Ramaite, I. D. I.Puka, L. R.Thenga, Dembe2026-01-142026-01-142025-09-05Thenga, D. 2025. Speciation analysis of chromium on natural water. . .https://univendspace.univen.ac.za/handle/11602/3076M.Sc (Chemistry)Department of ChemistryIndividuals residing in the vicinity face potential exposure to detrimental substances that could be present in the water from rivers and dams. Water pollution is a serious problem that the world is facing. Exposure to water pollution or contamination can occur through ingestion; drinking contaminated water; or the direct consumption of polluted water from taps, wells, rivers, dams, or other sources, which end up impacting human health and the environment. Determining the amount of chromium species present in water samples is therefore essential. The purpose of this research was to speciate analysis of chromium in natural water samples obtained from the Dzindi river, Mutale river, Luvuvhu river, and Nandoni dam in the Limpopo province using atomic absorption spectrometry. Speciation is the study of an element's chemical forms in a sample, revealing diverse bio availabilities, toxicities, and behaviours. Total chromium, trivalent chromium, and hexavalent chromium are the main species of interest. Chromium in natural water is crucial due to its environmental and human health impacts. In trace amounts, Cr3+ is necessary, but Cr6+ is highly toxic and carcinogenic, endangering ecosystems and human health. The high solubility and mobility of Cr6+ in water, which raises the possibility of it contaminating drinking water sources and being absorbed by living things, led to the identification of this species as the most toxic one in this study. After long-term exposure, Cr6+ can result in serious health problems such as liver damage, lung cancer, and other conditions. This study's speciation approach comprised collecting water samples and separating and quantifying Cr3+ and Cr6+ using methods including inductively coupled plasma optical emission spectrometry and flame atomic absorption spectroscopy. The instruments that were used in this study, inductively coupled plasma optical emission spectrometry, are particularly useful for chromium speciation due to their ability to accurately detect and quantify the total amount of chromium. Flame atomic absorption spectroscopy is employed in the analysis of total chromium and the hexavalent chromium concentration. Then the samples were additionally examined for physicochemical parameters: pH, temperature, electrical conductivity, and total dissolved solids. The World Health Organization (2008), SANS 241 (2006), and Canadian Guidelines (2007) were employed as benchmarks for water quality for drinking reasons. Results indicate that water samples from Nandoni dam exhibited elevated physicochemical parameters, including total dissolved solids and electrical conductivity, throughout the dry and rainy seasons. The quantification of Cr by inductively coupled plasma optical emission spectrometry revealed increased concentrations during the rainy season compared to the dry season. The chromium values during the dry season ranged from 2.607 ± 0.134 mg/L - 4.613 ± 0.236 mg/L; during the rainy season, they ranged from 3.687 ± 0.174 – 6.803 ± 0.462 mg/L. The water samples were analysed for the total Cr and Cr (VI) concentrations using flame atomic absorption spectroscopy. The total concentrations of chromium in the water of the Dzindi river during the dry season were measured to be 2.406 ± 0.105 μg/L, while during the rainy season, they were found to be 3.651 ± 0.204 μg/L. Similarly, in Mutale River, the concentrations during the dry season were 3.531 ± 0.324 μg/L; during the rainy season, they were 4.401 ± 0.073 μg/L. In Luvuvhu river, the concentrations during the dry season were 2.803 ± 0.215 μg/L; during the rainy season, they were 5.013 ± 0.342 μg/L. Finally, in Nandoni Dam, the concentrations during the dry season were 4.245 ± 0.402 μg/L; during the rainy season, they were 6.304 ± 0.431 μg/L. After conducting speciation analysis using flame atomic absorption spectroscopy, it was observed that hexavalent chromium's content was significantly high than trivalent chromium. The results of Cr (VI) in the Dzindi river during the dry season were 1.501 ± 0.092 μg/L, while during the rainy season, it was found to be 2.134 ± 0.143 μg/L. Similarly, values in the Mutale river were 2.021 ± 0.057 μg/L during the dry season and 3.704 ± 0.171 μg/L during the rainy season. In the Luvuvhu river, the values were 1.704 ± 0.142 μg/L in the dry season and 3.501 ± 0.184 μg/L in the rainy season. In conclusion, the values at Nandoni dam were 5.819 ± 0.158 μg/L during the rainy season and 3.434 ± 0.138 μg/L during the dry season. As the concentration of Cr (III) were found to be 0.905 ± 0.013 μg/L during dry season and 1.517 ± 0.061 μg/L during rainy season in Dzindi river, Mutale river were 1.510 ± 0.0267 μg/L during the dry season and 0.697 ± 0.098 μg/L during the rainy season. In the Luvuvhu river, the values were 1.009 ± 0.073 μg/L in the dry season and 1.512 ± 0.158 μg/L in the rainy season. Lastly, the values at Nandoni dam were 0.811 ± 0.264 μg/L during the rainy season and 0.485 ± 0.273 μg/L during the dry season as it was calculated the difference between the concentration of total chromium and Cr (VI). Based on the data collected from all sample sites (Dzindi river, Mutale river, Luvuvhu river, and Nandoni dam), it can be inferred that the concentration of Cr is within the World Health Organization (2017) and South African Standard guidelines (2005), even though the water contains more Cr (VI) than Cr (III), therefore it is suitable for domestic uses. Regularly monitoring chromium levels in water from all sampling locations is necessary to accurately determine the concentrations of different chromium species, especially the hazardous Chromium (VI) species, as it causes lung cancer. Examining seasonal variations can be accomplished across all the seasons. The municipality must enhance community awareness and educate residents about the impacts of water contamination.1 online resource (xii, 52 leaves)enChromium speciationUCTDWaterChromium pollutionICP-OESFAASNandoni DamDzindi RiverMutale RiverDissertationThenga D. Speciation analysis of chromium on natural water. []. , 2025 [cited yyyy month dd]. Available from:Thenga, D. (2025). <i>Speciation analysis of chromium on natural water</i>. (). . Retrieved fromThenga, Dembe. <i>"Speciation analysis of chromium on natural water."</i> ., , 2025.TY - Dissertation AU - Thenga, Dembe AB - Individuals residing in the vicinity face potential exposure to detrimental substances that could be present in the water from rivers and dams. Water pollution is a serious problem that the world is facing. Exposure to water pollution or contamination can occur through ingestion; drinking contaminated water; or the direct consumption of polluted water from taps, wells, rivers, dams, or other sources, which end up impacting human health and the environment. Determining the amount of chromium species present in water samples is therefore essential. The purpose of this research was to speciate analysis of chromium in natural water samples obtained from the Dzindi river, Mutale river, Luvuvhu river, and Nandoni dam in the Limpopo province using atomic absorption spectrometry. Speciation is the study of an element's chemical forms in a sample, revealing diverse bio availabilities, toxicities, and behaviours. Total chromium, trivalent chromium, and hexavalent chromium are the main species of interest. Chromium in natural water is crucial due to its environmental and human health impacts. In trace amounts, Cr3+ is necessary, but Cr6+ is highly toxic and carcinogenic, endangering ecosystems and human health. The high solubility and mobility of Cr6+ in water, which raises the possibility of it contaminating drinking water sources and being absorbed by living things, led to the identification of this species as the most toxic one in this study. After long-term exposure, Cr6+ can result in serious health problems such as liver damage, lung cancer, and other conditions. This study's speciation approach comprised collecting water samples and separating and quantifying Cr3+ and Cr6+ using methods including inductively coupled plasma optical emission spectrometry and flame atomic absorption spectroscopy. The instruments that were used in this study, inductively coupled plasma optical emission spectrometry, are particularly useful for chromium speciation due to their ability to accurately detect and quantify the total amount of chromium. Flame atomic absorption spectroscopy is employed in the analysis of total chromium and the hexavalent chromium concentration. Then the samples were additionally examined for physicochemical parameters: pH, temperature, electrical conductivity, and total dissolved solids. The World Health Organization (2008), SANS 241 (2006), and Canadian Guidelines (2007) were employed as benchmarks for water quality for drinking reasons. Results indicate that water samples from Nandoni dam exhibited elevated physicochemical parameters, including total dissolved solids and electrical conductivity, throughout the dry and rainy seasons. The quantification of Cr by inductively coupled plasma optical emission spectrometry revealed increased concentrations during the rainy season compared to the dry season. The chromium values during the dry season ranged from 2.607 ± 0.134 mg/L - 4.613 ± 0.236 mg/L; during the rainy season, they ranged from 3.687 ± 0.174 – 6.803 ± 0.462 mg/L. The water samples were analysed for the total Cr and Cr (VI) concentrations using flame atomic absorption spectroscopy. The total concentrations of chromium in the water of the Dzindi river during the dry season were measured to be 2.406 ± 0.105 μg/L, while during the rainy season, they were found to be 3.651 ± 0.204 μg/L. Similarly, in Mutale River, the concentrations during the dry season were 3.531 ± 0.324 μg/L; during the rainy season, they were 4.401 ± 0.073 μg/L. In Luvuvhu river, the concentrations during the dry season were 2.803 ± 0.215 μg/L; during the rainy season, they were 5.013 ± 0.342 μg/L. Finally, in Nandoni Dam, the concentrations during the dry season were 4.245 ± 0.402 μg/L; during the rainy season, they were 6.304 ± 0.431 μg/L. After conducting speciation analysis using flame atomic absorption spectroscopy, it was observed that hexavalent chromium's content was significantly high than trivalent chromium. The results of Cr (VI) in the Dzindi river during the dry season were 1.501 ± 0.092 μg/L, while during the rainy season, it was found to be 2.134 ± 0.143 μg/L. Similarly, values in the Mutale river were 2.021 ± 0.057 μg/L during the dry season and 3.704 ± 0.171 μg/L during the rainy season. In the Luvuvhu river, the values were 1.704 ± 0.142 μg/L in the dry season and 3.501 ± 0.184 μg/L in the rainy season. In conclusion, the values at Nandoni dam were 5.819 ± 0.158 μg/L during the rainy season and 3.434 ± 0.138 μg/L during the dry season. As the concentration of Cr (III) were found to be 0.905 ± 0.013 μg/L during dry season and 1.517 ± 0.061 μg/L during rainy season in Dzindi river, Mutale river were 1.510 ± 0.0267 μg/L during the dry season and 0.697 ± 0.098 μg/L during the rainy season. In the Luvuvhu river, the values were 1.009 ± 0.073 μg/L in the dry season and 1.512 ± 0.158 μg/L in the rainy season. Lastly, the values at Nandoni dam were 0.811 ± 0.264 μg/L during the rainy season and 0.485 ± 0.273 μg/L during the dry season as it was calculated the difference between the concentration of total chromium and Cr (VI). Based on the data collected from all sample sites (Dzindi river, Mutale river, Luvuvhu river, and Nandoni dam), it can be inferred that the concentration of Cr is within the World Health Organization (2017) and South African Standard guidelines (2005), even though the water contains more Cr (VI) than Cr (III), therefore it is suitable for domestic uses. Regularly monitoring chromium levels in water from all sampling locations is necessary to accurately determine the concentrations of different chromium species, especially the hazardous Chromium (VI) species, as it causes lung cancer. Examining seasonal variations can be accomplished across all the seasons. The municipality must enhance community awareness and educate residents about the impacts of water contamination. DA - 2025-09-05 DB - ResearchSpace DP - Univen KW - Chromium speciation KW - Water KW - Chromium pollution KW - ICP-OES KW - FAAS KW - Nandoni Dam KW - Dzindi River KW - Mutale River LK - https://univendspace.univen.ac.za PY - 2025 T1 - Speciation analysis of chromium on natural water TI - Speciation analysis of chromium on natural water UR - ER -