Pub Date : 2020-01-01DOI: 10.1080/23311843.2020.1834916
Barana Babiso Badesso, Aklilu Bajigo Madalcho, Merkineh Mesene Mena
Abstract Forest is one of the vital resources that determine the livelihood, environmental stability, and societal development. Duguna Fango is biologically diverse and deeply threatened in the region. The area has undergone extensive environmental changes since 1980s due to shifting cultivation, deforestation, urbanization, growing human population and drought. Thus, this research was conducted to investigate the status of forest change and degradation by using available satellite imageries at Duguna Fango Woreda. It was based on the corrected optical satellite data (Landsat 7 ETM of 2000, 2009, and Landsat 8 OLI/TIRS of 2018); available from the Global Land Cover Facility acquired in the drier seasons of the years was used for forest cover change analysis. Besides, normalized difference vegetation index (NDVI) indicators like (NDVI minimum, maximum, mean, and standard deviation) were also computed for the year 2000, 2009 and 2018 to determine the density of vegetation. The results showed in the period between 2000 and 2018, built up and cultivated lands increased with a mean annual rate of 92.18 and 366.96 ha/year, respectively. Followed by the reduction in dense forest with the mean annual rate of −228.27 ha/year. The NDVI minimum value showed a slight reduction from −0.09 in the year 2009 to −0.11 in the year 2018. The mean values are also decreased from 0.29 in 2009 to 0.16 in 2018. As indicated in the result of NDVI value, despite there is restoration, vegetation cover in general was reduced and the forests in particular were depleted from time to time.
{"title":"Trends in forest cover change and degradation in Duguna Fango, Southern Ethiopia","authors":"Barana Babiso Badesso, Aklilu Bajigo Madalcho, Merkineh Mesene Mena","doi":"10.1080/23311843.2020.1834916","DOIUrl":"https://doi.org/10.1080/23311843.2020.1834916","url":null,"abstract":"Abstract Forest is one of the vital resources that determine the livelihood, environmental stability, and societal development. Duguna Fango is biologically diverse and deeply threatened in the region. The area has undergone extensive environmental changes since 1980s due to shifting cultivation, deforestation, urbanization, growing human population and drought. Thus, this research was conducted to investigate the status of forest change and degradation by using available satellite imageries at Duguna Fango Woreda. It was based on the corrected optical satellite data (Landsat 7 ETM of 2000, 2009, and Landsat 8 OLI/TIRS of 2018); available from the Global Land Cover Facility acquired in the drier seasons of the years was used for forest cover change analysis. Besides, normalized difference vegetation index (NDVI) indicators like (NDVI minimum, maximum, mean, and standard deviation) were also computed for the year 2000, 2009 and 2018 to determine the density of vegetation. The results showed in the period between 2000 and 2018, built up and cultivated lands increased with a mean annual rate of 92.18 and 366.96 ha/year, respectively. Followed by the reduction in dense forest with the mean annual rate of −228.27 ha/year. The NDVI minimum value showed a slight reduction from −0.09 in the year 2009 to −0.11 in the year 2018. The mean values are also decreased from 0.29 in 2009 to 0.16 in 2018. As indicated in the result of NDVI value, despite there is restoration, vegetation cover in general was reduced and the forests in particular were depleted from time to time.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2020.1834916","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43595330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/23311843.2020.1807275
K. Tassie, Birara Endalew
Abstract Households which are the primary producers of solid waste and suffer from the effects of uncollected solid waste should be able to participate in improving SWM. Accordingly, the contribution of urban dwellers on SWM service plays a great role for better improvement of SWM at the community. Therefore, this study aims to estimate households’ willingness to pay for improved solid waste management services and analyze its determinant using binary logit econometrics model. A total of 350 randomly selected households were interviewed to address the objective of this study. The study was used both descriptive and econometrics analysis. Finally, the survey result indicated that 86.3% of sample households were willing to pay for improved solid waste management services. Following this, the one and one half bounded contingent valuation result revealed that the mean willingness to pay is 13.10 ETB[Money official Exchange rate of 1$ = 31.45 Ethiopian Birr (ETB)]/month with the total willingness to pay of 494587ETB/month which is much higher than the amount of money collected by Bahir Dar city municipality (335,000 ETB/month). Additionally, the model result demonstrated that educational level of the household, monthly aggregate income, and quantity of waste generated per week, access to solid waste management services and respondents’ responsibility on solid waste management had significant positive effect on households’ willingness to pay unlike sex of household head and number of children in the household. The municipality of Bahir Dar city should consider these significant variables to design and implement improved solid waste management services.
{"title":"Willingness to pay for improved solid waste management services and associated factors among urban households: One and one half bounded contingent valuation study in Bahir Dar city, Ethiopia","authors":"K. Tassie, Birara Endalew","doi":"10.1080/23311843.2020.1807275","DOIUrl":"https://doi.org/10.1080/23311843.2020.1807275","url":null,"abstract":"Abstract Households which are the primary producers of solid waste and suffer from the effects of uncollected solid waste should be able to participate in improving SWM. Accordingly, the contribution of urban dwellers on SWM service plays a great role for better improvement of SWM at the community. Therefore, this study aims to estimate households’ willingness to pay for improved solid waste management services and analyze its determinant using binary logit econometrics model. A total of 350 randomly selected households were interviewed to address the objective of this study. The study was used both descriptive and econometrics analysis. Finally, the survey result indicated that 86.3% of sample households were willing to pay for improved solid waste management services. Following this, the one and one half bounded contingent valuation result revealed that the mean willingness to pay is 13.10 ETB[Money official Exchange rate of 1$ = 31.45 Ethiopian Birr (ETB)]/month with the total willingness to pay of 494587ETB/month which is much higher than the amount of money collected by Bahir Dar city municipality (335,000 ETB/month). Additionally, the model result demonstrated that educational level of the household, monthly aggregate income, and quantity of waste generated per week, access to solid waste management services and respondents’ responsibility on solid waste management had significant positive effect on households’ willingness to pay unlike sex of household head and number of children in the household. The municipality of Bahir Dar city should consider these significant variables to design and implement improved solid waste management services.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2020.1807275","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46201392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The study was undertaken in Northern Ethiopia, at Emba Alaje District, to assess forage yield of the natural pasture over sown with adapted legume forage. The design was a single plot design and the treatments were farmers’ practice and Vicia sativa over sown. A total of 60 quadrats of 1 by 1 m2 size were used for herbaceous species composition, above ground biomass and dry matter yield and analyzed by t-test equal variances using R-software. Over sowing legume forage increased dry matter yield significantly as compared with the farmers’ practice pasture land. The higher dry matter yield was recorded for pasture land over sown with Vicia sativa (3.43 ton/ha). Vicia sativa over sown also increased the basal cover of herbaceous (2.28) compared to farmers’ practice (1.47). Similarly, the Vicia sativa over sown pasture land had significantly (p < 0.001) higher forage biomass than the farmers’ practice area. Results from the comparative analysis also indicated that Vicia sativa over sown on the degraded grazing land had a higher cost effective than the existing farmers’ practice as the calculated net return was found to be positive. It is, therefore, concluded that over sowing degraded grazing land with Vicia sativa improves biomass yield, and it is also cost-effective as compared with farmers’ practice. Therefore, based on the finding of the study it is highly recommended that the concerned governmental and nongovernmental organization should give emphasis to promote Vicia sativa over sown for the rehabilitation of degraded pasture land.
{"title":"Improving the productivity of degraded pasture land through demonstration of legume forage over sowing: The case of Ayba pasture land, South Tigray, Ethiopia","authors":"Tesfay Atsbha, Solomon Wayu, Hagos Kidane, Kiflom Degf, Girmay Abreha","doi":"10.1080/23311843.2020.1778997","DOIUrl":"https://doi.org/10.1080/23311843.2020.1778997","url":null,"abstract":"Abstract The study was undertaken in Northern Ethiopia, at Emba Alaje District, to assess forage yield of the natural pasture over sown with adapted legume forage. The design was a single plot design and the treatments were farmers’ practice and Vicia sativa over sown. A total of 60 quadrats of 1 by 1 m2 size were used for herbaceous species composition, above ground biomass and dry matter yield and analyzed by t-test equal variances using R-software. Over sowing legume forage increased dry matter yield significantly as compared with the farmers’ practice pasture land. The higher dry matter yield was recorded for pasture land over sown with Vicia sativa (3.43 ton/ha). Vicia sativa over sown also increased the basal cover of herbaceous (2.28) compared to farmers’ practice (1.47). Similarly, the Vicia sativa over sown pasture land had significantly (p < 0.001) higher forage biomass than the farmers’ practice area. Results from the comparative analysis also indicated that Vicia sativa over sown on the degraded grazing land had a higher cost effective than the existing farmers’ practice as the calculated net return was found to be positive. It is, therefore, concluded that over sowing degraded grazing land with Vicia sativa improves biomass yield, and it is also cost-effective as compared with farmers’ practice. Therefore, based on the finding of the study it is highly recommended that the concerned governmental and nongovernmental organization should give emphasis to promote Vicia sativa over sown for the rehabilitation of degraded pasture land.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2020.1778997","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46111225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/23311843.2020.1860451
Sintayehu Legesse Gebre, Nasreddin Temam, A. Regassa
Abstract Malaria has long been a cause of human suffering and mortality in Sub-Saharan Africa, particularly in Ethiopia. The objective of this study was to assess the spatial distribution of malaria risk using MCE (Multi-Criteria Evaluation). To analyze and generate a spatial malaria risk level distribution map. Factors that affect the spatial malaria hazard and risk distribution have been considered. Such as; temperature, rainfall, altitude, slope, distance from the river, population density, and land use land cover factors were selected to produce a malaria risk map of the Didessa district area. GIS based multi-criteria evaluation method applied using weighted overlay analysis by considering three map layer factors (i.e. malaria hazard map layer, element at risk map layer, and vulnerability map layer), an optimum malaria risk map is produced. The malaria risk map result shows that 0.68%, 36.2%, 30.1%, 27.52% 5.5% of the study area falls under very high, high, moderate, low, and very low spatial malaria risk levels respectively. Our findings indicate that malaria is heavily influenced by major environmental parameters and socio-economic factors and these factors play a vital role either directly or indirectly in the occurrence of this vector-borne disease. In conclusion, 36.88% (31034.88 ha) of the study area has a high potential risk of malaria disease manifestation and occurrence. The result of this report indicates that there are high malaria risk areas in the district. This ascertains the communities living in those areas are prone to the disease. Therefore, there is an urgent need to prevent and progressively reduce malaria disease distribution through policy formulation and health care implementation in prioritized areas. This study is useful to use as a guideline for further research study in combating malaria distribution, particularly in developing countries.
{"title":"Spatial analysis and mapping of malaria risk areas using multi-criteria decision making in Didessa District, South West Ethiopia","authors":"Sintayehu Legesse Gebre, Nasreddin Temam, A. Regassa","doi":"10.1080/23311843.2020.1860451","DOIUrl":"https://doi.org/10.1080/23311843.2020.1860451","url":null,"abstract":"Abstract Malaria has long been a cause of human suffering and mortality in Sub-Saharan Africa, particularly in Ethiopia. The objective of this study was to assess the spatial distribution of malaria risk using MCE (Multi-Criteria Evaluation). To analyze and generate a spatial malaria risk level distribution map. Factors that affect the spatial malaria hazard and risk distribution have been considered. Such as; temperature, rainfall, altitude, slope, distance from the river, population density, and land use land cover factors were selected to produce a malaria risk map of the Didessa district area. GIS based multi-criteria evaluation method applied using weighted overlay analysis by considering three map layer factors (i.e. malaria hazard map layer, element at risk map layer, and vulnerability map layer), an optimum malaria risk map is produced. The malaria risk map result shows that 0.68%, 36.2%, 30.1%, 27.52% 5.5% of the study area falls under very high, high, moderate, low, and very low spatial malaria risk levels respectively. Our findings indicate that malaria is heavily influenced by major environmental parameters and socio-economic factors and these factors play a vital role either directly or indirectly in the occurrence of this vector-borne disease. In conclusion, 36.88% (31034.88 ha) of the study area has a high potential risk of malaria disease manifestation and occurrence. The result of this report indicates that there are high malaria risk areas in the district. This ascertains the communities living in those areas are prone to the disease. Therefore, there is an urgent need to prevent and progressively reduce malaria disease distribution through policy formulation and health care implementation in prioritized areas. This study is useful to use as a guideline for further research study in combating malaria distribution, particularly in developing countries.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2020.1860451","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47594499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/23311843.2020.1813451
Mulugeta Atnaf, D. Wegary, K. Tesfaye, K. Dagne, Yalew Mazengia, Birhanu Ayalew, Adane Melak, M. Jaleta
Abstract White lupin is an important grain legume in the Ethiopian farming system. However, farmers’ cultivars contain undesirable characters, such as high alkaloid level, are susceptible to diseases and low yielders. In order to ascertain the extent of these constraints with the farmers and document their experiences and practices on white lupin production and processing, detailed baseline survey was conducted in white lupin producing areas of north western Ethiopia. Household level survey data collected from 303 farmers is used for the analysis. The study showed that farmers have long experience in producing lupin on marginal lands for food, feed, soil fertility management, and to generate cash income from sale. It also indicated that majority of lupin farmers perform minimum crop management practices to grow lupin. High alkaloid level in traditional cultivars, prevalence of different lupin diseases and lack of improved varieties are among the top production constrains voiced by most surveyed farmers. The development of white lupin variety would help a lot in overcoming this undesirable feature and boosting grain productivity. Enhancing further research and development initiatives on lupin could help smallholder farmers living on marginal lands to generate better food for home consumption, feed for their livestock, cash income from sale, fix nitrogen for better soil fertility, and rehabilitation of degraded lands.
{"title":"Exploring forgotten opportunity: White Lupin development for food, feed, cash, health, and soil fertility management in Ethiopia","authors":"Mulugeta Atnaf, D. Wegary, K. Tesfaye, K. Dagne, Yalew Mazengia, Birhanu Ayalew, Adane Melak, M. Jaleta","doi":"10.1080/23311843.2020.1813451","DOIUrl":"https://doi.org/10.1080/23311843.2020.1813451","url":null,"abstract":"Abstract White lupin is an important grain legume in the Ethiopian farming system. However, farmers’ cultivars contain undesirable characters, such as high alkaloid level, are susceptible to diseases and low yielders. In order to ascertain the extent of these constraints with the farmers and document their experiences and practices on white lupin production and processing, detailed baseline survey was conducted in white lupin producing areas of north western Ethiopia. Household level survey data collected from 303 farmers is used for the analysis. The study showed that farmers have long experience in producing lupin on marginal lands for food, feed, soil fertility management, and to generate cash income from sale. It also indicated that majority of lupin farmers perform minimum crop management practices to grow lupin. High alkaloid level in traditional cultivars, prevalence of different lupin diseases and lack of improved varieties are among the top production constrains voiced by most surveyed farmers. The development of white lupin variety would help a lot in overcoming this undesirable feature and boosting grain productivity. Enhancing further research and development initiatives on lupin could help smallholder farmers living on marginal lands to generate better food for home consumption, feed for their livestock, cash income from sale, fix nitrogen for better soil fertility, and rehabilitation of degraded lands.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2020.1813451","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47555394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/23311843.2020.1823633
J. Kihila, Jonas G. Balengayabo
Abstract Onsite sanitation is widely adopted in developing countries. Septic tanks being one of the onsite treatment systems is still adopted and scaled up especially in urban settlements. But, experience shows that septic tanks are designed without due considerations of the site and environmental conditions as a result public health risks are imposed and higher operating costs are incurred. A study was conducted in two selected informal settlements in Dar es Salaam Tanzania to understand the practice, status and implication for the existing septic tanks. Results indicate that most of the systems are improperly designed and installed as a result they are equipped with low performance efficiency and a number of operational challenges. The main reported operational challenge is frequent desuldging that has impacts on both the public health and economy. In addition, level of awareness and low priority on sanitation were identified to be among the factors affecting sanitation. In this article, options under which the situation would be improved are considered and disscussed. Apart from proper designs, modifications of the septic tanks with consideration of the environmental conditions is considered to achieve better results than the conventional septic tank systems. Capacity building of local masons in the design and installation of septic tank systems; awareness sensitization to the public; and review of policy and guidelines to incoporate tailored designs are among the recommendations.
{"title":"Adaptable improved onsite wastewater treatment systems for urban settlements in developing countries","authors":"J. Kihila, Jonas G. Balengayabo","doi":"10.1080/23311843.2020.1823633","DOIUrl":"https://doi.org/10.1080/23311843.2020.1823633","url":null,"abstract":"Abstract Onsite sanitation is widely adopted in developing countries. Septic tanks being one of the onsite treatment systems is still adopted and scaled up especially in urban settlements. But, experience shows that septic tanks are designed without due considerations of the site and environmental conditions as a result public health risks are imposed and higher operating costs are incurred. A study was conducted in two selected informal settlements in Dar es Salaam Tanzania to understand the practice, status and implication for the existing septic tanks. Results indicate that most of the systems are improperly designed and installed as a result they are equipped with low performance efficiency and a number of operational challenges. The main reported operational challenge is frequent desuldging that has impacts on both the public health and economy. In addition, level of awareness and low priority on sanitation were identified to be among the factors affecting sanitation. In this article, options under which the situation would be improved are considered and disscussed. Apart from proper designs, modifications of the septic tanks with consideration of the environmental conditions is considered to achieve better results than the conventional septic tank systems. Capacity building of local masons in the design and installation of septic tank systems; awareness sensitization to the public; and review of policy and guidelines to incoporate tailored designs are among the recommendations.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2020.1823633","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48429715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/23311843.2020.1809072
T. Tran
Abstract The reduction of the fuel consumption and the exhaust gases emission is always significant to improve the ship energy efficiency management in the field of shipping transportation industry. The study of the novelty numerical method has been addressed in this research to decrease the fuel consumption of diesel engine and restrict the exhaust gases emission from the ship operational activities. This numerical method was supported by Matlab simulation environment through the curve fitting tool. The internal factors related to the energy efficiency operational indicator (EEOI) would be investigated like the probability samples by the developing Monte Carlo (MC) simulation method. The central limit theorem of the numerical simulation method has been employed into the novelty method. The determination of the optimal values has also been collected from this proposed method. In particular, the heavy fuel oil is 1450 (Tons), the diesel oil is 13 (Tons), the mass of cargo carried is 130,000 (Tons), and the distance traveled is 7,500 (Nautical Miles) for the target ship. When we compared the fuel consumption value between the results collected from the novelty simulation method and the experimental data then the reduction of the fuel consumption is approximately 550 (Tons) corresponding to save 27.5% from the novelty numerical simulation method. Additionally, the future prediction trends for EEOI have also been approached with the high determination coefficient (R2) 0.99 and 0.9995, respectively. The EEOI index has also been dropped down 5.10−6 compared with the calculated value from the experimental data. So, this one was meaningful to reduce the exhaust gases emission through the reduction of the fuel consumption on ship. The research results will help the ship operators and ship owners to decrease the fuel consumption in the field of ship energy efficiency management.
{"title":"The novelty numerical simulation method for reducing the fuel oil consumption and the greenhouse gas emission in shipping transportation industry","authors":"T. Tran","doi":"10.1080/23311843.2020.1809072","DOIUrl":"https://doi.org/10.1080/23311843.2020.1809072","url":null,"abstract":"Abstract The reduction of the fuel consumption and the exhaust gases emission is always significant to improve the ship energy efficiency management in the field of shipping transportation industry. The study of the novelty numerical method has been addressed in this research to decrease the fuel consumption of diesel engine and restrict the exhaust gases emission from the ship operational activities. This numerical method was supported by Matlab simulation environment through the curve fitting tool. The internal factors related to the energy efficiency operational indicator (EEOI) would be investigated like the probability samples by the developing Monte Carlo (MC) simulation method. The central limit theorem of the numerical simulation method has been employed into the novelty method. The determination of the optimal values has also been collected from this proposed method. In particular, the heavy fuel oil is 1450 (Tons), the diesel oil is 13 (Tons), the mass of cargo carried is 130,000 (Tons), and the distance traveled is 7,500 (Nautical Miles) for the target ship. When we compared the fuel consumption value between the results collected from the novelty simulation method and the experimental data then the reduction of the fuel consumption is approximately 550 (Tons) corresponding to save 27.5% from the novelty numerical simulation method. Additionally, the future prediction trends for EEOI have also been approached with the high determination coefficient (R2) 0.99 and 0.9995, respectively. The EEOI index has also been dropped down 5.10−6 compared with the calculated value from the experimental data. So, this one was meaningful to reduce the exhaust gases emission through the reduction of the fuel consumption on ship. The research results will help the ship operators and ship owners to decrease the fuel consumption in the field of ship energy efficiency management.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2020.1809072","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48347599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/23311843.2020.1785137
B. Utete, B. Fregene
Abstract Metal concentrations in water, sediments and gills and edible stomach muscle tissues of two fish species, African Sharptooth mud catfish (Clarias gariepinus) and the Nile Tilapia (Oreochromis niloticus) in Eleyele Lake, Nigeria, were assessed in the rainy season (April), mid-dry spell time (July) and dry period (November) in 2017 to evaluate the potential ecological risks they pose to aquatic organisms. The concentrations of Fe, Co, Pb, Ni and Zn were significantly (p < 0.05) high in water and sediments and in some cases exceeded Nigerian Standards for Drinking Water Quality and World Health Organization guideline values. Study results highlight no significant spatial variation of all metals in the water and sediment phases and tissues for both fish species in the lake. Significant temporal variation in metals noted in the water and sediment phases most likely relate to the seasonal heterogeneity of catchment anthropogenic sources such as domestic sewer and fertilisers and pesticides from farming and backyard aquacultural enterprises. High Co, Cd and Zn concentrations recorded in tissues of the ecologically dichotomous two fish species corroborate with high metal levels in water and sediments. All pollution indices detected metal contamination in sediments whereas Ni posed a serious ecological risk to the fish (and possibly the fish consumers) in the lake indicating that nutrient retention especially within sediments is central to the pollution dynamics of Eleyele Lake and must inform management of the system.
{"title":"Heavy metal concentrations in surface water, sediments and fish and their potential toxicity in highly degraded multipurpose peri-urban Eleyele Lake, Ibadan City, Oyo State, south-western Nigeria","authors":"B. Utete, B. Fregene","doi":"10.1080/23311843.2020.1785137","DOIUrl":"https://doi.org/10.1080/23311843.2020.1785137","url":null,"abstract":"Abstract Metal concentrations in water, sediments and gills and edible stomach muscle tissues of two fish species, African Sharptooth mud catfish (Clarias gariepinus) and the Nile Tilapia (Oreochromis niloticus) in Eleyele Lake, Nigeria, were assessed in the rainy season (April), mid-dry spell time (July) and dry period (November) in 2017 to evaluate the potential ecological risks they pose to aquatic organisms. The concentrations of Fe, Co, Pb, Ni and Zn were significantly (p < 0.05) high in water and sediments and in some cases exceeded Nigerian Standards for Drinking Water Quality and World Health Organization guideline values. Study results highlight no significant spatial variation of all metals in the water and sediment phases and tissues for both fish species in the lake. Significant temporal variation in metals noted in the water and sediment phases most likely relate to the seasonal heterogeneity of catchment anthropogenic sources such as domestic sewer and fertilisers and pesticides from farming and backyard aquacultural enterprises. High Co, Cd and Zn concentrations recorded in tissues of the ecologically dichotomous two fish species corroborate with high metal levels in water and sediments. All pollution indices detected metal contamination in sediments whereas Ni posed a serious ecological risk to the fish (and possibly the fish consumers) in the lake indicating that nutrient retention especially within sediments is central to the pollution dynamics of Eleyele Lake and must inform management of the system.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2020.1785137","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46395534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/23311843.2020.1856459
P. D. Dissanayake, C. Sonne, W. Cho, Chang Hee Kim, Y. Ok
Abstract Extensive energy consumption has become a major concern due to increase of greenhouse gas emissions and global warming. Hence, hydrogen has attracted attention as a green fuel with zero carbon emission for green transportation through production of electric vehicles with hydrogen fuel cells. South Korea has launched a hydrogen society policy with the objective of expanding production of hydrogen from renewable energy sources. The hydrogen economy will play a critical role in reducing atmospheric pollution and global warming. However, new development of infrastructure for hydrogen refueling and increasing awareness of the hydrogen economy is required together with reduced prices of hydrogen-driven vehicles that are promising options for a sustainable green hydrogen economy.
{"title":"South Korea’s big move to hydrogen society","authors":"P. D. Dissanayake, C. Sonne, W. Cho, Chang Hee Kim, Y. Ok","doi":"10.1080/23311843.2020.1856459","DOIUrl":"https://doi.org/10.1080/23311843.2020.1856459","url":null,"abstract":"Abstract Extensive energy consumption has become a major concern due to increase of greenhouse gas emissions and global warming. Hence, hydrogen has attracted attention as a green fuel with zero carbon emission for green transportation through production of electric vehicles with hydrogen fuel cells. South Korea has launched a hydrogen society policy with the objective of expanding production of hydrogen from renewable energy sources. The hydrogen economy will play a critical role in reducing atmospheric pollution and global warming. However, new development of infrastructure for hydrogen refueling and increasing awareness of the hydrogen economy is required together with reduced prices of hydrogen-driven vehicles that are promising options for a sustainable green hydrogen economy.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2020.1856459","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41647648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.1080/23311843.2020.1726093
Abah James, Mashebe Percy, Sylvanus A. Onjefu
Abstract The main objective of this study was to assess the current pollution status of environmentally concerned heavy metals in the surface soil within the vicinity of the Katima Mulilo urban open land wastewater disposal centre. Multiple top soil samples (at 0–10 cm depth) were collected at four different points fortnightly over five sampling days from June to July 2018. The samples collected at each point were pooled together, homogenized and 12 sub-samples (<2 mm soil fraction) were obtained for laboratory digestion according to EPA method 3050B. Then, the digestates were analyzed for the heavy metals’ concentrations using ICP-OES (Perkin Elmer Optima 7000 DV). The results revealed consistent pattern with Fe recording the highest mean concentration (mg/kg) at each sampling point while Cd recorded the lowest mean concentration. Result of analysis of variance of the metals’ mean concentrations differed statistically (p < 0.05). The sites contamination revealed that the Point source > A200m > B400m > Control site, but the potential ecological risk indices revealed environmental low-risk levels (Er <40). Apart from Arsenic which showed moderate contamination at the point source, the geo-accumulation indices of the heavy metals mainly revealed uncontaminated to moderately contaminated levels (0 < Igeo < 1). Generally, the mean concentrations of the heavy metals were lower than the WHO’s maximum permissible limits for the protection of human and ecosystem’s health. However, due to their environmental persistence, non-degradable and bio-accumulative characteristics, heavy metals are potential toxins. Therefore, we recommend periodic monitoring of the metals levels and advising precautionary measures to minimize unintended human exposures to excessive metal contents.
{"title":"Heavy metals pollution status of the Katima Mulilo Urban open land wastewater disposal centre and the immediate vicinity","authors":"Abah James, Mashebe Percy, Sylvanus A. Onjefu","doi":"10.1080/23311843.2020.1726093","DOIUrl":"https://doi.org/10.1080/23311843.2020.1726093","url":null,"abstract":"Abstract The main objective of this study was to assess the current pollution status of environmentally concerned heavy metals in the surface soil within the vicinity of the Katima Mulilo urban open land wastewater disposal centre. Multiple top soil samples (at 0–10 cm depth) were collected at four different points fortnightly over five sampling days from June to July 2018. The samples collected at each point were pooled together, homogenized and 12 sub-samples (<2 mm soil fraction) were obtained for laboratory digestion according to EPA method 3050B. Then, the digestates were analyzed for the heavy metals’ concentrations using ICP-OES (Perkin Elmer Optima 7000 DV). The results revealed consistent pattern with Fe recording the highest mean concentration (mg/kg) at each sampling point while Cd recorded the lowest mean concentration. Result of analysis of variance of the metals’ mean concentrations differed statistically (p < 0.05). The sites contamination revealed that the Point source > A200m > B400m > Control site, but the potential ecological risk indices revealed environmental low-risk levels (Er <40). Apart from Arsenic which showed moderate contamination at the point source, the geo-accumulation indices of the heavy metals mainly revealed uncontaminated to moderately contaminated levels (0 < Igeo < 1). Generally, the mean concentrations of the heavy metals were lower than the WHO’s maximum permissible limits for the protection of human and ecosystem’s health. However, due to their environmental persistence, non-degradable and bio-accumulative characteristics, heavy metals are potential toxins. Therefore, we recommend periodic monitoring of the metals levels and advising precautionary measures to minimize unintended human exposures to excessive metal contents.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2020.1726093","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43336927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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