Abiotic degradability of four phthalic acid esters （PAEs） in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunli...Abiotic degradability of four phthalic acid esters （PAEs） in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunlight irradiation for evaluating the degradation rate via hydrolysis or photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to winter in Osaka, Japan. The efficiency of abiotic degradation of the PAEs with relatively short alkyl chains, such as butylbenzyl phthalate （BBP） and di-nbutyl phthalate （DBP）, at neutral pH was significantly lower than that in the acidic or alkaline condition. Photolysis was considered to contribute mainly to the total abiotic degradation at all pH. Neither hydrolysis nor photolysis of di-ethylhexyl phthalate （DEHP） proceeded significantly at any pH, especially hydrolysis at neutral pH was negligible. On the other hand, the degradation rate of di- isononyl phthalate （DINP） catalyzed mainly by photolysis was much higher than those of the other PAEs, and was almost completely removed during the experimental period at pH 5 and 9. As a whole, according to the half-life （t1/2） obtained in the experiments, the abiotic degradability of the PAEs was in the sequence： DINP （32-140 d） 〉 DBP （50-360 d）, BBP （58-480 d） 〉 DEHP （390-1600 d） under sunlight irradiation （via photolysis plus hydrolysis）. Although the abiotic degradation rates for BBP, DBP, and DEHP are much lower than the biodegradation rates reported, the photolysis rate for DINP is comparable to its biodegradation rate in the acidic or alkaline condition.展开更多
Biodegradability of di-n-butyl phthalate （DBP）, butylbenzyl phthalate （BBP）, di-ethylhexyl phthalate （DEHP）, and di-isononyl phthalate （DINP） under an anaerobic condition was evaluated using three natural sedi...Biodegradability of di-n-butyl phthalate （DBP）, butylbenzyl phthalate （BBP）, di-ethylhexyl phthalate （DEHP）, and di-isononyl phthalate （DINP） under an anaerobic condition was evaluated using three natural sediment microcosms obtained from ponds in Osaka, which had not been significantly polluted by the chemicals. The degradabilities of the four phthalic acid esters（PAEs） were analyzed by a first-order kinetic model with a lag phase and ranked as DBP〉BBP〉〉DEHP〉DINP. The PAEs with shorter alkyl-chains, DBP and BBP, were degraded with quite short lag phases near to zero and short half-lives of a few days. The PAEs with longer alkyl-chains, DEHP and DINP, were degraded with lag phases of 5-30 d and the quite long half-lives of a couple of hundred days. Although no data was available on the anaerobic biodegradability of D1NP before this study, it was clarified that DINP can be degraded with slow degradation rates. The fact that all the three intact sediments were capable of biodegradation of the PAEs suggests that potential of anaerobic biodegradation of PAEs is widespread in the aquatic environment.展开更多
Total suspended particulate mater （TSP） concentrations were monitored for one year from July 2000 and for one year from April 2003 in Jakarta City. Thirteen elemental TSP components, aluminum （Al）, sodium （Na）, ...Total suspended particulate mater （TSP） concentrations were monitored for one year from July 2000 and for one year from April 2003 in Jakarta City. Thirteen elemental TSP components, aluminum （Al）, sodium （Na）, iron （Fe）, lead （Pb）, potassium （K）, zinc （Zn）, titanium （Ti）, manganese （Mn）, bromine （Br）, copper （Cu）, chromium （Cr）, nickel （Ni）, and vanadium （V） were analyzed by a sequential X-ray fluorescence spectrometer. Al, Na, Fe, K, and Pb were major components at most of the sampling locations in 2000. However, only Pb in 2003 dramatically decreased to one tenth. The phase-out of leaded gasoline began on July 1, 2001 in Jakarta City and lead content in gasoline decreased to one tenth, too. The decrease in Pb concentration was a result of the phase-out of leaded gasoline, as lead emissions mainly are exhaust gas from vehicles.展开更多
To generate cost-effective technologies for the removal of arsenic from water, we developed an enrichment culture of chemolithoau- totrophic arsenite oxidizing bacteria （CAOs） that could effectively oxidize widely r...To generate cost-effective technologies for the removal of arsenic from water, we developed an enrichment culture of chemolithoau- totrophic arsenite oxidizing bacteria （CAOs） that could effectively oxidize widely ranging concentrations of As（III） to As（V）. In addition, we attempted to elucidate the enrichment process and characterize the microbial composition of the enrichment culture. A CAOs enrichment culture capable of stably oxidizing As（III） to As（V） was successfully constructed through repeated batch cultivation for more than 700 days, during which time the initial As（iiI） concentrations were increased in a stepwise manner from 1 to 10-12 mmol/L. As（III） oxidation activity of the enrichment culture gradually improved, and 10-12 mmol/L As（III） was almost completely oxidized within four days. Terminal restriction fragment length polymorphism analysis showed that the dominant bacteria in the enrichment culture varied drastically during the enrichment process depending on the As（III） concentration. Isolation and characterization of bacteria in the enrichment culture revealed that the presence of multiple CAOs with various As（Ⅲ） oxidation abilities enabled the culture to adapt to a wide range of As（Ⅲ） concentrations. The CAOs enrichment culture constructed here may be useful for pretreatment of water from which arsenic is being removed.展开更多
文摘Abiotic degradability of four phthalic acid esters （PAEs） in the aquatic phase was evaluated over a wide pH range 5-9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunlight irradiation for evaluating the degradation rate via hydrolysis or photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to winter in Osaka, Japan. The efficiency of abiotic degradation of the PAEs with relatively short alkyl chains, such as butylbenzyl phthalate （BBP） and di-nbutyl phthalate （DBP）, at neutral pH was significantly lower than that in the acidic or alkaline condition. Photolysis was considered to contribute mainly to the total abiotic degradation at all pH. Neither hydrolysis nor photolysis of di-ethylhexyl phthalate （DEHP） proceeded significantly at any pH, especially hydrolysis at neutral pH was negligible. On the other hand, the degradation rate of di- isononyl phthalate （DINP） catalyzed mainly by photolysis was much higher than those of the other PAEs, and was almost completely removed during the experimental period at pH 5 and 9. As a whole, according to the half-life （t1/2） obtained in the experiments, the abiotic degradability of the PAEs was in the sequence： DINP （32-140 d） 〉 DBP （50-360 d）, BBP （58-480 d） 〉 DEHP （390-1600 d） under sunlight irradiation （via photolysis plus hydrolysis）. Although the abiotic degradation rates for BBP, DBP, and DEHP are much lower than the biodegradation rates reported, the photolysis rate for DINP is comparable to its biodegradation rate in the acidic or alkaline condition.
文摘Biodegradability of di-n-butyl phthalate （DBP）, butylbenzyl phthalate （BBP）, di-ethylhexyl phthalate （DEHP）, and di-isononyl phthalate （DINP） under an anaerobic condition was evaluated using three natural sediment microcosms obtained from ponds in Osaka, which had not been significantly polluted by the chemicals. The degradabilities of the four phthalic acid esters（PAEs） were analyzed by a first-order kinetic model with a lag phase and ranked as DBP〉BBP〉〉DEHP〉DINP. The PAEs with shorter alkyl-chains, DBP and BBP, were degraded with quite short lag phases near to zero and short half-lives of a few days. The PAEs with longer alkyl-chains, DEHP and DINP, were degraded with lag phases of 5-30 d and the quite long half-lives of a couple of hundred days. Although no data was available on the anaerobic biodegradability of D1NP before this study, it was clarified that DINP can be degraded with slow degradation rates. The fact that all the three intact sediments were capable of biodegradation of the PAEs suggests that potential of anaerobic biodegradation of PAEs is widespread in the aquatic environment.
基金The authors greatly appreciate the financial support of the Nissan Science Foundation for part of this study. Gratitude is also extended to EMC staff, and to the JICA Decentralized Environmental Management System Project.
文摘Total suspended particulate mater （TSP） concentrations were monitored for one year from July 2000 and for one year from April 2003 in Jakarta City. Thirteen elemental TSP components, aluminum （Al）, sodium （Na）, iron （Fe）, lead （Pb）, potassium （K）, zinc （Zn）, titanium （Ti）, manganese （Mn）, bromine （Br）, copper （Cu）, chromium （Cr）, nickel （Ni）, and vanadium （V） were analyzed by a sequential X-ray fluorescence spectrometer. Al, Na, Fe, K, and Pb were major components at most of the sampling locations in 2000. However, only Pb in 2003 dramatically decreased to one tenth. The phase-out of leaded gasoline began on July 1, 2001 in Jakarta City and lead content in gasoline decreased to one tenth, too. The decrease in Pb concentration was a result of the phase-out of leaded gasoline, as lead emissions mainly are exhaust gas from vehicles.
基金This work was supported by a Grant-in-Aid for Challenging Exploratory Research No. 20651017 from the Japan Society for the Promotion of Science (JSPS),Japanthe DOWA Techno Fund
文摘To generate cost-effective technologies for the removal of arsenic from water, we developed an enrichment culture of chemolithoau- totrophic arsenite oxidizing bacteria （CAOs） that could effectively oxidize widely ranging concentrations of As（III） to As（V）. In addition, we attempted to elucidate the enrichment process and characterize the microbial composition of the enrichment culture. A CAOs enrichment culture capable of stably oxidizing As（III） to As（V） was successfully constructed through repeated batch cultivation for more than 700 days, during which time the initial As（iiI） concentrations were increased in a stepwise manner from 1 to 10-12 mmol/L. As（III） oxidation activity of the enrichment culture gradually improved, and 10-12 mmol/L As（III） was almost completely oxidized within four days. Terminal restriction fragment length polymorphism analysis showed that the dominant bacteria in the enrichment culture varied drastically during the enrichment process depending on the As（III） concentration. Isolation and characterization of bacteria in the enrichment culture revealed that the presence of multiple CAOs with various As（Ⅲ） oxidation abilities enabled the culture to adapt to a wide range of As（Ⅲ） concentrations. The CAOs enrichment culture constructed here may be useful for pretreatment of water from which arsenic is being removed.
