Review Article
Trihalomethane Formation in Zanzibar Groundwater: Environmental Drivers, Hydrochemical Controls, and Disinfection Practices
Mulhat Mohd Fasih*
Issue:
Volume 14, Issue 4, August 2026
Pages:
118-129
Received:
20 July 2026
Accepted:
17 August 2026
Published:
8 September 2026
Abstract: Trihalomethanes (THMs) are regulated disinfection by-products generated when chlorine reacts with natural organic matter and other reactive precursors in water. Their formation and speciation depend on hydrochemical conditions, halide availability, climate, and operational disinfection practices. This review examines the interacting factors that may control THM formation in Zanzibar groundwater, a tropical coastal aquifer system affected by seawater intrusion, sanitation-related pollution, agricultural activities, high temperatures, and seasonal variability. Peer-reviewed studies published from 2010 to 2025 were synthesized thematically, with emphasis on seawater intrusion, organic matter and nutrient pollution, climate variability, water hardness and inorganic chemistry, and local chlorination practices. The evidence indicates that bromide enrichment from saline mixing can shift THM speciation toward more toxic brominated compounds, while natural and algal organic matter provide reactive carbon precursors. Warm conditions accelerate halogenation reactions, and carbonate alkalinity and hardness stabilize the chemical environment in which chlorine reacts with organic matter. Inconsistent chlorine dosing, limited monitoring, and inadequate precursor removal may further increase disinfection by-product risks. The review identifies major local gaps, particularly the limited routine measurement of bromide, THMs, and organic-matter reactivity. It concludes that Zanzibar requires hydrochemically informed monitoring, improved source protection, precursor-removal measures, and adaptive disinfection strategies that account for spatial and seasonal water-quality variability while maintaining effective microbial control.
Abstract: Trihalomethanes (THMs) are regulated disinfection by-products generated when chlorine reacts with natural organic matter and other reactive precursors in water. Their formation and speciation depend on hydrochemical conditions, halide availability, climate, and operational disinfection practices. This review examines the interacting factors that ma...
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Research Article
Effect of NPS and Urea Fertilizer Rates on Phenology, Growth and Yield Components of Bread Wheat
(Triticum Aestivum L.) in West Guji Southern Oromia
Deme Megersa Jida*
Issue:
Volume 14, Issue 4, August 2026
Pages:
130-141
Received:
27 July 2026
Accepted:
10 August 2026
Published:
8 September 2026
Abstract: Bread wheat (Triticum aestivum L.) is one of the major food crops cultivated in West Guji and plays a significant role in ensuring food security in Ethiopia. However, low soil fertility and inadequate fertilizer application are among the major constraints limiting wheat productivity in the study area. The study took place in the West Guji southern Oromia, during the main cropping season in 2023. The study was aimed to determine the combined application of NPS and urea (N) fertilizer rates for bread wheat (Triticum aestivum L.) production. The treatments were (0 NPS) negative control, 60 kg NPS, 120 kg NPS, and 180 kg NPS, and (0 N) negative control, 140 kg N, 280 kg N, and positive control (100/100 kg ha⁻1 NPS/N). The treatments were arranged in a randomized complete block design and replicated three times. The results of the analysis of variance for agronomic characters indicated that the effects of fertilizer application rates were significant for the date of 50% heading, the date of 90% physiological maturity, plant height, the number of total tillers per plant, spike length per plant, effective tiller per plant, spikelet per spike, the number of grains per spike, thousand seed weight, and harvest index. The maximum duration of 50% days to heading (83.67 days) and day to 90% physiological maturity (136 days) was obtained from unfertilized plants, whereas the minimum duration of 50% day to heading (70.33 days) and day to 90% physiological maturity (120 days) was obtained from 180 kg NPS ha⁻1 + 280 kg N ha⁻1 fertilizer rates, respectively. The maximum plant height (92.5 cm) was also recorded under the highest fertilizer treatment, indicating a strong correlation between nutrient application and plant growth. These findings suggest that balanced fertilizer rates can significantly enhance both yield components and overall plant development. 21 cm), effective tiller per plant (5.21), number of total tillers per plant (5.25), spike length (9.21 cm), and 180 kg NPS ha⁻1 + 280 kg N ha⁻1 fertilizer rates, respectively. The maximum spikelet per spike (19) and number of grains per spike (74.67) were obtained from 120 kg NPS ha⁻1 + 140 kg N ha⁻1 fertilizer rates, respectively. The maximum thousand grains weight (38.00 gm) and harvest index (44.33%) were obtained from 180 kg NPS ha⁻1 + 140 kg N ha⁻1 fertilizer rates, respectively. Therefore, 180 kg/280 kg and 180 kg/140 kg ha⁻1 NPS/urea (N) are better, but 120/140 kg is best for gain yield, and the farming community can be used in the study area. This suggests that optimizing fertilizer application can significantly enhance bread wheat yield and yield components. Future research should focus on refining these rates further to maximize efficiency and sustainability in agricultural practices.
Abstract: Bread wheat (Triticum aestivum L.) is one of the major food crops cultivated in West Guji and plays a significant role in ensuring food security in Ethiopia. However, low soil fertility and inadequate fertilizer application are among the major constraints limiting wheat productivity in the study area. The study took place in the West Guji southern ...
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