Agricultural Science and Technology

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10 Invasive Plant Impacts on Soil Macrofauna through Allelopathy and Environmental Modification
(MJRD, 2026) Ojija, Fredrick; Bacaro, Giovanni; Ogwu, Matthew Chidozie
Soil macrofauna taxonomic groups such as annelids (earthworms), arthropods (insects and crustaceans) and molluscs (gastropods/snails) play an essential role in soil ecosystems (van Hengstum et al., 2014; Zulu et al., 2022; Mamabolo et al., 2024). These organisms help convert organic matter into forms that can be utilized by plants, ultimately supporting soil fer¬tility (Sofo et al., 2020; Mamabolo et al., 2024). They influence soil structure, organic matter decomposition, nutrient cycling, soil aeration and ecosystem functioning (van Hengstum et al., 2014; Ibrahima et al., 2017). Thus, their presence and diversity are integral to maintain¬ing soil fertility and productivity, making them important bioindicators for assessing soil health (Rousseau et al., 2013; Sofo et al., 2020). Soil macrofauna physically and biologically alter the soil structure, enhancing the permeability of the soil and improving water infiltration (Zhou et al., 2022). Besides, they contribute to the creation of microhabitats for other organisms, promoting biodiversity conservation (Huerta and van der Wal, 2012). For instance, earthworms, through their burrowing and feeding activities, not only recycle nutrients but also create channels in the soil that facilitate the movement of water and air (Ibrahima et al., 2017; Yang et al., 2024). Soil macrofauna – ants, termites and beetles – are involved in the breakdown of organic matter, including plant litter and animal remains, thereby playing a role in nutrient cycling (Jouquet et al., 2011; Ibrahima et al., 2017; Mamabolo et al., 2024). The presence and activity of these macrofauna can also influence the abun¬dance and diversity of soil microorganisms, further enhancing nutrient cycling (Zhou et al., 2022). Research conducted by Liu et al. (2020) and Singh et al. (2019) reveals
Accumulation and Distribution of Mercury in Agricultural Soils, Food Crops and Associated Health Risks: A Case Study of Shenda Gold Mine-Geita Tanzania
(ELSEVIER, 2023) Sanga, Tumikia R.; Maseka, Kenneth K.; Ponraj, Mohanadoss; Tungaraza, Clavery; Mng’ong’o, Marco E.; Mwakalapa, Eliezer B.
Contamination of the environment and foodstuffby potentially harmful elements (PHEs) has become a serious concern due to the associated health risks to the population. In the present study total mercury (Hg) levels in soil and food crops from farms around Shenda gold mine in Geita Tanzania was determined by Cold Vapor Atomic Fluorescence Spectrometry (CVAFS). Generally, it was found that there was significant different of Hg content in soil and food crops ( P < 0.05) among studied sites. The total Hg concentrations determined were in the ranges of; soils (0.003-0.1220 mg/kg), rice (0.0752-0.1587 mg/kg) and vegetables (0.0556-0.3439 mg/kg) all measurement were based on dry weight basis (dw). Total Hg levels in soil were compared with the maximum allowable concentration (MAC) set by Tanzania Bureau of Standards (TBS) and United Kingdom (UK). All studied soil samples were within acceptable range (2 mg/kg) set by TBS and UK (1 mg/kg). Total Hg contents in food crop samples were compared with Chinese MAC of Hg (0. 01 and 0.02 mg/kg for leafy vegetables and grains respectively in a fresh weight basis). It was observed that Hg contents in potato leaves, pumpkin leaves and Chinese cabbage were within the MAC while Hg levels in cassava leaves and rice grains exceeded the MAC. In addition, Hg associated health risks to consumers of contaminated foods for residents around Shenda gold mine were estimated. The estimated weekly intake (EWI) of Hg due to consumption of rice grain was above the provisional tolerable weekly intake (PTWI) set by FAO/WHO (1.6 mg/kg bw/week) while the EWI due to consumption of leafy vegetables were below the PTWI. Target hazard quotient (THQ) was < 1 due to consumption of vegetables while THQ value for rice was > 1, indicating a potential non-carcinogenic risk to adult population from the consumption of rice grain from the study area. Therefore, people living near Shenda goldmine might be potential victim of Hg accumulation in soil and food crops, thus necessary management options have to be in place
Accumulation and Distribution of Mercury in Agricultural Soils, Food Crops and Associated Health Risks: a Case Study of Shenda Gold Mine-Geita Tanzania.
(Elsevier, 2023-02-18) Sanga, Tumikia R.; Maseka, Kenneth K.; Ponraj, Mohanadoss; Tungaraza, Clavery; Mng’ong’o, Marco E.; Mwakalapa, Eliezer B.
Contamination of the environment and food stuff by potentially harmful elements (PHEs) has become a serious concern due to the associated health risks to the population. In the present study total mercury (Hg) levels in soil and food crops from farms around Shenda gold mine in Geita Tanzania was determined by Cold Vapor Atomic Fluorescence Spectrometry (CVAFS). Generally, it was found that there was significant different of Hg content in soil and food crops (P < 0.05) among studied sites. The total Hg concentrations determined were in the ranges of; soils (0.003-0.1220 mg/kg), rice (0.0752-0.1587 mg/kg) and vegetables (0.0556-0.3439 mg/kg) all measurement were based on dry weight basis (dw). Total Hg levels in soil were compared with the maximum allowable concentration (MAC) set by Tanzania Bureau of Standards (TBS) and United Kingdom (UK). All studied soil samples were within acceptable range (2 mg/kg) set by TBS and UK (1 mg/kg). Total Hg contents in food crop samples were compared with Chinese MAC of Hg (0. 01 and 0.02 mg/kg for leafy vegetables and grains respectively in a fresh weight basis). It was observed that Hg contents in potato leaves, pumpkin leaves and Chinese cabbage were within the MAC while Hg levels in cassava leaves and rice grains exceeded the MAC. In addition, Hg associated health risks to consumers of contaminated foods for residents around Shenda gold mine were estimated. The estimated weekly intake (EWI) of Hg due to consumption of rice grain was above the provisional tolerable weekly intake (PTWI) set by FAO/WHO (1.6 mg/kg bw/week) while the EWI due to consumption of leafy vegetables were below the PTWI. Target hazard quotient (THQ) was < 1 due to consumption of vegetables while THQ value for rice was > 1, indicating a potential non-carcinogenic risk to adult population from the consumption of rice grain from the study area. Therefore, people living near Shenda goldmine might be potential victim of Hg accumulation in soil and food crops, thus necessary management options have to be in place.
Accumulation and distribution of mercury in agricultural soils, food crops and associated health risks: A case study of Shenda gold mine-Geita Tanzania.
(ELSEVIER, 2023-02-18) Sanga, Tumikia R.; Maseka, Kenneth K.; Ponraj, Mohanadoss; Tungaraza, Clavery; Mng’ong’o, Marco E.; Mwakalapa, Eliezer B.
Contamination of the environment and foodstuff by potentially harmful elements (PHEs) has become a serious concern due to the associated health risks to the population. In the present study total mercury (Hg) levels in soil and food crops from farms around Shenda gold mine in Geita Tanzania was determined by Cold Vapor Atomic Fluorescence Spectrometry (CVAFS). Generally, it was found that there was significant different of Hg content in soil and food crops (P < 0.05) among studied sites. The total Hg concentrations determined were in the ranges of; soils (0.003-0.1220 mg/kg), rice (0.0752-0.1587 mg/kg) and vegetables (0.0556-0.3439 mg/kg) all measurement were based on dry weight basis (dw). Total Hg levels in soil were compared with the maximum allowable concentration (MAC) set by Tanzania Bureau of Standards (TBS) and United Kingdom (UK). All studied soil samples were within acceptable range (2 mg/kg) set by TBS and UK (1 mg/kg). Total Hg contents in food crop samples were compared with Chinese MAC of Hg (0. 01 and 0.02 mg/kg for leafy vegetables and grains respectively in a fresh weight basis). It was observed that Hg contents in potato leaves, pumpkin leaves and Chinese cabbage were within the MAC while Hg levels in cassava leaves and rice grains exceeded the MAC. In addition, Hg associated health risks to consumers of contaminated foods for residents around Shenda gold mine were estimated. The estimated weekly intake (EWI) of Hg due to consumption of rice grain was above the provisional tolerable weekly intake (PTWI) set by FAO/WHO (1.6 mg/kg bw/week) while the EWI due to consumption of leafy vegetables were below the PTWI. Target hazard quotient (THQ) was < 1 due to consumption of vegetables while THQ value for rice was >1, indicating a potential non-carcinogenic risk to adult population from the consumption of rice grain from the study area. Therefore, people living near Shenda goldmine might be potential victim of Hg accumulation in soil and food crops, thus necessary management options have to be in place.
Advances and Trends in Ecological Organic Agriculture (EOA) Technologies and Research on Fruit Vegetables Produced in Tanzania
(CAB International, 2022-05-17) Shango, Abdul J.; Maswi, Philip B.; Malya, Rashid B.; Maro, Janet F.; Mwaipopo, Rehema E.; Majubwa, Ramadhani O.; Kilewa, Ramadhan A.; Philipo, Mashamba L.
Ecological organic agriculture (EOA) is a holistic production management system that can solve many problems in the vegetable crops’ value chain (VC). It is, however, unclear about the EOA technologies for the fruit vegetable VC that have already been validated or are in process of validation in Tanzania. A systematic literature search on EOA technologies relevant in Tanzania was conducted for research articles from 2010 until 2021. Most 10(30.4%) studies on fruit vegetables were equally distributed each 5(15.2%) in the years 2019 and 2020, respectively. A total of 33 records on fruit vegetables covered eight (8) regions of mainland Tanzania and one (1) region from the island of Zanzibar. Most 18(55%) studies were conducted in the Morogoro region. Based on the fruit vegetable VC, 26(68.4%) studies were for field establishment and management. Nine (9) key areas were identified, where most 9(27.3%) studies were on crop productivity and protection. Seventeen (17) EOA technologies were applied in fruit vegetables, mostly biocontrol 7(21%) in tomatoes. Overall, 27(81.8%) studies only researched the EOA technologies, while 3(9.1%) studies validated the EOA technologies, 2(6.1%) researches were in progress, and 1(3.0%) was progressing validation. Few 3(9.1%) studies portrayed the involvement of youth and women using the principles of participatory action research (PAR) during the validation. Generally, the EOA technologies are readily available, require minimal skills and labour, are cost-effective, sustainable, easily implementable in the fruit vegetable VC and can be simply accessed and utilized in cultivating organic fruit vegetables.
Aflatoxin and Fumonisin Contamination of at-harvest and Storage Beans in Babati District, Northern Tanzania
(Greener Journal of Agricultural Sciences, 2016-11) NYANGI,CHACHA
The natural occurrence of total aflatoxin and fumonisin was determined in 38 bean at-harvest samples and 106 storage beans samples in the year 2013 in Babati District Northern Tanzania. Quantification for total aflatoxin and fumonisin was done using Enzymes Linked Immunosorbent Assay - ELISA (Reveal AccuScan® Neogen, USA), and the results were confirmed using Liquid Chromatography Tandem Mass Spectrometer (LC-MS/MS). Eighteen percent (7/38) of bean at harvest samples were contaminated with up to 3 µg/kg aflatoxins and no bean sample was contaminated with fumonisins. There was a significant correlation (p < 0.05) between the concentration of aflatoxins and fumonisins with climatic zones and agronomic practices. Only bean samples from the high-altitude high rain zone were contaminated with aflatoxins (mean level of 1.53 µg/kg). For storage beans, samples from Seloto village were associated with higher aflatoxin concentration (mean of 3.74 µg/kg) and those from long village were associated with higher fumonisin levels (mean of 9.0 mg/kg). These results indicate that beans consumers in the study area are exposed to the danger of chronic exposure to aflatoxin and fumonisin poisoning. Thus, those practices that reduce contamination should be adopted by all farmers in the study area to reduce the health hazards associated with consumption of contaminated beans. This also calls for further research to investigate human exposure to aflatoxin and fumonisin in the study area.
Aflatoxin production mechanisms and management in the maize cropping systems of sub-Saharan Africa
(CAB International, 2025-09-11) Kwigizile, Owekisha H.; Mng’ong’o ,Marco E.; Mushongi , Arnold; Mbega Ernest; Mashamba,Philipo
In sub-Saharan African countries, the maize crop is a major staple food crop, providing up to 70% of the population’s total caloric intake. Aflatoxins, toxic secondary metabolites primarily produced by Aspergillus flavus and Aspergillus parasiticus, pose significant threats to food safety, public health, and agricultural economies in sub-Saharan Africa (SSA), where maize is a staple crop. This review synthesizes current knowledge on the mechanisms of aflatoxin production and its management within maize cropping systems of SSA. The occurrence and severity of aflatoxin contamination are influenced by multiple factors, including high temperatures, drought stress, insect damage, poor post-harvest handling, and inadequate storage conditions. Maize has been linked to being contaminated by roughly eighteen (18) different forms of aflatoxins, which are severely poisonous, and contribute to public health issues. The review explores the biological and environmental triggers of aflatoxin biosynthesis, highlighting molecular pathways and fungal-host interactions. Additionally, it evaluates integrated management strategies encompassing host resistance, good agricultural practices, biocontrol agents (such as Aflasafe), proper harvesting, drying, and storage techniques. Socio-economic and institutional barriers to effective aflatoxin control are also discussed, along with policy and research recommendations. The review also emphasizes on the necessity to apply novel and existing techniques to prevent aflatoxin. The study featured the need for a multidisciplinary and region-specific approach to sustainably mitigate aflatoxin risks in SSA. Best bet recommendations are provided given different levels of scenarios at the farmer, farm plot, maize farming systems, and eventually the nodes across the entire maize value chain.
Aflatoxins and Fumonisin Contamination of Marketed Maize, Maize Bran and Maize Used as Animal Feed in Northern Tanzania.
(AFRICAN SCHOLARLY SCIENCE COMMUNICATIONS TRUST, 2016-07) Nyangi Chacha; Mugula J.K; Beed F.; Boni S.; Koyano E.; Sulyok, M.
The objective of this study was to investigate the occurrence of total aflatoxin and total fumonisin in maize and maize-based products in Babati, northern Tanzania. A total of 160 samples were collected in 2013-14. Quantification for total aflatoxin and fumonisin was done using enzyme-linked immunosorbent assay (Reveal AccuScan® Neogen, USA) and the results were confirmed using Liquid Chromatography Tandem Mass Spectrometer. Aflatoxin was detected in 32% of maize samples (mean 3.4 ± 0.3 µg/kg; range 2.1–16.2 µg/kg) and fumonisin in 39% of samples (mean 5.6 ± 1.40 mg/kg; range 0.4–62.0 mg/kg). Among marketed products, maize bran (used for animal feed) was the most contaminated (2.4 µg/kg aflatoxin and 1 mg/kg fumonisin), followed by whole maize in market stalls (1.9 µg/kg aflatoxin and 0.4 mg/kg fumonisin) and then maize flour (1.4 µg/kg aflatoxin and 0.3 mg/kg fumonisin). Un-marketed maize sorted out by farmers as “bad” and intended for animal feeding was the most contaminated (overall mean aflatoxin and fumonisin levels of 1.7 µg/kg and 7.4 mg/kg, respectively). The results indicate that levels of aflatoxin and fumonisin contamination in marketed maize were within tolerable limits.
Allelopathic Effects of Sphaeranthus suaveolens on Seed Germination and Seedling Growth of Phaseolus vulgaris and Oryza sativa
(Hindawi, 2021-02-15) Laizer, Hudson C; Chacha, Musa N; Ndakidemi, Patrick A
Weeds with allelopathic effect have been reported to cause significant damage in agriculture particularly in smallholder farming systems. ,is study assessed the allelopathic effects of different concentrations of crude extract of a noxious weed Sphaeranthus suaveolens on seed germination and seedling growth of Phaseolus vulgaris and Oryza sativa by examining germination, seedling height, and total chlorophyll content after seven and fourteen days of crude extract treatment, respectively. Results showed that seed germination and seedling growth were significantly (p<0.001) decreased with increase in concentration of crude extract, signifying concentration dependency. Highest concentration (100%) of S. suaveolens crude extracts resulted in 90% and 100% inhibition of P. vulgaris and O. sativa seed germination, respectively. Chlorophyll content, fresh weight, and root and shoot length of both P. vulgaris and O. sativa were also significantly (p<0.001) affected by highest concentration (100%) of S. suaveolens crude extracts. Results from this study suggest that the extract of S. suaveolens contains water-soluble allelochemicals which significantly reduce growth and productivity of P. vulgaris and O. sativa.
An Assessment of the Current Status and Regeneration Potential of the Traditional Conserved Forests (Ngitili) in Kishapu District, Tanzania
(TROPICAL PLANT RESEARCH, 2020) Malunguja, Gisandu K.; Rubanza, Chrispinus K. D.; Devi, Ashalata
The current study was carried out in the community forests conserved under the indigenous knowledge known as “Ngitili” in Kishapu district of Tanzania. The aim was to assess the current status and determines its regeneration potential in terms of plant species diversity, herbaceous productivity and tree stocking. A field survey was conducted for recording the current status while the phytosociological was carried to recognize vegetation composition and diversity. Regeneration potential was determined based on the population size of seedlings, saplings and adults. Disturbance index was used to calculate the level of disturbances while herbaceous productivity and tree stocking were estimated based on allometric models. Descriptive statistics for quantitative data was analysed using SPSS version 20. The study recorded a total of 10 Ngitili in Kishapu district, out of which, 9 still existing but highly threatened and disturbed, only 1 Ngitili was recorded to be dead (not existing). A total of 66 plant species were recorded of which 20 were grasses, 18 were forbs, and 28 species (17 genera and 13 families) were trees and shrubs. The dominant grass species were Aristida funiculata (28.9%) and Cynodon dactylon, while Monechma debile (4.6%) was the dominant forb. Similarly, Acacia drepanolobium (45.4) and Balanites aegyptiaca (42.9) trees dominated the area. The majority of tree species exhibited a “not regenerating” condition (51.8%) only a few (2.11%) showed a “good regeneration” condition while “newly regeneration” condition recorded 0.00%, with a diversity ranging from 1.86–2.44. Herbaceous and tree stocking potential was 1.23±0.05 t DM ha-1 and 5.66±0.21 t Cha-1 respectively, with a standing stem density (stems ha-1) of 512.07±193.86. The study observed great degradation of the Ngitili characterized by low diversity and poor regeneration conditions. This signified that these community forests are currently threatened and its sustainability is highly at risk unless strong initiatives take place.
Analysis of Machine Learning Technique to Predict Eggs Production in Poultry Farms
(MUST Journal of Research and Development (MJRD), 2022-09-01) Magemo Award, Minga Lusajo,and Kusyama, Sadiki Lameck
Machine learning techniques have emerged as a great tool for improving agriculture's economic activities. Machine Learning has specifically been applied in chicken farming to forecast egg output, enhancing both the economies of the farmers and the nation. In this research, we present a study devoted to the analysis of machine learning approaches to forecast egg output. The study looked at four (4) machine learning algorithms, the quantity of features utilized as input, and the strengths and weaknesses of each method. A number of features with a mean value of more than 6 are employed by an Artificial Neural Network, yet this network is unable to extract features from the dataset. Fuzzy logic uses many features with a mean value of more than 4.5 but few datasets. Few datasets and features with a mean value of less than 4 are used by Random Forest and Support Vector Machine. Compared to other techniques, Artificial Neural Network is the most popular and has a high mean value of features, but it is unable to extract core features from the dataset. Additionally, it only employs small datasets. The model's stability is reduced when limited features and datasets are used. Deep learning is built on the Artificial Neural Network, but so far only feedforward and backward architecture have been applied. It is obvious that poultry farmers would benefit from using machine learning to manage both their marketing and production processes. This study recommends the use of deep learning techniques with the best architecture due to the drawbacks of the currently existing techniques. These techniques will be able to employ numerous features and a large number of datasets, improving the stability of the model.
Argemone Mexicana’s Leaf Crude Extract Suppresses Phaseolus Vulgaris And Zea Mays Germination And Growth
(Zibeline International, 2023-10-30) Ojija ,Fredrick
The Argemone mexicana plant species is invading many habitats in Tanzania. Nevertheless, there have not been many studies to assess how it affects crops. In petri dishes and pot experiments, we investigated the suppressive effects of A. mexicana on Phaseolus vulgaris and Zea mays germination and seedling growth. Different concentrations of A. mexicana leaf (AmL) crude extract was applied to the seeds and seedlings of P. vulgaris and Z. mays. At higher concentrations (>70%), AmL crude extract concentrations reduced the germination and growth of P. vulgaris and Z. mays seeds. The fresh biomass, root lengths, stem diameters, and heights of P. vulgaris seedlings were reduced at higher concentrations (>75%) of AmL, which had a negative impact on their growth vigour. Although this study shows that P. vulgaris and Z. mays germination and growth were inhibited by A. mexicana crude extract, field research experiments should investigate the suppressive effects of this invasive weed on native plant species. The study recommends further management of A. mexicana to protect native biodiversity. It is expected that these results will be helpful in developing policies and programs for managing invasive plants while taking into account the effects on people's livelihoods
Assessment of Current Post-Harvest Handling Techniques for Mango and Avocado in Mbeya Region, Tanzania
(Elsevier, 2025-07-31) Mng’ong’o , Marco E.; Komanya, Absalom.; Maro, Lilian.; Mshora , Abubakar M.; Matimbwa , Hadija
Mango (Mangifera indica) and avocado (Persea americana) are valuable fruits in Tanzania, known for their nutritional and economic importance. However, their perishability leads to significant post-harvest losses, especially for smallholder farmers in Mbeya. The limited knowledge about post-harvest handling identifies a research gap. This study assessed practices and challenges among mango and avocado farmers to improve handling techniques. A survey of 150 smallholder farmers in Kyela and Rungwe districts (August–September 2024) examined harvesting, storage, transportation, and post-harvest challenges. Data analysis revealed that 64 % of farmers use traditional harvesting methods that lead to mechanical damage. While 68.8 % manually hand-harvest, others rely on tree shaking (8.3 %) and sticks or stones (18.8 %), further increasing fruit damage. Storage at ambient temperature (46 %) fails to extend shelf-life, causing rapid quality deterioration. Trans- portation by motorcycle (44 %) and head carrying (34 %) exposes fruits to damage. Key challenges included fruit drop (36 %), rotting before harvest (28 %), and insect infestation (24 %). Only 23.4 % of farmers had reliable market access, highlighting a major constraint. Education level influenced challenges, with lower-educated farmers facing more rotting and pest issues. Findings indicate current post-harvest practices are inadequate, leading to major losses. Simple, cost-effective technologies like edible coatings and training on improved har- vesting, storage, and transportation are necessary. Investment in affordable cold storage and better transport infrastructure is crucial. This study provides actionable insights for policymakers and stakeholders to enhance mango and avocado value chains in Tanzania.
Assessment of Current Post-harvest Handling Techniques for Mango and Avocado in Mbeya region, Tanzania: Challenges and Opportunities for Improvemen
(Elsevior, 2025) Mng’ong’o, Marco E.; Matimbwa,Hadija; Komanya,Absalom; Maro, Lilian,; Mshora Abubakar, M
Mango (Mangifera indica) and avocado (Persea americana) are valuable fruits in Tanzania, known for their nutritional and economic importance. However, their perishability leads to significant post-harvest losses, especially for smallholder farmers in Mbeya. The limited knowledge about post-harvest handling identifies a research gap. This study assessed practices and challenges among mango and avocado farmers to improve handling techniques. A survey of 150 smallholder farmers in Kyela and Rungwe districts (August–September 2024) examined harvesting, storage, transportation, and post-harvest challenges. Data analysis revealed that 64 % of farmers use traditional harvesting methods that lead to mechanical damage. While 68.8 % manually hand-harvest, others rely on tree shaking (8.3 %) and sticks or stones (18.8 %), further increasing fruit damage. Storage at ambient temperature (46 %) fails to extend shelf-life, causing rapid quality deterioration. Trans portation by motorcycle (44 %) and head carrying (34 %) exposes fruits to damage. Key challenges included fruit drop (36 %), rotting before harvest (28 %), and insect infestation (24 %). Only 23.4 % of farmers had reliable market access, highlighting a major constraint. Education level influenced challenges, with lower-educated farmers facing more rotting and pest issues. Findings indicate current post-harvest practices are inadequate, leading to major losses. Simple, cost-effective technologies like edible coatings and training on improved har vesting, storage, and transportation are necessary. Investment in affordable cold storage and better transport infrastructure is crucial. This study provides actionable insights for policymakers and stakeholders to enhance mango and avocado value chains in Tanzania.
Assessment of Heavy Metals in Wild and Farmed Tilapia (Oreochromis Niloticus) on Lake Kariba, Zambia: Implications for Human and Fish Health
(Taylor & Francis Group, 2021-08-20) Simukoko, Chalumba Kachusi.; Mwakalapa, Eliezer Brown.; Bwalya, Patricia.; Muzandu, Kaampwe.; Berg, Vidar.; Mutoloki, Stephen.; Polder, Anuschka.; Lyche, Jan Ludvig
The aim of this study was to assess the levels of heavy metals in both wild and farmed tilapia on Lake Kariba in Zambia and to evaluate the impact of intensive fish farming on wild tilapia. Three sites for wild fish (2 distant and 1 proximal to fish farms) and two fish farms were selected. One hundred fish (52 from distant sites; 20 near fish farms; 28 farmed fish) were sampled and muscle tissues excised for analysis of heavy metals (Mg, Fe, Zn, Al, Cu, Se, Co, Mo, As, Cr, V, Ni, Hg, Pb, Li, Cd, and Ag) by acid (HNO3) digestion and ICP-MS. All metals were found to be below the maximum limits (MLs) set by WHO/EU. Essential metals were higher in farmed tilapia, whereas non-essential metals were higher in wild tilapia. Significantly higher levels of essential metals were found in wild fish near the fish farms than those distant from the farms. Estimated weekly intake (EWI) for all metals were less than the provisional tolerable weekly intakes (PTWI). Target hazard quotients (THQ) and Hazard Indices (HI)<1 were indicating no health risks from a lifetime of fish consumption. Selenium Health Benefit Value (HBVSe) was positive for all locations, indicating protective effects of selenium against mercury in fish. Total cancer risk (CR) due to As, Cr, Cd, Ni and Pb was less than 1 × 10−4, indicating less than 1 in 10,000 carcinogenic risk from a lifetime consumption of tilapia from Lake Kariba. Hg levels (0.021 mg/kg) in wild tilapia at site 1 were higher than the Environmental quality standard (EQS = 0.020 mg/kg) set by EU, indicating possible risk of adverse effects to fish. Except for Hg, levels of metals in fish were safe for human consumption and had no adverse effects on fish
Assessment of Industrial Wastewater Pretreatment Plants and Their Influence on The Seasonal Performance of the Kalobe Waste Stabilization Ponds in Mbeya City, Tanzania
(Mbeya University of Science and Technology, 2025-12-03) Gerson, Eline
This study assessed the effectiveness of industrial wastewater pretreatment plants and evaluated their impact on the performance of the Kalobe Waste Stabilization Ponds (WSP) in Mbeya City. The investigation focused on three major industries—Tanzania Breweries Limited (TBL), Coca-Cola Kwanza, and Pepsi SBC—whose discharges form a substantial portion of the influent entering the WSP. Weekly sampling was conducted from March to July, covering both wet and dry seasons, and water quality parameters including BOD, COD, TSS, nitrate, phosphate, pH, and flow were analyzed using standard laboratory methods. The results revealed that industrial effluent significantly influences the loading and performance of the Kalobe WSP. TBL exhibited the highest organic loads, particularly COD and BOD, while Coca-Cola showed elevated phosphate concentrations linked to chemical usage in production. Seasonal variation was also evident; wet-season inflows caused hydraulic surges that reduced hydraulic retention time and lowered pollutant removal efficiency. Removal efficiencies for COD and phosphate remained below Tanzania Bureau of Standards (TBS) limits, indicating persistent treatment challenges. Variations in pollutant loads were primarily attributed to measurable factors such as fluctuations in chemical dosing efficiency, variations in pretreatment system performance, and increased hydraulic loading during periods of stormwater infiltration. The study concludes that the underperformance of Kalobe WSP is driven by high industrial loads, inadequate pretreatment efficiency, sludge accumulation, and wet-season hydraulic stress. Strengthening industrial source control, enforcing national discharge standards, and upgrading the WSP with supplementary treatment units such as constructed wetlands or chemical precipitation systems are essential. The quantitative findings, based solely on measured influent and effluent characteristics, provide a clear assessment of operational performance and support evidence-based improvement strategies for wastewater management in Mbeya City.
Assessment of Knowledge, Attitudes, and Practices in relation to Mycotoxin Contamination in Tanzania
(East African Journal of Health and Science, 2024-03-16) Nyangi, Chacha; Siyame, Prisca; Hussein, Zaharan
This study assessed the knowledge, attitude, and practices (KAP) of the population in three districts in Tanzania on issues related to mycotoxin contamination and exposure. The study employed a cross-sectional design. Data were collected using a questionnaire survey, which was administered to gather quantitative data in 180 randomly selected households in three districts of Tanzania. In addition, qualitative data were collected using key informant interviews (KIIs) of 12 purposively selected respondents and 6 focus group discussions (FGDs) of six to twelve participants. Quantitative data were analysed in SPSS version 20 for Windows using descriptive statistics and a chi-square test. While the qualitative data were analysed in ATLAS.ti 8 for Windows. A majority of respondents (25.1%) had never heard of mycotoxins, 20.1% were not aware of how mycotoxins are acquired, and none (0%) of the respondents claimed to never become sick after eating moulded/contaminated crops. The majority, 14.5% and 2.8% of the respondents, were not aware of prevention measures for animals and humans from mycotoxins, respectively. Only 8.9% agree that they are at risk of getting mycotoxins, 14% agree that it is safe to eat contaminated food, and 52.5% do not discard the mycotoxins contaminated food. The majority, 81.6%, dry their crops on top of the floor or bare grounds, almost 42.5% do not sort their crops before storage, and 28.5% agree to consume the defective/sorted crops. Therefore, it is recommended that health education interventions to create awareness among the public should be a priority and should be integrated into the existing control strategies.
ASSESSMENT OF PRE-HARVEST AFLATOXIN AND FUMONISIN CONTAMINATION OF MAIZE IN BABATI DISTRICT, TANZANIA
(AFRICAN SCHOLARY SCIENCE TRUST, 2016-07) NYANGI, C; BEED, F
A survey was conducted in 2013 to establish total aflatoxin and total fumonisin in maize, as well as farmers’ practices relating to maize cultivation and awareness of mycotoxins, in three villages of Babati District, northern Tanzania. Quantification of total aflatoxin and fumonisin was done using enzyme-linked immunosorbent assay (Reveal AccuScan® Neogen, USA) and the results were confirmed using Liquid Chromatography Tandem Mass Spectrometer. The mean aflatoxin was 2.94 µg/kg and all samples (n=440) were within the East African Community (EAC) standard of 10 µg/kg for total aflatoxin, but the mean fumonisin was 5.15 mg/kg, more than double the EAC standard of 2 mg/kg, and 35% of samples exceeded this standard. Maize samples obtained from farmers in the village in the mid altitude, dry zone had significantly higher mean aflatoxin (3.32 µg/kg) and significantly lower mean fumonisin (3.17 mg/kg) than maize from the other two villages (in the high and mid altitude, high rainfall zones). Most farmers (n=442) were male (72%), educated to primary school level (77%) and aware of mycotoxins (62%). As well as participating in a development program, Africa Research in Sustainable Intensification for the Next Generation, most (86%) farmers had experience of working with other development programs. All farmers used flat planting, most used improved seeds (98%), ox ploughing (78%), insecticides (78%) and early planting (36%). Practices associated with mycotoxins were planting time, tillage methods, previous season planted crops, and use of insecticides. Awareness of mycotoxins and climatic conditions were also associated with mycotoxin prevalence. In conclusion, good practices are associated with acceptable aflatoxin levels and should be continued. However, the high level of fumonisins warrants further investigation.
Assessment of the physico-chemical and sensory properties of frozen fillets of tuna and tunarelated fish species marketed along the Tanga and Mtwara coastlines, Tanzania
(Taylor & Francis, 2022-11-10) Lujuo,E.J.; Mkupasi, E.M.; Lamtane,H.A.
Tuna and tuna-related fish are valuable marine species lacking standardized quality assessment parameters. This study assessed the physico-chemical and sensory properties of skipjack (Katsuwonus pelamis), bigeye (Thunnus obesus), yellowfin (Thunnus albacares), and kawakawa (Euthynnus affinis) tuna fish fillets marketed in Tanga and Mtwara, Tanzania. Laboratory AOAC methods evaluated total volatile basic-nitrogen (TVB-N), pH, color (lightness L*), and texture (hardness) properties. The quality index method (QIM) assessed tuna fillets’ sensory properties (color, texture, and odor). The pH ranged between 5.60 ± 0.08 and 6.10 ± 0.30, the TVB-N between 34 ± 7.00 mg/ 100 g and 38.04 ± 10.50 mg/100 g, color lightness (L*) between 24.33 ± 1.82 and 40.10 ± 1.50, and texture (hardness) from 3.84 ± 1.20 N to 8.56 ± 1.84 N. The tuna fillets got an overall score of 2 in the sensory analysis, which indicated good quality according to the QIM. Furthermore, the present study showed significant differences (p < .05) between the tuna species in pH, hardness (instrumental), and color lightness properties (L*). There were no significant differences (p > .05) in average TVB-N results across all tuna fillets. There were significant correlations among the assessed quality properties. Based on the combined quality properties results and correlation analysis, the tuna and tuna-related fish marketed in the study areas were of good quality. This study recommends the establishment of standardized quality assessment parameters for tuna and related fish species.
Assessment of the Population size, Distribution and Threats to Conservation of Rhampholeon Acuminatus in Nguru Mountain, Morogoro, Tanzania
(Mbeya University of Science and Technology, 2025-12-01) John, Enoka Munduka
Nguru Spiny Pygmy Chameleon (Rhampholeon acuminatus) is a critically endangered dwarf chameleon endemic to the Nguru Mountains in Morogoro, Tanzania. The species faces severe threats due to habitat degradation as a result of human activities, particularly agricultural expansion. This study assessed the population size, distribution, habitat conditions and conservation challenges of R. acuminatus in the Mkingu Nature Forest Reserve (MNFR) which is part of the Nguru Mountains. A combination of field surveys, environmental assessments and community interviews was employed to determine population dynamics, habitat quality and community’s perceptions on the conservation of R. acuminatus. Findings showed that, a total of 57 individuals of R. acuminatus were recorded, with 88 % in montane forests (≥1400 m.a.s.l.), 12 % in submontane forests (700–1400 m.a.s.l.), and none in lowland areas. The species' distribution correlated strongly with elevation, canopy cover and humidity, with montane forests providing the most suitable habitat. There is significant variation in population density between habitat zones (p < 0.05), with montane forests offering more stable environmental conditions for the species. The species’ limited range highlights its vulnerability to deforestation and habitat degradation. Local communities exhibited limited awareness of the species, with only 23.4% of respondents correctly identifying it. Additionally, 31.5% of respondents expressed no perceived benefits of conserving the species (p = 0.001), and 25.2% were unaware of threats (p = 0.0148). With 88.3% of respondents reporting land clearance for farming. Notably, 97% of respondents indicated that no formal education programs on R. acuminatus had been conducted, highlighting a significant gap in conservation awareness. Findings from this research emphasize the urgent need for targeted conservation strategies, including habitat restoration, law enforcement against deforestation and community-based education programs. Enhancing local awareness and integrating sustainable agricultural practices into conservation initiatives are critical to mitigating threats to R. acuminatus. Without immediate intervention, the species faces an increasing risk of extinction. This study provides baseline data for future conservation planning and policy formulation, ensuring the long-term survival of R. acuminatus within its natural habitat in the Nguru Mountains.

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