Water Pollution
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Browsing Water Pollution by Subject "Kenya Marine and Fisheries Research Institute"
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Publication Application of phytoplankton community structure for ranking the major riverine catchments influencing the pollution status of a lake basin(Wiley, 2020-02-18) Aura, Christopher Mulanda; Odoli, Cyprian; Nyamweya, Chrisphine S.; Njiru, James M.; Musa, Safina; Miruka, Jared Babu; Owili, Monica Ochieng; Omondi, Reuben; Raburu, Phillip; Manyala, Julius; Mwamburi, Job; Ogari, Zachary; Mbaru, Emmanuel K.The present study demonstrates the application of a multi‑metric Phytoplankton Index of Biotic Integrity (PIBI) approach for ranking of major river catchments in the Kenyan part of Lake Victoria on the basis of their pollution status. The index utilizes water quality and zooplankton data, phytoplankton diversity, abundance and attributes, as well as literature information. The rivers were sampled from 2016 to 2018 during the wet season (March) and dry season (July). The separation power of the Mann–Whitney U test (p < .05) qualified eight discriminant metrics for phytoplankton samples into a scoring system of 1, 3 and 5, based on high, fair and slight deviation from the best site, respectively, in development of the final PIBI. The Kuja and Sondu‑Miriu rivers had the highest PIBI, signifying least pollution influence on the lake. In contrast, the Yala and Nzoia rivers exhibited the lowest PIBI, representing the catchments with a higher pollution influence on the lake. The fair to poor integrity classes for the major river catchments in the region signified a deteriorating lakescape. The present study presents the preliminary results of using phytoplankton metrics for development of the Index of Biotic Integrity (IBI) approach in the region as a decision‑making support tool for the effective management and sustainable use of water resources in the lake basin.Publication Diversity, composition and abundance of macroinvertebrates associated with water hyacinth mats in Lake Victoria, Kenya(African Journal of Education,Science and Technology, 2015-03-30) Orwa, Patrick; Omondi, Reuben; William, Ojwang; Josephat, MwanchiThis study is set to investigate the macroinvertebrate community structure within water hyacinth in the Kenyan waters of Lake Victoria. This is helpful in determining the relationship between water hyacinth and macroinvertebrates. A total of four replicates were taken from 18 sampling stations within the lake using a Ponar grab and a 500 µm scoop net. The samples were washed through a 300 µm sieve and sorted alive in the field. The organisms were then identified to genus level and further categorized into functional feeding guilds using available keys and literature. The vertical position of the organisms at a water hyacinth mat was also examined. The data was then analyzed for diversity and abundance. One way ANOVA was further done to test any significant variation in community attributes between stations within the lake. All the physic-chemical parameters measured varied significantly though pairwise comparison revealed that most stations were in same sub set. A total of 14 orders and 34 genera were identified during the study. Out of which, 13 genera which include Chironomus, Lymneae, Hirudo, Tubifex, Platycnemis, Sympetrum, Trithemis, Melanoides, Biomphalaria, Ilybius, Elmis, Leptocerus, and Hexagenia were found at every sampling station. Most of the taxa found were predators probably feeding on mosquito larvae which could explain their absence. There was no significant difference in the diversity between stations though they varied in abundance. It is thus concluded that water hyacinth influences the distribution of macroinvertebrates and can thus be used to predict their presence. The feeding guilds were however assigned using existing literature. It is therefore recommended that a further study be done to confirm the feeding habits and the presence of mosquito larvae. Key words: Macroinvertebrates, hyacinth, Lake VictoriaPublication Diversity, composition and abundance of macroinvertebrates associated with water hyacinth mats in Lake Victoria, Kenya(Academic Journals, 2015-03-30) Orwa, Patrick; Omondi, Reuben; William, Ojwang; Josephat, MwanchiThis study is set to investigate the macroinvertebrate community structure within water hyacinth in the Kenyan waters of Lake Victoria. This is helpful in determining the relationship between water hyacinth and macroinvertebrates. A total of four replicates were taken from 18 sampling stations within the lake using a Ponar grab and a 500 µm scoop net. The samples were washed through a 300 µm sieve and sorted alive in the field. The organisms were then identified to genus level and further categorized into functional feeding guilds using available keys and literature. The vertical position of the organisms at a water hyacinth mat was also examined. The data was then analyzed for diversity and abundance. One way ANOVA was further done to test any significant variation in community attributes between stations within the lake. All the physic-chemical parameters measured varied significantly though pairwise comparison revealed that most stations were in same sub set. A total of 14 orders and 34 genera were identified during the study. Out of which, 13 genera which include Chironomus, Lymneae, Hirudo, Tubifex, Platycnemis, Sympetrum, Trithemis, Melanoides, Biomphalaria, Ilybius, Elmis, Leptocerus, and Hexagenia were found at every sampling station. Most of the taxa found were predators probably feeding on mosquito larvae which could explain their absence. There was no significant difference in the diversity between stations though they varied in abundance. It is thus concluded that water hyacinth influences the distribution of macroinvertebrates and can thus be used to predict their presence. The feeding guilds were however assigned using existing literature. It is therefore recommended that a further study be done to confirm the feeding habits and the presence of mosquito larvae. Key words: Macroinvertebrates, hyacinth, Lake VictoriaPublication Effect of Eichhornia crassipes on coliforms load in small water bodies within Lake Victoria basin, Kenya(Academic Journals, 2015-03-11) Veronica, Ombwa; Orwa, Patrick; Alice, Mutie; Omondi, Reuben; Kenneth, Werimo; Ouko, JohnThe study investigates the effects of Eichhornia crassipes (water hyacinth) infestation based on coliform loads which are pollution indicator organisms. These dams have fish and the waters are commonly used for domestic purposes without any treatment hence it is necessary to check their status. Sampling was done on 25 small water bodies and from which water samples were taken for microbial determination. Membrane filtration method was used to enumerate fecal coliforms by use lauryl sulphate broth and incubated at 44 ± 0.5°C for 18 to 24 h. The results show that water bodies infested by water hyacinth harbored higher levels of fecal coliforms compared to those devoid of the weed. The high fecal coliform levels have negative impacts on the lives of communities using these water bodies. In addition, it reduces native species and disrupts food chains and nutrient cycle. The small water bodies within the Lake Victoria basin need frequent monitoring in order to give the relevant authorities concrete information for proper sensitization to the communities. Water hyacinth should also be properly managed so that it does not chock dams that are used for domestic and fishing activities.Publication Effect of vegetated filter strips on infiltration and survival rates of Escherichia coli in soil matrix at Mau, Njoro River Watershed, Kenya(Springer Link, 2017-04) Olilo, C. O.; Muia, A. W.; Onyando, J. O.; Moturi, W. N.; Ombui, P.; Shivoga, W. A.Overland flows contaminated with manure borne pathogens pose risks to public health, because fecal pathogens may infiltrate into soil matrix from overland flows and contaminate soil water aquifers. The objective of this study was to evaluate the effect of vegetative filter strip (VFS) on infiltration rates (CFU 100 ml−1 h−1) of Escherichia coli (E. coli) in overland flow and their survival rates in soil matrix. Thirty samples of the specimen were collected from VFSs each sampling time. The samples were each filtered, followed by a series of ten dilutions; then analyses for E. coli using membrane filtration technique. Wet oxidation method and potassium persulfate technique were used to analyze particulate organic carbon (POC) and dissolved organic carbon (DOC) at (p < 0.05) level of significance, respectively. A strong relationship was obtained between E. coli, POC and DOC in the overland flows (R2 = 0.89, p ≤ 0.05; df = 29). This study confirms the hypothesis that DOC released from Napier grass and Kikuyu grass exudates supported the initial survival, subsequent growth and adaptation of E. coli in its new secondary habitat outside its primary host. Thus, in the soil habitat, DOC and POC provided the initial energy for microbial cell multiplication from the VFS grasses. VFS influenced partitioning, infiltration and survival of E. coli in the overland flow into soil matrix. Thus, root zone retention data and information on E. coli in VFS systems are significant and could be used for scientific and management of soil erosion and the control of fecal pathogens entering surface water ecosystems both locally in Mau Ranges, Njoro River Watershed and internationally in other areas with similar environmental problems. VFS could be utilized under various designs of VFSs with different plants that have different setup of plants’ root zone cover and penetrations systems that could help in infiltrating overland flow manure borne pathogens, a process that could be useful in the management of these pathogens in agro-pastoral systems locally and internationally.Publication Effect of vegetated filter strips on transport and deposition rates of Escherichia coli in overland flow in the eastern escarpments of the Mau Forest, Njoro River Watershed, Kenya(Springer Link, 2016-06) Olilo, C. O.; Onyando, J. O.; Moturi, W. N.; Muia, A. W.; Ombui, P.; Shivoga, W. A.; Roegner, A. F.The fate and transport of Escherichia coli (E. coli) in lotic waters through vegetated filter strips (VFSs) was evaluated in a field model pasture, utilizing VFSMOD Windows along with direct pathogen testing. This study assessed effects of VFS on transport and deposition rates of E. coli in lotic overland flow waters. The VFS measured 44 m long by 40 m wide, covering an area of 1584 m2 and land slope of 15 %. Cowpat was applied onto the model pasture and washed by overland flow into the VFS. The 4-methylumbelliferyl β-D-glucuronide substrate confirmed the identity of E. coli prior to cowpat application and after isolating them from soil using centrifugation and membrane filtration techniques. Napier grass root system recorded the highest recovery rates of E. coli at 99.9 % along the length of VFS III. This efficiency reduced significantly (p < 0.05; df = 29) to 95 % in Kikuyu grass and 75 % in Couch grass-Buffer grass. The data demonstrated similarity in transport of manure-borne E. coli and organic carbon (OC) through all the simulated VFS. These results indicated that OC could be used as a true natural tracer of manure-borne E. coli, a pollution indicator organism of lentic and lotic surface waters provided the OC release kinetics from cowpat were similar to that of E. coli kinetics. Thus, efficient filtering to reduce E. coli concentrations and load in overland flows requires managing combined grass species, agro-pastoral systems models and dispersed or preferential flows to enhance surface water quality standards.Publication Intriguing case of ecosystem dynamics in the Lake Victoria: Water Hyacinth (Eichhornia crassipes) and Escherichia coli(International Journal of Fisheries and Aquatic Studies, 2015-03-15) Mutie, Alice; Ojwang, William; Werimo, Kenneth; Omondi, Reuben; Ouko, JohnWater hyacinth (Eichhornia crassipes) is a noxious weed with immense impact on the health and the livelihoods of communities’ in the tropical sub-Saharan African countries. This study was aimed at assessing the effects of water hyacinth on Escherichia coli levels in Kenyan Lake Victoria. Sampling was done in waters infested by water hyacinth (roots and mats) and in open water areas (devoid of the weed). Membrane filtration method was used to enumerate Escherichia coli at 44.5 ºC for 18-24 h. Results showed that E. coli levels were higher in water hyacinth infested areas compared to areas in the open waters and those under water hyacinth mats. The levels of E. coli in the open water areas ranged from undetectable levels to 1140 cfu/100 ml. Whereas, levels of E. coli from areas under water hyacinth mats ranged from 10 cfu/100 ml to 1549 cfu/100 ml while E. coli levels from waters from water hyacinth roots ranged from undetectable levels to 6387 cfu/100 ml. Therefore, general marked differences in levels of E.coli in hyacinth thriving areas with regard to free areas indicate potential ability of the plant to harbor microbiological contaminants and if its spread is left unchecked, incidences of water borne related diseases like the cholera may increase incredibly among the riparian communities with consequent loss of many lives. It is therefore imperative that a plan of action is put in place to control the spread of water hyacinth in Lake Victoria.Publication Macrophytes of Lake Victoria and succession after invasion of Water Hyacinth(AQUA DOCS, 2006) Omondi, Reuben; Kusewa, MwendeThe distribution of Lake Victoria macrophytes is described. Succession of macrophytes in the lake became more dramatic and dynamic after invasion of water hyacinth. The weed pushes and smothers other free-floating macrophytes like Pistia stratiotes. It then provides substrates for the emergent Vossia cuspidata, which later reduces its population by competition for light and nutrients. The noxious weed is believed to have led to extinction of Azolla nilotica in the lake.Publication Survival and avoidance response of the freshwater gastropod Melanoides tuberculatus (Muller) to different concentrations of tobacco waste(Aquaculture Research, 2012) Ogello, Erick Ochieng; Omondi, Reuben; Opiyo, Mary A.; Charo‐Karisa, Harrison; Munguti, Jonathan; Aura, Christopher MulandaThe Gastropod Melanoides tuberculatus plays a significant role in hampering fish larval production in earthen ponds. This study investigated use of tobacco waste to assess behavioural and survival responses of M. tuberculatus at different concentrations of tobacco waste solution of 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75 and 2 g L−1. Mean escape time varied significantly among concentrations (P < 0.05). Escape time decreased in 1‐, 2‐ and 3‐day‐old solutions. Percentage survival decreased significantly with increasing concentrations of tobacco waste solution and exposure time (P < 0.05). Concentrations of 1.75 g L−1 and 2.0 g L−1 had high hazard ratios and low survival rates of gastropods and were the most effective in eradication of M. tuberculatus, hence recommended dose for preparing ponds for stocking. We conclude that tobacco waste solution can be used for control of M. tuberculatus.Publication Survival and avoidance response of the freshwater gastropod Melanoides tuberculatus (Muller) to different concentrations of tobacco waste(Wiley, 2012-09-13) Ogello, Erick Ochieng; Omondi, Reuben; Opiyo, Mary A.; Charo-Karisa, Harrison; Munguti, Jonathan; Aura, Christopher MulandaThe Gastropod Melanoides tuberculatus plays a significant role in hampering fish larval production in earthen ponds. This study investigated use of tobacco waste to assess behavioural and survival responses of M. tuberculatus at different concentrations of tobacco waste solution of 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75 and 2 g L−1. Mean escape time varied significantly among concentrations (P < 0.05). Escape time decreased in 1-, 2- and 3-day-old solutions. Percentage survival decreased significantly with increasing concentrations of tobacco waste solution and exposure time (P < 0.05). Concentrations of 1.75 g L−1 and 2.0 g L−1 had high hazard ratios and low survival rates of gastropods and were the most effective in eradication of M. tuberculatus, hence recommended dose for preparing ponds for stocking. We conclude that tobacco waste solution can be used for control of M. tuberculatus.Publication Using the Multi-metric Index of Biotic Integrity methodological approach to determine the major river catchment that most pollutes a lake(Aquatic Ecosystem Health, 2021-12-20) Aura, Christopher; Nyamweya, Chrisphine; Njiru, James; Omondi, Reuben; Manyala, Julius; Musa, Safina; Owiti, Horace; Guya, Fredrick; Ongore, Collins; Ogari, Zachary; Mwamburi, Job; Health and Management, Aquatic EcosystemWe present the Multi-metric Index of Biotic Integrity methodological approach that allows for the ranking of major river catchments based on pollution status in the Kenyan portion of Lake Victoria, Africa. The study has a broader applicability to all of Lake Victoria, other African Great Lakes, and all lakes that have riverine discharge. The method presented utilizes water quality and environmental data, local knowledge, and pre-existing literature. The parameters considered were sampled from 2016 to 2018 during the dry season (July sampling) and the wet season (March sampling). Separation power of Mann-Whitney U test (p < 0.05) qualified 11 discriminant metrics for both macroinvertebrate and fish samples into the scoring system of 1, 3 and 5 in the formulation of final Multi-metric Index of Biotic Integrity methodological approach. Rivers in the northern section had lower Multi-metric Index of Biotic Integrity methodological approach scores, as compared to southern counterparts. The Multi-metric Index of Biotic Integrity methodological approach ranking herein was validated by community perceptions on pollution levels. River Nzoia catchment emerged as the most polluted, followed by River Yala, River Kuja, and Sondu-Miriu. Siltation, domestic washing, litter and refuse emerged as the main agents of pollution. Management authorities ought to reinforce a balanced utilization of the vital water resources to minimize future impacts, and promote catchment wide practices that ensure ecological health sustainability of the lake ecosystem.Publication Water hyacinth Eichhornia crassipes (Mart.) Solms-Laubach dynamics and succession in the Nyanza Gulf of Lake Victoria (east Africa): implications for water quality and biodiversity conservation(Hindawi Publishing Corporation, 2012) Gichuki, John; Omondi, Reuben; Boera, Priscillar; Okorut, Tom; Matano, Ally Said; Jembe, Tsuma; Ofulla, AyubThis study, conducted in Nyanza Gulf of Lake Victoria, assessed ecological succession and dynamic status of water hyacinth. Results show that water hyacinth is the genesis of macrophyte succession. On establishment, water hyacinth mats are first invaded by native emergent macrophytes, Ipomoea aquatica Forsk., and Enydra fluctuans Lour., during early stages of succession. This is followed by hippo grass Vossia cuspidata (Roxb.) Griff. in mid- and late stages whose population peaks during climax stages of succession with concomitant decrease in water hyacinth biomass. Hippo grass depends on water hyacinth for buoyancy, anchorage, and nutrients. The study concludes that macrophyte succession alters aquatic biodiversity and that, since water hyacinth infestation and attendant succession are a symptom of broader watershed management and pollution problems, aquatic macrophyte control should include reduction of nutrient loads and implementing multifaceted approach that incorporates biological agents, mechanical/manual control with utilization of harvested weed for cottage industry by local communities.Publication Water Quality of Selected Fishing Beaches of Lake Victoria Kenyan Gulf(Scientific Research, 2020-01) Orina, Paul S.; Onyango, David M.; Lungayia, Henry; Oduor, Andrew; Sifuna, Anthony W.; Otuya, Petronila; Owigar, Rosemary A.; Kowenje, Chrispin B.; Hinzano, Sheban M.Lake Victoria the second largest fresh water body in the world located in East Africa is a shared resource between Kenya, Tanzania and Uganda and enjoys a wide range of streams and rivers from as far as Burundi and Rwanda. The lake has environmentally undergone physical, chemical and biological changes in the last four decades, particularly rise in its trophic condition and decline in oxygen level, which affects the water quality and fish population dynamics. This study therefore set out to determine the quality of water in selected fishing beaches of Lake Victoria, Kenya with a view to report the possible pollution levels. pH was highest at Nyamasari and Kotieno (9.3 ± 0.1) and lowest at Nyachebe and Kichinjio (7.08 ± 0.1) whereas temperature was highest at Nyamasari (29.5°C ± 0.0°C) and lowest at Kichinjio (23.4°C ± 0.2°C). DO was highest at Kotieno (10.3 ± 0.2 mgL) and lowest at Seka (2.4 ± 0.1 mgL). Turbidity was highest at Uyoga (125.5 ± 0.90 NTU) and lowest at Osieko (2.7 ± 0.1 NTU). Ammoniacal nitrogen was highest at Dunga (1278.3 ± 0.8 μ∙gl-1) and lowest at Nyamasari (12.4 ± 0.8), all a factor of human activities, lake substratum and effluents from rivers and surface runoff. All parameters assessed showed significant differences across sampling sites and depth except pH which did not vary significantly with distance from lakeshore. Further, all parameters did not show a clear pattern with respect to distance from the lakeshore possibly due to adequate mixing in the gulf. There is a need for further water quality monitoring by seasons to inform policy decisions towards sustainable lake exploitation.