31 research outputs found
Distribution of fluoride in beans and maize grown along the slope of Mount Meru, Tanzania
This research article published by the Journal of Biodiversity and Environmental Sciences, Vol. 15, No. 5, 2019This study assessed the uptake and distribution of fluoride in maize and beans grown in fluoride
contaminated soils, (Ngarenanyuki) around Mount Meru in Northern Tanzania during the rainy season. The
study revealed that fluoride uptake increases with increasing fluoride concentration in soils except in a stem
and root part of maize and beans respectively. It was observed that fluoride accumulation followed the order
of soil >roots > leaves >stem >grain > cob for maize, while the order soil> root> grain> stem was observed for
the beans. when the soil contained 116.93ppm of fluoride, the corresponding plants harvested had the mean
fluoride accumulation (ppm dry weight) in root, leaves, stem, grain, and cob of maize of 38.560, 24.251,
10.629, 7.7756 and 2.100 respectively, while the soil with 129.2ppm mean fluoride concentration, the
accumulation in root, grain, and stem of beans were 16.27, 11.328 and 8.459 respectively. It was reported that
beans plant had a higher efficiency in fluoride uptake to bean grain than maize plant. Maize and bean grain
collected from Ngarenanyuki contains higher fluoride levels than other fluoride endemic areas. It was also
reported that fluoride in the soil samples has a strongly positive correlation with sodium (p-0.000). This
suggests that there is a high possibility of fluoride to be present in the form of NaF. Significant accumulation
of fluoride in both bean and maize were observed in this study at p≤ 0.05
Removal of Selected Heavy Metal Ions from Industrial Wastewater Using Rice and Corn Husk Biochar
This research article Springer Nature Switzerland AG., 2020This study investigated the removal of heavy metal ions from industrial wastewater by using rice and corn husk biochar. The choice of the materials was influenced by their large surface area, abundance of functional groups as well as their availability in the local environment. Rice and corn husks were pyrolyzed at 500, 600, and 700 °C to make biochars that were used to treat low-quality industrial wastewater. Initial metal ion levels in wastewater and residual levels after the application of biochars were measured using an atomic adsorption spectrophotometer. Carbonization of rice husks at 600 °C produced the best removal efficiencies for Cr (65%), Fe (90%), and Pb (> 90%). The carbonization of corn husks at 600 °C produced the worst removal efficiencies for Cr (only 20%) and Pb (slightly > 35%). Regardless of the carbonization temperature, rice husk biochars performed better than corn husk biochars. Experimental data fitted well the Langmuir and Freundlich isotherm models (R2 values ranging between 0.82 and 0.99). The Langmuir separation factor, RL, had negative values, probably due to the low initial concentration of the adsorbates in the raw wastewater. All the biochars showed a relatively short contact time (20 to 30 min) to attain maximum adsorption efficiencies and are a promising feature for future industrial applications. The studied biochar materials from rice and corn husk have the potential to remove heavy metal ions from industrial wastewater; rice husk biochar showed higher removal capacity than corn husk biochars
Community awareness on fluoride contaminant sources: a case study at Mount Meru slopes in Northern Tanzania
This research article published by the International Journal of Biosciences, Vol. 15, No. 4, 2019A study was conducted around the slopes of Mount Meru in Arumeru district of Arusha region at Ngarenanyuki
ward, to update the awareness of the potential routes of human exposure to unacceptable levels of fluoride. Long
term consumption of fluorine contaminated water and food, in addition to the use of fluoridated products,
increases fluoride accumulation in the body. A cross-sectional, multi-phase sample design, in-depth structured
questionnaires, informant interviews, and group discussions were carried out. Women aged between 15-45 years
were involved. Participants identified water used for domestic purposes was the leading (68.63%) route of
fluoride contaminant. Findings revealed that the majority (70.6%) of the participants were not aware of the
potential sources of fluoride contaminants such as grown food crops/vegetables and fluoridated products. In
addition, most (84.93%) of the respondents were using fluoridated toothpaste and children were not assisted or
supervised as they use it which could lead to swallowing of the paste and increase the accumulation of fluoride in
the body. Most (77 %) of the participants reported that their children had brown teeth enamel and use tap water
as their primary source of domestic and drinking water. There were neither household‘s fluoride management
methods nor alternative domestic water sources identified by participants at the household level. This study
recommends an in-depth study to evaluate fluoride levels in all potential routes of contamination, to guide
management of dental and skeletal fluorosis in the community. Interventions to reduce fluoride contamination
in this endemic area are necessary to combat health risks associated with their exposure
Effects of Climate Smart Agricultural practices and Planting Dates on Maize Growth and Nutrient Uptake in Semi-Arid Tanzania
This article published by International Journal of Biosciences, 2020The shift of growing season’s onset due to rainfall and seasonal variability are among the climate change impacts
affecting agricultural productivity in semi-arid. Previous studies have also noted the seasonal variations in
planting windows in semi-arid Tanzania. Because of such rainfall variability due to uncertainties of climate
change, farmers face difficulties in determining the appropriate planting dates. Though, climate-smart
agriculture (CSA) practices are reinforced to mitigate such climatic extremes and sustain crop production, there
is limited information on the performance of CSA practices under the uncertainty of planting windows due to
unpredictable rainfall on-set and patterns. This study assessed the effects of CSA practices at different planting
windows on maize growth and nutrient uptakes at Mlali village of Dodoma, Tanzania. A split-plot experimental
design was adopted, treatments involved CSA practices (Chololo pits, tied ridges, intercropping and Oxcultivation – as a control) and/at planting windows (Early, Normal and Late planting). The planting windows
were determined based on previous studies and Tanzania national weather forecasts. The results showed that,
CSA practices had a significant (p < 0.05) effect on maize height and N nutrient uptake. Similar biomass and Mg
nutrient uptake were significantly affected (p < 0.05) by both CSA practices and planting dates though Leaf Area
Index (LAI) were significantly affected (p < 0.05) by planting windows. Chololo pits and tied ridges and late
planting dates had the highest soil moisture, plant heights, and biomass. Ox-cultivation had a slight high N, K
and Mg nutrient uptake followed with Chololo pits and tied ridges
Tracing the dominant sources of sediment flowing towards Lake Victoria using geochemical tracers and a Bayesian mixing model
PurposeLake Victoria has been increasingly silting over the past decades, impacting water quality and loss of biodiversity. Sediment control strategies require information on the relative and absolute contributions of sediment from different sources. However, to date, there is no continuous monitoring of sediment flux or water quality in any of the tributaries, prohibiting an assessment of the scale of the problem. The aim of this study was to trace the dominant sources of riverine sediment using geochemical fingerprinting, thereby generating a knowledge base for improving land management and reducing sediment yields in Simiyu River catchment, one of the main contributing rivers to Lake Victoria.Materials and methodsGeochemical tracer concentrations were analyzed in transported sediment from the main river and two tributaries (riverbed sediments) and from soils in five dominant land use types (agricultural land, bush land, forest land, channel banks, and main river banks). Dominant sources to the Simiyu main river sediment were attributed using the Bayesian MixSIAR model.Results and discussionThe mixing model outputs showed that the Simiyu tributary was the dominant source of sediment to the Simiyu main river with 63.2%, while the Duma tributary accounted for 36.8%. Cultivated land was shown to be the main land use source of riverine sediment, accounting for 80.0% and 86.4% in Simiyu and Duma sub-tributaries, respectively, followed by channel banks with 9.0% in both sub-tributaries. Direct unmixing of the Simiyu main river sediment to the land use sources yielded 64.7% contribution of cultivated land and 26.5% of channel banks.ConclusionThe demonstrated application of sediment source tracing provides an important pathway for quantifying the dominant sources of sediment in the rivers flowing towards Lake Victoria. Eroded soil from agricultural areas is the biggest contributor to transported sediment in the Simiyu River. This information is vital for the design of catchment wide management plans that should focus on reducing soil erosion and sediment delivery from farming areas to the river networks, ultimately supporting both food security and water quality in the Lake Victoria Basin
Insecticidal Efficacy of Syzygium aromaticum, Tephrosia vogelii and Croton dichogamus Extracts against Plutella xylostella and Trichoplusia ni on Brassica oleracea crop in Northern Tanzania
This research article published by AIMS Agriculture and Food, 2020The insecticidal efficacy of 10%, 5% and 1% w/v of Tephrosia vogelii, Croton
dichogamus and Syzygium aromaticum aqueous plant extracts were assessed against larvae of
Plutella xylostella and Trichoplusia ni on Brassica oleracea var. capitata crop field. Synthetic
organophosphate pesticide (Chlorpyrifos) was used as a positive control and the negative controls
were water and water plus soap. It was revealed that, aqueous plant extracts significantly (P ≤ 0.05)
controlled the number of P. xylostella and T. ni larvae compared to negative controls. The 10%
concentration of aqueous plant extracts showed significant higher efficacy in terms of reducing the
insect population and their damage than 1% and 5 % concentration. The population of P. xylostella
larvae per B. oleracea in five weeks of treatment applications at 10% w/v of T. vogelii, C.
dichogamus and S. aromaticum aqueous plant extracts were 0.08, 0.15, 0.13, 0.05 and 0.08; 0.08,
0.20, 0.15, 0.13 and 0.18; 0.03, 0.05, 0.15, 0.18 and 0.13, respectively which was significantly (P ≤ 0.05)
lower than in water (1.13, 1.68, 2.28, 2.20 and 3.28) and water plus soap (0.75, 1.60, 2.58, 1.83
and 3.30) negative controls respectively. The number of T. ni larvae per B. oleracea in five weeks of
treatment applications at 10% w/v of T. vogelii, C. dichogamus and S. aromaticum of aqueous plant
extracts were 0.00, 0.03, 0.05, 0.03 and 0.00; 0.03, 0.08, 0.05, 0.08 and 0.08; 0.05, 0.03, 0.00, 0.05
and 0.03, respectively which was significantly (P ≤ 0.05) lower than in water (0.50, 0.63, 0.60, 0.48
and 0.78) and water plus soap (0.30, 0.48, 68, 0.65 and 0.80) negative controls. The percentage
damage of B. oleracea in five weeks of treatment applications at 10% w/v of T. vogelii, C.
dichogamus and S. aromaticum aqueous plant extracts were 10.0, 6.3, 7.5, 7.5 and 5.6; 11.3, 11.3,
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AIMS Agriculture and Food Volume 6, Issue 1, 185–202.
11.3, 11.3 and 12.5; 8.8, 8.1, 6.9, 8.1 and 9.4, respectively compared with water (33.8, 33.1, 38.8,
45.0 and 70.6) and water plus soap (30.0, 31.9, 41.3, 41.3 and 56.3). These pesticidal plants can be
recommended for smallholder farmers to significantly control P. xylostella and T. ni larvae in B.
oleracea cro
Fluoride contamination of selected food crops, domestic water, and milk consumed by communities around mount Meru in Northern Tanzania.
This research article published by Taylor & Francis Online, 2021This study assessed fluoride levels in domestic water, commonly consumed food crops, cow's, and human milk. Samples of vegetables were collected from farmer's home gardens, green banana from local markets, maize flour, and domestic water from households, while cow's and human (breast) milk were obtained from cows and lactating mothers. Fluoride levels were determined by using a fluoride ion-selective electrode. Fluoride levels were 0.03 ± 0.02 mg/kg in maize, In leafy vegetables the highest levels were found in nightshade 0.081 ± 0.008 mg/kg, while for banana varieties the highest levels were found in in East African highland 0.025 ± 0.004 mg/kg. Levels in cows and human breast milk were 0.34 ± 0.2 mg/L and 0.077 ± 0.06 mg/L, respectively. Levels in domestic and public tap water were 4.57 ± 0.4 mg/L and 4.74 ± 0.8 mg/L, respectively. Study provided useful knowledge of fluoride levels in several crops, milk, and domestic water
A computer-based approach for developing linamarase inhibitory agents
This research article published by Walter de Gruyter GmbH, 2020Cassava is a strategic crop, especially for developing countries. However, the presence of cyanogenic compounds in cassava products limits the proper nutrients utilization. Due to the poor availability of structure
discovery and elucidation in the Protein Data Bank is limiting the full understanding of the enzyme, how to
inhibit it and applications in different fields. There is a need to solve the three-dimensional structure (3-D) of
linamarase from cassava. The structural elucidation will allow the development of a competitive inhibitor and
various industrial applications of the enzyme. The goal of this review is to summarize and present the available
3-D modeling structure of linamarase enzyme using different computational strategies. This approach could
help in determining the structure of linamarase and later guide the structure elucidation in silico and experimentall
Determining tributary sources of increased sedimentation in East-African Rift Lakes.
This research article published by Elsevier B.V., 2020Temporal and spatial sediment dynamics in an East-African Rift Lake (Lake Manyara, Tanzania), and its river inputs, have been evaluated via a combination of sediment tracing and radioactive dating. Changes in sedimentation rates were assessed using radioactive dating of sediment cores in combination with geochemical profile analysis of allogenic and autogenic elements. Geochemical fingerprinting of riverine and lake sediment was integrated within a Bayesian mixing model framework, including spatial factors, to establish which tributary sources were the main contributors to recent lake sedimentation. The novel application of Bayesian source attribution on sediment cores and subsequent integration with sedimentation data permitted the coupling of changes in the rate of lake sedimentation with variations in sediment delivery from the tributaries. These complimentary evidence bases demonstrated that Lake Manyara has experienced an overall upward trajectory in sedimentation rates over the last 120 years with distinct maxima between 0.80 and 0.85 g cm yr in the 1960s and between 0.84 and 1.81 g cm yr in 2010. Increased sedimentation rates are largely a result of a complex interaction between increased upstream sediment delivery following changes in land cover and natural rainfall fluctuations. Modelling results identified two specific tributaries as responsible for elevated sedimentation rates, contributing 58% and 38% of the recently deposited lake sediment. However, the effects of sedimentation were shown to be spatially distinct given the domination of different tributaries in various areas of Lake Manyara. The application of source-tracing techniques constrained sedimentation problems in Lake Manyara to specific tributary sources and established a link between upstream land degradation and downstream ecosystem health. This novel application provides a solid foundation for targeted land and water management strategies to safeguard water security and environmental health in Lake Manyara and has potential application to fill knowledge gaps on sediment dynamics in other East-African Rift Lakes
Rare earth elements and uranium in Minjingu phosphate fertilizer products : plant food for thought
DATA AVAILABILITY :
Data will be made available on request.Minjingu phosphate ore is Tanzania's sole domestic supply of phosphorus (P). The ore contains medium to high concentrations of naturally occurring P2O5 (20–35 %) and relevant concentrations of uranium and rare earth elements (REEs) are also suspected to be present. Currently, neither uranium nor REEs are recovered. They either end up in mine tailings or are spread across agricultural soils with fertilizer products. This work provides a first systematic review of the uranium and REE concentrations that can be expected in the different layers of Minjingu phosphate ore, the way the ore is presently processed, as well as a discussion on alternative processing pathways with uranium/REE recovery. The study analyzed ten distinct Minjingu phosphate ore layers, four mine tailings, and five intermediate and final mineral fertilizer products from the Minjingu mine and processing plant located in northern Tanzania. The results confirm that the uranium concentrations and to a lesser degree, the REE concentrations are indeed elevated if compared to concentrations in other phosphate ores. The study does not identify a significant risk resulting from this. The development of techno-economic solutions for more comprehensive utilization of Minjingu ore is, however, strongly encouraged and suggestions on such processes are provided.The Tanzania Atomic Energy Commission (TAEC), Nelson Mandela African Institution of Science and Technology (NM-AIST), the Austrian Federal Ministry of Education, Science and Research (BMBWF) through Austria's Agency for Education and Internationalization (OeAD) and BMBWF/OeAD support through a Ernst Mach Grant.https://www.sciencedirect.com/journal/resources-conservation-and-recyclinghj2024Chemical EngineeringChemistrySDG-09: Industry, innovation and infrastructur