Browsing by Author "Obuseng, Veronica"

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    Bile acids as specific faecal pollution indicators in water and sediments
    (European Scientific Journal, 2013-04) Obuseng, Veronica; Moshoeshoe, Mohau; Nareetsile, Florence
    Microbiological indicators such as Escherichia coli (E. coli) have been extensively applied to monitor sewage contamination in waters and sediments. However, it has been accomplished by many researchers that microorganism indicators of faecal pollution in aquatic environments have limited applicability, owing to their lack of specificity and variable life span induced by environmental factors such as sunlight and chlorination. This review highlights the use of chemical indicators for faecal or sewage pollution monitoring. It highlights that the differences in bile acid distributions in animal faeces could be utilized to differentiate inputs in an environment. Furthermore, the high resistance to degradation by some of the bile acids would make them better suited for long standing pollution compared to coprostanol, as it is more readily degraded. Bile acid data could be used in conjunction with other available evidence, be it ethnographic or as part of a multi-biomarker approach, employing 5 ฀-stanols and bacterial indicators, such as C. perfringens, to distinguish amongst the different environmental inputs.
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    Simultaneous determination of Nitrate, nitrite and Phosphate in environmental samples by high performance liquid Chromatography with UV detection
    (South African Chemical Institute, 2018-06-15) Moshoeshoe, Mohau N; Obuseng, Veronica
    An HPLC method using an UV detector was developed for the simultaneous determination of nitrites, nitrates and phosphates in environmental samples. Chromatographic separation was achieved isocratically on a Phenomenex Synergi Polar-RP LC column using acetonitrile and acidified water (pH 2.7) at 60:40 v/v as mobile phase. Baseline resolution of all the three analytes was achieved within 3 min. The developed method was applied to water samples obtained from the wastewater treatment plant in Gaborone, Botswana. The use of HPLC technique in this study demonstrated its ability to carry out a simultaneous determination of NO 2 – , NO 3 – and PO 4 3– in water samples. The treatment plant was found to be functioning within expectations, removing 97.6 % NO 2 – , 88.0 % NO 3 – and 90.9 % PO 4 3– from the received wastewater. Results of the developed method were comparable with those of the traditional ion chromatography method, showing accuracy values between 95.22 % and 98.04 %. The precision of the method for the determination of all analytes was determined by RSD values, all of which were lower than 5 %. The method is of low cost, fast, has an easy procedure and avoids the use of many reagents – some of which may be hazardous.