Browsing by Author "Kimambo, Offoro N."

Now showing 1 - 8 of 8

Dependence of air quality on meteorological parameters in Dar es Salaam, Tanzania
(Tanzania Journal of Natural and Applied Sciences, 2010) Mkoma, Stelyus L.; Kimambo, Offoro N.; Mabiki, Faith P.; Tungaraza, Clavery T.
The influence of meteorology on air quality in Dar es Salaam was investigated. Precipitation, temperature, relative humidity and wind speed were measured during wet and dry seasons of 2005 and 2006 period and their relationship with reported mass of particles of aerodynamic diameter smaller than 10 μm (PM10) for the site was assessed. Results indicate that the highest median concentrations for the PM10 mass (58 μg/m 3 ) was observed during the 2005 dry season and the lowest median (40 μg/m 3 ) during the 2006 wet season. It is interpreted that reasons for the higher levels of the PM10 mass in the dry season are due to temperature inversions, soil dust dispersal and absence of rain wash-down. The observed PM10 levels are also affected by the variations in sources strengths and in meteorological conditions such as mixing height, precipitation, relative humidity, wind speed and direction as supported by air mass trajectories.
Energy efficient refuse derived fuel (rdf) from municipal solidwaste rejects: a case for coimbatore
(International journal of environment, 2014-05-17) Kimambo, Offoro N.; Subramanian, P.
In this paper production of energy efficient Refuse Derived Fuel (RDF) from municipal solid waste rejects was carried out during August 2012 – April 2013 in Coimbatore City India. Municipal Solid wastes rejects (paper, plastics with exception of polyvinyl chloride, textiles) were collected from waste dump yard of Coimbatore City. Sawdust, coir dust, water hyacinth and rice husk were mixed with the collected wastes at a fixed amount of 20 percent. After grinding, cassava starch was used as a binder to produce RDF briquettes with the help of uniaxial piston briquettes making machine. Physical, chemical and thermal characteristics of the RDF were studied to assess their potential use as energy efficient material. The analyses were divided into three categories namely, physical, proximate and ultimate analyses. Results indicated that, under physical and proximate analyses; impact resistance index (IRI) for all the RDF samples were 200, density were less than 1 kg cm - 3, moisture were less than 10 % wt, ash content varied from 2.8 to 9.2 % wt, whilst volatile mater had mean value of 83.1 % wt and fixed carbon which is by subtraction ranged from 1.4 to 9.2 % wt. With respect to Ultimate analysis, Oxygen, carbon, hydrogen varied from 27.01 to 39.78 % wt, 44.8 to59.7 % wt, 5.9 to 8.1 % wt respectively. On the other hand nitrogen, sulfur and chlorine ranged from 0.18 to 0.87 % wt, 0.27 to 0.71 % wt and 0.339 to0.521 % wt respectively. Calorific values (high heating values) ranged from 5085 to 6474.9 kcal kg -1 . The results were compared with Energy research Centre for the Netherland database and noted that with exception to moisture, fixed carbon and hydrogen other parameters had a significant lower or higher differences. From the study, RDF from municipal solid wastes rejects along with the additives produced high energy efficient materials.
Harmful algae in aquaculture systems in Ngerengere Catchment, Morogoro, Tanzania: Descriptive community structure and environmental concerns
(Elsevier Ltd, 2022) Kimambo, Offoro N.; Gumbo, Jabulani R.; Msagati, Titus A.M.; Chikoore, Hector
Climate variability, anthropogenic activities, and hydrological shifts are fueling the nuisance of harmful algal blooms in water bodies. Unfortunately, cyanobacterial harmful algal blooms (CyanoHABs) dynamics have not received much attention in Tanzania. The study aimed to identify and characterize common species of cyano bacteria and examine their possible change in composition and succession in the Ngerengere catchment, Morogoro, Tanzania. Water samples from the selected reservoirs were collected quarterly between October 2017 and September 2018 for physico-chemical parameters in situ and in the laboratory. A benchtop FlowCAM was used for the identification of cyanobacteria and compared with the literature and available online databases. Principal component analysis (PCA) was used to examine the association between the physico-chemical variables and meteorological patterns. The study found common CyanoHABs such as Microcystis, Cylindrospermopsis, Anabaena (Dolichospermum), Lyngbya as well as other species such as diatoms and Euglena which are also considered nuisance. Virtually, a colonial cyanobacteria species dominated the fishponds, while Mindu Dam was more of filamentous species. The study suggest that Mindu dam, based on Carlson’s Trophic State Index (TSI), falls under eutrophic while the fishponds were hypereutrophic. Associated physico-chemical conditions, heavy rainfall and prolonged dry conditions influenced cyanobacteria bloom dynamics. The hydrological connectivity between the fishponds and the Mindu Dam poses a threat to public health because a significant population in Morogoro depends on Mindu Dam for domestic water supply. There is a need for the development of a frame work for mitigative and adaptive measures in the catchment, especially during pre-and post-occurrence of blooms.
The occurrence of cyanobacteria blooms in freshwater ecosystems and their link with hydro-meteorological and environmental variations in Tanzania
(Elsevier Ltd, 2019-03) Kimambo, Offoro N.; Gumbo, Jabulani R.; Chikoore, Hector
Cyanobacteria (blue-green algae) are photosynthetic bacteria that under favorable environmental conditions produce secondary metabolites (cyanotoxins) which are harmful to the environment, including humans. The mass proliferation of harmful cyanobacteria is termed CyanoHABs. CyanoHABs can adapt to different climatic fluctuations, therefore, understanding their dynamics in freshwater systems is crucial. Variation in climatic and hydrological processes, changing land use and economic growth all influence the occurrence and distribution of CyanoHABs. There have been inadequate CyanoHAB studies at local scales, therefore their occurrence and dynamics cannot be generalized. This study reviews and synthesizes cases of CysnoHAB occurrence, magnitude, and timing and how these are linked with climatic and hydrological variations in the United Republic of Tanzania. In this study, a scoping review approach was adopted. Research articles, reports, and databases were consulted. The most common species of toxin-producing cyanobacteria were identified in different water bodies in Tanzania, as well as the record of mass fatality of birds (Lesser Flamingo) in Lake Manyara, which in almost all cases occurred during dry years. While previous studies on CyanoHAB dynamics and their links to climate, hydrological, and environmental changes have not been undertaken in Tanzania, there are studies in Lake Victoria and Tanganyika. Therefore, there should be an immediate response from water users, managers, researchers, and water authorities to address and actively engage in monitoring and managing the risks associated with CyanoHABs in Tanzania.
Rapid environmental flow assessment for sustainable water resource management in Tanzania’s Lower Rufiji River Basin: a scoping review
(Heliyon, 2023) Kimambo, Offoro N.; Mbungu, Winfred; Massawe, Goodluck D.; Hamad, Amina A.; Ligate, Elly J.
The use of Environmental flow (e-Flow) assessment is a widely adopted approach to facilitate informed decision-making concerning sustainable management and utilization of water resources in river systems. The Lower Rufiji River Basin faces various developmental pressures from several sectors, including hydropower, mining, agriculture, livestock, fishing, and tourism, necessitating effective management of the sub-catchment area to prevent significant environmental impacts. Consequently, it is essential to acquire a comprehensive comprehension of the catchment’s at tributes, encompassing both climatic and non-climatic factors. Supported by e-Flow batch anal ysis of the available data at Stiegler’s Gorge using the global environmental flow calculator, a scoping review was conducted to determine the status of environmental flow in the lower Rufiji River basin. The findings suggest that, while there has been progress in understanding eFlow estimation, limited data and ecohydrological processes’ poor comprehension still present chal lenges. Hydrological and holistic methodologies are commonly employed in Tanzania; however, uncertainties remain, raising questions concerning trust between decision-making tools and water resource utilization by the public. Climate variability influences e-Flow in the Rufiji River Basin, and the projections under various scenarios indicate an increased temperature, varying rainfall, and humidity levels. Further, the area has been identified as a vulnerable “hotspot” where communities face greater climate stressor risks. With the existing and planned developmental projects in the basin, including hydroelectric dams, mining, agriculture, livestock, and fisheries, it is critical to assess e-Flow in the Lower Rufiji River basin to ensure resource sustainability. Advocating for preserving a dynamic environmental flow regime in rivers is recommended, considering the Rufiji River Basin’s habitat connectivity. The future research direction should be quantifying the contribution of base flow to the surface flow, and salinity dynamics in the Lower Rufiji River Basin, which can affect the Delta’s biodiversity.
Retrospective analysis of Chlorophyll-a and its correlation with climate and hydrological variations in Mindu Dam, Morogoro, Tanzania
(Elsevier Ltd, 2014-11-06) Kimambo, Offoro N.; Chikoore, Hector; Gumbo, Jabulani R.; Msagati, Titus A. M.
The measurement of Chlorophyll-a in aquatic systems has usually correlated to harmful algae in water bodies. Harmful algal blooms (HABs) are as a result of massive proliferation of blue-green algae (Cyanobacteria). Harmful algal blooms (HABs) pose threats to both the environment as well as human health, and despite this well-known fact, their monitoring and management are still challenging. Climate change, extreme weather events, and hy- drological changes are the main drivers and predicted to benefits HABs dynamics in most parts of the world. In Tanzania, studies of HABs proliferation and their possible correlation with variability in climate and hydrology still lag behind despite high demand for developing predicting tools and prevention of HABs proliferation. The present study reports on the retrospective analysis of HABs variation in Mindu Dam located in Morogoro, Tanzania using remote sensing techniques. In the present study comparison between in situ measurement and ocean color (OC2) Chlorophyll-a with the surface reflectance's (band and band combinations) of Landsat 7 and Landsat 8 Operational Land Imager (OLI), was performed. Another approach involved searching for patterns and trends, and teleconnection between Chlorophyll-a index (best band ration) and the climate and hydrological variations in the catchment. The findings demonstrated that minimum and maximum temperatures, solar radi- ation, Chlorophyll-a concentration registered significant increasing trends. Wind speed and directions, water levels for Mindu Dam showed a significant decreasing trend. On the other hand, rainfall showed no trend. The patterns suggest that there are link and causality between the HABs variations and meteorological parameters such as temperatures, solar radiations, and water levels. The study, therefore, contributes to the application of recent advances in remote sensing and retrospectively analysis of bloom dynamics and search for their link with climate and hydrological changes.
Tornadoes in South Africa: an overview with a case study
(University of Venda, 2018-11-26) Kimambo, Offoro N.
This paper contributes to the understating of tornadoes in South Africa using case study analysis. In South Africa tornadoes are the recurring phenomenon (the climatology) but so far they have received less attention. Damages from storms itself (tornadoes inclusive) are significant in South Africa relative to other weather-related disasters for example floods, heat waves, and droughts. For their understanding, a case study approach was adopted in the current study. Data were in courtesy of the following, National Oceanic and Atmospheric Administration (NOAA), National Centers for Environmental Predictions (NCEP), Eumetsat Germany, and South African Weather Service (SAWS). The aim of the study was to provide an overview of the occurrence of tornadoes in South Africa using a Klerksdorp tornado, which occurred on March 4, 2007, Northwest Province in South Africa. From the case study analysis, the tornado was associated with the cold front and cut-off low (both are extratropical circulation) which were the dominant weather systems of the day. Therefore we conclude that, a case study approach may be the best way to study events of these nature for a more informed decision, for example, issuing an early warning system. In future, case studies, for example, involving interaction between extratropical and tropical circulation will also be an interesting study.
The unusual reddish-bloom appearance in a freshwater fishpond at Kingolwira National Fish Farming Center, Morogoro, Tanzania
(IJE, 2020-05) Kimambo, Offoro N.; Gumbo, Jabulani R.; Msagati, Titus A.M; Chikoore, Hector
The study aimed to examines a case of what constituted the uncommonly reddish-bloom appearance in the fishponds during the dry season (September 2018) at Kingolwira National Fish Farming Center located in Morogoro, Tanzania. The study used a benchtop FlowCAM® to investigate species' morphology. One-time assessment of physico-chemical characteristics during the event was performed from the reddish and non- reddish fishponds. Images were compared with the available literature, but also t-test statistics were performed to examine the difference between the fishponds. The results show that the fishponds were significantly (p<0.05) different from each other in terms of physico-chemical parameters except for water temperatures. Furthermore, Microcystis species dominated the non-reddish fishpond whereas Euglenophytes species were pervasive in the reddish fishpond. The two species have the potential to produce secondary metabolites (toxins) or to produce a hypoxia condition that is harmful to the fishery, aquatic ecology, and human. To confirm toxicity nature and dynamics further, future studies should consider extensive and regular diurnal and long-term monitoring.