Browsing by Author "Mpumi, Nelson"

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Agro-Waste-Derived Hybrid Biochar Exhibits High-Efficiency Removal of Endocrine-Disrupting Compounds
(Springer International Publishing, 2025-04-11) Kasambala, Hildegard; Rwiza, Mwemezi; Mpumi, Nelson; Mwema, Mwema; Njau, Karoli
Poor waste management of the products and products used in water sources becomes a problem for living organisms’ health. Using biosorbent from agro-waste materials becomes the solution for waste management and wastewater treatment. This study investigated the removal of progesterone from aqueous solutions using a biochar adsorbent derived from mixed banana and mango peels. The biosorbent shows high progesterone removal of 97.8 ± 0.02% at 700℃ preparation temperature at an optimal biosorbent concentration of 0.50 g and pH of 8. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Isotherm analysis revealed that the adsorption data best fitted the Freundlich model (R2 = 0.96), with a maximum adsorption capacity (qmax) of 307 mg g−1, indicating multilayer adsorption with a heterogeneous surface. The Brunauer–Emmett–Teller (BET) surface area was 652 m2g−1 with abundant functional groups verified by Fourier Transform Infrared Spectroscopy (FTIR). The Scanning Electron Microscopy image (SEM) indicated that the biochar is porous, contributing to its effectiveness as an adsorbent. Thermodynamics results indicate that the spontaneous nature of adsorption reveals the process. The findings proved the potential of using agricultural mixed waste-derived biochar containing various chemical and physical characteristics as an effective and sustainable adsorbent to remove endocrine disruptors. This technique addresses environmental concerns about water hormone pollution and promotes sustainable waste management practices, but the gradual decrease in adsorption efficiency highlights the importance of optimizing the biochar's chemical composition and structural reliability to maximize its performance.
Bacterial Diversity Dynamics in Sandy Loam Soils in Tanzania Under Varying Fertilizer-Derived Uranium Concentrations
(Microorganisms, 2025-08-13) Mwalongo, Dennis; Lisuma, Jacob; Haneklaus, Nils; Maged, Ali; Brink, Hendrik; Carvalho, Fernando; Wacławek, Stanisław; Mpumi, Nelson; Amasi, Aloyce; Mwimanzi, Jerome; Chuma, Furaha; Kivevele, Thomas; Mtei, Kelvin
The presence of radiotoxic uranium (U) in mineral fertilizers is of global concern. A pilot study was conducted in Tabora (Tanzania) to determine the release of U from three brands of phosphate fertilizers and its impact on soil bacteria. The experiment used three types of fertilizer: Minjingu Powder (MP), Nafaka Plus (NP), a mixed and granulated fertilizer made from Minjingu Phosphate Rock (MPR), and YaraMila Cereal (YC) fertilizer. There was also a control treatment that was not fertilized (NF). Alpha diversity and the R tool were used to analyze bacterial diversity in four samples within an average sequencing depth of 74,466 reads, using metrics like ASVs, Shannon index, and Chao1. The results showed that the number of amplicon sequence variants (ASVs) in the DNA from soil bacteria decreased, specifically to 400 ASVs, in the NP treatment, which was in line with the higher U concentration (3.93 mg kg−1) in the soils. In contrast, the MP fertilizer treatment, associated with a lower U concentration (3.06 mg kg−1) in soils, exhibited an increase in ASVs within the DNA of soil bacteria, reaching 795; the highest ASV value (822) was observed in the NF treatment. Higher amounts of U in the soil plots seemed to have resulted in more types of bacteria, with the Actinobacteriota phylum being the most common in all of the treatments. The NP (3.93 mg kg−3 U concentration) and MP (3.06 mg kg−3 U concentration) treatments were the only ones that showed Halobacteriota and Crenarchaeota phyla. Nonetheless, bacterial diversity may also account for the alterations in soil phosphorus and nitrogen following fertilizer application. The YaraMila Cereal treatment did not seem to be linked to any particular bacterial phylum. This means that in this study it did not have any measurable effect on the soil bacteria species compared to the MP and NP treatments
Biochars derived from banana and mango peels in isolated systems revealed high removal efficiency of endocrine-disrupting compounds from water.
(Springer Nature, 2024-10-01) Kasambala, Hildegard; Rwiza, Mwemezi; Mpumi, Nelson; Mwema, Mwema Felix; Njau, Karoli
This study investigated the effectiveness of biochar derived from banana and disrupting endocrine-disrupting compounds (EDCs) from water in isolated systems. The study aimed to provide an eco-friendly solution for water purification using agricultural waste products. Banana and mango peels were dried, ground, and calcinated at 300, 550, and 700 °C temperatures. The biochar was tested through a batch adsorption experiment for the removal of progesterone, and the remaining progesterone was analyzed using high-performance liquid chromatography (HPLC). Results indicated that the banana peel biochar (BPB) and mango peel biochar (MPB) achieved the highest adsorption capacities of 92.8 and 87.9%, respectively, when subjected to pyrolysis at 700 °C. The effect of other factors on adsorbent efficiency and its characteristics were subsequently analyzed by biochar calcinated at 700 °C. Results indicate that as the concentration of adsorbent increases, the adsorption efficiency increases while the adsorption capacity decreases. The Langmuir model fits better in BPB, while the Freundlich model fits better in MPB. The maximum adsorption capacities of the Langmuir model were 43.42 and 37.80 mg of progesterone per g of BPB and MPB, respectively. The scanning electron microscopy image (SEM) showed that biochar from 700 °C presents higher porosities than biochar. The Brunauer–Emmett–Teller (BET) showed that both biochars had high surface area and equal pore volume. Therefore, the study suggests that BPB and MPB are the best eco-friendly agricultural waste materials for development of sustainable water treatment technologies for removal of EDCs from water.
A comprehensive review on the distribution of per- and poly-fluoroalkyl substances in the environment across Sub-Saharan Africa revealed significant variation in their concentrations
(Elsevier, 2024-08) Kasambala, Hildegard; Rwiza, Mwemezi; Mpumi, Nelson; Mwema, Mwema; Machunda, Revocatus; Mtei, Kelvin; Njau, Karoli
Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals known for their widespread use in various industrial and consumer products. They enter the food chain via contaminated water, air, and soil, resulting in bioaccumulation in plants, fishes, foods, human milk, and blood serum. Here, we critically reviewed the literature published from 2005 to 2021 on the occurrence and distribution of Perfluorooctanoic acid (PFOA) and perfluoro-octane sulfonate (PFOS) as the most occurring PFAS in the aquatic environment in sub-Saharan Africa (SSA). To our knowledge, this is the first paper to review the status of PFAS in the SSA environment. This review found that almost all matrices studied in SSA regions have been polluted by PFAS with varying concentrations. This information suggests that the levels of PFAS in the environment deserve immediate attention. Furthermore, SSA faces unique challenges in understanding and managing PFAS contamination due to the scarcity of data in specific regions and the need for more administrative guidelines for monitoring PFAS in water. This review provides vital baseline information on the occurrences, distribution and contributing factors for their distribution in the SSA environment for better understanding to protect the environment and public health, and to develop sustainable solutions for the PFAS growing concern.
Efficacy of Aqueous Extracts from Syzygium aromaticum, Tephrosia vogelii, and Croton dichogamus against Myzus persicae on Brassica oleracea in Northern Tanzania
(Hindawi Limited, 2021-07-19) Mpumi, Nelson; Mtei, Kelvin; Machunda, Revocatus; Ndakidemi, Patrick
The effectiveness of 1, 5, and 10% w/v of aqueous extracts of Croton dichogamus, Tephrosia vogelii, and Syzygium aromaticum and their mixture (2.5 and 5%) was evaluated against Myzus persicae on Brassica oleracea under field conditions. The synthetic chemical insecticide, chlorpyrifos, was used as positive control, and water and water plus soap were used as negative controls. Aqueous extracts significantly () lowered M. persicae population compared with negative controls. The 5% of the aqueous extract from mixed plants and 10% of each plant used in this study significantly () reduced aphid, M. persicae population comparable to chlorpyrifos in 2019 and 2020. However, the 1 and 5% concentrations of aqueous extracts of C. dichogamus, T. vogelii, and S. aromaticum and 2.5% of aqueous extracts from the mixed plants significantly lowered the population of M. persicae compared with negative controls in 2019 and 2020 wet seasons. The weekly observations revealed that, at weeks 1, 2, 3, 4, and 5 after application of treatments, the population of M. persicae differed significantly (). Also, the aqueous extracts from the mixed plants at 5% concentrations significantly () reduced M. persicae population as compared with other treatments. It was as effective as synthetic chemical pesticide (chlorpyrifos). Also, 1 and 5% of C. dichogamus, T. vogelii, and S. aromaticum and the 2.5% of aqueous extracts from the mixed plants significantly reduced the population of M. persicae for all 6 weeks of study compared with negative controls. Therefore, these pesticidal plants can be recommended to smallholder farmers for the control of M. persicae in B. oleracea crops.
Efficiency of honey–grape blend in reducing radiation-induced mucositis in locally advanced head and neck squamous cell carcinoma
(AIMS Press, 2025-03-12) Kyomo, Magaisha; Mpumi, Nelson; Sauli, Elingarami; Lidenge, Salum
This study assessed the efficacy of a honey–grape blend in reducing the severity and onset of radiation oral mucositis (ROM) in patients with locally advanced squamous cell carcinoma of the head and neck. Oral mucositis is an acute side effect caused by chemotherapy or radiotherapy in the head and neck region. ROM affects patients’ quality of life and treatment expenses. Various pharmaceutical and natural remedies, such as sucralfate, aloe vera, and amifostine are used to mitigate the effects of ROM. However, the available modalities’ efficacy is low and is associated with many side effects. Materials and methods: This cohort study was conducted at the Ocean Road Cancer Institute and Besta Polyclinic in Tanzania. The study included 73 patients with locally advanced squamous cell carcinoma of the head and neck treated from March 2024 to August 2024. The World Health Organization mucositis grading system was used to assess patients’ progress weekly. Data analysis was conducted using Statistical Package for Social Science (SPSS) version 27. Results: Delayed onset (15% Grade 3 for the honey–grape group and 45% Grade 3 for the control group at 28 days) and reduced the severity of ROM (only 20% Grade 3 with no Grade 4 for the honey–grape group while for the control group, it was 25% Grade 3 and 20% Grade 4 at 45 days) (p-value < 0.001). Body weight changes at starting and after completion of radiotherapy were observed (2.65 kg average weight loss for the control group and 1.8 kg, 0.45 kg weight gain for the honey group and honey–grape blend group). Prevalence between genders was 62% males and 38% females. Conclusions: Honey and honey 91 blended with grapes can minimize the severity and delay the onset of ROM in patients with locally advanced head and neck cancer. More studies are needed, since no study has been conducted addressing the efficacy of honey–grape blends in reducing ROM severity.
Evaluation of selected botanicals as insecticides against cabbage insect pests in Tanzania
(NM-AIST, 2022-06) Mpumi, Nelson
Synthetic pesticides are frequently and unwisely used to control cabbage insect pests by smallholder farmers despite the environmental pollution and insect pests’ resistance development. This work assessed the insecticidal efficacy of botanicals from Tephrosia vogelii, Croton dichogamus and Syzygium aromaticum against cabbage insect pests in Northern Tanzania. Firstly, larvicidal action of extracts against Crocidolomia binotalis and Plutella xylostella larvae was assessed in the laboratory. Secondly, insecticidal and synergistic actions of aqueous extracts against cabbage insect pests were assessed in field experiment. Lastly, chemical compounds in S. aromaticum and in C. dichogamus were determined. The larvicidal activities of extracts were assessed for mortality of ten larvae into 9 cm Petri-dishes for 24 hours of exposure. Chlorpyrifos and acetone were used as a positive and negative control, respectively. The insecticidal efficacy of 10%, 5% and 1% w/v of T. vogelii, C. dichogamus and S. aromaticum aqueous extracts and their mixture (2.5% and 5%) was assessed against cabbage insect pests in the field. Chlorpyrifos was used as a positive control, and water and water plus soap were used as negative controls. The GC-MS was used for compounds identification in C. dichogamus and in S. aromaticum. Results from the study revealed that S. aromaticum extract (16, 24 and 32 mg/mL), T. vogelii (24 and 32 mg/mL) and C. dichogamus (32 mg/mL) gave 100 ± 0.0% mortality of C. binotalis larvae after 24 hours of exposure. Moreover, S. aromaticum extract (8, 16, 24 and 32 mg/mL), T. vogelii (16, 24 and 32 mg/mL) and C. dichogamus (32 mg/mL) gave 100 ± 0.0% mortality of P. xylostella larvae after 24 hours of exposure. The aqueous extracts from those plants significantly (P ≤ 0.05) lowered the population of cabbage insect pests compared with negative controls. The 5% of aqueous extract from mixed plants possessed significantly (P ≤ 0.01) lower population of cabbage insect pests in both wet seasons compared with other concentrations. Then, it was followed by 10% of S. aromaticum, C. dichogamus and T. vogelii aqueous extracts and 1% and 5% of aqueous extracts of S. aromaticum, C. dichogamus and T. vogelii and 2.5% of aqueous extracts from the mixed plants significantly lowered the population of insect pests compared with negative controls in both seasons. The compounds identified in S. aromaticum, at higher percent were Eugenol (52.66%); Eugenol acetate (20.46%) and β-caryophyllene (7.52%). Moreover, the compounds identified in C. dichogamus at higher percent were 4,6-Bis (4-chloro-3-(trifluoromethyl) phenoxy)-2-pyrimidinol (25.08%); Cholestan-6-en-3-ol (18.63%) and 1-Heptadecene (7.34%). These compounds could be responsible for larvicidal and insecticidal activities against cabbage ii insect pests. Therefore, these plants can be recommended to be used by smallholder farmers for cabbage insect pest control at higher concentrations and development of insecticides.
Insecticidal Efficacy of Syzygium aromaticum, Tephrosia vogelii and Croton dichogamus Extracts against Plutella xylostella and Trichoplusia ni on Brassica oleracea crop in Northern Tanzania
(AIMS Agriculture and Food, 2020-12-30) Mpumi, Nelson; Machunda, Revocatus; Mtei, Kelvin; Ndakidemi, Patrick
The 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, 186 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 crop
Invasive weeds with pesticidal properties as potential new crops
(Elsevier, 2017) Belmain, Steven; Mkindi, Angela; Mpumi, Nelson; Tembob, Yolice; Stevenson, Phillip; Ndakidemi, Patrick; Mtei, Kelvin; Machunda, Revocatus
Plants with pesticidal properties have been investigated for decades as alternatives to synthetics, but only a handful have been commercialised and developed as non-food cash crops. One of the reasons why pesticidal plants are failing to deliver new pesticidal products is that they are often not evaluated under field conditions by farmers. Furthermore, many aspects of pesticide use related to environmental safety, such as their impact on beneficial organisms, remain under-evaluated. With a view to overcoming these bottlenecks, extracts made from six abundant weed species found across sub-Saharan Africa (Bidens pilosa, Lantana camara, Lippia javanica, Tithonia diversifolia, Tephrosia vogelii and Vernonia amygdalina) were evaluated in on-station and on-farm trials over two years (2015 and 2016) in two different countries (Tanzania and Malawi) on common bean plants (Phaseolus vulgaris). All plant species offered effective control of key pest species that was comparable in terms of harvested bean yield to a synthetic pyrethroid. Furthermore, the plant pesticide treatments had significantly lower negative effects on natural enemies (hover flies, lacewings, ladybird beetles and spiders). Thus, pesticidal plants were better able to support ecosystem services whilst effectively managing pests. Small holder farmer rankings on their perceived efficacy of the different plant species indicated that T. vogelii was the most preferred and effective, achieving bean yields as good as the synthetic, if not better. As T. vogelii is fast growing with a wellknown and understood phytochemistry, it is an excellent candidate for commercial development to supplement pyrethrum production by African small holder farmers.
Invasive weeds with pesticidal properties as potential new crops
(Elsevier, 2017-12-30) Mkindi, Angela; Mpumi, Nelson; Tembo, Yolice; Stevenson, Phillip; Ndakidemi, Patrick; Mtei, Kelvin; Machunda, Revocatus; Belmain, Steven
Plants with pesticidal properties have been investigated for decades as alternatives to synthetics, but only a handful have been commercialised and developed as non-food cash crops. One of the reasons why pesticidal plants are failing to deliver new pesticidal products is that they are often not evaluated under field conditions by farmers. Furthermore, many aspects of pesticide use related to environmental safety, such as their impact on beneficial organisms, remain under-evaluated. With a view to overcoming these bottlenecks, extracts made from six abundant weed species found across sub-Saharan Africa (Bidens pilosa, Lantana camara, Lippia javanica, Tithonia diversifolia, Tephrosia vogelii and Vernonia amygdalina) were evaluated in on-station and on-farm trials over two years (2015 and 2016) in two different countries (Tanzania and Malawi) on common bean plants (Phaseolus vulgaris). All plant species offered effective control of key pest species that was comparable in terms of harvested bean yield to a synthetic pyrethroid. Furthermore, the plant pesticide treatments had significantly lower negative effects on natural enemies (hover flies, lacewings, ladybird beetles and spiders). Thus, pesticidal plants were better able to support ecosystem services whilst effectively managing pests. Small holder farmer rankings on their perceived efficacy of the different plant species indicated that T. vogelii was the most preferred and effective, achieving bean yields as good as the synthetic, if not better. As T. vogelii is fast growing with a well-known and understood phytochemistry, it is an excellent candidate for commercial development to supplement pyrethrum production by African small holder farmers.
Invasive weeds with pesticidal properties as potential new crops
(Elsevier, 2017) Mkindi, Angela; Mpumi, Nelson; Tembo, Yolice; Stevenson, Phillip; Ndakidemi, Patrick; Mtei, Kelvin; Machunda, Revocatus; Belmain, Steven
Plants with pesticidal properties have been investigated for decades as alternatives to synthetics, but only a handful have been commercialised and developed as non-food cash crops. One of the reasons why pesticidal plants are failing to deliver new pesticidal products is that they are often not evaluated under field conditions by farmers. Furthermore, many aspects of pesticide use related to environmental safety, such as their impact on beneficial organisms, remain under-evaluated. With a view to overcoming these bottlenecks, extracts made from six abundant weed species found across sub-Saharan Africa (Bidens pilosa, Lantana camara, Lippia javanica, Tithonia diversifolia, Tephrosia vogelii and Vernonia amygdalina) were evaluated in on-station and on-farm trials over two years (2015 and 2016) in two different countries (Tanzania and Malawi) on common bean plants (Phaseolus vulgaris). All plant species offered effective control of key pest species that was comparable in terms of harvested bean yield to a synthetic pyrethroid. Furthermore, the plant pesticide treatments had significantly lower negative effects on natural enemies (hover flies, lacewings, ladybird beetles and spiders). Thus, pesticidal plants were better able to support ecosystem services whilst effectively managing pests. Small holder farmer rankings on their perceived efficacy of the different plant species indicated that T. vogelii was the most preferred and effective, achieving bean yields as good as the synthetic, if not better. As T. vogelii is fast growing with a well-known and understood phytochemistry, it is an excellent candidate for commercial development to supplement pyrethrum production by African small holder farmers.
Pesticidal Plant Extracts Improve Yield and Reduce Insect Pests on Legume Crops Without Harming Beneficial Arthropods
(Original Research, 2018-09-28) Tembo, Yolice; Mkindi, Angela; Mkenda, Prisila; Mpumi, Nelson; Mwanauta, Regina; Stevenson, Philip; Ndakidemi, Patrick; Belmain, Steven
In the fight against arthropod crop pests using plant secondary metabolites, most research has focussed on the identification of bioactive molecules. Several hundred candidate plant species and compounds are now known to have pesticidal properties against a range of arthropod pest species. Despite this growing body of research, few natural products are commercialized for pest management whilst on-farm use of existing botanically-based pesticides remains a small, but growing, component of crop protection practice. Uptake of natural pesticides is at least partly constrained by limited data on the trade-offs of their use on farm. The research presented here assessed the potential trade-offs of using pesticidal plant extracts on legume crop yields and the regulating ecosystem services of natural pests enemies. The application of six established pesticidal plants (Bidens pilosa, Lantana camara, Lippia javanica, Tephrosia vogelii, Tithonia diversifolia, and Vernonia amygdalina) were compared to positive and negative controls for their impact on yields of bean (Phaseolus vulgaris), cowpea (Vigna unguiculata), and pigeon pea (Cajanus cajan) crops and the abundance of key indicator pest and predatory arthropod species. Analysis of field trials showed that pesticidal plant treatments often resulted in crop yields that were comparable to the use of a synthetic pesticide (lambda-cyhalothrin). The best-performing plant species were T. vogelii, T. diversifolia, and L. javanica. The abundance of pests was very low when using the synthetic pesticide, whilst the plant extracts generally had a higher number of pests than the synthetic but lower numbers than observed on the negative controls. Beneficial arthropod numbers were low with synthetic treated crops, whereas the pesticidal plant treatments appeared to have little effect on beneficials when compared to the negative controls. The outcomes of this research suggest that using extracts of pesticidal plants to control pests can be as effective as synthetic insecticides in terms of crop yields while tritrophic effects were reduced, conserving the non-target arthropods that provide important ecosystem services such as pollination and pest regulation. Thus managing crop pests using plant secondary metabolites can be more easily integrated in to agro-ecologically sustainable crop production systems.
Selected Insect Pests of Economic Importance to Brassica oleracea, Their Control Strategies and the Potential Threat to Environmental Pollution in Africa
(MDPI, 2020-05-08) Mpumi, Nelson; Machunda, Revocatus; Mtei, Kelvin; Ndakidemi, Patrick
The most common destructive insect pests affecting cabbages in African smallholder farmers include Plutella xylostella, Helula undalis, Pieris brassicae, Brevycoryne brassicae, Trichoplusia ni and Myzus persicae. Those insect pests infest cabbages at different stages of growth, causing huge damage and resulting into huge yield losses. The African smallholder farmers use cultural and synthetic pesticides to control insect pests and minimize infestations. The cultural practices like crop rotation, weeding and handpicking are used to minimize the invasion of cabbage pests. However, those practices are not sufficiently enough to control cabbage insect pests although they are cheap and safe to the environment. Also, the African smallholder famers rely intensively on the application of broad-spectrum of synthetic pesticides to effectively control the cabbage pests in the field. Due to severe infestation of cabbages caused by those insects, most of African smallholder farmers decide to; first, increase the concentrations of synthetic pesticides beyond the recommended amount by manufacturers. Secondly, increase the rate of application of the synthetic pesticides throughout the growing season to effectively kill the most stubborn insect pests infesting cabbages (Brassica oleracea var. capitata). Thirdly, they mix more than two synthetic pesticides for the purpose of increasing the spectrum of killing the most stubborn insect pests in the field. All those scenarios intensify the environmental pollution especially soil and water pollution. Moreover, most of insecticides sprayed are made with broad-spectrum and are hazardous chemicals posing environmental pollution and threats to natural enemies’ ecosystems. Therefore, this paper reviews Brassica oleracea var. capitata insect pests and control measures as a potential environmental pollution threat in African smallholder farmers.
Social determinants for household clean water accessibility in northern Tanzania: A case of Kikwe peri-urban ward in Arusha
(African Quarterly Social Science Review, 2025-06-26) Ngayaga, Mwahija; Nade, Paschal; Mpumi, Nelson; Ripanda, Asha; Rwiza, Mwemezi
Clean water accessibility is vital to human health and well-being, a fundamental human right. Over 1.7 billion people do not have consistent access to safe drinking water, negatively affecting their health and socioeconomic status. Despite global recognition of clean water as a fundamental human right, many households in peri-urban areas of developing countries, including northern Tanzania, continue to face significant challenges in accessing reliable water sources. In the Kikwe peri-urban ward, disparities in access to clean water are influenced by various social determinants such as education level, gender roles, marital status, and proximity to water sources. These social factors contribute to unequal water distribution and increased vulnerability to waterborne diseases and economic burdens, especially among women and marginalized groups. However, limited empirical data exists on how these social determinants specifically affect household water access in Kikwe, hindering the development of targeted, evidence-based interventions. This study, therefore, aimed to investigate the social determinants of household clean water accessibility in Kikwe peri-urban ward of northern Tanzania. The cross-sectional survey combined quantitative and qualitative research methods on 353 respondents sampled from the Kikwe ward. Inference and descriptive statistics were employed to analyze the social determinants and respective associations with clean water accessibility. Results show that 64% of respondents finished elementary school, 53% were male, the majority 25.8% aged between 45 to 54, 73.7% were married, 37.4% rely on water from the rivers, 33.7% use public standpipes as the primary source of water, 62.9% female primarily responsible for fetching water and 84.7% of users do not treat water for their daily use. A weak significant correlation existed between water sources and social variables tested, implying clean water is an essential commodity, which needs to be distributed equally regardless of individual status. The findings highlight that clean water accessibility in peri-urban Kikwe is significantly influenced by social inequalities, particularly gender, and proximity to water sources. While the statistical correlations were weak, the trends point to systemic disparities that require deliberate policy attention. It is concluded that equitable access to clean water cannot be achieved without addressing these underlying social determinants. Therefore, it is recommended that targeted educational programs using mobile platforms be introduced to enhance awareness on water treatment and conservation. Additionally, empowering communities through participatory water governance, investing in affordable and decentralized water treatment solutions, and improving local infrastructure is critical for long-term water security and public health resilience in peri-urban areas like Kikwe.
Sustainable insect pest management for cabbage production in Sub-Saharan Africa: Challenges, organic alternatives and climate change impacts
(Elsevier, 2025-10) Lekamoi, Upendo; Mashamba, Philipo; Laizer, Hudson; Mpumi, Nelson; Mbega, Ernest
Cabbage (Brassica oleracea) is an important vegetable crop in Sub-Saharan Africa contributing significantly to household food security and economic stability. Despite this importance, cabbage production has been declining due to several challenges including insect pest infestations which are intensified by climate change. In response, farmers predominantly rely on synthetic insecticides which have raise concerns on environmental degradation and human health risks. As an alternative, organic insecticides derived from animal byproducts, plants and microbes offer a more sustainable approach to insect pest management under changing climatic conditions. These organic insecticides not only mitigate the negative effects of synthetic chemicals but also enhance environmental and human health safety. This review explores the role of organic insecticides in sustainable cabbage production, discussing their efficacy, impact on insect pest life cycles and adaptability to climate change. Additionally, it highlights the top ten cabbage-producing countries in Sub-Saharan Africa, major insect pests affecting cabbage, insect pest management strategies and the influence of climate change on the bioactive compounds of organic insecticides. By integrating organic pest control measures, cabbage farmers in Sub-Saharan Africa can enhance resilience against climate-induced pest challenges while promoting sustainable agricultural practices.
Uranium Dissemination with Phosphate Fertilizers Globally: A Systematic Review with Focus on East Africa
(MDPI, 2024-01-09) Mwalongo, Dennis; Haneklaus, Nils; Lisuma, Jacob; Mpumi, Nelson; Amasi, Aloyce; Mwimanzi, Jerome; Chuma, Furaha; Kivevele, Thomas; Mtei, Kelvin
Growing concern has been expressed about uranium (U) accumulation in agricultural soils caused by the long-term application of mineral fertilizers. More than 80% of naturally occurring U transfers from phosphate rock (PR), the raw material used in mineral fertilizer production, to phosphorus (P) fertilizers. These fertilizers are then distributed on agricultural soils, where the U could accumulate over time and become a risk to the environment. The objective of this work was to review the reported content of U in P fertilizers, its potential dispersion in soils, and its uptake by plants in different countries in the world as reported in the literature. The articles for this systematic review were selected from the Scopus database published between 2003 and 2022. The preferred reporting items for systematic reviews and meta-analyses (PRISMA) protocol were used. A total of 54 articles were assessed based on the standard inclusion and exclusion criteria. U concentrations in P fertilizers, agricultural soil dissemination, and plant uptake for available data were obtained and assessed. In order to compare a set of related data from the collected articles, box and whisker plots showing the distribution of U in P fertilizers are presented by region. The results from the reviewed articles show that the U concentrations in P fertilizer were in the range of 0.1–653 mg kg−1. Interestingly, Minjingu P fertilizers from Tanzania, which are used in six East African countries, showed the highest U concentrations (159 to 653 mg kg−1, average 390 mg kg−1). The reported U concentrations for these fertilizers are, in fact, comparable to those of conventional low-grade uranium deposits mined in Namibia and elsewhere. Additionally, approximately 96% of the reviewed articles indicate that fertilized soil has higher U concentrations than non-fertilized soils, hinting at a measurable effect of mineral fertilizer use. The review recommends U extraction during mineral fertilizer production so that potential environmental risks can be reduced and U resources that would otherwise be lost can be recovered and used to substitute conventional U mining elsewhere.