Browsing by Author "Moirana, Ruth"

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A comparative study of the adhesive effects of cassava peels, banana peels, and potato peels on the durability of briquettes made from coconut husk charcoal
(AIP Advances, 2025-05-14) Mng’onya, Angel; Moirana, Ruth; Maagi, Mtaki; Chacha, Nyangi
Over-dependency on traditional energy sources, particularly in African countries, significantly contributes to deforestation and carbon emis- sions. Agricultural waste presents a suitable alternative to conventional energy through bio-briquettes; however, they are underutilized. This study evaluated bio-briquettes’ mechanical properties, including abrasion resistance, impact resistance, and water penetration resistance, made from carbonized coconut husks using cassava peels, banana peels, and potato peels as binders. Briquettes bound with potato peels had the highest impact resistance of 96.55%, 96.43%, and 95.26% for ratios 80:20, 70:30, and 60:40, respectively. In comparison, cassava peel-bound briquettes exhibited moderate impact resistance, increasing to 87.71% at a 60:40 ratio. In contrast, banana peel binders had the lower impact resistance, with a maximum impact resistance of 76.72%. Abrasion resistance followed the same trend; in briquettes bound with potato peel, abrasion resistance increased up to 88.69% at 60:40, while banana peels performed the least effectively; the abrasion resistance was 70.09% at 60:40 ratio. Water penetration resistance improved with the increase in binder concentration, with potato peel-bound briquettes reach- ing 79.82% at 60:40, while cassava and banana peel-bound briquettes showed complete disintegration at an 80:20 ratio. Overall, this study indicates that agricultural waste functions as an efficient binder in briquette production, supporting sustainable household energy use. This study contributes to renewable energy innovation, waste valorization, and climate change mitigation by promoting sustainable alternatives to traditional biomass energy.
A Study on Phytochemical and Nutrient Profile of Six Inedible Seaweed Species Found on the Coasts of Tanzania
(John Wiley & Sons Lt, 2025-08-29) Manga, Shengelo; Msuya, Flower; Mbega, Ernest; Moirana, Ruth
Coastal accumulation of inedible seaweeds generates substantial biomass that remains largely underutilized despite its agronomic potential. Tis study characterized six inedible seaweed species (Sargassum spp., Ulva spp., Enteromorpha spp., Hypnea spp., Padina spp., and Laurencia spp.) collected from the Tanzanian coastline to evaluate their suitability as inputs for organic fertilizer production. Samples were analyzed for pH, electrical conductivity, organic carbon, ash content, macro- and micronutrients, and phytohormones. Ulva spp. exhibited the highest organic carbon (24.1%), indole-3-acetic acid (6.29 ± 0.53 mg/kg), and naph- thaleneacetic acid (7 ± 0.50 mg/kg). Sargassum spp. exhibited the highest potassium (78,667 mg/kg), gibberellic acid (14.78 ± 0.70 mg/kg), and kinetin (20.82 ± 6.12 mg/kg) levels, indicating its potential value in promoting shoot growth. Padina spp. were richest in calcium (218,567 mg/kg) and magnesium (17,350 mg/kg). Enteromorpha spp. showed substantial organic carbon (22.53%) and high calcium (190,967 mg/kg). Hypnea spp. had the highest phosphorus content (1697 mg/kg) and exceptionally high sodium contents (52,933 mg/kg), while Laurencia spp. had higher iron contents (5373 mg/kg) and alkaline pH (7.88). Tese fndings confrm that underutilized coastal seaweeds are valuable sources of nutrients and plant hormones and can be converted into organic fertilizers to restore soil fertility and support sustainable agriculture.
Assessing the impact of phosphate fertilizer application on radionuclide accumulation in soil and Spinacia oleracea
(Journal of Ecological Engineering, 2025-06-23) Mankala, James; Sawe, Shovi; Moirana, Ruth
Phosphate fertilizers improve phosphorus-depleted agricultural soil for better plant growth; however, overuse may lead to human health issues. Analyzed soil samples were treated with five phosphate fertilizers and Spinacia oleracea to quantify the levels of natural radionuclides 232 Th, 226 Ra, and 40 K. The study aimed to investigate how phosphate fertilizers contribute to the accumulation of radionuclides 232 Th, 226 Ra, and 40 K in Spinacia oleracea using a high-performance germanium detector. Results revealed the mean activity concentrations in agricultural soil mixed with phosphate fertilizer were 232 Th (66.66 ± 6.39 Bq/kg), 226 Ra (54.78 ± 5.41 Bq/kg), and 40 K (837.17 ± 62.89 Bq/kg); Spinacia oleracea were 232 Th (5.79 ± 0.83 Bq/kg), 226 Ra (40.24 ± 5.38 Bq/ kg), and 40 K (1268.12 ± 129.95 Bq/kg). The soil-to-plant transfer factors were 232 Th (0.244), 226 Ra (0.572), and 40K (1.756). The mean annual limits on the intake of radionuclides were 232 Th (231.67 ± 33.20 Bq/kg), 226 Ra (1609.53 ± 215.33 Bq/kg), and 40 K (50724.67 ± 5,198.13 Bq/kg). The mean annual effective dose was 0.849 ± 0.103 mSv/year, and the internal radiation index was 0.504 ± 0.059 Bq/kg. The results indicate that the mean activity concentrations of 232 Th, 226 Ra and 40 K are below standards but exceed those of the control sample, suggesting regular monitoring of phosphate fertilizer quantity applied to the soil for cultivation.
Hydroxyapatite-activated seaweed biochar for enhanced remediation of fluoride contaminated soil at various pH ranges.
(Elsevier Ltd., 2022-12-10) Moirana, Ruth; Mkunda, Josephine; Machunda, Revocatus; Paradelo, Marcos; Mtei, Kelvin
This study investigated the defluoridation efficiency of hydroxyapatite-activated seaweed (Eucheuma Cottonii) biochar (HSB) at various soil pH ranges (3–11) while monitoring the impact of contact time (30 min - 2.5 h), adsorbent dosage (0.1–0.5 g) as well as the initial fluoride concentration and compare its performance to its respective seaweed biochar (SB). Activation of SB with the hydroxyapatite lead to a shift in its point-zero-charge (pHPZC) from 6 to 7.4 broadening its defluoridation pH range from a solitary 5 to amid 3 through 11. The fluoride adsorption mechanism was found to follow both Langmuir (R2 = 0.956) and Freundlich (R2 = 0.942) isotherm models with a maximum defluoridation capacity of 3.03 mg/g equivalent to the defluoridation efficiency of 79%. This is accounted to the existence of soil ions, SB active sites, and the attached hydroxyapatite, as fluoride adsorption sites each exhibiting a dissimilar fluoride removal mechanism. Therefore, the HSB could be a promising adsorbent for fluoride removal in the fluoride contaminated agricultural soils of inclusive pH ranges.
The Influence of Fertilizers on the Behavior of Fluoride Fractions in the Alkaline Soil
(Elsevier, 2021-08-23) Moirana, Ruth; Mkunda, Josephine; Perez, Marcos; Machunda, Revocatus; Mtei, Kelvin
It has been established that fluoride bioavailability in the soil is defined by the form which it exists rather than the amount of total fluoride. In the soil, fluoride exist in different fractions such as water soluble (Ws-F), Exchangeable (Ex-F), bound to iron/manganese (Fe/Mn-F), organic matter bound (Or-F), and the residual (Res-F). All of these fractions are bioavailable however to different extents in an order Ws-F>Ex-F>Fe/Mn-F>Or-F>Res-F. Agricultural practices such as fertilizer application alters the behavior of these fractions which further affects fluoride bioavailability in the soil. This study investigated the influence of the three commonly used fertilizers (Di-ammonium Phosphate (DAP), Urea, and cow-manure) on the bioavailability of soil fluoride in an alkaline soil. The soil was mixed with either one of the fertilizers then incubated for a period of five months. All three fertilizers increased the amount of Ws-F by 7.8 ± 0.6, 4.1 ± 0.2, 9.6 ± 1.1 mg/kg and Fe/Mn-F by 2.24 ± 0.3, 0.44 ± 0.2, and 2.1 ± 0.2 mg/kg, for DAP, Urea, and manure amendments, respectively, but had no impact on the amount of Or-F. All three fertilizers were observed to enhance the bioavailability of fluoride in the soil by increasing the amount of Ws-F. The fertilizers could have increased the bioavailability of fluoride in the soil directly or indirectly through alteration of pH and the soil elemental composition. The three fertilizers might not be suitable for use in fluoride contaminated alkaline soils as they accelerate fluoride release and hence bioavailability in the soil.
Micro and Nanoplastics: Contamination of Soil
(Springer, 2025-06-17) Pegu, Ratul; Paul, Sarmistha; Hezron, Elkana; Paul, Bishal; Moirana, Ruth
Micro- and nano-plastics (MNPs) are tiny particles formed from the breakdown of plastic waste. They enter the soil through landfills, agricultural practices like mulching, and irrigation with sewage water and cause several environmental problems. The movement of MNPs within the soil depends on factors like soil organisms and the soil's physical and chemical properties. When MNPs mix with soil, they change its structure and interact with other soil components, impacting soil health and behavior. MNPs also increase the adsorption of harmful pollutants, worsening soil pollution and in turn harming plants, animals, microbes, and even humans. These tiny particles can be eaten by soil organisms due to their small size, allowing them to travel through the food chain. This causes both physical and physiological harm. Therefore, in recent decades, environmental specialists and contributors have raised awareness and issued warnings regarding the pollution of micro- and nano-plastics in the soil environment. The rapid increase in plastic waste is now one of the most serious environmental challenges. Therefore, through this chapter authors aim to explain the effects of MNPs on soil properties, soil microbes, soil animals, and human health.
Remediation of Soils Contaminated by Fluoride Using a Fermentation Product of Seaweed (Eucheuma cottonii)
(Hindawi, 2022-10-03) Moirana, Ruth; Mkunda, Josephine; Paradelo, Marcos; Machunda, Revocatus; Mtei, Kelvin
is study investigated the e cacy of fermented seaweed (Eucheuma cottonii) on the remediation of uoride-contaminated soil. e soil was amended with either 1.25, 3.0, or 5.0% (w/w) fermented seaweed (FSW), parallel with the controls (0%). e amendment improved the physicochemical properties of the soil particularly pH regulated from strong alkaline (9.3) to neutral (7.0) which is essential for germination, crop growth, and yield. e amount of water soluble- uoride (Ws-F) dropped from 81.7 ± 3.1 mg/kg to 42.7 ± 2.4, 33.7 ± 1.2, 19.6 ± 0.9, and 12 ± 1.3 mg/kg following 0, 1.25, 3, and 5% amendment dosage, re spectively. Most of the Ws-F was converted into exchangeable uoride (Ex-F) and to uoride-bound to iron and manganese (Fe/ Mn-F). Furthermore, the amendment also enhanced microbial mass and diversity in the soil. e FSW contains organic acids which participate in ionic bonding with the multivalent cations in the soil. e formed compound participates in ion exchange with clay or with anionic adsorption to positively charged clay sites at the edges. is interaction is further essential for enhancing the uoride holding capacity of the soil. e use of seaweed reduced the bioavailability of uoride in the agricultural soils and had positive e ects on promoting soil fertility. However, further studies to observe its e ects on crop performance is of signi cance.
Remediation of soils contaminated with fluoride using seaweed-derived materials: case of slopes of mount Meru
(NM-AIST, 2023-08) Moirana, Ruth
While exposure to low fluoride is essential for stronger bones and teeth, exposure to high concentration (> 3 mg/L/day) leads to hyperostosis and osteoporosis. This research evaluated the role of fertilizer application on soil’s fluoride release, and assess the effectiveness of using seaweed (Eucheuma cottonnii) derived materials for remedial purposes. The soil characterization results in the study area, indicated the availability of diverse fluoride fractions and in different quantities in the soil such that; water-soluble (Ws-F) (39.5 ± 0.5 mg/kg), Exchangeable (Ex-F) (3.5 ± 0.5 mg/kg), bound to iron/manganese (Fe/Mn-F) (3.1 ± 1.0 mg/kg), and organic matter bound (Or-F) (9.1 ± 2.1 mg/kg) fluoride whereas the total fluoride (Tot-F) was 422 ± 52.9 mg/kg. The study further reports that the use of three studied fertilizers (diammonium phosphate (DAP), Urea, and farmyard manure) accelerates the bioavailability of fluoride in the soil by increasing Ws-F. These results deliver alerts to the plant health regulators suggesting proper management of the quality of fertilizers used for the enhancement of crop quality particularly those used in fluoride-contaminated agricultural soils. While fertilizer application accelerated the bioavailability of fluoride in the soil, soil amendment with dried seaweed (DSW) led to a decrement of Ws-F from 81.7 ± 3.1 mg/kg up to 28.5 mg/kg whereas the fermented seaweed (FSW) decreased Ws-F from 81.7 ± 3.1 mg/kg to 12 ± 1.3 mg/kg following 5 % (w/w) amendments. But unlike DSW and FSW, seaweed-derived biochar (SB) adsorbed fluoride at specific pH five (5) from 103.1 mg/kg to 91.2 ± 3.2 mg/kg whereas hydroxyapatite activated seaweed-biochar (HSB) exhibited defluoridation capabilities at varies pH (3 – 11) with a maximum Ws-F reduction from 103.1 mg/kg to 21.6 ± 2.1 mg/kg which is close to the recommended limit of 16.4 mg/kg. The DSW and FSW defluoridation was based on complexation reactions, alteration of soil properties, and increasing the soil-specific surface area, but SB and HSB defluoridation was through chemisorption. Therefore, seaweed-derived materials are capable of remediation of fluoride contaminated soils and the study recommends further investigation on fluoride uptake by crops in pot and field experiments post-amendment with seaweed derived materials.
Trends towards Effective Analysis of Fluorinated Compounds Using Inductively Coupled Plasma Mass Spectrometry (ICP-MS)
(Hindawi, 2021-02-03) Moirana, Ruth; Kivevele, Thomas; Mkunda, Josephine; Mtei, Kelvin; Machunda, Revocatus
Increased demand for monitoring and identification of novel and unknown fluorinated compounds (FCs) has demonstrated the need of sensitive fluorine-specific detectors for unknown FCs in both biological and environmental matrices. Inductively coupled plasma mass spectrometry (ICP-MS) is a promising technique for analysis of FCs and has been rated as the most powerful tool in analytical chemistry. However, direct determination of fluorine using this technique is challenged by high ionization potential of fluorine together with spectral and nonspectral interferences which affect the quality of results. To enhance the quality of results, several studies have reported modifications of a conventional ICP-MS analysis procedure on sample preparation, introduction, analysis, and instrument optimization. Therefore, the focus of this study is to discuss different ICP-MS optimizations and future trends towards the effective analysis of FCs using ICP-MS.