Growing trends in industrialization in Ethiopia have raised concerns about pollution of water bodies particularly of lakes. This study was therefore conducted to 1) characterize the chemical contents of major industri...Growing trends in industrialization in Ethiopia have raised concerns about pollution of water bodies particularly of lakes. This study was therefore conducted to 1) characterize the chemical contents of major industrial effluents (namely textile ceramic and soft drink factories) that reached Lake Hawassa and 2) investigate the effects of the above mentioned factory effluents on survival of larvae fish and growth of algae. Effluent samples were collected from the outlet lagoons of each factory in December, 2009. Then, effluent samples were analyzed for total N, NO3-N, NH4-N, S2-, , , COD, total dissolved solids (TDS) and heavy metals at the federal Environmental Protection Agency (EPA) Laboratory, Addis Ababa. The experiments on the impact of effluents on survival of fish larvae and growth of algae were conducted using six concrete paved ponds (with different concentration of effluent). The results of chemical analysis showed that textile effluent had high COD (nearly 3 times higher), TDS (19 times higher) as well as (39 times higher) than the maximum permissible limits (MPL) set by Environmental Protection Authority (EPA). Among heavy metals, Zn and Fe of textile effluent were much higher (41 and 1.5 times higher, respectively) than the MPL set by EPA. Ceramic effluent also contained high concentration of (24.5 times), S2-, (2 times) and Zn (14 times) exceeding the limit of EPA. Regarding soft drink factory, high values of COD, and Zn were found in the effluent than the limit specified by EPA. The biological treatment lagoons of the respective source were not effective since the effluents were taken from the last treatment lagoon (outlet lagoon) and some of the measured parameters were higher than MPL. Results of the pond experiment showed that 5%, 10% and 20% concentration levels of the HTF effluent killed significantly high proportion of the fry (65%, 86.8% and 88.7%, respectively). In contrast, fry mortality in ceramic and soft drink effluent treatments, even at 10 and 20% concentration levels, stayed nearly below 10%, which were not far off from the mortality of the control groups. Algal biomass in the treated ponds varied with the type of effluent treatment and concentration level. Compared with the first day, chlorophyll “a” concentration measured on the 7th day had increased by 51%, 48%, 74%, 27% and 31% at 0%, 1%, 5%, 10% and 20% concentrations, respectively of textile effluent. The 5% treatment level of textile effluent caused the highest rate of algal growth above the growth rate observed in the control pond, but further increased in concentration to 10% and 20% resulted in a lower growth of algae than in the control pond. Therefore, textile effluent may boost up algae growth at lower concentrations (~5%) but at higher concentration levels its toxic effect may become inhibitory. Regarding the effluent of soft drink factory, algal growth progressively diminished with increasing concentration of the effluent. The overall change (between initial and day 7) in chlorophyll “a” concentration was highest in the control pond (36.2%) and decreased with increasing effluent concentration (1% to 20%) from 21.7% to -9.4%. On the other hand, algal growth under ceramic effluent treatment was comparable with that observed in the control pond.展开更多
Quantifying the hydrologic response of land use/land cover change (LULCC) is of paramount importance to improve land management. This study was carried out to analyze the effect of LULCC on water quality and quantity....Quantifying the hydrologic response of land use/land cover change (LULCC) is of paramount importance to improve land management. This study was carried out to analyze the effect of LULCC on water quality and quantity. LULCC of the watershed in 1986, 1999 and 2011 was analyzed from Landsat satellite images using supervised classification. Time series and point data were collected from the upper and lower sections of Wedesa, Wesha and Hallo Rivers. Water quality parameters (turbidity, suspended solid (SS), total dissolved solid (TDS), pH, electric conductivity (EC), total organic carbon (TOC), ammonia, nitrate and phosphate) were analyzed in the laboratory. A considerable decline in forest and an increase in woodland were observed in the watershed during the indicated periods. Turbidity, SS, TDS and EC were significantly higher (P < 0.05) in the lower section of the rivers compared to the upper ones. Ammonia, nitrate and phosphate were higher in the lower section of some rivers compared to the upper ones. In general, water quality in the upper watershed of the three rivers was better than the lower one with respect to considered parameters, which might be related to the observed LULCC. Most water quality parameters varied (P < 0.05) seasonally in both the upper and lower sections of the rivers. Despite the irregular rainfall pattern and increased water consumption from the catchment, the annual discharge of the Tikur-Wuha River to Lake Hawassa shows an increasing trend. We concluded that the discharge is not only related to the upstream LULCC but also to the management of the Cheleleka wetland. However, further investigation is required to determine the dominant factors affecting inflow discharge to Lake Hawassa.展开更多
Urban green areas are essential elements of cities and contribute to the quality of life in numerous ways by maintaining and regulating the environment.However,increased urbanization and development have placed urban ...Urban green areas are essential elements of cities and contribute to the quality of life in numerous ways by maintaining and regulating the environment.However,increased urbanization and development have placed urban green areas under extreme pressure,while unplanned urban growth has resulted in the loss of urban landscape and ecosystem.This study’s objective was the public perception on the role of urban green infrastructure and land use management.The 385 sample households were selected by using random sampling method.Descriptive and econometric analyses were used for analyzing both quantitative and qualitative data by using SPSS version 25.Among the major factors influencing the urban green infrastructure by respondents perception were education,income,family size,sex of respondent,marital status,type of employment,ownership of house,participation on public involvement,and frequency of visit to nearer planning which are significant variables in the model.Individuals visited the given green structure at least twice a week,and those not done it were 47.9% and 52.1%.The amount of individuals who visited it twice a week in positive perceivers was 64%,and the amount of those who have not done it was 36%.The Chi-square value of 10.9 was very big and telling us that the frequency of visit was determinant factor of perception.It is vital to keep in mind that while the built-up area and the agricultural areas are rising due to urbanization,the core-ecosystem land is being“eaten”as a result of the past and present land uses inside the administrative limits,as well as the services they provide.In the last 6 years,the rate at which the most precious ecosystems are disappearing has tripled.The population,which reflects the demand for these services and benefits,is still growing,putting more strain on the environment.The recommendations include:Public involvement in urban green space planning and development was determinant and core variable of the study.The government of the town administration should prepare the meeting.The result showed a high correlation between urban green planning and land use changes.展开更多
Background:Diarrhoea is the leading cause of morbidity and mortality in children under 5 years of age in developing countries,including Ethiopia.It is caused by a wide range of pathogens,including parasites,bacteria a...Background:Diarrhoea is the leading cause of morbidity and mortality in children under 5 years of age in developing countries,including Ethiopia.It is caused by a wide range of pathogens,including parasites,bacteria and viruses.The aim of this study was to determine the prevalence of infection with intestinal parasites(IPs)(and types)among children under 5 years of age with diarrhoeal diseases.Methods:A cross-sectional study was conducted at Adare Hospital and Millennium Health Centre,both located in Hawassa,South Ethiopia,from June 6 to October 28,2011.Children under 5 years of age with diarrhoea who visited these health facilities during the study period were included in the study.Data relating to demography and risk factors associated with intestinal parasitic infections(IPIs)were gathered using a structured questionnaire.Single,fresh stool specimens were examined for IPs using the direct wet mount examination,followed by Ziehl-Neelsen staining of formol-ether concentrated samples,as per standard procedures.Data were analysed using SPSS Statistics 20 software.Results:A total of 158 children(51.3%male and 48.7%female)participated in the study.Overall,the prevalence of IPs was 26.6%(42/158).Two species of IPs were detected in six children(3.8%).Entamoeba histolytica/dispar/moshkovskii was the predominant parasite identified(11.4%),followed by Giardia duodenalis(7.0%).The multivariable analysis revealed that the age group≥24 months was significantly associated(AOR=0.221,95%CI:0.085–0.576)with prevalence of IPIs.Conclusion:This study found that intestinal parasites are common among children with diarrheal diseases.The most frequently detected species was E.histolytica/dispar/moshkovskii.Health information about how to prevent diarrheal diseases in general and IPIs in particular should be provided to parents of young children.展开更多
Bean(Phaseolus vulgaris)yields in Africa can be increased through the application of phosphorus and nitrogen fertilizers,as both nutrients are low in African soils.However,using greener technologies is preferred to mi...Bean(Phaseolus vulgaris)yields in Africa can be increased through the application of phosphorus and nitrogen fertilizers,as both nutrients are low in African soils.However,using greener technologies is preferred to mineral fertilizers for maintaining soil health.In this study,Rhizobium inoculation and moderate P supply(0,10,20,and 30 kg·ha^(-1))to two bean cultivars were evaluated in consecutive years at Hawassa for their effects on plant growth,nodulation,and grain yield.The results showed that,relative to the uninoculated control,the two bean cultivars responded strongly to Rhizobium inoculation,with strain HB-429 outperforming strain GT-9 in both 2012 and 2013.Shoot biomass,nodule number and nodule dry matter per plant were increased by 9%,40%,and 54%,respectively,in 2012,and by 20%,39%,and13%in 2013 with strain HB-429 inoculation.This resulted in increased pod number per plant,seed number per pod and grain yield by 56%,51%,and 49%in 2012,and by 38%,25%,and 69%in 2013,respectively,with strain HB-429inoculation.Bean inoculation with GT-9 also increased grain yield by 35%and68%in 2012 and 2013,respectively.Applying 10–30 kg·ha^(-1)P to bean cultivars increased shoot biomass,nodule number,and nodule dry matter per plant by7%to 39%,23%to 59%,and 59%to 144%in 2012,respectively,and by 10%to40%,21%to 43%,and 12%to 35%in 2013,respectively.Relative to the zero-P control,adding only 10 kg·ha^(-1)P increased pod number per plant,seed number per pod,and grain yield by 10%,30%,and 61%in 2012,and by 11%,11%,and 38%in 2013,respectively.The combined use of Rhizobium inoculation with low P application(20 kg·ha^(-1))was found to increase bean production in Ethiopia and is thus recommended to resource-poor farmers.展开更多
文摘Growing trends in industrialization in Ethiopia have raised concerns about pollution of water bodies particularly of lakes. This study was therefore conducted to 1) characterize the chemical contents of major industrial effluents (namely textile ceramic and soft drink factories) that reached Lake Hawassa and 2) investigate the effects of the above mentioned factory effluents on survival of larvae fish and growth of algae. Effluent samples were collected from the outlet lagoons of each factory in December, 2009. Then, effluent samples were analyzed for total N, NO3-N, NH4-N, S2-, , , COD, total dissolved solids (TDS) and heavy metals at the federal Environmental Protection Agency (EPA) Laboratory, Addis Ababa. The experiments on the impact of effluents on survival of fish larvae and growth of algae were conducted using six concrete paved ponds (with different concentration of effluent). The results of chemical analysis showed that textile effluent had high COD (nearly 3 times higher), TDS (19 times higher) as well as (39 times higher) than the maximum permissible limits (MPL) set by Environmental Protection Authority (EPA). Among heavy metals, Zn and Fe of textile effluent were much higher (41 and 1.5 times higher, respectively) than the MPL set by EPA. Ceramic effluent also contained high concentration of (24.5 times), S2-, (2 times) and Zn (14 times) exceeding the limit of EPA. Regarding soft drink factory, high values of COD, and Zn were found in the effluent than the limit specified by EPA. The biological treatment lagoons of the respective source were not effective since the effluents were taken from the last treatment lagoon (outlet lagoon) and some of the measured parameters were higher than MPL. Results of the pond experiment showed that 5%, 10% and 20% concentration levels of the HTF effluent killed significantly high proportion of the fry (65%, 86.8% and 88.7%, respectively). In contrast, fry mortality in ceramic and soft drink effluent treatments, even at 10 and 20% concentration levels, stayed nearly below 10%, which were not far off from the mortality of the control groups. Algal biomass in the treated ponds varied with the type of effluent treatment and concentration level. Compared with the first day, chlorophyll “a” concentration measured on the 7th day had increased by 51%, 48%, 74%, 27% and 31% at 0%, 1%, 5%, 10% and 20% concentrations, respectively of textile effluent. The 5% treatment level of textile effluent caused the highest rate of algal growth above the growth rate observed in the control pond, but further increased in concentration to 10% and 20% resulted in a lower growth of algae than in the control pond. Therefore, textile effluent may boost up algae growth at lower concentrations (~5%) but at higher concentration levels its toxic effect may become inhibitory. Regarding the effluent of soft drink factory, algal growth progressively diminished with increasing concentration of the effluent. The overall change (between initial and day 7) in chlorophyll “a” concentration was highest in the control pond (36.2%) and decreased with increasing effluent concentration (1% to 20%) from 21.7% to -9.4%. On the other hand, algal growth under ceramic effluent treatment was comparable with that observed in the control pond.
文摘Quantifying the hydrologic response of land use/land cover change (LULCC) is of paramount importance to improve land management. This study was carried out to analyze the effect of LULCC on water quality and quantity. LULCC of the watershed in 1986, 1999 and 2011 was analyzed from Landsat satellite images using supervised classification. Time series and point data were collected from the upper and lower sections of Wedesa, Wesha and Hallo Rivers. Water quality parameters (turbidity, suspended solid (SS), total dissolved solid (TDS), pH, electric conductivity (EC), total organic carbon (TOC), ammonia, nitrate and phosphate) were analyzed in the laboratory. A considerable decline in forest and an increase in woodland were observed in the watershed during the indicated periods. Turbidity, SS, TDS and EC were significantly higher (P < 0.05) in the lower section of the rivers compared to the upper ones. Ammonia, nitrate and phosphate were higher in the lower section of some rivers compared to the upper ones. In general, water quality in the upper watershed of the three rivers was better than the lower one with respect to considered parameters, which might be related to the observed LULCC. Most water quality parameters varied (P < 0.05) seasonally in both the upper and lower sections of the rivers. Despite the irregular rainfall pattern and increased water consumption from the catchment, the annual discharge of the Tikur-Wuha River to Lake Hawassa shows an increasing trend. We concluded that the discharge is not only related to the upstream LULCC but also to the management of the Cheleleka wetland. However, further investigation is required to determine the dominant factors affecting inflow discharge to Lake Hawassa.
文摘Urban green areas are essential elements of cities and contribute to the quality of life in numerous ways by maintaining and regulating the environment.However,increased urbanization and development have placed urban green areas under extreme pressure,while unplanned urban growth has resulted in the loss of urban landscape and ecosystem.This study’s objective was the public perception on the role of urban green infrastructure and land use management.The 385 sample households were selected by using random sampling method.Descriptive and econometric analyses were used for analyzing both quantitative and qualitative data by using SPSS version 25.Among the major factors influencing the urban green infrastructure by respondents perception were education,income,family size,sex of respondent,marital status,type of employment,ownership of house,participation on public involvement,and frequency of visit to nearer planning which are significant variables in the model.Individuals visited the given green structure at least twice a week,and those not done it were 47.9% and 52.1%.The amount of individuals who visited it twice a week in positive perceivers was 64%,and the amount of those who have not done it was 36%.The Chi-square value of 10.9 was very big and telling us that the frequency of visit was determinant factor of perception.It is vital to keep in mind that while the built-up area and the agricultural areas are rising due to urbanization,the core-ecosystem land is being“eaten”as a result of the past and present land uses inside the administrative limits,as well as the services they provide.In the last 6 years,the rate at which the most precious ecosystems are disappearing has tripled.The population,which reflects the demand for these services and benefits,is still growing,putting more strain on the environment.The recommendations include:Public involvement in urban green space planning and development was determinant and core variable of the study.The government of the town administration should prepare the meeting.The result showed a high correlation between urban green planning and land use changes.
基金We thank Jimma University for funding this study.We are grateful to the administration and laboratory staff of the two health facilities included in this study for their support during data collection.We are also grateful to the study participants and their parents/guardians.
文摘Background:Diarrhoea is the leading cause of morbidity and mortality in children under 5 years of age in developing countries,including Ethiopia.It is caused by a wide range of pathogens,including parasites,bacteria and viruses.The aim of this study was to determine the prevalence of infection with intestinal parasites(IPs)(and types)among children under 5 years of age with diarrhoeal diseases.Methods:A cross-sectional study was conducted at Adare Hospital and Millennium Health Centre,both located in Hawassa,South Ethiopia,from June 6 to October 28,2011.Children under 5 years of age with diarrhoea who visited these health facilities during the study period were included in the study.Data relating to demography and risk factors associated with intestinal parasitic infections(IPIs)were gathered using a structured questionnaire.Single,fresh stool specimens were examined for IPs using the direct wet mount examination,followed by Ziehl-Neelsen staining of formol-ether concentrated samples,as per standard procedures.Data were analysed using SPSS Statistics 20 software.Results:A total of 158 children(51.3%male and 48.7%female)participated in the study.Overall,the prevalence of IPs was 26.6%(42/158).Two species of IPs were detected in six children(3.8%).Entamoeba histolytica/dispar/moshkovskii was the predominant parasite identified(11.4%),followed by Giardia duodenalis(7.0%).The multivariable analysis revealed that the age group≥24 months was significantly associated(AOR=0.221,95%CI:0.085–0.576)with prevalence of IPIs.Conclusion:This study found that intestinal parasites are common among children with diarrheal diseases.The most frequently detected species was E.histolytica/dispar/moshkovskii.Health information about how to prevent diarrheal diseases in general and IPIs in particular should be provided to parents of young children.
基金supported with funds from the Bill and Melinda Gates Foundation(BMGF)under the auspices of the BMGF project on Capacity Building in Africa(awarded to Tshwane University of Technology,Pretoria)the Gates Foundation for a competitive doctoral fellowship awarded under the BMGF project to Hawassa University for study leaveThe National Research Fund(NRF),the South African Research Chair in Agrochemurgy and Plant Symbioses,and the Tshwane University of Technology。
文摘Bean(Phaseolus vulgaris)yields in Africa can be increased through the application of phosphorus and nitrogen fertilizers,as both nutrients are low in African soils.However,using greener technologies is preferred to mineral fertilizers for maintaining soil health.In this study,Rhizobium inoculation and moderate P supply(0,10,20,and 30 kg·ha^(-1))to two bean cultivars were evaluated in consecutive years at Hawassa for their effects on plant growth,nodulation,and grain yield.The results showed that,relative to the uninoculated control,the two bean cultivars responded strongly to Rhizobium inoculation,with strain HB-429 outperforming strain GT-9 in both 2012 and 2013.Shoot biomass,nodule number and nodule dry matter per plant were increased by 9%,40%,and 54%,respectively,in 2012,and by 20%,39%,and13%in 2013 with strain HB-429 inoculation.This resulted in increased pod number per plant,seed number per pod and grain yield by 56%,51%,and 49%in 2012,and by 38%,25%,and 69%in 2013,respectively,with strain HB-429inoculation.Bean inoculation with GT-9 also increased grain yield by 35%and68%in 2012 and 2013,respectively.Applying 10–30 kg·ha^(-1)P to bean cultivars increased shoot biomass,nodule number,and nodule dry matter per plant by7%to 39%,23%to 59%,and 59%to 144%in 2012,respectively,and by 10%to40%,21%to 43%,and 12%to 35%in 2013,respectively.Relative to the zero-P control,adding only 10 kg·ha^(-1)P increased pod number per plant,seed number per pod,and grain yield by 10%,30%,and 61%in 2012,and by 11%,11%,and 38%in 2013,respectively.The combined use of Rhizobium inoculation with low P application(20 kg·ha^(-1))was found to increase bean production in Ethiopia and is thus recommended to resource-poor farmers.
