Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation...Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II)and Mn(II)by Pseudomonas taiwanensis(marked as P4)and Pseudomonas plecoglossicida(marked as G1)contains rich reactive oxygen functional groups,which play critical roles in the removal efficiency and immobilization of heavymetal(loid)s in co-contamination system.The isolated strains P4 and G1 can growwell in the following environments:pH 5-9,NaCl 0-4%,and temperature 20-30℃.The removal efficiencies of Fe,Pb,As,Zn,Cd,Cu,and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system(the initial concentrations of heavy metal(loid)were 1 mg/L),approximately reaching 96%,92%,85%,67%,70%,54%and 15%,respectively.The exchangeable and carbonate bound As,Cd,Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil,thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s.This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.展开更多
Precipitation patterns are vital to water resource management and hydrological research,especially in the upper reaches of inland rivers in arid and semiarid areas.However,estimating spatiotemporal precipitation patte...Precipitation patterns are vital to water resource management and hydrological research,especially in the upper reaches of inland rivers in arid and semiarid areas.However,estimating spatiotemporal precipitation patterns at a basin scale is challenging due to limited observations.In this study,spatiotemporal patterns of precipitation amount,frequency,duration,and intensity at different time scales from 2014 to 2019 are estimated using the Bayesian maximum entropy method in the Tianlaochi catchment of the Heihe River watershed,northwest China.The study's results show that the annual average precipitation amount was 535.9 mm from 2014 to 2019,with precipitation amount between May and September accounting for 85.9%of the annual precipitation amount.For daily precipitation,the average frequency rate of light precipitation is highest at 59.55%,however,the average contribution rate of moderate precipitation is highest at 50.33%.The spatial distribution of precipitation is characterized by high-value areas concentrated in the central valley and low-value areas located at the catchment's outlet.The most important driving factors of precipitation patterns are elevation,relative humidity,and wind direction.These outcomes can be used to establish accurate hydrological models in the catchment and provide support for water resource management in the Heihe River watershed.展开更多
基金supported d by the National Key Research and Development Program of China(No.2018YFC1802905).
文摘Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II)and Mn(II)by Pseudomonas taiwanensis(marked as P4)and Pseudomonas plecoglossicida(marked as G1)contains rich reactive oxygen functional groups,which play critical roles in the removal efficiency and immobilization of heavymetal(loid)s in co-contamination system.The isolated strains P4 and G1 can growwell in the following environments:pH 5-9,NaCl 0-4%,and temperature 20-30℃.The removal efficiencies of Fe,Pb,As,Zn,Cd,Cu,and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system(the initial concentrations of heavy metal(loid)were 1 mg/L),approximately reaching 96%,92%,85%,67%,70%,54%and 15%,respectively.The exchangeable and carbonate bound As,Cd,Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil,thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s.This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.
基金supported by the National Natural Science Foundation of China[grant number 31901130]China Postdoctoral Science Foundation[grant number 2020M673532]+1 种基金the Natural Science Foundation of Gansu Province,China[grant numbers 20JR5RA277,20JR5RE645]the Fundamental Research Funds for the Central Universities in Lanzhou University[grant number lzujbky-2020-kb35].
文摘Precipitation patterns are vital to water resource management and hydrological research,especially in the upper reaches of inland rivers in arid and semiarid areas.However,estimating spatiotemporal precipitation patterns at a basin scale is challenging due to limited observations.In this study,spatiotemporal patterns of precipitation amount,frequency,duration,and intensity at different time scales from 2014 to 2019 are estimated using the Bayesian maximum entropy method in the Tianlaochi catchment of the Heihe River watershed,northwest China.The study's results show that the annual average precipitation amount was 535.9 mm from 2014 to 2019,with precipitation amount between May and September accounting for 85.9%of the annual precipitation amount.For daily precipitation,the average frequency rate of light precipitation is highest at 59.55%,however,the average contribution rate of moderate precipitation is highest at 50.33%.The spatial distribution of precipitation is characterized by high-value areas concentrated in the central valley and low-value areas located at the catchment's outlet.The most important driving factors of precipitation patterns are elevation,relative humidity,and wind direction.These outcomes can be used to establish accurate hydrological models in the catchment and provide support for water resource management in the Heihe River watershed.
