Browsing by Author "Kilulya, Kessy F."
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Item Effect of Natural Blue-Green Algal Cells Lysis on Freshwater Quality(CoNAS - UDSM, 2017) Kilulya, Kessy F.; Msagati, Titus A.M.; Mamba, Bhekie B.Blue-green algae grow in freshwater bodies when they are provided with suitable factors such as nutrients and appropriate weather conditions. Their cell lysis occurs naturally when they encounter unfavourable conditions. This study reports on the types and amounts of fatty acids added into freshwater due to the algal cell lysis. The investigation on the amount of fatty acids released into water due to algal cells lysis was performed by placing samples in two compartments, one with no light allowing the algae cells to die while the other compartment was kept in favourable conditions enough to sustain the life of algae. Fatty acids were then extracted from both dead and living cells as well as their respective water filtrates. Determination of fatty acids was performed using GCxGC-TOF-MS. Identified fatty acids were mainly; tetradecanoic acid, 7-hexadecenoic acid, hexadecanoic acid, 9,12,15-octadecatrienoic acid, 6,9,12,15-octadecatetraenoic acid, 9,12-octadecadienoic, 9-octadecenoic and octadecanoic acids. It was found that water from the dead cells had higher amounts of fatty acids than water samples from the living cells. Unsaturated fatty acids increased from 0.85 mg/L to 2.70 mg/L in filtrate water from the dead algae. The pH of water samples from the dead cells decreased from 6.8 to 6.1Item Levels of heavy metals in urine samples of school children from selected industrial and non-industrial areas in Dar es Salaam, Tanzania(Makerere University Medical School, 2018-12) Mahugija, John A.M.; Kasenya, Zainab S.; Kilulya, Kessy F.Objectives: The levels of lead, zinc, iron, copper and cadmium metals in the urine samples of selected school children in industrial and non-industrial areas in Dar es Salaam were investigated. Methods: Urine samples were collected from 120 children in industrial areas and 120 children in non-industrial areas then digested in concentrated acids and analysed using atomic absorption spectrophotometry (AAS). Results: The concentrations of the heavy metals in the urine samples ranged from below detection limit/non-detectable (ND) to 1.92 mg/L for lead, ND to 2.55 mg/L for zinc, ND to 8.98 mg/L for iron and ND to 0.05 mg/L for copper. Cadmium was not detected. Significant differences were found between the concentrations of heavy metals in urine of pupils from the industrial areas and those from non-industrial areas. The mean concentrations of lead and copper in samples from industrial areas were significantly higher than those found in non-industrial areas (p < 0.002), while the mean concentrations of zinc and iron found in samples from non-industrial areas were significantly higher than those found in industrial areas (p < 0.0001). Conclusion: The contamination levels were generally high in samples from both areas indicating exposure from various sources. The findings indicate public health risks.