This pilot study documented the occurrence and levels of brominated flame retardants in the tissues of farmed and wild salmon in southern Chile.Samples of Coho salmon and rainbow trout were obtained from fish farms,ri...This pilot study documented the occurrence and levels of brominated flame retardants in the tissues of farmed and wild salmon in southern Chile.Samples of Coho salmon and rainbow trout were obtained from fish farms,rivers and lakes in the Patagonia in Aysen Region,Chile.The samples were analyzed by Gas Chromatography Negative Chemical Ionization Mass Spectrometry for the different polybrominated diphenyl ether（PBDE） congeners.Contaminants were observed in all the samples,and the congeners BDE 17,28,47 and 66 were observed in all both farmed and wild samples.The concentrations were higher in the farmed Coho salmon,presenting significant differences with wild salmon.The levels reached 182 pg/g wet weight（ww） vs.120 ww.In the case of the rainbow trout,the concentrations were lower,although the congener profile was quite similar.The levels reached an average of 100 pg/g ww in the farmed fish versus 110 pg/g ww in wild fish,and no significant difference was observed between the species.In both species,the congener with the highest concentration was BDE 47.Based on this information,the BDE ？ow was estimated for commerce,which is a form of pollutant transport not usually considered in POP pollution studies.A preliminary estimation indicated that the quantity of PBDEs mobilized by commerce was in the order of kg,and in the case of Chile might reach almost 1 kg.展开更多
The transformation of biomasses from agro-industrial waste can significantly impact the production of green chemicals from sustainable resources.Pectin is a biopolymer present in lignocellulosic biomass as Orange Peel...The transformation of biomasses from agro-industrial waste can significantly impact the production of green chemicals from sustainable resources.Pectin is a biopolymer present in lignocellulosic biomass as Orange Peel Waste(OPW)and has possibilities for making platform compounds such as furfural for sustainable chemistry.In this work,we studied the transformation to furfural of OPW,pectins,and d-galacturonic acid(D-GalA),which is the main component(65 wt%)of pectin.We analyzed pectins with different degrees of esterification(45,60 and 95 DE)in a one-pot hydrolysis reaction system and studied the differences in depolymerization and dehydration of the carbohydrates.The results show that the production of furfural decreases as the DE value increases.Specifically,low DE values favor the formation of furfural since the decarboxylation reaction is favored over deesterification.Interestingly,the furfural concentration is dependent upon the polysaccharide composition of pentoses and uronic acid.The obtained concentrations of furfural(13 and 14 mmol/L),d-xylose(6.2 and 10 mmol/L),and L-arabinose(2.5 and 2.7 mmol/L)remained the same when the galacturonic acid was fed either as a polymer or a monomer under the same reaction conditions(0.01 M SA,90 min and 433 K).OPW is proposed as a feedstock in a biorefinery,in which on a per kg OPW dry basis,90 g of pectin and 15 g of furfural were produced in the most favorable case.We conclude that the co-production of pectin and furfural from OPW is economically feasible.展开更多
The physicochemical properties and catalytic activity of pure and sulfated titanium oxide (TiO2 and ) is described in this work. Titanium hydroxide synthesized by the sol-gel method was impregnated with a 1 N H2SO4 so...The physicochemical properties and catalytic activity of pure and sulfated titanium oxide (TiO2 and ) is described in this work. Titanium hydroxide synthesized by the sol-gel method was impregnated with a 1 N H2SO4 solution, varying amount of sulfate ions () in the range from 10 to 20 wt%. Pure and modified hydroxides were calcined at 500°C for 3 h and then characterized by TGA-DTG, XRD, BET, FT-IR, potentiometric titration with n-butylamine and 2-propanol dehydration. Catalytic activity of materials was tested in the n-hexane isomerization at 350°C. The results showed that TiO2 and mainly developed anatase phase. All have acceptable specific surface area (95-105 m2/g). Potentiometric titration with n-butylamine revealed that showed higher acidity (430-530 mV) than compared to pure TiO2 (﹣15 mV), indicating that this oxide only has weak acidity. The results showed good relationship between acidity determined by potentiometric titration with n-butylamine and the catalytic activity evaluated by 2-propanol dehydration and n-hexane isomerization. Titanium oxide with 20 wt% ofions was the material that demonstrated the highest catalytic activity for both reactions.展开更多
Background:The European rabbit(Oryctolagus cuniculus L.1758)was introduced into different regions of the world,generating significant trade‑offs that critically impacted native vegetation.Here,we evaluate the rabbit’...Background:The European rabbit(Oryctolagus cuniculus L.1758)was introduced into different regions of the world,generating significant trade‑offs that critically impacted native vegetation.Here,we evaluate the rabbit’s forage intakes in three vegetation types(forests,shrublands,and grasslands)along the four seasons in a temperate forest landscape in Southern Patagonia and discuss the potential threats over native vegetation.We formulated the following questions:(i)what is the forage offer at each vegetation type?(ii)what is the rabbit’s forage intake and how it varied across the seasons along the year?and(iii)which vegetation types and plant life forms were more used according to the rabbit’s forage intakes?Methods:We censused understory vegetation to characterize the forage offer at each vegetation type and determined seasonal dietary intakes using microhistological analysis of pellets.The plant species identified in the field were grouped according to life form classes(tree regeneration,shrubs,forbs,graminoids,orchids,ferns,bryophytes,and hemiparasites).Data were analysed through uni‑and multi‑variate analyses,determining relationships between forage offer and the rabbit’s forage intakes.Results:Forage intakes revealed changes in plant life form consumption across vegetation types,where intake pressure was considerably different for tree regeneration(p=0.001),graminoids(p=0.001),and hemiparasites(p=0.001).Besides,significant changes in consumption among seasons were detected for shrubs(p=0.001),ferns(p=0.030),and hemiparasites(p=0.002).Although many species play an important role in the rabbit’s forage intake networks(e.g.,Chiliotrichum diffusum,Holcus lanatus),the strongest intake linkages were found in exotic grasses(e.g.,Poa pratensis and Festuca sp.),native hemiparasites(e.g.,Misodendrum sp.),native shrubs(e.g.,Empetrum rubrum),and native trees(e.g.,Nothofagus sp.).The summer and autumn seasons presented higher intake compared to the winter and spring seasons.Furthermore,hemiparasites intake(e.g.,Misodendrum sp.)suggests that rabbits utilize different forage sources depending on the vegetation types.Conclusions:Rabbits regularly inhabit the forest,even though it is not their preferred vegetation type to live.Rabbit management entails isolating regions that are more favourable to intake and emphasizing the year’s season for rabbit control efforts.展开更多
基金supported by Fondecyt No. 1080294 and Fondecyt 1110719 (R Barra)
文摘This pilot study documented the occurrence and levels of brominated flame retardants in the tissues of farmed and wild salmon in southern Chile.Samples of Coho salmon and rainbow trout were obtained from fish farms,rivers and lakes in the Patagonia in Aysen Region,Chile.The samples were analyzed by Gas Chromatography Negative Chemical Ionization Mass Spectrometry for the different polybrominated diphenyl ether（PBDE） congeners.Contaminants were observed in all the samples,and the congeners BDE 17,28,47 and 66 were observed in all both farmed and wild samples.The concentrations were higher in the farmed Coho salmon,presenting significant differences with wild salmon.The levels reached 182 pg/g wet weight（ww） vs.120 ww.In the case of the rainbow trout,the concentrations were lower,although the congener profile was quite similar.The levels reached an average of 100 pg/g ww in the farmed fish versus 110 pg/g ww in wild fish,and no significant difference was observed between the species.In both species,the congener with the highest concentration was BDE 47.Based on this information,the BDE ？ow was estimated for commerce,which is a form of pollutant transport not usually considered in POP pollution studies.A preliminary estimation indicated that the quantity of PBDEs mobilized by commerce was in the order of kg,and in the case of Chile might reach almost 1 kg.
基金supported by the project:“Obtención de biocombustibles y compuestos químicos de alto valor agregado a partir de biomasas de desecho ricas en pectina”,CONAHCYT agreement:CB 255527-2016the Fellowship with reference number:654271 from the Mexican Council for Science and Technology,CONAHCYT was assigned to Eva Estela Rivera Cedillo as PhD student.
文摘The transformation of biomasses from agro-industrial waste can significantly impact the production of green chemicals from sustainable resources.Pectin is a biopolymer present in lignocellulosic biomass as Orange Peel Waste(OPW)and has possibilities for making platform compounds such as furfural for sustainable chemistry.In this work,we studied the transformation to furfural of OPW,pectins,and d-galacturonic acid(D-GalA),which is the main component(65 wt%)of pectin.We analyzed pectins with different degrees of esterification(45,60 and 95 DE)in a one-pot hydrolysis reaction system and studied the differences in depolymerization and dehydration of the carbohydrates.The results show that the production of furfural decreases as the DE value increases.Specifically,low DE values favor the formation of furfural since the decarboxylation reaction is favored over deesterification.Interestingly,the furfural concentration is dependent upon the polysaccharide composition of pentoses and uronic acid.The obtained concentrations of furfural(13 and 14 mmol/L),d-xylose(6.2 and 10 mmol/L),and L-arabinose(2.5 and 2.7 mmol/L)remained the same when the galacturonic acid was fed either as a polymer or a monomer under the same reaction conditions(0.01 M SA,90 min and 433 K).OPW is proposed as a feedstock in a biorefinery,in which on a per kg OPW dry basis,90 g of pectin and 15 g of furfural were produced in the most favorable case.We conclude that the co-production of pectin and furfural from OPW is economically feasible.
文摘The physicochemical properties and catalytic activity of pure and sulfated titanium oxide (TiO2 and ) is described in this work. Titanium hydroxide synthesized by the sol-gel method was impregnated with a 1 N H2SO4 solution, varying amount of sulfate ions () in the range from 10 to 20 wt%. Pure and modified hydroxides were calcined at 500°C for 3 h and then characterized by TGA-DTG, XRD, BET, FT-IR, potentiometric titration with n-butylamine and 2-propanol dehydration. Catalytic activity of materials was tested in the n-hexane isomerization at 350°C. The results showed that TiO2 and mainly developed anatase phase. All have acceptable specific surface area (95-105 m2/g). Potentiometric titration with n-butylamine revealed that showed higher acidity (430-530 mV) than compared to pure TiO2 (﹣15 mV), indicating that this oxide only has weak acidity. The results showed good relationship between acidity determined by potentiometric titration with n-butylamine and the catalytic activity evaluated by 2-propanol dehydration and n-hexane isomerization. Titanium oxide with 20 wt% ofions was the material that demonstrated the highest catalytic activity for both reactions.
文摘Background:The European rabbit(Oryctolagus cuniculus L.1758)was introduced into different regions of the world,generating significant trade‑offs that critically impacted native vegetation.Here,we evaluate the rabbit’s forage intakes in three vegetation types(forests,shrublands,and grasslands)along the four seasons in a temperate forest landscape in Southern Patagonia and discuss the potential threats over native vegetation.We formulated the following questions:(i)what is the forage offer at each vegetation type?(ii)what is the rabbit’s forage intake and how it varied across the seasons along the year?and(iii)which vegetation types and plant life forms were more used according to the rabbit’s forage intakes?Methods:We censused understory vegetation to characterize the forage offer at each vegetation type and determined seasonal dietary intakes using microhistological analysis of pellets.The plant species identified in the field were grouped according to life form classes(tree regeneration,shrubs,forbs,graminoids,orchids,ferns,bryophytes,and hemiparasites).Data were analysed through uni‑and multi‑variate analyses,determining relationships between forage offer and the rabbit’s forage intakes.Results:Forage intakes revealed changes in plant life form consumption across vegetation types,where intake pressure was considerably different for tree regeneration(p=0.001),graminoids(p=0.001),and hemiparasites(p=0.001).Besides,significant changes in consumption among seasons were detected for shrubs(p=0.001),ferns(p=0.030),and hemiparasites(p=0.002).Although many species play an important role in the rabbit’s forage intake networks(e.g.,Chiliotrichum diffusum,Holcus lanatus),the strongest intake linkages were found in exotic grasses(e.g.,Poa pratensis and Festuca sp.),native hemiparasites(e.g.,Misodendrum sp.),native shrubs(e.g.,Empetrum rubrum),and native trees(e.g.,Nothofagus sp.).The summer and autumn seasons presented higher intake compared to the winter and spring seasons.Furthermore,hemiparasites intake(e.g.,Misodendrum sp.)suggests that rabbits utilize different forage sources depending on the vegetation types.Conclusions:Rabbits regularly inhabit the forest,even though it is not their preferred vegetation type to live.Rabbit management entails isolating regions that are more favourable to intake and emphasizing the year’s season for rabbit control efforts.
