Evaluation of Malaysian river water quality index based of selected physico-chemical parameters
Determination of the river water quality is one of the most important parts for the management and conservation of water resources, aquatic plants and animals. In Malaysia, the river water quality is classified according to National Water Quality Standards (NWQS). However, classification of water qu...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2020
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| Subjects: | |
| Online Access: | https://eprints.ums.edu.my/id/eprint/42039/1/24%20PAGES.pdf https://eprints.ums.edu.my/id/eprint/42039/2/FULLTEXT.pdf |
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| Summary: | Determination of the river water quality is one of the most important parts for the management and conservation of water resources, aquatic plants and animals. In Malaysia, the river water quality is classified according to National Water Quality Standards (NWQS). However, classification of water quality according to this standard is very difficult as the tested parameters may fall in different classes. Due to this, a simpler and more convenient formulation of Water Quality Index (WQI) that based on only 6 parameters namely, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS) and ammoniacal nitrogen (NH3-N) has been used since 1982. In this study, 4 sampling sites along the Moyog River Penampang, Kota Kinabalu, Sabah were chosen in this study. Five in situ parameters such as temperature, dissolved oxygen (DO), pH, electrical conductivity (EC), and turbidity; together with another seven ex situ parameters which are biochemical oxygen demand (BOD), chemical oxygen demand (COD), true colour, total suspended solids (TSS), phosphorus (PO4 3--P), ammoniacal nitrogen (NH3-N), and metal ions were determined to assess water quality and classification of these rivers based on Malaysian WQI and Canadian WQI. In situ parameters were determined using the ProDSS YSI multimeter, while ex situ parameters were determined following the standard methods of American Public Health Association (APHA) and US Environmental Protection Agency (US EPA). Through this study, it was found that the 4 sampling sites fall in different classification according to Malaysian WQI and Canadian WQI. The results revealed that the Malaysian WQI is less stringent as compared to Canadian WQI. Further investigation of each water quality parameters through lab based analysis showed that there are correlations between the parameters in the Malaysian WQI. The measured physico-chemical parameters, for instance, can be arranged into three groups where each parameter under the same group is correlated but they are not related across the group. The results show that ammoniacal nitrogen is directly related to water pH; while BOD, COD, TSS with DO has an inverse relationship; whilst BOD, COD, true colour with DO has an inverse relationship. Statistical analysis of the lab based study revealed that true colour of the water sample can be a good parameter to replace BOD, COD and DO. Overall, the results imply that pH, ammoniacal nitrogen, TSS and true colour can be the determining parameters in the assessment of river water quality. Hence, the improved Malaysian WQI that was developed based on the four core physico-chemical parameters can accurately determine the quality of a river water without jeopardizing the current WQI. |
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