Universidade Zambeze

Abstract Groundwater is the primary source of potable and irrigation water in Gashua, Northeastern Nigeria, where arid climatic conditions limit surface water availability. Unlike previous studies in the Chad Basin that focused on limited chemical parameters, this study applies integrated geospatial modelling and multivariate statistics to delineate hydrochemical facies and anthropogenic hotspots in a semi-arid aquifer. Twenty-five groundwater samples were analyzed for pH, electrical conductivity, total dissolved solids, total hardness, major cations (Ca²⁺, Mg²⁺, Na⁺, K⁺), and anions (Cl⁻, SO₄²⁻, NO₃⁻, HCO₃⁻). Results showed pH values from 5.7 to 7.9, EC between 415 and 1464 µS/cm, and TDS from 265.6 to 937.0 mg/L. 80% (20/25) of the samples exceeded the Nigerian Standard for Drinking Water Quality (NSDWQ) limit for hardness. Piper and Durov diagrams revealed Ca²⁺–Mg²⁺–Cl⁻–SO₄²⁻ and Ca²⁺–Mg²⁺–HCO₃⁻ facies, reflecting carbonate and sulphate dissolution, cation exchange, and evaporative concentration. Spatial analysis delineated recharge zones in the north and discharge zones in the south, with higher salinity and nitrate levels in peri-urban areas. Nitrate ranged from 10.8 to 88 mg/L, with one sample exceeding the World Health Organization (WHO) limit of 50 mg/L; sampling was conducted during the dry season. Principal Component Analysis (PCA) explained 79% of total variance and identified mineralization, pH buffering, and nitrate pollution as key processes. Hierarchical Cluster Analysis (HCA) classified wells into recharge, transitional, and discharge zones. Irrigation suitability assessed by SAR, Na⁺%, PI, KR, and MH confirmed that most samples are suitable, though moderate salinity (C2S1) and isolated sodicity risks highlight the need for site-specific management. These findings emphasize the vulnerability of groundwater to both natural geochemical evolution and human activities. The integrated hydrogeochemical and multivariate approach provides actionable implications: protecting recharge areas in the north, routine surveillance of southern salinity and nitrate hotspots, and tailored farmer advisories for irrigation practices. Such measures are critical for sustainable aquifer management in arid regions.

Cartography is a fundamental science in the teaching of Geography due to its essential role in understanding and representing geographic space. Therefore, this article discusses the importance of the use and production of cartographic material in secondary schools in Mozambique. The research, based on a bibliographic review, used a qualitative approach through the observation of pedagogical practice in the teaching of Geography, analysis and interpretation of empirical information obtained through questionnaires applied to 90 students of the 8th 18 Geography teachers and 9 pedagogical managers. In addition, the research included the application of practical activities with students and teachers in the production and use of cartographic material. Data collection was carried out in three schools located in different regions of the country. The results revealed that lack of planning, time overload, lack of initiatives and creativity, financial limitations and the absence of a pedagogical workshop are factors that restrict the use and production of cartographic material in teaching Geography. The use and production of cartographic material not only reinforce theoretical learning, but also develop practical and critical skills in students, as well as facilitate the teaching-learning process for teachers. This process, when combined with an appropriate pedagogical methodology, makes the teaching of geography more interactive and effective.

Satellite imagery is crucial for studying shoreline evolution due to its ability to provide consistent, high-resolution, and large-scale data over time (Gomes da Silva et al., 2024); and it plays a crucial role in countries with limited coastal information sources. The aim of this study is to explore the use of satellite imagery to investigate shoreline evolution at three different locations in Mozambique: Morrungulo Beach, Barra Beach, and Tofo Beach in Inhambane Province. These three locations are characterized as exposed and mesotidal beaches and were selected as representative of the typical coastal archetype in the south coast of Mozambique. This study uses satellite imagery provided by Planet Labs, which is explored with the open-source code CoastSat.PlanetScope toolkit to map and analyze in detail shoreline changes in the study sites (Doherty et al., 2022). PlanetScope satellite imagery has a spatial resolution of approximately 3 meters and almost daily temporal resolution, allowing for detailed observation of shoreline features. For the automated extraction of the shoreline, CoastSat.PlanetScope takes into account the beach slope and tide to provide shoreline positions along user-defined transects, determined using a water index and pixel thresholding. The temporal scope of the satellite imagery utilized in this study extends from July 2016 to June 2024, using one image per month, offering a comprehensive dataset for examining monthly to multiannual shoreline dynamics. Shoreline positions have been evaluated using data total of 101 shorelines for Barra Beach, 94 shorelines for Morrungulo Beach, and 108 shorelines for Tofo Beach. Through this analysis, it was also possible to determine the shoreline impacts of tropical cyclones that made landfall in the region. Barra Beach revealed a strong erosion rate of 3.7 m/year as calculated using the End Point Rate (EPR) method, which measures the net shoreline change over time, and a moderate erosion rate of 0.5 m/year based on the Linear Regression (LR) method, suggesting relative stability in shoreline position when more shoreline positions are considered. Morrungulo Beach presented an accretion rate of 1.7 m/yr based on EPR, but evidenced an erosion rate of 0.4 m/yr with LR. Tofo Beach presented more consistent erosion, with a rate of 1.8 m/yr for EPR and 0.7 m/yr for LR. The analysis of shoreline changes across the three selected beaches in Mozambique highlights distinct patterns of erosion and accretion over the study period. Barra Beach demonstrated considerable differences in erosion rate according to the method, while Morrungulo Beach exhibited a mix of accretion and minor erosion, depending on the analysis method used. Conversely, Tofo Beach showed consistent erosion. These findings highlight the need to carefully consider shoreline change metrics, selecting those that better represent the coastal processes of interest to ensure site-specific management strategies along Mozambique’s coastline. This study has been funded by DOORS project (H2020 – 101000518 – DOORS), and co-funded by the FI AGAUR grant (2022 FI_B 00897).

Flooding in the Manhaua neighborhood is caused by changes in the hydrological cycle, topography, soil impermeabilization, and inadequate land use. These floods have economic, social, and public health impacts. Sustainable Urban Drainage Systems (SUDS) are alternatives that aim to increase the infiltration of rainwater into the soil and control surface runoff to minimize this problem. The objective of this study was to develop an improvement plan for the current rainwater drainage system in the Manhaua neighborhood in Quelimane city. To achieve the proposed objectives, interviews were conducted with the local community and the Quelimane City Council to characterize the drainage system and identify the related issues of rainwater. A mapping of flood-prone areas was also carried out using the Analytic Hierarchy Process (AHP) and the development of a mathematical model with weightings of influencing factors, through the ArcGIS Software. As a result, possible solutions were proposed, involving both structural and non-structural measures throughout the study area, such as permeable pavements, detention basins, and tree planting. It is concluded that the application of SUDS represents an evolution in drainage systems, not replacing conventional systems but complementing and improving the existing ones.

This study examines the potential of implementing a systematic approach to piloting desalination plants, with the objective of evaluating energy improvements in water desalination processes. The introduction of new reverse osmosis membranes is imperative at the small-scale level. The findings can be extrapolated to inform the operation of large-scale desalination plants. The objective of this approach is to achieve the optimal water quality standard at the lowest possible cost. In this manner, pilot tests are being conducted prior to the determination of whether to alter the reverse osmosis membranes, as this represents a substantial investment. The objective of these tests is to minimise the risk of making an erroneous decision and to ensure optimal results in terms of energy consumption, operating costs and reduction of environmental impact, while complying with the requisite water quality standards. In this instance, the Pareto analysis is utilised to ascertain the two or three most significant causes whose treatment affects more than 80 % of the potential energy savings to be implemented. This article introduces a novel approach to studying a total of 180 desalination plants at the territorial level in the Canaries.

Water temperature is a critical environmental parameter that significantly influences fish metabolism. This study assessed the metabolism of florfenicol (FF) in tilapia (Oreochromis niloticus) at water temperatures typical of tropical and subtropical regions. Fish were treated with FF by oral administration of a dose of 10 mg kg-1 bw for 10 consecutive days. Fish fillet, liver, and kidney were sampled during the treatment phase (1, 5, and 10 days) and posttreatment (1, 2, 3, and 5 days after the last FF administration). FF, florfenicol amine (FFA), monochloro florfenicol (FFCl), and florfenicol alcohol (FFOH) were determined in the sampled tissues using a validated LC-LC-MS/MS method. The highest FF, FFA, and FFOH concentrations were determined on day 5 during the treatment phase. For FF, the concentration order is kidney > liver > fillet, while for the metabolites FFOH and FFA, the order is liver > kidney > fillet. In fillet and liver, the concentrations of FFOH were higher than the FFA concentrations, indicating that FFOH was the primary metabolite in these tissues. FFCl was only quantified at concentrations lower than 90 μg kg-1 in all tissues. The results indicated that FF can be readily absorbed and rapidly eliminated in tilapia cultivated in warm water environments. This study revealed FFOH as the primary and most persistent metabolite in tilapia farmed in warm water, followed by FFA.

Rice consumption, particularly of highly processed white rice (WR), has been associated with increased risk of insulin resistance (IR). This study aimed to compare the impact of consuming WR versus brown rice (BR) from five common local rice varieties in Nigeria on the development of IR using a Wistar albino rat model. Five local rice cultivars (Jamila, Kwandala, MBC, Yarkatabore, Farar jalof) were collected, with one set kept unpolished (BR) and the other polished (WR). Proximate analysis and quantification of bioactive compounds (total phenols, flavonoids) were performed. Wistar albino rats were fed either a normal diet, high-fat diet, or diets containing 100% BR or WR for 12 weeks. Body weight, fasting blood glucose, glycogen, triglycerides were assessed. BR varieties had higher protein, fiber, and carbohydrate content compared to WR. BR also exhibited significantly greater total phenolic and flavonoid contents. Rats fed BR showed no significant weight gain (p<0.05), while some WR groups gained weight. Fasting blood glucose was elevated in WR groups versus control and BR groups. Blood glycogen was lower, and triglycerides higher, in certain WR groups. Consumption of BR varieties may confer protective effects against IR compared to WR in this rat model. These findings highlight the potential metabolic health benefits of incorporating local BR varieties into the diet to mitigate development of chronic disorders.

Grande parte dos compostos oriundos das plantas medicinais são sensíveis aos processos de secagem. Dessa forma, é importante a adequação das condições de secagem, como temperatura e velocidade do ar, visando um processo eficiente, e que não influencie negativamente a qualidade do produto. Assim, objetivou-se avaliar o efeito de diferentes sistemas de secagem sobre a cor e os compostos das folhas de B. forficata e P. aduncum. Realizou-se a secagem nas temperaturas de 40, 50 e 60°C em leito fixo e fluidizado. Avaliou-se a cor das folhas frescas e secas, posteriormente feita a extração dos compostos, com etanol. O estudo foi conduzido seguindo um delineamento inteiramente casualizado em esquema fatorial 3 × 2 e quatro repetições. Conclui-se que a condição de 60°C em ambos os sistemas de secagem e 40°C em leito fluidizado resultou em maiores concentrações dos compostos oriundos das folhas de B. forficata. Enquanto para os extratos de P. aduncum, as maiores concentrações dos compostos foram na temperatura de 60°C em ambos os sistemas de secagem, e 50°C em leito fixo. Após a secagem, as folhas de B. forficata ficaram mais esverdeadas, amarelas, e claras, e apresentaram cores mais intensas, porém com menor tonalidade. Já as folhas de P. aduncum ficaram mais avermelhadas, azuis e escuras, expondo cores menos intensas, porém com maior tonalidade.