Journal Articles

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1-D transport behaviour of emerging contaminants in the unidirectional flowing surface waters of the Msimbazi River
(College of Natural and Applied Sciences, University of Dar es Salaam, 2020) Miraji, Hossein; Mureithi, Eunice; Othman, Othman C.; Ngassapa, Faustin
The primary objectives of this investigation of environmental pollution were to assess spatio-temporal concentrations and predictions of transport behaviour of pollutants in aqueous media. In order to attain these goals for the Msimbazi river, the analytical and numerical solutions to the 1-D advection-dispersion equation (ADE) implemented the first-type inlet condition. The MATLAB software was used to solve the analytical equation resulting from the ADE equation. The solution to the ADE model enabled effective prediction of contaminants’spatial distribution within a distance of 200 m from a point source in the direction of flowing water. Among the first and third-types inlet conditions, the first-type had the best exponential concentration prediction with descending concentration gradients between –100 ng/L.m and –0.4 ng/L.m, while beyond it the concentration gradient was merely constant. These findings are the first of this type in our region to the best of our knowledge, and hence a milestone for understanding the transport behaviour of emerging contaminants, and enable estimation of probable pollution-free zones. This study gave results that can form a basis for analytical and public interventions.
3D geocellular modeling for reservoir characterization of lacustrine turbidite reservoirs: Submember 3 of the third member of the Eocene Shahejie Formation, Dongying depression, Eastern China
(Elsevier, 2022) Lutome, Marco Shaban; Lin, Chengyan; Chunmei, Dong; Zhang, Xianguo; Bishanga, Januarius Matata
3D geocellular modeling is increasingly essential in the petroleum industry; it brings together all petroleum disciplines, and it is commonly used in simulation and production forecast. However, modeling slope and deep-water turbidite reservoirs using conventional modeling methods pose a significant challenge due to the structural complexity and thin-beds associated with these reservoirs. Through the innovative modeling technology of PaleoScan, the reservoirs in Sub member 3 of the third member of the Shahejie Formation are modeled to understand the structural framework. The resulting model is populated with petrophysical properties i.e., porosity and permeability to predict their lateral and vertical distribution within these sandstone reservoirs. The study suggests that the reservoir in the highstand system tract (HST) is characterized by the clinoforms configuration framework. The reservoir is highly faulted mainly in the northern and southeastern parts of the depression. The sedimentary layers are deposited across the slope and downlapping, thinning, and terminating toward to the west. The two isochore surface maps reveal sediment thickness variation and depositional trends within each individual depositional layer. The zones or areas that corresponds to low values on the thickness maps suggest minor uplifts associated with intensive faulting in the Eocene period. These topographical highs played a fundamental role in distributing the sediments delivered to the basin from distant sources. The maps reveal that sediments that filled the basin appear to come from different source points, primarily delivered from the north, southeast, and northeast of the basin with varying depositional trends. The modeled porosity and permeability indicate that the delta fed turbidite reservoirs are characterized by medium to high porosity values of 10e20% and low to medium permeability values of 30-410mD, respectively. The porosity values increase to the southeast and toward the basinwards (west) while permeability varies within the individual sedimentary layers. The distribution of porosity and permeability is not uniform vertically. This suggests the presence of mixed none-reservoir layers with locally and periodically deposited sandstone reservoirs within the stratigraphic during rapid delta progradation. The HST is characterized by six different delta progradation cycles; each phase produced locally deposited lacustrine turbidite sandstones in the basin, which are essential reservoirs in this Formation. The innovative PaleoScan interpretation technology has successfully created a high-resolution 3D reservoir model of this complex geology-such innovative technology is vital to similar complex geology globally.
9 - Holocene environmental magnetic records of Indian monsoon fluctuations
(Elsevier, 2022) Basavaiah, N.; Seetharamaiah, J.; Appel, Erwin; Juyal, Navin; Prasad, Sushma; Rao, Nageswara K.; Khadkikar, A.S.; Nowaczyk, N.; Brauer, A.
Holocene history of the Indian monsoon reconstruction using environmental magnetism has emerged as an effective paleoclimate proxy with its fast, efficient, and repeatable measuring procedures. In this chapter, we have made an attempt to provide a broad synthesis of the available sediment magnetic records obtained from the loess-paleosols (central Himalaya), lake (western India), delta and lagoon sequences (eastern coast Godavari and Iskapalli). Variations in magnetomineralogical S-ratio values of sediment archives were combined and stacked as a surrogate for Holocene paleomonsoon change. High S-ratio results from low weathering rates were attributed to more wet conditions, while low S-ratios were related to dry conditions from intense low temperature oxidation. Combining the S-ratio data from diverse environments collectively revealed three broad climate phases with minor oscillations during the past 20 ka. These are (i) a step-wise intensification of the SW monsoon since the Last Glacial Maximum with its peak level at ∼9.0 ka, (ii) the prevalence of a prolonged dry spell along the eastern coast and western India at ∼3.5 ka that led to the collapse of the Harappan civilization, and (iii) reduction of monsoon rainfall during the period of global cooling events such as Last Glacial Maximum, Younger Dryas, and Little Ice Age. We observed that instead of the concentration-specific magnetic susceptibility (χ), the combined remanence S-ratio seems to be a more sensitive proxy responding to the monsoon variability both at centennial and millennial time scales.
Advancing sanitary surveillance: Innovating a live-feed sewer monitoring framework for effective water level and chamber cover detections
(Elsevier BV, 2024) Utepov, Yelbek; Neftissov, Alexandr; Mkilima, Timoth; Shakhmov, Zhanbolat; Akhazhanov, Sungat; Kazkeyev, Alizhan; Mukhamejanova, Assel Toleubekovna; Kozhas, Aigul Kenzhebekkyzy
Efficient sanitation system management relies on vigilant sewage surveillance to uphold environmental hygiene. The absence of robust monitoring infrastructure jeopardizes unimpeded conduit flow, leading to floods and contamination. The accumulation of harmful gases in sewer chambers, coupled with tampered lids, compounds sewer network challenges, resulting in structural damage, disruptions, and safety risks from accidents and gas inhalation. Notably, even vehicular transit is vulnerable, facing collisions due to inadequately secured manholes. The core objective of this research was to deconstruct and synthesize a prototype blueprint for a live-feed sewer monitoring framework (LSMF). This involves creating a data gathering nexus (DGN) and empirically assessing diverse wireless sensing implements (WSI) for precision. Simultaneously, a geographic information matrix (GIM) was developed with algorithms to detect sewer surges, blockages, and missing manhole covers. Three scrutinized sensors—the LiDar TF-Luna, laser TOF400 VL53L1X, and ultrasonic JSN-SR04T—were evaluated for their ability to measure water levels in sewer vaults. The results showed that the TF-Luna LiDar sensor performed favorably within the 1.0–5.0 m range, with a standard deviation of 0.44–1.15. The TOF400 laser sensor ranked second, with a more variable standard deviation of up to 104 as obstacle distance increased. In contrast, the JSN-SR04T ultrasonic sensor exhibited lower standard deviation but lacked consistency, maintaining readings of 0.22–0.23 m within the 2.0–5.0 m span. The insights from this study provide valuable guidance for sustainable solutions to sewer surveillance challenges. Moreover, employing a logarithmic function, TF-Luna Benewake exhibited reliability at approximately 84.5%, while TOF400 VL53L1X adopted an exponential equation, boasting reliability approaching approximately 89.6%. With this navigational tool, TF-Luna Benewake maintained accuracy within ±10 cm for distances ranging from 8 to 10 m, showcasing its exceptional performance.
Advancing sanitary surveillance: Innovating a live-feed sewer monitoring framework for effective water level and chamber cover detections
(Elsevier BV, 2024) Yelbek Utepov; Alexandr Neftissov; Timoth Mkilima; Zhanbolat Shakhmov; Sungat Akhazhanov; Alizhan Kazkeyev; Assel Toleubekovna Mukhamejanova; Aigul Kenzhebekkyzy Kozhas
Efficient sanitation system management relies on vigilant sewage surveillance to uphold environmental hygiene. The absence of robust monitoring infrastructure jeopardizes unimpeded conduit flow, leading to floods and contamination. The accumulation of harmful gases in sewer chambers, coupled with tampered lids, compounds sewer network challenges, resulting in structural damage, disruptions, and safety risks from accidents and gas inhalation. Notably, even vehicular transit is vulnerable, facing collisions due to inadequately secured manholes. The core objective of this research was to deconstruct and synthesize a prototype blueprint for a live-feed sewer monitoring framework (LSMF). This involves creating a data gathering nexus (DGN) and empirically assessing diverse wireless sensing implements (WSI) for precision. Simultaneously, a geographic information matrix (GIM) was developed with algorithms to detect sewer surges, blockages, and missing manhole covers. Three scrutinized sensors—the LiDar TF-Luna, laser TOF400 VL53L1X, and ultrasonic JSN-SR04T—were evaluated for their ability to measure water levels in sewer vaults. The results showed that the TF-Luna LiDar sensor performed favorably within the 1.0–5.0 m range, with a standard deviation of 0.44–1.15. The TOF400 laser sensor ranked second, with a more variable standard deviation of up to 104 as obstacle distance increased. In contrast, the JSN-SR04T ultrasonic sensor exhibited lower standard deviation but lacked consistency, maintaining readings of 0.22–0.23 m within the 2.0–5.0 m span. The insights from this study provide valuable guidance for sustainable solutions to sewer surveillance challenges. Moreover, employing a logarithmic function, TF-Luna Benewake exhibited reliability at approximately 84.5%, while TOF400 VL53L1X adopted an exponential equation, boasting reliability approaching approximately 89.6%. With this navigational tool, TF-Luna Benewake maintained accuracy within ±10 cm for distances ranging from 8 to 10 m, showcasing its exceptional performance.
Analogue sandbox scaled modelling of oblique and orthogonal extension rifting in Rukwa rift basin, Tanzania
(University of Dar es Salaam, 2021) Ojok, Tonny; Duot, John BK; Namaganda, Majorine; Sadiki, Nasra; Msabi, Michael
Fault evolution in oblique and orthogonal rift systems in the brittle upper crust of the Rukwa rift basin was simulated using scaled sandbox modelling by varying the angle between the rift axis and the extension direction, α, through 45° and 90°, over a 10 cm displacement. The 45° oblique model exhibits a half-graben architecture bounded by a planar fault, intra-rift faults and a conjugate fault in some vertical sections. The map view of the model’s basin trends in the NW-SE direction, and is comparable with the Rukwa rift basin orientation. The 90° oblique model forms a basin structure which is orthogonal to the extension direction of the model in aerial photos. Its linear fault remains orthogonal to the extension direction, while the flexural side of the model segments into sinuous normal faults. Planar to slightly curved intra-rift faults are observed in vertical sections. The half-grabens have similar geometries in vertical sections for both models, while intra-rift faults elongate in vertical sections. The results of the oblique model are similar to natural examples of rift fault systems like the Rukwa rift. The fault geometries of the sandbox models can serve as examples for recognizing fault styles in oblique rift systems.
Analysis of challenges related to poor environmental regulatory framework on mineral exploration projects: A case of Tanzania
(Scientific Research Publishing, 2016) Lema, Meserecordias Wilfred
In the United Republic of Tanzania (URT), all environmental issues related to the mining industry are regulated according to two principle Acts: The Mining Act and the Environmental Management Act, and their respective regulations. The current acts were enacted in 2010 and 2004 respectively. Mineral exploration (that includes all on-site activities performed before a mining project is declared feasible) projects in URT appears to be “unforgotten phenomena” in the two major legislative documents, when it comes to environmental considerations. This phenomenon is believed to be causing detrimental effects to the environment. This paper, therefore, analyzes the current environmental regulatory framework on mineral exploration projects in URT and discusses few examples in which mineral exploration projects have caused damage to the indigenous environment. Furthermore, this study reviews environmental regulatory frameworks from other few countries in comparison with existing environmental regulatory framework prevailing in URT.
Analysis of methods used to validate remote sensing and GIS-based groundwater potential maps in the last two decades: A review
(Elsevier BV, 2024) Bennett, G.
The integration of remote sensing data, machine learning and geographic information system in managing and analysing spatial data helps in generating maps showing groundwater potential. These maps are important tools for aiding stakeholders and decision-makers in groundwater resources to make informed decisions during groundwater development and management; to ensure the reliability of these maps, validation with the field data is conducted. This study analysed 125 scientific articles spanning the period from 2002 to 2023. The results show that around 85% of articles contain validated maps, indicating a significant number of researchers adhere to validate the remote sensing and GIS-based maps with field data, which is crucial in scientific research. However, 15% of articles contain non-validated maps. This is an alarming figure; therefore, journals should be strict in ensuring that validation is adhered to. In the reviewed articles, a total of 10 methods were used to validate groundwater potential maps using various parameters such as well yield, well/spring discharge rate, aquifer transmissivity, well specific capacity, and presence of wells/springs. This study will also add to the knowledge of selecting appropriate methods for validating remote sensing and GIS-based groundwater potential maps. The use of field data reflecting aquifer productivity is more appropriate for validation of groundwater potential maps.
Analysis of methods used to validate remote sensing and GIS-based groundwater potential maps in the last two decades: A review
(Elsevier BV, 2024) Bennett, George
The integration of remote sensing data, machine learning and geographic information system in managing and analysing spatial data helps in generating maps showing groundwater potential. These maps are important tools for aiding stakeholders and decision-makers in groundwater resources to make informed decisions during groundwater development and management; to ensure the reliability of these maps, validation with the field data is conducted. This study analysed 125 scientific articles spanning the period from 2002 to 2023. The results show that around 85% of articles contain validated maps, indicating a significant number of researchers adhere to validate the remote sensing and GIS-based maps with field data, which is crucial in scientific research. However, 15% of articles contain non-validated maps. This is an alarming figure; therefore, journals should be strict in ensuring that validation is adhered to. In the reviewed articles, a total of 10 methods were used to validate groundwater potential maps using various parameters such as well yield, well/spring discharge rate, aquifer transmissivity, well specific capacity, and presence of wells/springs. This study will also add to the knowledge of selecting appropriate methods for validating remote sensing and GIS-based groundwater potential maps. The use of field data reflecting aquifer productivity is more appropriate for validation of groundwater potential maps.
Analysis of methods used to validate remote sensing and GIS-based groundwater potential maps in the last two decades: A review
(Elsevier BV, 2024) Bennett, G.
The integration of remote sensing data, machine learning and geographic information system in managing and analysing spatial data helps in generating maps showing groundwater potential. These maps are important tools for aiding stakeholders and decision-makers in groundwater resources to make informed decisions during groundwater development and management; to ensure the reliability of these maps, validation with the field data is conducted. This study analysed 125 scientific articles spanning the period from 2002 to 2023. The results show that around 85% of articles contain validated maps, indicating a significant number of researchers adhere to validate the remote sensing and GIS-based maps with field data, which is crucial in scientific research. However, 15% of articles contain non-validated maps. This is an alarming figure; therefore, journals should be strict in ensuring that validation is adhered to. In the reviewed articles, a total of 10 methods were used to validate groundwater potential maps using various parameters such as well yield, well/spring discharge rate, aquifer transmissivity, well specific capacity, and presence of wells/springs. This study will also add to the knowledge of selecting appropriate methods for validating remote sensing and GIS-based groundwater potential maps. The use of field data reflecting aquifer productivity is more appropriate for validation of groundwater potential maps
Analysis of ore hand-crushed size distribution for grinding process in the artisanal and small-scale gold mines production: a case study of Nholi mine, Bahi district
(College of Engineering and Technology, University of Dar es Salaam, 2022) Tembo, Malugu M.; Mdee, Ombeni J.
In many parts of the world, artisanal and small-scale gold mines (ASGM) employed numbers of people compared to large-scale mines. The ASGM has been played a crucial role in poverty alleviation and rural development, particularly in developing countries. The mined ore is crushed and ground for beneficiation of gold. The grinding process involved the size reduction of blasted materials to acquire minerals of interest. This paper presents the size distribution of hand-crushed for blasted materials using sieve analysis and digital image processing. The sieve test results for hand-crushed blasted material of three muck-piles were ranged between 17 mm and 36 mm that is equivalent to 20% and 80% passings respectively, with an average of 26 mm. The digital image processing results were about 19.8 mm for 20% passing and 58 mm for 80% passing, with an average of 36.06 mm. The hand-crushed provided a wide range of material distribution than the required size in the grinding unit and increased oversize by 18%. The hand-crushed of blasted materials provides different sizes distribution leading to increase the residence time and power consumption of the grinding units.
Analysis of performance characteristics predicted from several experimental data and conversion methods for pumps as turbine application using statistical techniques
(University of Dar es Salaam, 2020) Mdee, Ombeni J.; Kimambo, Cuthbert Z. M.; Nielsen, Torbjorn K.; Kihedu, Joseph
Different performance characteristics have been indicated when running centrifugal pumps in the reverse direction. The water flows from the discharge side of the pump to the suction side to run in the reverse direction and generate the mechanical rotational energy for the micro-hydropower plant. The current study evaluates the extent of variation of performance characteristics predicted by several experimental data from different pump-specific speeds and conversion methods. The performance characteristics discussed include the head, flow rate, efficiency and specific speed. The flow rate and head of a pump operating in pump mode divided with the characteristic of the pump operating in the reverse mode, at the best efficiency point, the resulting coefficient of determination (R 2 ) values were of 0.890 and 0.708, respectively. Also, the graph of head versus flow rate coefficients, which is a second- order polynomial function, has shown the value of R 2 of 0.954 for pump-specific speed ranging between 9 and 94 rpm. However, the pump in the reverse mode has smaller performance characteristics for efficiency and specific speed compared to the pump mode operation with R 2 of 0.966 and 0.999, respectively. Furthermore, schematic empirical statistical models were developed to predict the performance characteristics of several conversion methods using pump data obtained from the manufacturers.
Analytical Evaluation of Head and Flow Rate Off-Design Characteristics for Pump as Turbine Application
(The American Society of Mechanical Engineers, 2019) Mdee, Ombeni J.; Kimambo, Cuthbert Z.; Nielsen, Torbjorn K.; Kihedu, Joseph
Head and flow rate are the important parameters for proper selection of centrifugal pump. However, the reversed operation of centrifugal pump leads to the off-design characteristic of head and flow rate. This paper presents an analytical model developed by using the system curves and velocity relations derived from pump application. Also, the differential technique is applied to the analytical model to develop the off-design characteristics of head ratio and flow rate ratio relations. The off-design characteristic relations were compared with literature and available conversion methods. Then, the analytical model coefficient (AMC) with the range between −4 and +4 was developed from the off-design characteristics of head ratio and flow rate ratio relations. The AMC value was equal to 1 when the pump operates in turbine mode and pump mode at the pump best efficiency point (BEP) and extended to either side up to ±4 when tested with literature data. Therefore, the analytical model consists of the off-design head and flow rate characteristics, when simplified leading to the AMC that could be applied to select the possible boundary limits of head and flow rate for different pumps.
Anhydrous monoalkylguanidines in aprotic and nonpolar solvents: models for deprotonated arginine side chains in membrane environments
(ACS Publications, 2017) Banyikwa, Andrew Toyi; Miller, Stephen E.; Krebs, Richard A.; Xiao, Yuewu; Carney, Jeffrey M.; Braiman, Mark S.
In this study, the synthesis of crystalline dodecylguanidine free base and its spectroscopic characterization in nonpolar environments are described. IR as well as 1H and 15N NMR spectra of the free base dissolved in aprotic solvents are substantially different from the previously reported spectra of arginine, or other monoalkylguanidinium compounds, at high hydroxide concentrations. The current results provide improved modeling for the spectroscopic signals that would be expected from a deprotonated arginine in a nonpolar environment. On the basis of our spectra of the authentic dodecylguanidine free base, addition of large amounts of aqueous hydroxide to arginine or other monoalklyguanidinium salts does not deprotonate them. Instead, hydroxide addition leads to the formation of a guanidinium hydroxide complex, with a dissociation constant near ∼500 mM that accounts for the established arginine pK value of ∼13.7. We also report a method for synthesizing a compound containing both phenol and free-base guanidine groups, linked by a dodecyl chain that should be generalizable to other hydrocarbon linkers. Such alkyl-guanidine and phenolyl-alkyl-guanidine compounds can serve as small-molecule models for the conserved arginine–tyrosine groupings that have been observed in crystallographic structures of both microbial rhodopsins and G-protein-coupled receptors.
Application of machine learning in the prediction of compressive, and shear bond strengths from the experimental data in oil well cement at 80 °C. Ensemble trees boosting approach
(Elsevier, 2022) Nyakilla, Edwin E.; Jun, Gu; Kasimu, Naswibu A.; Robert, Edwin F.; Innocent, Ndikubwimana; Mohamedy, Thamudi; Shaame, Mbarouk; Ngata, Mbega Ramadhani; Mabeyo, Petro E.
The current study aimed at predicting shear bond strength (SBS) and compressive strength (CS) using ensemble techniques of gradient boosting regression tree (GBRT) from the experimental data. Experimental data were obtained from CS and SBS studies using class F fly ash as supplementary cementitious materials at different proportions. The experimental results showed that the application of class F fly ash increases both CS and SBS with curing time due to the pozzolanic action of the fly ash. The SBS and CS for 15% replacement after 28 days were 0.353 and 41.9 MPa, respectively compared to 0.324 and 39.5 Mpa for 30% fly ash. This means higher fly ash content decreases both CS and SBS. Cement, OWC, water, fly ash, curing time, and dispersant were set as input data for machine learning (ML) while experimental SBS and CS as output. ML results showed that GBRT overperformed Artificial neural network (ANN), support vector machine (SVM), and Gaussian process regression (GPR)models since it gave the greatest R2 = 0.995 for CS, 0.989 for SBS and the least loss functions (MSE = 0.160 , MAE = 0.174), and (MSE = 0.0005 , MAE = 0.0031) for CS and SBS, respectively.. The comparative findings of both experimental and estimation, therefore affirm that for the long life of oil and gas wells, GBRT can be implemented as an improved approach for cement hydration prediction.
Application of response surface methodology for optimization of vat leaching parameters in small scale mines: case study of Tanzania
(Open Science Publisher, 2015) Hiji, Morris Frank; Maganga, Sospeter Pastory
In this work, the Response Surface Methodology (RSM) was used to study and optimize the vat leaching operating parameters namely as cyanide concentration, slurry pH and particle size. The experimental design was performed with aid of Minitab (version 16) statistical software. The Central Composite Design (CCD) was used to model and analyse the effect of the operating parameters. According to a quadratic model, the optimal conditions for highest gold leach recovery of 83% were found by a cyanide concentration of 950 ppm, slurry pH of 10.5 and particle size of 240 µm. The results are much significant compared with the current gold recovery of between 60 to 70%. The samples were collected at Nyarugusu small scale mines (Geita, Tanzania).
Assessment of ground water potentiality in semi-arid area of central Tanzania. implication from geology and geomorphology of the dodoman supergroup
(Taylor & Francis, 2022) Godfray, Godson; Tembo, Malugu M.
Semiarid areas face challenges in the availability of water for domestic, agricultural and industrial use. The freshwater availability in semi-arid is limited due to low periods of rainfall and high evaporation rate. Groundwater resource is the only promisingsource of freshwater in semi-arid regions. The increased demand for freshwaterin the semiarid region has increased the demand for groundwater exploration. Theavailability of groundwater in the subsurface is influenced by the subsurfacegeology, geomorphological properties and climatical condition of the region. This review aimed to analyse and combine pieces of available information on groundwater potential assessments in the central part of Tanzania. Central TANZANIA is within the craton basement rocks, where most aquifers are crystalline and fractured crystalline rocks. The groundwater origin, movement and existence rely upon numerous geomorphological and geological factors. Because of the terrain's geology and the compartmentalization of aquifers, determining the groundwater potential is difficult in basement terrain. Studying the geomor-phology and geology of groundwater recharge zones is the key to exploring groundwater availability. The integration of geomorphological, geological and geophysical information yields a promising groundwater potential zone for placement of a well. The selection of the geophysical methods depends on the nature and geology of the area. Electrical Resistivity Tomography (ERT) can beutilized in combination with other geophysical methods in fractured andweathered crystalline rocks in the semiarid environment, as in the Dodomaregion, because it is the best geophysical tool for groundwater exploration in thefractured aquifer
Assessment of groundwater vulnerability zones using GIS-based DRASTIC model: A case of Makutupora basin, Dodoma-Tanzania
(Indian Journals.com, 2016) Kisaka, Mary J.; Lema, Meserecordias W.
This study was conducted in the Makutupora basin to evaluate the vulnerability of groundwater to contamination using DRASTIC method in a GIS (Geographical Information System) environment. ILWIS 3.0 (Integrated Land and Water Information System) and Arc view 3.2a GIS software were also used to find water vulnerable zones in the aquifers. Estimation of DRASTIC Index involves multiplying each parameter weight by its rating corresponding to its study area and summing the total. A groundwater pollution potential map was prepared and the DRASTIC Index (DI) of the area was calculated. The values for the DRASTIC index were classified into five classes: extremely low, low, moderate, high and extremely high. From this study, it was found that about 30% of the study area is occupied by high to extreme vulnerability, 20% is occupied by moderate vulnerability and 50% is occupied by the low to extremely low vulnerability. Areas with high to extreme vulnerability were due to fractures associated with aquifer, high recharge potential, shallow water table as well as agriculture activities. The vulnerability map produced could be useful for planners and decision makers for initiating groundwater quality development in their specific areas.
Assessment of hydropower resources in Tanzania. A review article
(EDP Sciences, 2018) Mdee, Ombeni J.; Nielsen, Torbjorn K.; Kimambo, Cuthbert Z.; Kihedu, Joseph
The hydropower resources have become an attractive means of generating electricity to the off-grid network, especially in rural areas. This article assesses the small, mini and large hydropower resources and identified to reach 5.3GW for electricity generation in Tanzania. The technology development discussed comprises of hydro turbine manufacturers, classification and turbine selection. The barriers presented include the presence of sediment in the hydropower reservoirs, financial viability, policy and regulatory issues related to hydropower development. This reviewed article serves the investors and policymakers to understand the status of hydropower resources in Tanzania.
Assessment of soil quality along river Ng'ombe impacted by battery recycling factory at Ubungo in Dar-es-Salaam
(Elsevier BV, 2023) Kwikima, Muhajir Mussa; Mhagama, Aloyce M.
Urban soils and streams contaminated with heavy metals have grown ubiquitous around the world throughout the industrialization age, severely reducing the quality and diversity of life. Industrial waste, such as chemicalreleasing factories, is one of the primary anthropogenic sources of heavy metal contamination in soil and water bodies. To analyze the impact of industries to heavy metal contamination, the study assessed the soil quality along the heavy metals polluted river Ng’ombe near the battery recycling plant in Dar es Salaam, Tanzania’s commercial city. The research looked at three heavy metals (Cu, Pb, and Zn) in a total of eight samples. Soils were found contaminated with both metals i.e., Copper, Lead, and Zinc at 4.68, 4.08 mg/L and, 5.79, respectively. Based on the soil samples taken surrounding the industry, it is possible to establish that the industry contributes significantly to the contamination in the soil and river Ng’ombe stream. Pb contamination was found to be fairly equally distributed across the area (2 to 6 mg/kg), as opposed to Zn (0.8 to 17 mg/kg) and Cu (0.04 to 19 mg/kg), which were shown to vary greatly on soil samples obtained around the area. Different pollution indices including geo-accumulation index, Potential contamination index, Contamination factor, Pollution load index and Modified degree of contamination were also used to investigate the impact of soil contamination, and all of them revealed that industrial discharges were an influence. However; study found the levels to be in permissible limit, but still, it exposes the community to cumulative consequences of metals bioaccumulation.

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