Browsing by Author "Kwetegyeka, Justus"
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Item Concentrations and sources apportionment of polycyclic aromatic hydrocarbons in 1 sediments from the 2 Uganda side of Lake Victoria(Environmental Science: Processes & Impacts, 2017) Kerebba, Nasifu; Ssebugere, Patrick; Kwetegyeka, Justus; Arinaitwe, Kenneth; Wasswa, JohnThis paper presents the levels and possible sources of selected polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Napoleon Gulf and Murchison Bay of Lake Victoria. Sediment samples were extracted and cleaned up for PAHs using UNEP, 1992 and EPA method 3630C protocols, respectively. The analysis of sample extracts was done using a gas chromatograph coupled to a mass spectrometer. Fifteen congeners, mostly the high molecular weight PAHs (HPAHs) (4-6 rings) were detected. Total (Σ) concentrations varied from 44.2 to 80.2 ng g-1 dry weight (d.w.) at Napoleon Gulf while those at the Murchison Bay ranged from 17.0 to 55.0 ng g-1 d.w. Statistical analysis showed no significant difference in the concentrations of PAHs among sites (p <0.05, ANOVA). It was noted that the concentrations for most sampling sites were far below the lowest effect levels based on the Sediment Quality Guidelines except for one station at the Napoleon Gulf. Principal component analysis and diagonistic ratios indicated that PAHs of combustion and petroleum origin were dominant and brought mainly by atmospheric deposition.Item The fatty acid composition of edible grasshopper Ruspolia differens (Serville) (Orthoptera: Tettigoniidae) feeding on diversifying diets of host plants(Entomological Research, 2018) Rutaro, Karlmax; Malinga, Geoffrey M.; Lehtovaara, Vilma J.; Opoke, Robert; Valtonen, Anu; Kwetegyeka, Justus; Nyeko, Philip; Roininen, HeikkiRuspolia differens (Serville) (Orthoptera: Tettigoniidae) is a highly valued edible grasshopper species in Africa. However, the effects of plant diets on lipid content and fatty acid composition of R. differens are not well understood. We tested the effects of four diets on the total lipid content and fatty acid composition of R. differens. Sixth instar nymphs of R. differens were reared on one, and mixtures of two, three, and six natural plant inflorescences. Individuals collected from the field constituted a control treatment.We extracted lipids and analyzed the fatty acidmethyl esters using gas chromatography–mass spectrometry. We analyzed if the total lipid content, body weight, and fatty acid composition differed among diets and between the sexes using two-way ANOVAs and a PERMANOVA model, respectively. The total lipid content and weight of R. differens did not differ among the diets. The nine common fatty acids were palmitic (mean across treatments, 26%), oleic (22%), palmitoleic (18%), linoleic (13%), stearic (7%), myristic (6%), myristoleic (4%), α-linolenic (2%) and arachidic acid (1%). The composition of fatty acids and the proportion of essential fatty acids significantly differed among the diets. The proportion of essential fatty acids was highest in the control treatment (21%) but low in less diversified (one to three feed) diets (12–13%). This study demonstrates that the fatty acid composition in R. differens can be influenced through diet. Thus, with dietary manipulations, using local plants in Africa, it is possible to produce R. differens with preferred high quality essential fatty acids for human consumption.Item Fatty Acid Composition of Muscle, Liver, and Adipose Tissue of Freshwater Fish from Lake Victoria, Uganda(Journal of Aquatic Food Product Technology, 2011) Masa, Justus; Ogwok, Patrick; Muyonga, John H.; Kwetegyeka, Justus; Makokha, Vincent; Ocen, DenisFish oils may differ in fatty acid (FA) composition depending on diet. Oils extracted from muscle, liver, and adipose tissue of Nile perch (Lates niloticus), Nile tilapia (Oreochromis niloticus), silver fish (Rastrineobola argentea), lungfish (Protopterus aethiopicus), Victoria squeaker (Synodontis victoriae), and two catfishes (Clarias gariepinus and Bagrus docmac) from Lake Victoria, a tropical freshwater lake, were evaluated for FA composition. Oil contents of muscles, livers, and adipose tissues were in the range of 3.16 to 13.8%, 3.62 to 53.4%, and 28.8 to 42.4%, respectively. Omega-3 polyunsaturated FA, particularly alpha-linolenic (ALA), eicosapentaenoic (EPA), docosapentaenoic (DPA), and docosahexaenoic (DHA) acids, were found to be in substantial amounts in oils from all seven fish species. Ratios of polyunsaturated FA to saturated FA (0.79 to 1.18) were in the range considered adequate for normal health. Overall, the results show that the fish species studied are a rich source of omega-3 polyunsaturated FA.Item Organochlorine pesticide residues in Uganda’s honey as a bioindicator of environmental contamination and reproductive health implications to consumers(Ecotoxicology and Environmental Safety, 2021) Mukiibi, Stuart Ben; Nyanzi, Steven Allan; Kwetegyeka, Justus; Olisah, Chijioke; Matthew Taiwo, Adewale; Mubiru, Edward; Tebandeke, Emmanuel; Matovu, Henry; Odongo, SilverHoney has multifaceted nutritional and medicinal values; however, its quality is hinged on the floral origin of the nectar. Taking advantage of the large areas that they cover; honeybees are often used as bioindicators of environmental contamination. The focus of the present paper was to examine the quality of honey from within the vicinity of an abandoned pesticide store in Masindi District in western Uganda. Surficial soils (< 20 cm depths) and honey samples were collected from within the vicinity of the abandoned pesticide store and analysed for organochlorine pesticide (OCP) residues using gas chromatograph coupled to an electron capture detector (GCECD). The mean level of ΣDDTs in all the soil samples was 503.6 μg/kg dry weight (d.w). ΣDDTs contributed 92.2% to the ΣOCPs contamination loads in the soil samples, and others (lindane, aldrin, dieldrin, and endosulfans) contributed only 7.8%. Ratio (p, p′-DDE + p, p′ -DDD)/p, p′ -DDT of 1.54 suggested historical DDT input in the area. In all the honey samples, the mean level of ΣDDTs was 20.9 μg/kg. ΣDDTs contributed 43.3% to ΣOCPs contamination loads in the honey samples, followed by lindane (29.8%), endosulfans (23.6%) and dieldrin (3.2%), with corresponding mean levels of 14.4, 11.4 and 1.55 μg/kg, respectively. Reproductive risk assessment was done based on the hazard quotient (HQ) and hazard index (HI) procedure. In our study, the calculated HIs for adults (102.38), and children (90.33) suggested high potential health risks to the honey consumers. Lindane, endosulfan and p, p′ -DDD detected in the honey samples at levels exceeding the acute reference dose (ARfD) are known risk factors for spontaneous abortion, reduced implantation, menstrual cycle shortening, impaired semen quality, and prostate cancer in exposed individuals and experimental animal models.Item Variations in the contents of heavy metals in arable soils of a major urban wetland inlet drainage system of Lake Victoria, Uganda(Lakes & Reservoirs: Research & Management, 2010) Mbabazi, Jolocam; Bakyayita, Grace; Wasswa, John; Muwanga, Andrew; Twinomuhwezi, Hannington; Kwetegyeka, JustusLittle is known about the effects of urbanization on the chemical quality of soils in suburban wetland inlet drainage systems to the Uganda side of Lake Victoria, on which food crops are extensively grown. It is feared that pollution in the soils might eventually enter food chains through such crops being consumed by urban populations unaware of their occurrence. Soil samples were collected from cultivated areas of a major wetland drainage system (Nakivubo Channel), at Kampala, Ubanda, near Lake Victoria and from a rural control wetland site (Senge). The soil from this site had similar properties as those from the urban test site (i.e., soil texture; porosity; humus content). Analysis of heavy metals with atomic absorption spectrophotometry (AAS) yielded the following soil concentration ranges: manganese (190–780), cadmium (<0.001–1.0), zinc (6.0–10.0) and lead (10–20 mg kg)1) dry weight for the control site, and 450–900, 1.0–2.0, 131– 185, 40–60 mg kg)1 dry weight, respectively, for the urban wetland, indicative of relatively heavy metal pollution in the suburban drainage system. Heavy metal levels in cocoyam (Colocasia Esculenta) and sugarcane (Saccharum Officinarum) grown on both wetland soils also were evaluated via AAS with a modified wet-acid-digestion technique. The results highlighted high cadium and lead levels (P £ 0.0003) in the crops from urban wetland cultivation. Cadmium and lead concentrations in cocoyam from urban wetland soils exceeded those from the control site by 0.17 and 3.54 mg kg)1, respectively. The corresponding results for sugarcane indicated a similar increase of 0.56 and 2.14 mg kg)1 of juice extract. Cadmium and lead levels in both urban wetland crops were higher than the maximum permissible limits of the Codex Alimentarius Commission, indicating that these concentrations pose potential health risks to urban consumers, and call for early counter-measures to combat urban pollution entering the lake.