Nile Research Articles

Fishery characteristics, population dynamics and the impacts of the invasive red swamp crayfish (Procambarus clarkii) in the Nile River, Egypt

Alien intrusive species are one of the extreme pressures on biodiversity for their rapid reproduction and adaptation to new environments. Crayfish Procambarus clarkii entered Egyptian freshwater ecosystems at the beginning of 1980's. After many years of negative effects of its introduction onto the Egyptian waters, it became one of the commercially important species. Population parameters of P. clarkii are estimated based on 1355 specimens collected from the Nile off El-Minya during 2019–2020. The isometric growth of the species under the study is confirmed according to the obtained b-value of length–weight relationship (LWR). Annual sex ratio (female : male) was in favour of females with an annual sex ratio 1.44 : 1. The values of growth coefficient (K) and the asymptotic total length (L∞) were assessed for males, females and combined sexes. Using mortality estimates, the exploitation ratio was 0.64 year–1. Investigation of relative yield per recruit (Y'/R) and analysis of relative biomass per recruit (B'/R) for P. clarkii in the Nile off El-Minya provides the highest (Y'/R) at Emax = 0.81 and the E0.5 (utilisation level that preserves the spawner stock biomass at 50% of the virgin spawning biomass) was 0.38. From fisheries management point of view, the current exploitation level should be decreased to that maintain the spawning stock biomass (from 0.64 to 0.38).

Strain selection and adaptation of a fungal-yeast-microalgae consortium for sustainable bioethanol production and wastewater treatment from livestock wastewater

This study explores the potential of strain selection and adaptation for developing a fungi-yeast-microalgae consortium capable of integrated bioethanol production and livestock wastewater treatment. We employed a multi-stage approach involving isolation and strain selection/adaptation of these consortiums. The study started with screening some isolated fungi to grow on the cellulosic biomass of the livestock wastewater (saccharification) followed by a fermentation process using yeast for bioethanol production. The results revealed that Penicillium chrysogenum (Cla) and Saccharomyces cerevisiae (Sc) produced a remarkable 99.32 ppm of bioethanol and a concentration of glucose measuring 0.56 mg ml− 1. Following the impact of fungi and yeast, we diluted the livestock wastewater using distilled water and subsequently inoculated Nile River microalgae into the wastewater. The findings demonstrated that Chlorella vulgaris emerged as the dominant species in the microalgal community. Particularly, the growth rate reached its peak at a 5% organic load (0.105385), indicating that this concentration provided the most favorable conditions for the flourishing of microalgae. The results demonstrated the effectiveness of the microalgal treatment in removing the remaining nutrients and organic load, achieving a 92.5% reduction in ammonia, a 94.1% reduction in nitrate, and complete removal of phosphate (100%). The algal treatment also showed remarkable reductions in COD (96.5%) and BOD (96.1%). These findings underscore the potential of fungi, yeast, and Nile River microalgae in the growth and impact on livestock wastewater, with the additional benefit of bioethanol production.Graphical abstract

Description of Pegethrix niliensis sp. nov., a Novel Cyanobacterium from the Nile River Basin, Egypt: A Polyphasic Analysis and Comparative Study of Related Genera in the Oculatellales Order.

In this paper, we examine the filamentous cyanobacterial strain NILCB16 and describe it as a new species within the genus Pegethrix. The original population was sampled from a mat growing in an irrigation canal in the Nile River, Egypt. Initially classified under Plectonema or Planktolyngbya, the strain is a potential producer of the toxins microcystin and β-N-Methylamino-L-Alanine (BMAA). Additionally, we reviewed the taxonomic relationships between the Oculatellales genera. To describe the new species, we conducted a polyphasic study, encompassing 16S rRNA gene phylogenetic analyses performed using both Maximum Likelihood and Bayesian methods, sequence identity (p-distance) analysis, 16S-23S ITS secondary structures, and morphological and habitat comparisons. The phylogenetic analysis revealed that strain NILCB16 clustered within the Pegethrix clade with strong phylogenetic support, but in a distinct position from other species in the genus. The strain shared a maximum 16S rRNA gene identity of 97.3% with P. qiandaoensis and 96.1% with the type species, P. bostrychoides. Morphologically, NILCB16 can be differentiated from other species in the genus by its lack of false branching. Our phylogenetic analyses also show that Pegethrix, Cartusia, Elainella, and Maricoleus are clustered with strong phylogenetic support. They exhibit high 16S rRNA gene identity and are morphologically indistinguishable, suggesting they could potentially be merged into a single genus in the future.

Assessing the influences of future water development projects in Tekeze-Atbara-Setit basin on the Nile River inflow at Aswan, Egypt

Study regionThe Tekeze-Atbara-Setit (TAS) basin as a portion of the Eastern Nile Basin (ENB) in Africa. Study focusENB consists of four sub-basins; one of them is the Tekeze-Atbara-Setit basin. TAS basin is subject to future water development projects, including irrigation projects and hydropower dams. Potential impacts of these projects need to be assessed regarding the inflow and hydroelectric generation at Egypt's High Aswan Dam (HAD). New hydrological insights for the regionTwo models are coupled offline; The Soil Water Assessment Tool (SWAT) model and HEC-Reservoir Simulation Model (HEC-ResSim). Base-case scenario is created without the expected future projects, in addition to five additional scenarios representing hydropower and irrigation projects. The maximum annual inflow at HAD declines by 1.6 km3 in the hydropower scenarios, while the produced power at HAD descends by 9.5 %. The maximum reduction in the annual inflow for hydropower and irrigation projects scenario at HAD is 4.63 km3 and 35.2 % for power reduction. Finally, the proposed future development project in TAS basin will have negative impacts on the flow, and generated hydropower at HAD in Egypt.

Wintering waterbird community responses to anthropogenic land cover at multiple spatial scales along the Nile in Egypt

The human population is growing rapidly, increasing pressure on natural habitats. Suitable habitats for resident and migratory waterbirds are, therefore, more threatened. This study analyses how the presence of anthropogenic land cover (urban area and cropland) at multiple spatial scales affects the community composition of waterbirds along the Nile in Egypt. We analysed data collected during the international waterbird census, 2017–2018, combined with data from satellite images on land cover from the same period. The census covered 970 km, compromising 194 transects of 5 km along the River Nile, Egypt. The area includes a broad gradient of human disturbance, making this dataset ideal for assessing effects of anthropogenic land cover on waterbird community composition. We tested whether the waterbird community indices (abundance, species richness, diversity and evenness) and guild composition were associated with urban area and cropland, and other land covers (e.g. grassland, wetland) at spatial scales of 100, 500, 1000 and 5000 m. We recorded over 96000 waterbirds and show that landscape characteristics at larger spatial scales (5000 m) explained more of the species and guilds' presence than smaller scales. Species richness increased with increasing water surface area of the river within the transect and decreased with increasing urban area. Waders were negatively associated with urban area. Overall, the guilds' composition was poorly predicted by anthropogenic land cover and other landscape compositions, probably because species within a guild do not react similarly to increasing human disturbance. The probability of observing red‐listed species decreased with increasing urban area. With this study, we expand on the existing evidence by showing that species richness negatively correlates with anthropogenic pressure, and we highlight the importance of studying the responses of species rather than guilds. Our study shows the relevance of considering the landscape at larger scales (5000 m) while planning for conservation measures.

Spatial variation in physicochemical water quality parameters associated with Rice farming in the Dakalt Branch Canal, Kafrelsheikh governorate, Egypt

AbstractThe inappropriate use of chemical fertilizers and pesticides in rice farming has been identified as a significant source of pollution in the aquatic environments. The declining water quality has been a cause of concern for the riparian communities owing to ill health associated with the usage of contaminated water from lotic systems draining such rice‐growing areas and its potential to cause lethal and sublethal effects on aquatic organisms. The spatial variation of selected water quality parameters was assessed using multivariate techniques. Data from three sampling stations, collected in triplicates, were analyzed to understand the effects of rice farming practices on the Dakalt Branch Canal's water quality. Eleven physicochemical parameters were measured in situ with a portable multimeter, while nutrients and other chemical parameters were determined following the standard procedures outlined in the American Public Health Association using the UV/Visible spectrophotometer. One‐way ANOVA was used to establish whether or not there were significant differences among means of various parameters. The findings revealed considerable spatial variability in the means for nearly all water quality parameters (p < 0.05). The Water Quality Index revealed that all the sampling stations were polluted with indices of more than 100. We conclude that poor rice management practices are responsible for the observed pollution of the River Nile and potentially lethal and sublethal effects on aquatic organisms and human health. We therefore recommend regular monitoring of the water quality of the Dakalt Branch Canal and that the relevant stakeholders, including farmers, embrace Best Management Practices, especially when applying pesticides and fertilizers.

Evidence of palaeoenvironmental and climatic changes from the interpreted radar wave pictures of near surface sediments around the River Nile, Assiut, Egypt

Different palaeoenvironmental features that pose natural geological, environmental, and engineering hazards to human operations occur frequently around the Nile Valley. Moreover, where these features were initially created, their relevance focuses on how the urban communities responded to the processes. So, a ground penetrating radar (GPR) field survey was carried out on different paleoenvironments of Pre-Quaternary and Quaternary sediment around Assiut. Deep and critical analyses of georadar facies were made to obtain clear images of these features with unprecedented resolution. The main objective of this study is to find some reasonable geological interpretations for these features. From this study, it is possible to identify and differentiate these features originating from different geological environments and climatological conditions in arid regions such as those around Assiut. In addition, the study serves as guidelines for environmental management and climatic changes for enhancing knowledge of urban development. Also, the study demonstrates how georadar can be used to create precise images of intricate shallow subsurface anatomy with possible palaeoenvironmental and palaeoclimatic indicators.

Evaluation of Praziquantel effectiveness in treating Nile tilapia clinostomid infections and its relationships to fish health and water quality

This study aimed to conduct a multidisciplinary investigation integrating detailed morphology, molecular characterization, water parameters, histopathology alteration, and the trials of treatment of Clinostomum spp. In this study, 300 Nile tilapia (Oreochromis niloticus) were collected from the farmed and wild Nile River at Al Bahr Al Aazam, Giza Governorate to assess Clinostomid infection prevalence. Fish and water samples were collected from private fish farms, and water drains at Dakahlia, and Giza, Egypt. Analysis of the water revealed inadequate water quality, particularly in the fish farms. Snails and piscivorous birds were abundant at fish collection sites. The recovered Clinostomid MCs morphological characteristics and COI gene sequence analysis identified them as Clinostomum complanatum, C. phalacrocoracis, and Euclinostomum heterostomum. Clinostomid MCs disturbed the fish’s hematological and biochemical blood parameters. Bath treatment of parasitized fish with praziquantel (2 mg/L for 24 h) revealed a significant reduction in the number of vital MCs vs. infected fish (non-treated). Praziquantel (PZQ) is an effective and safe therapy for controlling Clinostomid infections affecting farmed Nile tilapia. The current findings indicate a link between poor environmental conditions and Clinostomum infections in tilapia. The study highlights the impacts of Clinostomid MCs on fish health and recommends bath treatment with PZQ as an efficient control method for these dangerous parasites to protect human and fish health.

Experimental study based on the usage of polymers for greywater treatment

Water scarcity presents a pressing challenge in Egypt, exacerbated by factors such as population growth, urbanization, and climate change impacts. With over 95% reliance on the Nile River for freshwater supply, Egypt's water resources are strained, particularly with a population exceeding 100 million. Egypt's arid climate intensifies water scarcity, necessitating sustainable management strategies. This study explored greywater treatment as a solution to alleviate water scarcity in Egypt, investigating its technical feasibility, economic viability, and environmental benefits. Greywater, derived from domestic activities, is an underutilized resource that can be reclaimed and treated for reuse, reducing demand for freshwater sources. Through greywater treatment systems, households and communities can recycle water, conserve resources, and mitigate pollution. The study investigated using polymers as a coagulant in greywater treatment, examining its efficacy in removing contaminants and improving water quality. Experimental trials were conducted to evaluate the performance of polymer addition in greywater treatment compared to conventional methods. Results demonstrate that polymer addition reduces turbidity, suspended solids, and organic pollutants in greywater. Poly aluminum chloride (PAC) polymer, in particular, exhibits strong coagulation capabilities, versatility across pH ranges, and high efficiency in contaminant removal. Additionally, PAC offers operational advantages such as low dosage requirements and reduced sludge production.

Rodents of Bahir Dar Blue Nile River Millennium Park, Ethiopia.

Rodents are mammals of the order Rodentia, which are found in all continents except Antarctica. They are the most diverse groups of mammals representing 41% of all mammals and they are known with 33 families, 481 genera, and about 2277 species. The present study was conducted from December 2018 to August 2019 both during the dry and wet seasons using Sherman traps and live traps. Four trap sites namely forest, bushland, grassland, and sugarcane plantation were selected for data collection. Shannon-Wiener diversity index (H') was used to compute rodent species diversity, Simpson's index (D) to assess the number and abundance of rodents in the different habitats, and one-way ANOVA and independent samples t-test were used for data analysis. A total of 163 individual rodents were captured in 1776 trap nights of which 125 individuals were captured using live traps in 1176 trap nights and 38 individuals using snap traps in 600 trap nights. Among the total individual rodents captured in the Bahir Dar Blue Nile River Millennium Park, 63.8% (n = 104) were males and 36.2% (n = 59) were females. Males outnumbered females in all the grids and the difference was significant (t = 31.5, df = 10, p < 0.05). The relative abundance of rodent species indicated that 42.4% (n = 53) were Arvicanthis niloticus, 26.4% (n = 33) Rattus rattus, 17.6% (n = 22) Mus musculus, 8% (n = 10) Mastomys natalensis, and 5.6% (n = 7) Arvicanthis abyssinicus. There are more individual specimens of A. niloticus than other species identified in the area (F = 698.22, df = 4, p < 0.05). Distribution of rodents varied among the different habitats. As a result, the bushland habitat showed more diversity of rodents (H = 0.98) and comprised relatively the highest (51.2%, n = 64) number of individuals captured, while the forest habitat supported the lowest number of rodents (4%, n = 5), and the difference showed a significant difference (F = 873.37, df = 3, p < 0.05). Population density with 95% confident interval estimated as 166 individuals/ha (95% CI:164.43-167.57). The present study provides basic information about population dynamics of rodents and contributes to design conservation strategies for rodents in particular and other biota of the area in general.

Basement Depth Map Estimation and Linear Features Detection Depending on Interpretation of Magnetic Data at Qarun Oil Field and Surrounding Areas, North Western Desert, Egypt

This investigation primarily targets a specific area situated in the northeastern Western Desert and northwest Beni-Suef, covering Wadi Al Rayan area, Gindi basin, Kattaniya inversion, and El-Fayum depression. It extends to the east of the river Nile. This study aims to Evaluate the depth of the basement complex in the area under investigation. The total aeromagnetic intensity data was reduced to the north pole (RTP) for clarity. 2D modeling of this RTP data was then used to evaluate the basement depth. The analysis of basement depth maps revealed significant variations in the subsurface structure of the study area, showing both elevated features (horsts) and depressed areas (grabens). The elevated basement (horsts) was found to be at a depth of approximately 813 meters, while the deepest depression (grabens) reached down to 7600 meters. Based on magnetic data combined with eight wells drilled into the basement complex, a basement lineament map of the area is delineated as a result of the investigation. This map shows a series of large alternating highs and valleys in ENE-WSW, NE-SW and E-W trending bands. Together with other minor trends, these major trends have shaped the basement surface into several tilted fault blocks, creating anticlinal and syncline zones of different depths and directions to form the Qattrani-El Gindi low trends. Whereas the high trend is located in El Fayum, El-Sagha, and Abu Rawash areas. The study helped to re-evaluate the subsurface structures affecting the Qarun oil field's hydrocarbon accumulation.

Characterization of recharge sources of the Miocene Fluvial Moghra aquifer in the North Western Desert of Egypt

Study regionThe Miocene Fluvial Moghra Aquifer in the North Western Desert of Egypt Study focusThe study integrates stable isotope analyses with aeromagnetic and hydrogeological datasets to accomplish the following: (1) define the primary source(s) of recharge to the Moghra aquifer, (2) assess aquifer connectivity with the Nile River aquifer, and (3) investigate the vertical connectivity of the Moghra aquifer with the underlying Nubian Aquifer System (NAS) through subvertical faults. New hydrological insights for the regionThe findings reveal (1) significant heterogeneity in groundwater isotopic compositions (Group A: δ18O: 1.1–13.8 ‰; δD: 4.6–73.5 ‰, B: δ18O:−0.99 to 0.85; δD: −7.58 to 4.38 ‰; and C: δ18O:−1.1 to −3.4; δD: − 6.3 to −18.2 ‰) indicative of variability in recharge sources. (2) Groundwater compositions west (up to 30 km) of the Nile River (Group A) resemble enriched modern Nile waters following the Aswan High Dam (AHD) construction that give way further west to relatively depleted groundwater (Group B) resembling historical pre-AHD Nile water compositions. (3) Further west from Group B depleted Group C samples occur along intersections of multiple fault systems (NW and NE-oriented faults) interpreted as mixtures of rising highly-depleted paleo Nubian Aquifer System (NAS) waters and pre-AHD Nile waters. (4) The advocated structural control is reported in similar settings in Egypt, suggesting that intersections of multiple fault systems provide regional connections between deep and shallow aquifers in northeast Africa, recharge overlying shallow aquifers, and should be considered in groundwater management scenarios.

Assessment of trace element occurrence in Nile Tilapia from the Rosetta branch of the River Nile, Egypt: Implications for human health risk via lifetime consumption

River pollution can harm human health through direct contact, drinking water, and the consumption of contaminated fish and irrigated agricultural products. Surface water and Nile tilapia (Oreochromis niloticus) samples were collected monthly from July 2022 to June 2023 at three sites (El-Rahawy, Sabal, and Tala) along the Rosetta Nile branch in Egypt to monitor the presence of eight trace elements. The potential human health risks from consuming contaminated fish were also assessed. Iron and manganese were consistently detected in all water samples across most seasons and locations, with concentrations generally below the WHO permissible levels. All 72 analyzed fish muscle samples were found to contain trace elements. The mean concentrations of metals in the fish muscle samples, in descending order, were: iron > zinc > copper > manganese > tin > antimony > lead > mercury. Significant spatial and seasonal variations were observed in both water and fish samples. El-Rahawy was identified as the most contaminated site, with summer exhibiting the highest contamination rate compared to other seasons. Fish samples collected from El-Rahawy demonstrated the highest bioconcentration factor (BCF) values for most elements, particularly mercury, lead, iron, manganese, and antimony. Target hazard quotient (THQ) calculations for the trace elements in Nile tilapia muscles revealed that all trace elements, except antimony, had THQ values below 1, suggesting that consuming Nile tilapia from these sites is unlikely to cause adverse health effects. However, THQ values for antimony exceeded the threshold of 1, indicating a potential health risk for consumers. Although the detected trace elements in the fish were below the permissible toxicity limits, some could pose a future threat to human health, necessitating further studies, ongoing monitoring, and preventive measures.

Assessment of monthly to daily streamflow disaggregation methods: A case study of the Nile River Basin

Study regionThe Nile River Basin Study focusThe lack of observed streamflow data at a short time scale poses a critical challenge for calibrating and validating hydrologic models. Therefore, many disaggregation methods were developed, resulting in various relative performances without a clear indication of the optimal choice. This study aims to iteratively assess eight monthly to daily streamflow disaggregation methods at 21 major subbasin outlets in the Nile River Basin (NRB) to identify the best-performing ones. These methods include one proportionality method and seven interpolation methods, i.e., linear, 2nd-order spline, 3rd-order spline, Piecewise Cubic Hermite Interpolating Polynomial (Pchip), Modified Akima (MAkima), mean preserved 2nd-order spline, and mean preserved 3rd-order spline. We assessed these methods using three metrics and visual investigations. New hydrologic insights for the regionThe results showed that the interpolation methods performed well, better than the proportionality method. However, their performances decreased at stations with high daily streamflow fluctuations. The interpolation methods’ performances were similar in mimicking the daily values but significantly different in preserving the mass balance. The mean preserving 3rd-order interpolation method (Lai 22) was the best in preserving the mass balance and capturing the low, moderate and high flows and, therefore, selected to generate the daily flow data in the NRB. The results of this study can guide a reliable method for obtaining daily streamflow data, which is important for the hydrologic and water management studies in the NRB.

Distribution and ecological health risk assessment of heavy metals in damietta branch of Nile River, Egypt

ABSTRACT The Nile River is one of the longest rivers in the world, serving as the lifeline of many countries. The river is subjected to significant anthropogenic pressures, and thus, understanding the magnitude of contamination and its possible consequences is needed. This research aimed to evaluate the presence of heavy metals in the surface water of an understudied region within the Nile River. The distribution and level of 18 elements along the Damietta branch were assessed, and their potential sources were estimated. Additionally, pollution indices and health risks were calculated. The results showed that most metals were within the acceptable levels of USEPA and WHO. However, Na, Mg, and Ca were higher than the permissible level of WHO, and K was higher than the permissible levels for irrigation. Furthermore, heavy metal pollution indicators, degree of contamination indices, heavy metal evaluation indices, Nemerow pollution indices, and water quality indices all pointed to very high standards for water quality. Also, the noncarcinogenic health risk index indicated a safe limit for dermal and oral exposure for adults and children. Overall, this study recommends management focus on anthropogenic activities in the Damietta branch of the Nile River.

Assessment of Water Quality, Bacteria, and Plankton Diversity at Thermal Pollution Sites along the River Nile, Egypt

Assessment of Water Quality, Bacteria, and Plankton Diversity at Thermal Pollution Sites along the River Nile, Egypt

The current situation of the floral components in reach one region of the Nile River: a comprehensive review

The current situation of the floral components in reach one region of the Nile River: a comprehensive review

Effect Of Nurses Long Working Hours On Patients’ Satisfaction At River Nile State Public Hospitals -Sudan

Background: The effect of long working hours on patient satisfaction is a critical issue in healthcare systems. Also, Extended working hours have the potential to compromise the quality of patient care. Objectives: this study was carried out to investigate the effect of nurses long working hours on patients’ satisfaction. Method: This was descriptive cross-sectional study was conducted during the period from August 2022 to August 2024 at the main three governmental hospitals of River Nile State-Sudan. The data was collected by questionnaire and Karen-patient satisfaction scale, one hundred patients participated in the study, data was analyzed by (SPSS) software program and presented in tables and figures, all data fixed or adjusted at level P- value less than (0.05). Results: The study results showed that less than two quarter (60.0%) of patients were male, with age less than half (40.0%) between 41-60 years. Also (27 %) of patients their education level did not exceed primary school. the results of this study revealed that more than two third (68.0%) they don’t have health insurance coverage. patient’s satisfaction with the quality of nursing care is very good. Conclusions: The study finding highlighted a significant gap in communication between nurses and patients, while patients reported high level of satisfaction with effective diagnosis and respectful treatment by staff. the study showed that no significant relationship between patient satisfaction levels and their demographic profiles

Comprehensive approach integrating water quality index and toxic element analysis for environmental and health risk assessment enhanced by simulation techniques

Due to water shortages and the potential impact of Ethiopia’s new dam on the Nile River, Egypt is seeking new water resources. This study assesses the drinking water quality and associated risks from potentially toxic elements (PTEs) in the Quaternary aquifer (QA) in Beni-Suef, Egypt. Using a comprehensive approach, including PHREEQC geochemical modeling, ionic ratios, multivariate statistical analyses, and the integrated weight water quality index (WQI), the study evaluated the sources of ion contamination and the mixing of Nile water with QA. Various indices, such as the Heavy Metal Pollution Index (HPI), ecological Risk Index (RI), Hazard Quotient (HQ), and Hazard Index (HI), were used to assess ecological and health risks. Monte Carlo simulations provided probabilistic assessments of non-carcinogenic risks for adults and children. GIS tools were used to map risk indices, identifying the most deteriorated locations for sustainable management. The hydrochemical analysis revealed water facies including Na–Cl, Ca–Mg–HCO3, and mixed types, influenced by carbonate dissolution, ion exchange, and silicate weathering. Contamination sources, particularly in the north and south, were linked to agricultural activities, irrigation return flow, municipal waste, and evaporation. The WQI indicated that 10.14% of samples were extremely poor, 21.7% were poor, 26% were medium, and 42% were good to excellent. PTE contamination varied, with HPI values indicating good water quality in the central area in 53.6% of the collected samples (HPI < 30), but contamination in the north and south is high (HPI > 51). Ecological Risk Index values were below the threshold in 100% of samples (RI < 30), confirming water safety regarding PTEs. In comparison, for hazard index (HI) through oral/ingestion, adults exhibited HI values ranging from 0.012 to 2.16, while children showed higher values, ranging from 0.045 to 8.25. However, the hazard index for oral/ingestion exceeded safe limits in the north and south (HI oral > 1), posing non-carcinogenic risks. Monte Carlo simulations revealed significant risks from oral exposure to manganese (HQ oral > 1), particularly in El-Wasta and El-Fashn, necessitating further treatment and management.

One third of African rivers fail to meet the ’good ambient water quality’ nutrient targets

The ambition of Sustainable Development Goal (SDG) target 6.3 is to improve global water quality by 2030. SDG indicator 6.3.2 monitors progress towards this target by assessing water bodies against ‘good’ ambient water quality criteria, with nutrients (nitrogen and phosphorus) as part of the key metrics. However, large data gaps present a fundamental challenge, especially for Africa on how to assess the progress being made with respect to both the current and desired future situations. Here, a continental water quality model for Africa is presented to simulate river sediment load, Total Nitrogen (TN) and Total Phosphorus (TP) loads and concentrations. Furthermore, critical areas and hotspots of TN and TP pollution are mapped for the period 2017 – 2019, in relation to the United Nations Environment Programme (UNEP) target thresholds used for the assessment of SDG indicator 6.3.2. Utilizing the UNEP’s criteria, which designates a water body as having “good ambient water quality” if 80% or more of its monitored values meet their targets, it is estimated that 44 % and 15 % of African rivers fail to meet the set water quality thresholds for simulated TP and TN, respectively. When synthesizing data for both TP and TN, 34 % of the rivers do not qualify as having “good ambient water quality”. Geographically, the most pronounced nutrient pollution hotspots were in North Africa, Niger River Delta, Nile River basin, Congo River basin and specific zones in Southern Africa. These areas correlate with regions characterized by high inputs of fertilizers, manure and wastewater discharge.