwater obtained from selected DWA (Department of Water Affairs) monitoring boreholes in the Mooi River and Harts River catchment areas. Physico-chemical parameters included temperature, pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), sulphate and nitrate concentrations. Physical parameters were measured using a calibrated submerge-able multimeter and chemical parameters using specialised kits and a spectrophotometer. Microbiological parameters included heterotrophic plate counts and total and faecal coliform enumeration. Membrane filtration and culture based methods were followed for enumeration of bacteria. During the identification procedures multiplex PCR for E. coli identification and 16S rRNA gene sequencing for identification of heterotrophic plate count bacteria and amoeba resistant bacteria were used. For antibiotic resistance, the KirbyBauer (1996) disk diffusion method was used. During the warm and wet season high electrical conductivity and salinity were observed in the Trimpark (65.3 mS/m ; 325 ppm), School (125.1 mS/m ; 644 ppm), Warrenton (166.9 mS/m ; 867 ppm) and Ganspan (83.3 mS/m ; 421 ppm) boreholes. Warrenton borehole had a high sulphate level (450 mg/l) as well. High chemical oxygen demand was observed in the Blaauwbank (62 mg/l) and Warrenton (98.5 mg/l) boreholes. In the dry and cold season similar observations were made for the various boreholes. Electrical conductivity and salinity levels remained high for the Trimpark (70.1 mS/m ; 427.5 ppm), School (127 mS/m ; 645 ppm), Warrenton (173.3 mS/m ; 896.5 ppm) and Ganspan (88.1 mS/m ; 444.5 ppm) boreholes. Nitrate levels for the Trimpark (14.1 mg/l) and School (137 mg/l), as well as sulphate levels for the Warrenton (325 mg/l) borehole were also high.

Mots clés : Groundwater ; Rural communities ; Microbiological water quality ; HPC ; Amoeba resistant bacteria ; Antibiotic resistance ; Opportunistic pathogens ; 16S rRNA gene sequencing ; mdh. lacA.

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Page publiée le 19 septembre 2013, mise à jour le 1er avril 2020