Dissolved organic matter(DOM)in surface waters can vary markedly in character depending on seasonal variations such as rainfall intensity,UV radiations and temperature.Changes in DOM as well as temperature and rainfal...Dissolved organic matter(DOM)in surface waters can vary markedly in character depending on seasonal variations such as rainfall intensity,UV radiations and temperature.Changes in DOM as well as temperature and rainfall intensity over the year can affect the biochemical processes occurring in bank filtration(BF).Identification and characterization of DOM in the surface water could help to optimize the water treatment and provide stable and safe drinking water.This study investigated year-long variations of DOM concentrations and compositions in a surface water of a circulated outdoor pond(research facility)connected to a BF passage.DOM was dominated by humic substances and a changing pattern of DOM in surface water was observed throughout the year.A significant increase of DOM(~38%)in surface water was noted in August compared to November.The fluorescent DOM showed that DOM in summer was enriched with the degradable fraction whilst non-degradable fraction was dominated in winter.A constant(1.7±0.1 mg/L)effluent DOM was recirculated in the system throughout the year.DOM removal through BF varied between 4%to 39%and was achieved within a few meters after infiltration and significantly correlated with influent DOM concentration(R^(2)=0.82,p<0.05).However,no significant(p>0.05)change in the removal of DOM was observed in two subsurface layers(upper and lower).This study highlights the presence of a constant non-degradable DOM in the bank filtrate,which was not affected by temperature,redox conditions and UV radiations.展开更多
The occurrence of per-and polyfluoroalkyl substances(PFAS)in water cycles poses a challenge to drinking water quality and safety.In order to counteract the large knowledge gap regarding PFAS in German drinking water,8...The occurrence of per-and polyfluoroalkyl substances(PFAS)in water cycles poses a challenge to drinking water quality and safety.In order to counteract the large knowledge gap regarding PFAS in German drinking water,89 drinking water samples from all over Germany were collected with the help of residents and were analyzed for 26 PFAS by high-performance liquid chromatography with tandem mass spectrometry(HPLC-MS/MS).The 20 PFAS recently regulated by sum concentration(PFAS_(∑20)),as well as six other PFAS,were quantified by targeted analysis.In all drinking water samples,PFAS_(∑20 )was below the limit of 0.1μg/L,but the sum concentrations ranged widely from below the limit of quantification up to 80.2 ng/L.The sum concentrations(PFASP4)of perfluorohexanesulfonate(PFHxS),perfluorooctanesulfonate(PFOS),perfluorooctanoate(PFOA),and perfluorononanoate of 20 ng/L were exceeded in two samples.The most frequently detected individual substances were PFOS(in 52%of the samples),perfluorobutanesulfonate(52%),perfluorohexanoate(PFHxA)(44%),perfluoropentanoate(43%)and PFHxS(35%).The highest single concentrations were 23.5 ng/L for PFHxS,15.3 ng/L for PFOS,and 10.1 ng/L for PFHxA.No regionally elevated concentrations were identified,but some highly urbanized areas showed elevated levels.Concentrations of substitution PFAS,including 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate and 2,2,3-trifluor-3-[1,1,2,2,3,3-hexafluor-3-(trifluormethoxy)propoxy]-propanoate(anion of ADONA),were very low compared to regulated PFAS.The most frequently detected PFAS were examined for co-occurrences,but no definite correlations could be found.展开更多
Background Antimicrobial resistance is an increasing challenge in low and middle-income countries as it is wide-spread in these countries and is linked to an increased mortality.Apart from human and environmental fact...Background Antimicrobial resistance is an increasing challenge in low and middle-income countries as it is wide-spread in these countries and is linked to an increased mortality.Apart from human and environmental factors,animal-related drivers of antimicrobial resistance in low-and middle-income countries have special features that differ from high-income countries.The aim of this narrative review is to address the zoonotic sources and the spread of antimicrobial resistance from the perspective of low-and middle-income countries.Main body Contamination with extended-spectrum beta-lactamase(ESBL)-producingEscherichia coli is highest in poultry(Africa:8.9–60%,Asia:53–93%)and there is a risk to import ESBL-producingE.coli through poultry meat in Africa.In aquacultures,the proportion of ESBL-producers amongE.coli can be high(27%)but the overall low quality of published studies limit the general conclusion on the impact of aquacultures on human health.ESBL-producingE.coli colonization of wildlife is 1–9%in bats or 2.5–63%birds.Since most of them are migratory animals,they can disperse antimicrobial resistant bacteria over large distances.So-called‘filth flies’are a relevant vector not only of enteric pathogens but also of antimicrobial resistant bacteria in settings where sanitary systems are poor.In Africa,up to 72.5%of‘filth flies’are colonized with ESBL-producingE.coli,mostly conferred by CTX-M(24.4–100%).While methicillin-resistantStaphylococcus aureus plays a minor role in livestock in Africa,it is frequently found in South America in poultry(27%)or pork(37.5–56.5%)but less common in Asia(poultry:3%,pork:1–16%).Conclusions Interventions to contain the spread of AMR should be tailored to the needs of low-and middle-income countries.These comprise capacity building of diagnostic facilities,surveillance,infection prevention and control in small-scale farming.展开更多
基金supported by the German Academic Exchange Service (DAAD)and Higher Education Commission (HEC),Pakistan。
文摘Dissolved organic matter(DOM)in surface waters can vary markedly in character depending on seasonal variations such as rainfall intensity,UV radiations and temperature.Changes in DOM as well as temperature and rainfall intensity over the year can affect the biochemical processes occurring in bank filtration(BF).Identification and characterization of DOM in the surface water could help to optimize the water treatment and provide stable and safe drinking water.This study investigated year-long variations of DOM concentrations and compositions in a surface water of a circulated outdoor pond(research facility)connected to a BF passage.DOM was dominated by humic substances and a changing pattern of DOM in surface water was observed throughout the year.A significant increase of DOM(~38%)in surface water was noted in August compared to November.The fluorescent DOM showed that DOM in summer was enriched with the degradable fraction whilst non-degradable fraction was dominated in winter.A constant(1.7±0.1 mg/L)effluent DOM was recirculated in the system throughout the year.DOM removal through BF varied between 4%to 39%and was achieved within a few meters after infiltration and significantly correlated with influent DOM concentration(R^(2)=0.82,p<0.05).However,no significant(p>0.05)change in the removal of DOM was observed in two subsurface layers(upper and lower).This study highlights the presence of a constant non-degradable DOM in the bank filtrate,which was not affected by temperature,redox conditions and UV radiations.
文摘The occurrence of per-and polyfluoroalkyl substances(PFAS)in water cycles poses a challenge to drinking water quality and safety.In order to counteract the large knowledge gap regarding PFAS in German drinking water,89 drinking water samples from all over Germany were collected with the help of residents and were analyzed for 26 PFAS by high-performance liquid chromatography with tandem mass spectrometry(HPLC-MS/MS).The 20 PFAS recently regulated by sum concentration(PFAS_(∑20)),as well as six other PFAS,were quantified by targeted analysis.In all drinking water samples,PFAS_(∑20 )was below the limit of 0.1μg/L,but the sum concentrations ranged widely from below the limit of quantification up to 80.2 ng/L.The sum concentrations(PFASP4)of perfluorohexanesulfonate(PFHxS),perfluorooctanesulfonate(PFOS),perfluorooctanoate(PFOA),and perfluorononanoate of 20 ng/L were exceeded in two samples.The most frequently detected individual substances were PFOS(in 52%of the samples),perfluorobutanesulfonate(52%),perfluorohexanoate(PFHxA)(44%),perfluoropentanoate(43%)and PFHxS(35%).The highest single concentrations were 23.5 ng/L for PFHxS,15.3 ng/L for PFOS,and 10.1 ng/L for PFHxA.No regionally elevated concentrations were identified,but some highly urbanized areas showed elevated levels.Concentrations of substitution PFAS,including 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate and 2,2,3-trifluor-3-[1,1,2,2,3,3-hexafluor-3-(trifluormethoxy)propoxy]-propanoate(anion of ADONA),were very low compared to regulated PFAS.The most frequently detected PFAS were examined for co-occurrences,but no definite correlations could be found.
基金We acknowledge the open access fund of the University of Münster.
文摘Background Antimicrobial resistance is an increasing challenge in low and middle-income countries as it is wide-spread in these countries and is linked to an increased mortality.Apart from human and environmental factors,animal-related drivers of antimicrobial resistance in low-and middle-income countries have special features that differ from high-income countries.The aim of this narrative review is to address the zoonotic sources and the spread of antimicrobial resistance from the perspective of low-and middle-income countries.Main body Contamination with extended-spectrum beta-lactamase(ESBL)-producingEscherichia coli is highest in poultry(Africa:8.9–60%,Asia:53–93%)and there is a risk to import ESBL-producingE.coli through poultry meat in Africa.In aquacultures,the proportion of ESBL-producers amongE.coli can be high(27%)but the overall low quality of published studies limit the general conclusion on the impact of aquacultures on human health.ESBL-producingE.coli colonization of wildlife is 1–9%in bats or 2.5–63%birds.Since most of them are migratory animals,they can disperse antimicrobial resistant bacteria over large distances.So-called‘filth flies’are a relevant vector not only of enteric pathogens but also of antimicrobial resistant bacteria in settings where sanitary systems are poor.In Africa,up to 72.5%of‘filth flies’are colonized with ESBL-producingE.coli,mostly conferred by CTX-M(24.4–100%).While methicillin-resistantStaphylococcus aureus plays a minor role in livestock in Africa,it is frequently found in South America in poultry(27%)or pork(37.5–56.5%)but less common in Asia(poultry:3%,pork:1–16%).Conclusions Interventions to contain the spread of AMR should be tailored to the needs of low-and middle-income countries.These comprise capacity building of diagnostic facilities,surveillance,infection prevention and control in small-scale farming.
