- Title
- Spatial and seasonal variations of water quality determinants and pollutants as fitness-for-use and compliance assessments of the Mzimvubu catchment water resources for the proposed Mzimvubu Water Project, South Africa
- Creator
- Mutingwende, Nhamo
- Subject
- Water quality -- South Africa Water quality management
- Date
- 2018
- Type
- Thesis
- Type
- Doctoral
- Type
- PhD
- Identifier
- http://hdl.handle.net/10353/9308
- Identifier
- vital:34320
- Description
- The Department of Water Affairs as of late reported plans to build two substantial stockpiling dams in the Mzimvubu Catchment. The Mzimvubu stream basin is probably one of most prominent and undeveloped basin in South Africa. This is notwithstanding high yearly rainfall, high ecological status, high tourism potential, and appropriateness for afforestation, dryland/rainfed and water system agribusiness. Hence, the Department of Water Affairs researched the capability of building a multipurpose dam in the Mzimvubu catchment to catalyse financial and social improvement. The proposed dam will be based on the Tsitsa River. Often, scientific studies related to dam construction concentrate more on discovering the most, in fact, accessible place to construct it, than on the long haul socio-natural issues that come in its preparation. The water quality of the Tsitsa River, its tributaries and the underground drinking water sources within the Mzimvubu catchment are most likely to change once the dam wall is completed. Surface water resources are susceptible to chemical, physical, microbiological contamination and the so-called emerging pollutants either, through human or natural activities. A comprehensive baseline study on the water quality of the Mzimvubu water resources regarding traces of emerging pollutants and water quality determinants (physical, chemical and microbial) pre-dam construction is therefore essential. The objective of the water quality section of this study was to perform an in-depth analysis of water quality in the study area to form a baseline for future studies on how the built dam may affect these. The approach was to assess the spatial and seasonal variations of the pollutants (pharmaceuticals and pesticides) and water quality determinants for all water sources most likely to be affected by the development of the dam. The fitness-for-use and compliance assessments were conducted to assess if the current water resources are fit-for-use for various categories of use and if they comply with various water quality standards and guidelines as determined by the Department of Water Affairs and Forestry. Department of Water Affairs and Forestry is the overseer of South Africa's water assets, and its central goal is to keep up the fitness-for-use of water on a sustained basis. Water samples (500ml) were collected from sixteen (16) sample points, ranging from the proposed mouth of the dam to the N2 bridge point of the Tsitsa River. Points were selected where the Tsitsa River was accessible using the dam project development roads or where tributaries to the Tsitsa River were accessible using dam development roads. Taps/groundwater sources were sampled from the five selected villages. Monthly samples were collected upstream and downstream of the proposed dam wall, from June 2015 to April 2017.Seventeen (17) water quality indices were therefore analysed at sixteen sampling sites, over a two year period. The AB SCIEX TripleTOF™5600 LC/MS/MS was used to screen for pharmaceutical and pesticide pollutants. All the water quality indices were analysed using the AL400 Aqua lytic photometer, and the microbial analysis was done using the Rand Water Method Number 1.2.2.09.1 for enumerating the amount of E. coli and coliforms in the water samples (Rand Water, 2010f). The South African Water Quality Guidelines, Volumes 1 to 7 (DWS, 1996a-g) were used to assess the fitness-for-use of the water sources. To confirm the compliance of the water resources to various standards and guidelines, the water quality data were assessed against international and national guidelines and standards i.e. the WHO guideline, South African water quality guidelines (domestic, irrigation, livestock and watering, aquaculture, and aquatic ecosystems), and the SANS: 241 (2015) standard for drinking water. Non-parametric statistics were utilised to ascertain the changeability, which is a measure of how water quality may vary after some time. With non-parametric insights, the interquartile extent, which lies between the 25th and the 75th percentile, was utilised to depict inconstancy. The median value (50th percentile) was used as an indication of the central tendency or average. The 90th percentile was included as it can be used to assess the frequency of excursions into higher and possibly unacceptable water quality conditions. 3D Sigma plot was used to graphical present the spatial and seasonal variations of water quality indices and emerging pollutants against their concentrations. Fundamental statistical properties and correlations of water quality variables from the Tsitsa River, Tsitsa River tributaries and the drinking water sources were examined using SAS descriptive statistics. The water quality was determined to be of relatively sound quality, based on the comparison with guidelines and standards for the various intended uses, even though some of the water quality determinants were non-compliant and were “unacceptable” regarding fitness for purpose. The water quality of the Ntabalenga dam would most probably be affected by natural influences (for example rainfall, weathering and geological composition) and anthropogenic factors through non-point source pollution from agriculture activities, human settlements (pit latrines and open defecation) as well as industrial activities in the Maclear and Tsolo towns (wastewater treatments plants effluent, hospital effluent). The Tsitsa River had the highest number of non-compliances, especially to the World Health Organisation and Department of Water and Sanitation aquaculture guidelines. Therefore, the Tsitsa River’s water quality would be a significant factor that could compromise the water quality of the water collected in the dam. The human settlement conditions and agricultural inputs seem to be the factors contributing most to contamination of the surface water of the catchment area. The lack of sanitation systems and facilities means that community members have to use the bush and rivers for ablutions, thus contributing to microbial contamination of the environment. The direct application of manure and fertilisers on the fields by farmers further exacerbates microbial contamination and high nutrient inputs into the environment as observed in elevated microbial and phosphate contaminants during the study period. The data obtained from the analysis of pesticides and pharmaceuticals confirmed the contamination of the drinking water sources, the Tsitsa River and its tributaries with pesticides and pharmaceuticals through non-point source pollution. The origins of these pharmaceutical contaminants were identified as the pit latrines, open defecation and wastewater treatment plant effluent, while agricultural application of pesticides was identified as the source of pesticides in surface waters. If not monitored closely, the presence of these emerging pollutants will negatively affect the quality of the dam water both at spatial and temporal scales once the dam wall is completed. Pit latrines and wastewater treatment plants are a significant source of non-point source pollution. The results of this study will add to the ongoing efforts on water quality remediation by recording the spatial and seasonal variations in water quality across various water sources within the study area. The study also provides a baseline for future water quality fitness-for-use and compliance assessments. By these findings and conclusions, it is recommended that a long-term continuous monitoring programme be implemented, especially in areas where increased agricultural activities have been observed. Monitoring should be implemented for the Tsitsa River, its tributaries, and selected drinking water sources which showed the highest number of non-compliances and microbial contamination. All anthropogenic activities in the catchment areas of these sources, both upstream and downstream of the proposed dam wall, must be monitored and strictly managed to prevent and mitigate their possible impacts. Specific emphasis should be placed on agricultural development, which should be controlled to ensure sustainable livestock and cropping practises. Sanitation facilities, systems and community programmes should be put in place to minimise microbial contamination. It would be beneficial for the Department of Water and Sanitation office responsible for the Mzimvubu water resources to establish a central database for all information concerning the water quality of their water resources including the findings in this report. The database must be freely accessible to the residents of the Mzimvubu catchment.
- Format
- 160 leaves
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
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