Pub Date : 2019-01-01DOI: 10.1080/23311843.2019.1667709
S. M. Cabrini, S. Portela, P. Cano, D. López
Abstract Argentine Pampas are one of the major regions in the world for agricultural production. There is a trend towards system simplification in this area, with soybeans being the predominant crop. One major concern of “soybeanization” is its long-term effect on productivity. There is an increasing interest in more diverse and intensive cropping sequences in order to mitigate environmental concerns related to agricultural simplification, while increasing or maintaining crop production. The aims of this study were to assess the heterogeneity of agricultural land use schemes in Pergamino, Buenos Aires, and to determine environmental and economic indicators for the different land uses. Data were collected through surveys to a sample of farmers for three cropping years. For each farm, three environmental indicators (soil organic carbon, nitrogen and phosphorus balances) and two economic indicators (crop revenue and on-farm environmental cost associated to negative soil organic carbon and nutrient balances) were computed. Under current land use and crop management practices, soil nutrients and organic carbon tend to decrease. The estimated on-farm environmental cost from soil organic carbon and nutrients losses represents a 6% of crop revenue, on average. Farm size is related to land-use schemes and environmental and economic indicators. Smaller farms are associated with a lower proportion of full-season soybeans in crop rotations, lower nutrients and carbon losses, and lower environmental costs. There are farms in the sample with diverse and intensive rotation schemes and low environmental cost. The characterization of farming systems provides valuable information in the search of sustainable intensification alternatives.
{"title":"Heterogeneity in agricultural land use decisions in Argentine Rolling Pampas: The effects on environmental and economic indicators","authors":"S. M. Cabrini, S. Portela, P. Cano, D. López","doi":"10.1080/23311843.2019.1667709","DOIUrl":"https://doi.org/10.1080/23311843.2019.1667709","url":null,"abstract":"Abstract Argentine Pampas are one of the major regions in the world for agricultural production. There is a trend towards system simplification in this area, with soybeans being the predominant crop. One major concern of “soybeanization” is its long-term effect on productivity. There is an increasing interest in more diverse and intensive cropping sequences in order to mitigate environmental concerns related to agricultural simplification, while increasing or maintaining crop production. The aims of this study were to assess the heterogeneity of agricultural land use schemes in Pergamino, Buenos Aires, and to determine environmental and economic indicators for the different land uses. Data were collected through surveys to a sample of farmers for three cropping years. For each farm, three environmental indicators (soil organic carbon, nitrogen and phosphorus balances) and two economic indicators (crop revenue and on-farm environmental cost associated to negative soil organic carbon and nutrient balances) were computed. Under current land use and crop management practices, soil nutrients and organic carbon tend to decrease. The estimated on-farm environmental cost from soil organic carbon and nutrients losses represents a 6% of crop revenue, on average. Farm size is related to land-use schemes and environmental and economic indicators. Smaller farms are associated with a lower proportion of full-season soybeans in crop rotations, lower nutrients and carbon losses, and lower environmental costs. There are farms in the sample with diverse and intensive rotation schemes and low environmental cost. The characterization of farming systems provides valuable information in the search of sustainable intensification alternatives.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2019.1667709","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42992241","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 : 2019-01-01DOI: 10.1080/23311843.2019.1594511
Helen Nnoli, R. Kyerematen, S. Adu-Acheampong, J. Hynes
Abstract Insects are key indicators of change in the landscape. They are known to be sensitive to the environment and climate in both terrestrial and aquatic ecosystems. A systemic way of monitoring river ecosystems response to land-use and climate change is critical although lacking in most West African countries. This study explored the taxonomic composition of insect assemblages within the Pawmpawm River to quantify the level of change (if any) in biodiversity of aquatic insects as evidence of a land-use and climate change in a 40-year interval. We collected insect larvae from river shores, edges, and riffles and compared diversity indices of collected samples with that of previous study conducted within the same study area 40 years earlier prior to the current study. Our results show that there were no significant differences in taxonomic diversity of aquatic insects between the two studies. This indicates that diversity of insects in the Pawmpawm River and its environment has not changed significantly in the past 40 years. However, there were significant reductions of individual insect numbers or abundances within the river and its environment giving an indication of a possible climate and land-use change in the study area. We recommend using change in aquatic insect diversity and abundance as monitoring tools for change in environment and land-use within the Pawmpawm River and other such rivers in Ghana.
{"title":"Change in aquatic insect abundance: Evidence of climate and land-use change within the Pawmpawm River in Southern Ghana","authors":"Helen Nnoli, R. Kyerematen, S. Adu-Acheampong, J. Hynes","doi":"10.1080/23311843.2019.1594511","DOIUrl":"https://doi.org/10.1080/23311843.2019.1594511","url":null,"abstract":"Abstract Insects are key indicators of change in the landscape. They are known to be sensitive to the environment and climate in both terrestrial and aquatic ecosystems. A systemic way of monitoring river ecosystems response to land-use and climate change is critical although lacking in most West African countries. This study explored the taxonomic composition of insect assemblages within the Pawmpawm River to quantify the level of change (if any) in biodiversity of aquatic insects as evidence of a land-use and climate change in a 40-year interval. We collected insect larvae from river shores, edges, and riffles and compared diversity indices of collected samples with that of previous study conducted within the same study area 40 years earlier prior to the current study. Our results show that there were no significant differences in taxonomic diversity of aquatic insects between the two studies. This indicates that diversity of insects in the Pawmpawm River and its environment has not changed significantly in the past 40 years. However, there were significant reductions of individual insect numbers or abundances within the river and its environment giving an indication of a possible climate and land-use change in the study area. We recommend using change in aquatic insect diversity and abundance as monitoring tools for change in environment and land-use within the Pawmpawm River and other such rivers in Ghana.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2019.1594511","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48140423","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 : 2019-01-01DOI: 10.1080/23311843.2019.1595293
Bruno Kiilerich, A. Brejnrod, J. Vollertsen, P. Kiilerich
Abstract During transport of wastewater in force mains, sulphide and possibly methane formation take place due to prokaryotic activity. Sulphide has several detrimental effects and addition of ferrous or ferric iron for abatement by precipitation is commonly applied. Precipitation stoichiometry and efficiency of this process have been investigated in detail. However, it is largely unknown how ferrous and ferric iron influence prokaryotic populations of sewer biofilms. The microbiomes of iron-treated force main biofilms were, together with an untreated control, examined by sequencing of the 16S rDNA V3+ V4 regions. Differences in distribution and abundance of several bacterial and archaeal genera were observed, indicating that treatment with ferrous and ferric iron for sulphide abatement differentially changed sewer force main microbiomes. Furthermore, differences at the functional level (KEGG orthologs, KOs) indicate that ferrous and ferric iron treatment possibly can decrease methane formation, whereas functions related to dissimilatory sulphate reduction seemed unaffected.
{"title":"Variations in microbiome composition of sewer biofilms due to ferrous and ferric iron dosing","authors":"Bruno Kiilerich, A. Brejnrod, J. Vollertsen, P. Kiilerich","doi":"10.1080/23311843.2019.1595293","DOIUrl":"https://doi.org/10.1080/23311843.2019.1595293","url":null,"abstract":"Abstract During transport of wastewater in force mains, sulphide and possibly methane formation take place due to prokaryotic activity. Sulphide has several detrimental effects and addition of ferrous or ferric iron for abatement by precipitation is commonly applied. Precipitation stoichiometry and efficiency of this process have been investigated in detail. However, it is largely unknown how ferrous and ferric iron influence prokaryotic populations of sewer biofilms. The microbiomes of iron-treated force main biofilms were, together with an untreated control, examined by sequencing of the 16S rDNA V3+ V4 regions. Differences in distribution and abundance of several bacterial and archaeal genera were observed, indicating that treatment with ferrous and ferric iron for sulphide abatement differentially changed sewer force main microbiomes. Furthermore, differences at the functional level (KEGG orthologs, KOs) indicate that ferrous and ferric iron treatment possibly can decrease methane formation, whereas functions related to dissimilatory sulphate reduction seemed unaffected.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2019.1595293","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47475157","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 : 2019-01-01DOI: 10.1080/23311843.2019.1656444
H. Haftom, T. Girmay, B. Emiru, A. Haftu, H. Meseret, Fei Li
Abstract Trees on farm provide numerous supporting and regulating services. Some services are biodiversity conservation and enhancement of carbon stock storage. This depends upon the exclusion of livestock intervention to farmlands. In Ethiopia, exclosure has been implemented on communal grazing lands which brought better abundance and enhanced carbon stock than open grazing lands. Recently, the idea of exclosure has been implemented on farmlands. This study investigated the impact of farm exclosures on woody species abundance, diversity and carbon stock. Two farm types, such as farm exclosure, where there is exclusion of livestock throughout the year, and open farms, where livestock freely graze in the winter, were selected in the districts of Hawzen and Hintalo Wajirat, Tigray, Ethiopia. Eighteen farm sample plots having an area of half a hectare (100*50) were chosen randomly from each farm type, totaling 36 plots. Height, diameter at breast height and diameter at stump height were recorded for trees and shrubs found in the sample plots. Fifteen woody species representing 10 families were recorded in farm exclosures and nine species representing seven families were recorded in the open farms. Higher abundance, basal area, vegetation biomass and vegetation carbon stock were observed in the farm exclosures. Mean abundance of all woody species was 21.34 and 13.44 trees ha−1; basal area, 0.55 and 0.18 m2 ha−1; species richness, 2.72 and 2.11; Shannon diversity, 1.64 and 1.74; and vegetation carbon stock, 4.57 and 1.18 ton ha−1, for farm exclosures and open farms, respectively. The result showed that there is a significant difference in mean abundance (p < 0.05), basal area (p < 0.01) and carbon stock (p < 0.01) between the farm exclosures and open farms. Thus, exclosures applied in farmlands have a considerable contribution in increasing woody species abundance, basal area and vegetation carbon stock.
{"title":"Impact of farm exclosure on woody species abundance and carbon stock in Tigray, Northern Ethiopia","authors":"H. Haftom, T. Girmay, B. Emiru, A. Haftu, H. Meseret, Fei Li","doi":"10.1080/23311843.2019.1656444","DOIUrl":"https://doi.org/10.1080/23311843.2019.1656444","url":null,"abstract":"Abstract Trees on farm provide numerous supporting and regulating services. Some services are biodiversity conservation and enhancement of carbon stock storage. This depends upon the exclusion of livestock intervention to farmlands. In Ethiopia, exclosure has been implemented on communal grazing lands which brought better abundance and enhanced carbon stock than open grazing lands. Recently, the idea of exclosure has been implemented on farmlands. This study investigated the impact of farm exclosures on woody species abundance, diversity and carbon stock. Two farm types, such as farm exclosure, where there is exclusion of livestock throughout the year, and open farms, where livestock freely graze in the winter, were selected in the districts of Hawzen and Hintalo Wajirat, Tigray, Ethiopia. Eighteen farm sample plots having an area of half a hectare (100*50) were chosen randomly from each farm type, totaling 36 plots. Height, diameter at breast height and diameter at stump height were recorded for trees and shrubs found in the sample plots. Fifteen woody species representing 10 families were recorded in farm exclosures and nine species representing seven families were recorded in the open farms. Higher abundance, basal area, vegetation biomass and vegetation carbon stock were observed in the farm exclosures. Mean abundance of all woody species was 21.34 and 13.44 trees ha−1; basal area, 0.55 and 0.18 m2 ha−1; species richness, 2.72 and 2.11; Shannon diversity, 1.64 and 1.74; and vegetation carbon stock, 4.57 and 1.18 ton ha−1, for farm exclosures and open farms, respectively. The result showed that there is a significant difference in mean abundance (p < 0.05), basal area (p < 0.01) and carbon stock (p < 0.01) between the farm exclosures and open farms. Thus, exclosures applied in farmlands have a considerable contribution in increasing woody species abundance, basal area and vegetation carbon stock.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2019.1656444","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45043297","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 : 2019-01-01DOI: 10.1080/23311843.2019.1603607
Karyn E. Quansah, C. Gordon, F. Aboagye-Antwi, R. Gerchie
Abstract In most rural communities, women are the sole managers of water supply and sanitation and determine household water management choices and practices. This study investigated the perceptions and household water management practices among womenfolk within rural communities located in the Central Tongu district and the Ada East districts of Ghana. Data collection instruments included household surveys, direct observation and focus group discussions of women within the study communities. The data were analysed using statistical tools embedded in the Statistical Package for the Social Sciences software. Results indicate that socio-demographic factors such as age, education, occupation and cost of water sources shaped household water management decisions. Furthermore, respondents’ perception of climate variability and climate adaptation was low and this, in turn, influenced household water management practices. The paper recommends that capacity building workshops be organized for rural women within the study communities to equip them with the skills to increase their income and in due course, improve their water management choices. Additionally, we suggest the promotion of climate variability and adaptation sensitization workshops of suitable household water management adaptation measures by government and Non-Government Organizations (NGOs) among rural communities.
{"title":"The implication of climate variability on household water management; perception and practices among rural womenfolk in four communities in Ghana","authors":"Karyn E. Quansah, C. Gordon, F. Aboagye-Antwi, R. Gerchie","doi":"10.1080/23311843.2019.1603607","DOIUrl":"https://doi.org/10.1080/23311843.2019.1603607","url":null,"abstract":"Abstract In most rural communities, women are the sole managers of water supply and sanitation and determine household water management choices and practices. This study investigated the perceptions and household water management practices among womenfolk within rural communities located in the Central Tongu district and the Ada East districts of Ghana. Data collection instruments included household surveys, direct observation and focus group discussions of women within the study communities. The data were analysed using statistical tools embedded in the Statistical Package for the Social Sciences software. Results indicate that socio-demographic factors such as age, education, occupation and cost of water sources shaped household water management decisions. Furthermore, respondents’ perception of climate variability and climate adaptation was low and this, in turn, influenced household water management practices. The paper recommends that capacity building workshops be organized for rural women within the study communities to equip them with the skills to increase their income and in due course, improve their water management choices. Additionally, we suggest the promotion of climate variability and adaptation sensitization workshops of suitable household water management adaptation measures by government and Non-Government Organizations (NGOs) among rural communities.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2019.1603607","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43460626","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 : 2019-01-01DOI: 10.1080/23311843.2019.1579456
Metkel Aregay Gebreeyosus, Wassie Berhanu
Abstract The non-market welfare gain from different improved solid waste management options for households in Aksum city, Ethiopia, was estimated using choice modelling. The proposed improvements in solid waste management were presented by three service attributes (i.e. frequency of waste collection, waste disposal mechanism, and mode of transport used to transport waste) along with a monetary attribute (monthly charges of households for the service rendered). For the purpose of the survey, 150 dwellers of the town were randomly selected. Two multinomial logit models were used for the estimations. In both models, the coefficients of the attributes are significant and with the priori expected signs. Except for the gender of the respondent, family size and monthly income of the households, all included variables significantly affect utilities of the respondents. Implicit prices were calculated and found 4.6, 1.7 and 2.5 Birr for the frequency of waste collection, waste disposal mechanismand mode of transportation, respectively, for the extended model. The trade-offs between the non-monetary attributes were also calculated. Analogous results were found for the two models, and frequency of waste collection ranked top in terms of relative importance to households. Finally, the various hypothetical scenarios support that the dwellers of the town are willing to pay for improvements in the existing solid waste management activities.
{"title":"Households’ preferences for improved solid waste management options in Aksum city, North Ethiopia: An application of choice modelling","authors":"Metkel Aregay Gebreeyosus, Wassie Berhanu","doi":"10.1080/23311843.2019.1579456","DOIUrl":"https://doi.org/10.1080/23311843.2019.1579456","url":null,"abstract":"Abstract The non-market welfare gain from different improved solid waste management options for households in Aksum city, Ethiopia, was estimated using choice modelling. The proposed improvements in solid waste management were presented by three service attributes (i.e. frequency of waste collection, waste disposal mechanism, and mode of transport used to transport waste) along with a monetary attribute (monthly charges of households for the service rendered). For the purpose of the survey, 150 dwellers of the town were randomly selected. Two multinomial logit models were used for the estimations. In both models, the coefficients of the attributes are significant and with the priori expected signs. Except for the gender of the respondent, family size and monthly income of the households, all included variables significantly affect utilities of the respondents. Implicit prices were calculated and found 4.6, 1.7 and 2.5 Birr for the frequency of waste collection, waste disposal mechanismand mode of transportation, respectively, for the extended model. The trade-offs between the non-monetary attributes were also calculated. Analogous results were found for the two models, and frequency of waste collection ranked top in terms of relative importance to households. Finally, the various hypothetical scenarios support that the dwellers of the town are willing to pay for improvements in the existing solid waste management activities.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2019.1579456","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47334988","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 : 2019-01-01DOI: 10.1080/23311843.2019.1636548
Ademe Mihiretu, E. N. Okoyo, T. Lemma
Abstract Climate change exacerbates the daunting defy on agriculture in general and the livestock sector in particular. The aim of this study was to assess the determinant factors of climate change adaptation choices in the agro-pastoral dry lands of northeastern Ethiopia. Data on the household characteristics and adaptation choices were collected using interview schedule from a sample of 260 household heads. Multivariate probit regression and descriptive statistics were used for data analysis. The results indicated that 63.5% of farmers were applying portfolio diversification, enhancing livestock productivity, agro-ecological practices, and diversifying non-agricultural income choices to acclimatize the climate change. The model revealed that many explanatory variables, such as educational level, gender, farming experience, family size, farmland size, goat flock size, farm and non-farm income, frequency of extension contact, access to credit and climate information were significant factors for adaption choice decisions. The marginal success probability of adapting non-agricultural income diversification was the lowest compared to the agro-ecological practices, portfolio diversification and enhancing livestock productivity. The marginal success probability of jointly adapting agro-ecological practices, portfolio diversification, non-agricultural income diversification and enhancing livestock productivity choices was also lower comparing to their failure. Therefore, any effort projected to relax climate change effects should gear towards the provision of services resembling to eminence extension, vocational trainings, affordable credit, empowering vulnerable groups, community radios as well as local meteorology. Moreover, non-farm income generating initiatives on top of agricultural intensification through input supply would expedite context specific adaptation to the changing climatic status quo.
{"title":"Determinants of adaptation choices to climate change in agro-pastoral dry lands of Northeastern Amhara, Ethiopia","authors":"Ademe Mihiretu, E. N. Okoyo, T. Lemma","doi":"10.1080/23311843.2019.1636548","DOIUrl":"https://doi.org/10.1080/23311843.2019.1636548","url":null,"abstract":"Abstract Climate change exacerbates the daunting defy on agriculture in general and the livestock sector in particular. The aim of this study was to assess the determinant factors of climate change adaptation choices in the agro-pastoral dry lands of northeastern Ethiopia. Data on the household characteristics and adaptation choices were collected using interview schedule from a sample of 260 household heads. Multivariate probit regression and descriptive statistics were used for data analysis. The results indicated that 63.5% of farmers were applying portfolio diversification, enhancing livestock productivity, agro-ecological practices, and diversifying non-agricultural income choices to acclimatize the climate change. The model revealed that many explanatory variables, such as educational level, gender, farming experience, family size, farmland size, goat flock size, farm and non-farm income, frequency of extension contact, access to credit and climate information were significant factors for adaption choice decisions. The marginal success probability of adapting non-agricultural income diversification was the lowest compared to the agro-ecological practices, portfolio diversification and enhancing livestock productivity. The marginal success probability of jointly adapting agro-ecological practices, portfolio diversification, non-agricultural income diversification and enhancing livestock productivity choices was also lower comparing to their failure. Therefore, any effort projected to relax climate change effects should gear towards the provision of services resembling to eminence extension, vocational trainings, affordable credit, empowering vulnerable groups, community radios as well as local meteorology. Moreover, non-farm income generating initiatives on top of agricultural intensification through input supply would expedite context specific adaptation to the changing climatic status quo.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2019.1636548","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47612406","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 : 2019-01-01DOI: 10.1080/23311843.2019.1636549
Long-Xiu Cheng, P. Loh, Z. Lou, A. Jin, Xuegang Chen, C. Chen, Shuangyan He, Lin Yang, Hong-Wei Yuan
Abstract In this study, two sediment cores (C1 and C2) were collected from the Andong salt marsh southwest of Hangzhou Bay and analysed to determine their different sedimentary phosphorus (P) forms. The changes in the sedimentary P forms over the past 30 years and the implication of these changes on environmental risks were determined. The low mean total P (TP) contents along C1 (30.42 mg/kg) and C2 (68.60 mg/kg) indicate no P pollution in the Andong salt marsh. The sedimentary TP and all P forms decreased towards the present due to a reduction in particle size and an overall decrease in nutrient input. The sedimentary P contents were also affected by other factors, such as typhoons, bridge construction and aquaculture activities that facilitated erosion and increased P input, whereas drought caused a reduction in sedimentary P. Organic P (OP) represented more than half of the TP, and NaOH-P (P bound to Fe and Al oxides and hydroxides) represented more than half of the inorganic P (IP), indicating an overall high level of bioavailable P. Thus, the sediments in the Andong salt marsh could be releasing P during organic matter decomposition and under anoxic conditions.
{"title":"A 30-year record of sedimentary phosphorus species in a coastal salt marsh southwest of Hangzhou Bay, China","authors":"Long-Xiu Cheng, P. Loh, Z. Lou, A. Jin, Xuegang Chen, C. Chen, Shuangyan He, Lin Yang, Hong-Wei Yuan","doi":"10.1080/23311843.2019.1636549","DOIUrl":"https://doi.org/10.1080/23311843.2019.1636549","url":null,"abstract":"Abstract In this study, two sediment cores (C1 and C2) were collected from the Andong salt marsh southwest of Hangzhou Bay and analysed to determine their different sedimentary phosphorus (P) forms. The changes in the sedimentary P forms over the past 30 years and the implication of these changes on environmental risks were determined. The low mean total P (TP) contents along C1 (30.42 mg/kg) and C2 (68.60 mg/kg) indicate no P pollution in the Andong salt marsh. The sedimentary TP and all P forms decreased towards the present due to a reduction in particle size and an overall decrease in nutrient input. The sedimentary P contents were also affected by other factors, such as typhoons, bridge construction and aquaculture activities that facilitated erosion and increased P input, whereas drought caused a reduction in sedimentary P. Organic P (OP) represented more than half of the TP, and NaOH-P (P bound to Fe and Al oxides and hydroxides) represented more than half of the inorganic P (IP), indicating an overall high level of bioavailable P. Thus, the sediments in the Andong salt marsh could be releasing P during organic matter decomposition and under anoxic conditions.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2019.1636549","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47486970","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 : 2019-01-01DOI: 10.1080/23311843.2018.1564170
T. Bezuneh, Hinsermu Daba Derressa, Ramesh Duraisam, A. Tura
Abstract Considering the harmful effects of the synthetic termiticides and resistance development in the pest population, there is a need to search for economically viable, environmentally-friendly and effective termiticides. Therefore, the screening of alternative antitermiticidal activity from plant based products could be employed as a means in the termite control strategies. The present study was carried out to evaluate the anti-termitic activity of the hexane leaf extract of Prosopis juliflora against the termites of Macrotermes spp. at concentrations of 25, 50, 75 and 100 mg/L. It was found that, the LC50-LC90 values were 33.3–213.98, 12.71–66.33 and 9.41–34.71 mg/L after 24, 48 and 72 h of exposure, respectively. The phytochemical study of the crude extract showed the presence of steroids, saponins, terpenoids, alkaloids and flavonoids which might be responsible for its biocidal activity. These results suggested that hexane leaf extract of P. juliflora possessed biocidal activity aginst termites.
{"title":"Preliminary evaluation of anti-termitic activity of Prosopis juliflora leaf extract against Macrotermes spp (Isoptera: Termitidae)","authors":"T. Bezuneh, Hinsermu Daba Derressa, Ramesh Duraisam, A. Tura","doi":"10.1080/23311843.2018.1564170","DOIUrl":"https://doi.org/10.1080/23311843.2018.1564170","url":null,"abstract":"Abstract Considering the harmful effects of the synthetic termiticides and resistance development in the pest population, there is a need to search for economically viable, environmentally-friendly and effective termiticides. Therefore, the screening of alternative antitermiticidal activity from plant based products could be employed as a means in the termite control strategies. The present study was carried out to evaluate the anti-termitic activity of the hexane leaf extract of Prosopis juliflora against the termites of Macrotermes spp. at concentrations of 25, 50, 75 and 100 mg/L. It was found that, the LC50-LC90 values were 33.3–213.98, 12.71–66.33 and 9.41–34.71 mg/L after 24, 48 and 72 h of exposure, respectively. The phytochemical study of the crude extract showed the presence of steroids, saponins, terpenoids, alkaloids and flavonoids which might be responsible for its biocidal activity. These results suggested that hexane leaf extract of P. juliflora possessed biocidal activity aginst termites.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2018.1564170","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42366549","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 : 2019-01-01DOI: 10.1080/23311843.2019.1650416
Agegnehu Alemu, B. Lemma, N. Gabbiye
Abstract Chromium (III) is one of the chemicals widely used in various industrial processes. The wastewater containing Chromium (III) can be interconverted to Cr (VI) in the environment, which is one of the most toxic chemicals to biological systems. This paper investigates the removal of chromium (III) from aqueous solutions by adsorption process using abundant vesicular basalt available around Abbay River in Ethiopia. The batch adsorption method has been employed to evaluate the effect of various experimental parameters (pH, ionic strength, initial concentration and contact time) on Cr (III) adsorption. The adsorption process was highly dependent on pH. The maximum adsorption capacity was 0.976 mg g−1 at pH 6, initial concentration of 100 mg L−1 and adsorbent dosage of 50 g L−1. Kinetic experiments indicated that the pseudo-second-order model displayed the best correlation with adsorption kinetic data. The adsorption mechanism of Cr (III) onto the surface of the vesicular basalt involved film diffusion and/or intraparticle diffusion during the reaction. Equilibrium studies indicated that the Langmuir Isotherm model was found to be in better correlation with experimental data. This study indicated that vesicular basalt rock owned good potential for the treatment of Cr (III) containing polluted water.
摘要铬（III）是广泛应用于各种工业过程中的化学品之一。含有铬（III）的废水在环境中可以转化为Cr（VI），这是对生物系统毒性最大的化学物质之一。本文利用埃塞俄比亚阿贝河附近丰富的泡状玄武岩，研究了通过吸附法从水溶液中去除铬（III）的方法。采用分批吸附法评价了各种实验参数（pH、离子强度、初始浓度和接触时间）对Cr（III）吸附的影响。吸附过程与pH高度相关。在pH 6、初始浓度为100 mg L−1和吸附剂用量为50 g L−1的条件下，最大吸附容量为0.976 mg g−1。动力学实验表明，拟二阶模型与吸附动力学数据的相关性最好。Cr（III）在泡状玄武岩表面的吸附机制涉及反应过程中的膜扩散和/或颗粒内扩散。平衡研究表明，Langmuir等温模型与实验数据具有较好的相关性。研究表明，泡状玄武岩在处理含Cr（III）污水方面具有良好的潜力。
{"title":"Adsorption of chromium (III) from aqueous solution using vesicular basalt rock","authors":"Agegnehu Alemu, B. Lemma, N. Gabbiye","doi":"10.1080/23311843.2019.1650416","DOIUrl":"https://doi.org/10.1080/23311843.2019.1650416","url":null,"abstract":"Abstract Chromium (III) is one of the chemicals widely used in various industrial processes. The wastewater containing Chromium (III) can be interconverted to Cr (VI) in the environment, which is one of the most toxic chemicals to biological systems. This paper investigates the removal of chromium (III) from aqueous solutions by adsorption process using abundant vesicular basalt available around Abbay River in Ethiopia. The batch adsorption method has been employed to evaluate the effect of various experimental parameters (pH, ionic strength, initial concentration and contact time) on Cr (III) adsorption. The adsorption process was highly dependent on pH. The maximum adsorption capacity was 0.976 mg g−1 at pH 6, initial concentration of 100 mg L−1 and adsorbent dosage of 50 g L−1. Kinetic experiments indicated that the pseudo-second-order model displayed the best correlation with adsorption kinetic data. The adsorption mechanism of Cr (III) onto the surface of the vesicular basalt involved film diffusion and/or intraparticle diffusion during the reaction. Equilibrium studies indicated that the Langmuir Isotherm model was found to be in better correlation with experimental data. This study indicated that vesicular basalt rock owned good potential for the treatment of Cr (III) containing polluted water.","PeriodicalId":45615,"journal":{"name":"Cogent Environmental Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23311843.2019.1650416","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45054010","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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