Studies on the conservation and sustainability challenges of the wetland resources of the Baro-Akobo River Basin in Gambella and Benishangul-Gumuz regions, Ethiopia.

In this study, the water quality of the Baro-Akobo River Basin in Ethiopia was comprehensively assessed. Key parameters including temperature (°C), pH, dissolved oxygen (DO), electrical conductivity, total dissolved solids (TDS), and ion concentrations such as K+, Ca2+, Na+, NO3 -, NO2 -, PO4 3-, CO3 2-, HCO3 -, and NH4 +were measured using standard methods, alongside sampling of phytoplankton, zooplankton, macroinvertebrates, macrophytes, and fish. Phytoplankton and zooplankton were sampled using Hydrobios nets with mesh sizes of 30 µm and 55 µm, respectively, while macroinvertebrates were collected via the kicking method. Results indicated generally alkaline pH levels and elevated turbidity, but acceptable levels of dissolved oxygen and ion concentrations according to WHO and FAO guidelines. Moreover, the study suggests that the wetlands in Gambella and Benishangul-Gumz regions are currently in good condition, providing valuable insights for the conservation and sustainable management of Ethiopia's water resources, ensuring their conservation for both present and future generations. Local authorities can use the study's findings to implement remedial measures to protect water quality and biodiversity in the regions.

Factors impacting water quality and quantity in rapidly expanding urban areas based on the DPSIR model: experiences and challenges from Addis Ababa City, Ethiopia.

Due to the increasing pressures of global change, such as urbanization, climate change, population growth, and socioeconomic changes, cities around the world are facing significant water challenges, both in terms of supply and quality. This emphasizes the need for concerted effort to manage water supplies effectively for sustainable development. The driver, pressure, state, impact, and response (DPSIR) model was applied in this study to determine the underlying causes of Addis Ababa's water supply and quality issues. Field observations, key informant interviews, and previously published reports were used to identify these variables, impacts, and coping mechanisms. The model suggests that issues with urban water are caused by inadequate waste management, fast urbanization, climate change, sociodemographic shifts, economic challenges, changes in land use and land cover, and institutional pressures. As a result, aquatic ecosystems endure damage and there is also an increase in water-related diseases and unmet water demand. Some of the responses to these effects include using bottled water, digging boreholes, harvesting rainwater, planting trees, and soliciting funds. The study concludes by recommending an integrated approach to managing the risks of declining water quality and shortage. This study will advance the important empirical understanding of how urban water supply and quality are impacted by environmental stresses on a global scale. It will also positively impact the development of sustainable water management policies and practices.

The Ripple Effect of Climate Change: Assessing the Impacts on Water Quality and Hydrology in Addis Ababa City (Akaki Catchment).

This research aimed to evaluate the effects of climate change on the hydrology and water quality in the Akaki catchment, which provides water to Addis Ababa, Ethiopia. This was performed using the soil and water assessment tool (SWAT) model and an ensemble of four global climate models under two Shared Socioeconomic Pathways (SSP) emission scenarios from Coupled Model Intercomparison Project Phase 6 (CMIP6). The climate data were downscaled and bias-corrected using the CMhyd tool and calibrated and validated using the SWAT-CUP software package. Change points and patterns in annual rainfall and temperature were determined using the homogeneity test and Mann-Kendell trend test. Water quality data were obtained from Addis Ababa Water and Sewerage Authority (AAWSA), and more samples were taken and analyzed in accordance with APHA recommended procedures. The SWAT model output was then used to assess the impacts of climate change on hydrological components and water quality. Rainfall increased by 19.39 mm/year under SSP2-4.5 and 12.8 mm/year under SSP8.5. Maximum temperature increased by 0.03°C/yr for SSP2-4.5 and 0.04°C/yr for SSP5-8.5. Minimum temperature increased by 0.03°C/yr under SSP2-4.5 and 0.07°C/yr under SSP5-8.5. This warming will augment the evapotranspiration rate which in turn will have a negative impact on the freshwater availability. Streamflow will increase by 5% under SSP2-4.5 and 9.49% under SSP5-85 which may increase sporadic flooding events. Climate change is expected to contribute to the deterioration of water quality shown by 61%, 36%, 79%, 115%, and 70% increased ammonia, chlorophyll-a, nitrite, nitrate, and phosphorus loadings, respectively, from 2022. The increase in temperature results in increases in nutrient loading and a decrease in dissolved oxygen. Overall, this research demonstrated the vulnerability of the catchment to climate change. The findings of this research can offer vital knowledge to policymakers on possible strategies for the sustainable management of water.

Implications of land use/land cover dynamics on urban water quality: Case of Addis Ababa city, Ethiopia.

Water resources are often at the center of urban development but, as the city expands, the environmental pressure on its water resources increases. Therefore, in this study, we looked into how various land uses and changes in land cover affect the water quality in Addis Ababa, Ethiopia. Land use and land cover change maps were generated from 1991 to 2021 at intervals of five years. On the basis of the weighted arithmetic water quality index approach, the water quality for the same years was likewise divided into five classes. The relationship between land use/land cover dynamics and water quality was then evaluated using correlations, multiple linear regressions, and principal component analysis. According to the computed water quality index, the water quality decreased from 65.34 in 1991 to 246.76 in 2021. The built-up area showed an increase of over 338%, whereas the amount of water decreased by over 61%. While barren land exhibited a negative correlation with nitrates, ammonia loadings, total alkalinity, and total hardness of the water, agriculture and built-up areas positively correlated with water quality parameters such as nutrient loading, turbidity, total alkalinity, and total hardness. A principal component analysis revealed that built up areas and changes in vegetated areas have the biggest impact on water quality. These findings suggest that land use and land cover modifications are involved in the deterioration of water quality around the city. This study will offer information that might help reduce the dangers to aquatic life in urbanized environments.

Isolation and identification of major bacteria from three Ethiopian rift valley lakes live and processed fish, and water samples: implications in sanitary system of fish products.

Bacterial pathogens are a great threat to fish production. Gram-negative bacteria are among the major bacterial fish pathogens and are zoonotic with the potential to infect humans. This cross-sectional study was conducted to isolate and identify major gram-negative bacteria from live and processed fish, and water samples from Lakes Hawassa, Langanoo and Ziway. A total of 674 different types of samples: 630 tissue samples (210 samples for each intestine, Kkidney and liver collected from 210 live fish (Oreochromis niloticus, Cyprinus carpio and Clarias gariepinus), 20 processed fish samples from lake Ziway fish processing center and 24 lake water samples were included in the study from each lake. The mean values of pH, temperature, dissolved oxygen and nitrate in all water samples were within the normal range at which most freshwater fish species become non-stressed. Of a total of 674 samples included in the study, bacteria were isolated from 154(22.8%) samples with significant difference (P < 0.05) observed in some isolates with respect to sample origin. Of these 154 isolates, 103(66.8%) isolates were gram-negative bacteria consisting of 15 species based on morphology and a range of biochemical tests. From live fish samples, Escherichia coli was the dominant species with 15 isolates followed by Edwardsiella tarda (12), Salmonella Paratyphi (10), Salmonella Typhi (9),  Shigella dysenteriae (7), Shigella flexneri (7), Klebsiella pneumonia (7), Enterobacter aerogenes (6), Enterobacter cloacae (5), Pseudomonas aeruginosa (5), Vibrio parahemolyticus (5), Aeromonas sobria (4), Citrobacter freundii (4), Citrobacter koseri (4) and Plesiomonas shigelloides (3). The detection of the common fecal coliforms (E. coli, K. pneumoniae and E. aerogenes) and Salmonella spp. in processed fish indicates the potential danger of passage of pathogenic bacteria and/or their poisons to humans via infected and/or contaminated fish products. Human infection by pathogenic fish bacteria and food poisoning is possible through contamination of fish product in fish production chain due to inadequate handling, poor hygiene and contact with contaminated water. Therefore, producers, consumers and all other stakeholders need to be cautious during handling, processing and consumption of fish harvested from the study lakes.

Assessment of spatio-temporal variations of selected water quality parameters of Lake Ziway, Ethiopia using multivariate techniques.

Excess agrochemicals input from agricultural activities and industrial effluent around Lake Ziway catchment can pose a serious threat on the lake ecosystem. Lake Ziway is a shallow freshwater lake found in the northern part of the Ethiopian Rift Valley. It is characterized as semi-arid to sub-humid type of climate. Expansions of the flower industry, widespread fisheries, intensive agricultural activities, fast population growth lead to deterioration of water quality and depletion of aquatic biota. The spatial and temporal variations of selected water quality parameters were evaluated using multivariate techniques. The data were collected from nine sampling stations during dry and wet seasonal basis for analysis of fifteen water quality parameters. The physicochemical parameters were measured in-situ with portable multimeter and nutrients were determined by following the standard procedures outlined in the American Public Health Association using UV/Visible spectrophotometer. Mean nutrient concentrations showed increasing trend in all seasons. These sites were also characterized by high electrical conductivity and total dissolved solid (TDS). All the nine sampling sites were categorized into three pollution levels according to their water quality features using cluster analysis (CA). Accordingly, sampling sites Fb and Ketar River (Kb) are highly and moderately polluted in both seasons, respectively. On the other hand, sampling sites at the center (C), Meki river mouth (Ma), Ketar river mouth (Ka), Meki River (Mb), Korekonch (Ko) and Fa in dry season and Ka, C, Ma, Ko, Bulbula river mouth (B) and Fa during wet season were less polluted. Principal component analysis (PCA) analysis also showed the pollutant sources were mainly from Fb during dry season Mb and Kb during wet season. The values of comprehensive pollution index illustrated the lake is moderately and slightly polluted in dry and wet seasons, respectively. Comparatively, the pollution status of the lake is high around floriculture effluent discharge site and at the two feeding rivers (Kb and Mb) due to increasing trends in agrochemical loads. In order to stop further deterioration of the lake water quality and to eventually restore the beneficial uses of the lake, management of agrochemicals in the lake catchments should be given urgent priority.

Community perceptions towards the impacts of ecotourism development in the central highlands of Ethiopia: the case of Lake Wanchi and its adjacent landscapes.

Scientific studies harmonizing biodiversity conservation, ecotourism development, and local livelihoods in areas of natural endowments have significant importance in the welfare of society. The objective of this study was to investigate the local community's perception of the impacts of the Wanchi Ecotourism Association (WETA) and test the relationship between these perceptions and some socio-demographic predictor variables. Data was collected using household surveys, focus group discussions, key informant interviews, field observations, and document analysis. Simple statistical analysis, such as descriptive statistics, cross-tabulations, multiple response sets, and chi-square tests were used to analyze the socio-demographic characteristics and opinions on ecotourism development. Multinomial logistic regression was used to analyze the local community's perceptions towards the impacts of ecotourism using socio-demographic variables as predictors of the community responsiveness. The non-quantifiable information was analyzed using qualitative descriptions. There was enough evidence for the high resident's support for ecotourism development and perceptions of its positive impacts, while there was limited community participation, less economic benefit, and inequitable sharing of the revenues generated from WETA. The examination in the distribution of observed and expected perception responses on the impacts of ecotourism showed statistically significant differences ( x 2 = 110.833, df = 3, P = 0.000). The multinomial logistic regression revealed that the variables of educational level, duration of stay in the study landscape, ecotourism benefit, and place of residence from the ecotourism attraction center have a significant association with respondents' perception toward impacts of ecotourism. The study supported the social exchange theory, in that those who benefited from ecotourism viewed it as a development preference, and so are more likely to have positive attitudes concerning ecotourism.

Assessment on the prevalence and risk factors of gastrointestinal parasites on schoolchildren at Bochesa Elementary School, around Lake Zwai, Ethiopia.

OBJECTIVES: This study was aimed to assess the prevalence and risk factors of gastrointestinal parasites on schoolchildren at Bochesa Elementary School around Lake Zwai, Ethiopia. Cross-sectional study was conducted on 384 schoolchildren in May 2016. The gastrointestinal parasites were examined with wet mount and formol-ether concentration techniques. Chi-square (χ2) test was used to evaluate the association between categorical variables and infection prevalence. Binary logistic regression on SPSS version 21 was used, values were considered significant when the p-value was less than 0.05. RESULTS: The overall prevalence of gastrointestinal parasites was 22.6%. Males, 54 (14.1%) were more infected than females, 32 (8.3%), and 1-4 grade category, 64 (16.7%) were more infected than 5-8 grade category, 22 (5.7%). Age groups of 7-14, 78 (20.3%) were also more infected than > 15, 8 (2.1%); however, the variation was not significant (p > 0.05). In this study, parasitic coinfection was common; however, single gastrointestinal parasites were more dominant. The overall rate of gastrointestinal parasites shows that the environmental conditions where students pass their times are conducive to water-related diseases. Health education on personal and environmental hygiene keeping should be given to schoolchildren and safe wetland playing grounds should be prepared.

Corrigendum to "Removal of chromium (VI) from aqueous solution using vesicular basalt: A potential low cost wastewater treatment system" [Heliyon 4(7) (July 2018), Article e00682].

[This corrects the article DOI: 10.1016/j.heliyon.2018.e00682.].

Removal of chromium (VI) from aqueous solution using vesicular basalt: A potential low cost wastewater treatment system.

In this study, vesicular basalt volcanic rock was taken and its application for adsorption of chromium (VI) from aqueous solution was investigated. Different physical and chemical properties of the powdered rock was studied using Fourier transform infrared spectroscopy (FT-IR), Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). A series of batch experiments were carried out to study the effect of various experimental parameters (pH, ionic strength and contact time) on chromium (VI) adsorption. It was found that the removal efficiency of chromium (VI) decreased with increasing pH and ionic strength. The adsorption process was optimal at pH 2. The maximum adsorption capacity was 79.20 mg kg-1 at an initial concentration of 5.0 mg L-1 and adsorbent dosage of 50 g L-1. In individual adsorption tests, Pseudo-second-order kinetic and Freundlich isotherm models could better describe chromium (VI) adsorption on the vesicular basalt. This study indicated that vesicular basalt, which is inexpensive, has the potential to remove chromium (VI) from polluted water.

Assessing the Potential for Rooftop Rainwater Harvesting from Large Public Institutions.

As in many other cities, urbanization coupled with population growth worsens the water supply problem of Addis Ababa, Ethiopia, with a water supply deficit of 41% in 2016. To investigate the potential contribution of rooftop rainwater harvesting (RWH) from large public institutions, 320 such institutions were selected and grouped into 11 categories, from which 25-30% representative 588 rooftops were digitalized and the potential RWH volume computed based on a ten-year rainfall dataset. When comparing the resulting RWH potential with the water consumption, up to 2.3% of the annual, potable water supply can be provided. If reused only within one's own institution, the self-sufficiency varies from 0.9 to 649%. Non-uniform rainfall patterns add uncertainty to these numbers, since the size of the storage tank becomes critical for coverage in the dry season from October to May. Despite the low replacement potential at the city level, RWH from large institutions will enable a significant volume of potable water to be transferred to localities critically suffering from water shortage. Further, large institutions may demonstrate how RWH can be practiced, thus acting as a frontrunner for the dissemination of RWH to other types of rooftops. To narrow the water supply gap, considering rooftop RWH as an alternative water supply source is recommended. However, the present study assumed that financial constraints to install large sized storage tanks are considered as a possible challenge. Thus, future research is needed to investigate the cost-benefit balance along with the invention of a cheap storage tank as they may affect the potential contribution of RWH from rooftops.