This study aims to assess the impact of climate change on the water resources of the Upper Blue Nile basin using an integrated climate and hydrological model. The impact of climate change on water resources is being assessed using the regional climate model (RCM) under the representative concentration pathway (RCP4.5 and RCP8.5) scenarios and the Soil and Water Assessment Tool (SWAT) hydrological model. Future climate scenarios have been developed for the 2030s (2021–2040) and the 2050s (2041–2060). The study found that the projected rainfall shows a decreasing trend and is not statistically significant, while the temperature shows an increasing trend and is statistically significant. Due to the sharp rise in temperature, the annual evapotranspiration increased by about 10.4%. This and the declining trend of rainfall will reduce streamflow up to 54%, surface runoff up to 31%, and water yield up to 31%. Climate change causes seasonal and annual fluctuations in the water balance components. However, the projected seasonal changes are much greater than the annual changes. Therefore, the results of this study will be useful to basin planners, policymakers, and water resources managers in developing adaptation strategies to offset the adverse effects of climate change in the Upper Blue Nile basin.

Air pollution is recognized as the most important environmental factor that adversely affects human and societal wellbeing. Due to rapid urbanization, air pollution levels are increasing in the Sub-Saharan region, but there is a shortage of air pollution monitoring. Hence, exposure data to use as a base for exposure modelling and health effect assessments is also lacking. In this study, low-cost sensors were used to assess PM2.5 (particulate matter) levels in the city of Adama, Ethiopia. The measurements were conducted during two separate 1-week periods. The measurements were used to develop a land-use regression (LUR) model. The developed LUR model explained 33.4% of the variance in the concentrations of PM2.5. Two predictor variables were included in the final model, of which both were related to emissions from traffic sources. Some concern regarding influential observations remained in the final model. Long-term PM2.5 and wind direction data were obtained from the city’s meteorological station, which should be used to validate the representativeness of our sensor measurements. The PM2.5 long-term data were however not reliable. Means of obtaining good reference data combined with longer sensor measurements would be a good way forward to develop a stronger LUR model which, together with improved knowledge, can be applied towards improving the quality of health. A health impact assessment, based on the mean level of PM2.5 (23 µg/m³), presented the attributable burden of disease and showed the importance of addressing causes of these high ambient levels in the area.

Exposure to lead (Pb) through drinking water has been linked to adverse health outcomes. Children are particularly susceptible. This study was designed to measure Pb contamination level in drinking water of the Ethiopian city Addis Ababa and assess the associated health risks. Eighty-eight fully-flushed drinking water samples were collected from all ten sub-cities of Addis Ababa. Pb concentration was measured using an Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The chronic daily intake (CDI), the hazard quotient (HQ), and the cancer risk (CR) of Pb were determined to assess exposure levels and health effects. Blood lead level (B–Pb) for children was modelled using the integrated exposure uptake biokinetic model (IEUBK). The mean concentration of Pb in the drinking water was 17.8 μg/l, where >50% of the samples exceeded WHO's 10 μg/l guideline. Significant spatial variation of Pb was noticed among sub-cities. The mean CDI was 1.43 and 0.59 μg/kg/day for children and adults, respectively. The HQ showed that 8% of children and 2.3% of adults exceeded the safe limit. The predicted geometric mean of B–Pb ranged from 3.23 to 14.65 μg/dl. The risk of a child having a B–Pb level >5 μg/dl at the median water Pb concentration (10.5 μg/l) was estimated at 13.4%. Based on the 95^th percentile Pb concentration (75.1 μg/l), 89.6% of children would have B–Pb levels above the 5 μg/dl threshold. The estimated CR was found in the range of 1 × 10⁻⁷ to 9.9 × 10⁻⁵; hence cancer risks are not a concern. The study concluded that Addis Ababa's drinking water is likely to be a source of lead exposure where consumers at specific city locations are at risk of numerous non-cancer health effects. The impacts are expected to be severe in the Ethiopian context; hence further investigations and coordinated interventions are required.

Air pollution causes premature mortality and morbidity globally, but these adverse health effects occur over proportionately in low- and middle-income countries. Lack of both air pollution data and knowledge of its spatial distribution in African countries have been suggested to lead to an underestimation of health effects from air pollution. This study aims to measure nitrogen oxides (NO_x), as well as nitrogen dioxide (NO₂), to develop Land Use Regression (LUR) models in the city of Adama, Ethiopia. NO_x and NO₂ was measured at over 40 sites during six days in both the wet and dry seasons. Throughout the city, measured mean levels of NO_x and NO₂ were 29.0 µg/m³ and 13.1 µg/m³, respectively. The developed LUR models explained 68% of the NO_x variances and 75% of the NO₂. Both models included similar geographical predictor variables (related to roads, industries, and transportation administration areas) as those included in prior LUR models. The models were validated by using leave-one-out cross-validation and tested for spatial autocorrelation and multicollinearity. The performance of the models was good, and they are feasible to use to predict variance in annual average NO_x and NO₂ concentrations. The models developed will be used in future epidemiological and health impact assessment studies. Such studies may potentially support mitigation action and improve public health.

The Koka hydropower dam is one of the oldest large dams in Ethiopia. Damming is one of the anthropogenic activities impacting the distribution of aquatic life forms. However, to date, little attention has been focused on the dam’s impacts on the river macroinvertebrate assemblages in Ethiopia. The objective of this study was, therefore, to assess the impacts of the Koka hydropower dam on macroinvertebrate assemblages in the Awash River basin in Ethiopia. In the three river reaches on the Awash River (upstream near the source of the river, midstream above the dam, and downstream below the dam), a total of 15 sites were selected for sampling. The statistical analysis tested the null hypothesis that there are no differences in macroinvertebrate assemblage patterns or a range of univariate metrics between the three river reaches. Additional analyses involved the identification of taxa responsible for significant differences in macroinvertebrate structure (e.g., percentage similarity) and an exploration of the variables that structure macroinvertebrates (e.g., canonical correspondence analysis). In the upstream, midstream, and downstream reaches of the Awash River, we recorded a total of 73 taxa belonging to 43 families and 12 orders. Trichoptera was the dominant order in the upstream river reach, whereas Diptera dominated the midstream and downstream river reaches. The diversity of macroinvertebrates decreased from upstream to midstream and downstream. The three river reaches differed significantly in Shannon and Simpson diversity indices, % EPT, EPT taxa abundance, total taxa richness, evenness index, % collectors, and % scrapers. In this study, we observed that macroinvertebrate assemblage differences and spatial patterns were significantly associated with values of river flow changes (velocity), phosphate concentration, and substrate index. The findings of this study have broad implications for the assessment of the impacts of dam construction on the rivers of the studied region in the future.

: Fluoride toxicity has become a global public health concern, and its significant source of exposure is drinking water. This study aimed to determine groundwater fluoride level and assess its related human health risks. Its level was measured from groundwater samples using an ion-selective electrode. The total hazard index was assessed based on the chronic daily oral intake and dermal absorbed dose of groundwater fluoride. Analyses were conducted using ArcGIS and SPSS. This study reported groundwater fluoride ranged from 0.3 mg/L to 38 mg/L, with a mean annual level of 15 mg/L. Groundwater fluoride level above 5 mg/L was reported in 60 % of the water samples. Total hazard index values among sampled locations varied from 0.18 to 22.56. Half (51.5 %) of infants, 85.5 % of children, 82.5 % of adolescents, and 67.5 % of adults had a risk of developing a non-carcinogenic health effect. This study demonstrated that the fluoride level of the groundwater sources was high, and the water was not suitable for drinking, a result that is of special importance for children and adults since they are a hypersensitive subgroup of the population.