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| 1.
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Maki, Teruya ; Hirota, Wakana ; Motojima, Hiroyuki ; Hasegawa, Hiroshi ; Rahman, Mohammad Azizur
概要:
金沢大学理工研究域物質化学系<br />Aquatic arsenic cycles mainly depend on microbial activities that change the arsenic chemical forms
…
and influence human health and organism activities. The microbial aggregates degrading organic matter are significantly related to the turnover between inorganic arsenic and organoarsenic compounds. We investigated the effects of microbial aggregates on organoarsenic mineralization in Lake Kahokugata using lake water samples spiked with dimethylarsinic acid (DMA). The lake water samples converted 1μmolL-1 of DMA to inorganic arsenic for 28d only under anaerobic and dark conditions in the presence of microbial activities. During the DMA mineralization process, organic aggregates >5.0μm with bacterial colonization increased the densities. When the organic aggregates >5.0μm were eliminated from the lake water samples using filters, the degradation activities were reduced. DMA in the lake water would be mineralized by the microbial aggregates under anaerobic and dark conditions. Moreover, DMA amendment enhanced the degradation activities in the lake water samples, which mineralized 50μmolL-1 of DMA. The DMA-amended aggregates >5.0μm completely degraded 1μmolL-1 of DMA with a shorter incubation time of 7d. The supplement of KNO3 and NaHCO3 to lake water samples also shortened the DMA-degradation period. Presumably, the bacterial aggregates involved in the chemical heterotrophic process would contribute to the DMA-biodegradation process in Lake Kahokugata, which is induced by the DMA amendment. © 2011 Elsevier Ltd.
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| 2.
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Azizur Rahman, Mohammad ; Hasegawa, Hiroshi
概要:
Phytoremediation, a plant based green technology, has received increasing attention after the discovery of hyperaccumula
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ting plants which are able to accumulate, translocate, and concentrate high amount of certain toxic elements in their above-ground/harvestable parts. Phytoremediation includes several processes namely, phytoextraction, phytodegradation, rhizofiltration, phytostabilization and phytovolatilization. Both terrestrial and aquatic plants have been tested to remediate contaminated soils and waters, respectively. A number of aquatic plant species have been investigated for the remediation of toxic contaminants such as As, Zn, Cd, Cu, Pb, Cr, Hg, etc. Arsenic, one of the deadly toxic elements, is widely distributed in the aquatic systems as a result of mineral dissolution from volcanic or sedimentary rocks as well as from the dilution of geothermal waters. In addition, the agricultural and industrial effluent discharges are also considered for arsenic contamination in natural waters. Some aquatic plants have been reported to accumulate high level of arsenic from contaminated water. Water hyacinth (Eichhornia crassipes), duckweeds (Lemna gibba, Lemna minor, Spirodela polyrhiza), water spinach (Ipomoea aquatica), water ferns (Azolla caroliniana, Azolla filiculoides, and Azolla pinnata), water cabbage (Pistia stratiotes), hydrilla (Hydrilla verticillata) and watercress (Lepidium sativum) have been studied to investigate their arsenic uptake ability and mechanisms, and to evaluate their potential in phytoremediation technology. It has been suggested that the aquatic macrophytes would be potential for arsenic phytoremediation, and this paper reviews up to date knowledge on arsenic phytoremediation by common aquatic macrophytes.. © 2011 Elsevier Ltd.
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| 3.
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Azizur Rahman, Mohammad ; Mamunur, Rahman ; Kadohashi, K. ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
This study was conducted to investigate the effect of external iron status and arsenic species on chelant-enhanced iron
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bioavailability and arsenic uptake. Rice seedlings (Oryza sativa L.) were used as model plant, and were grown in artificially contaminated sandy soils irrigated with Murashige and Skoog (MS) culture solution. Arsenate uptake in roots and shoots of rice seedlings were affected significantly (p > 0.05) while dimethylarsinic acid (DMAA) was not by the additional iron and chelating ligand treatments. Regardless of iron concentrations in the soil solution, HIDS increased arsenic uptake for roots more than EDTA and EDDS. Chelating ligands and arsenic species also influenced iron uptake in rice roots. Irrespective of arsenic species, HIDS was found to be more effective in the increase of iron bioavailability and uptake in rice roots compared to other chelants. There was a significant positive correlation (r = 0.78, p < 0.05) between arsenate and iron concentrations in the roots of rice seedlings grown with or without additional iron indicating that arsenate inhibit iron uptake. In contrast, there was no correlation between iron and DMAA uptake in roots. Poor correlation between iron and arsenic in shoots indicated that iron uptake in shoots was neither affected by additional iron nor by arsenic species. Compared to the control, chelating ligands increased iron uptake in shoots of rice seedlings significantly (p < 0.05). Regardless of additional iron and arsenic species, iron uptake in rice shoots did not differed among EDTA, EDDS, and HIDS treatments. © 2011 Elsevier Ltd. All rights reserved.
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| 4.
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Habibullah, M. ; Rahman, Ismail M. M. ; Uddin, M. Ashraf ; Iwakabe, Koichi ; Azam, Anisul ; Hasegawa, Hiroshi
概要:
Densities and viscosities of the binary systems of phenylmethanol with 2-butanone were measured for the entire compositi
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on range at T = (303.15, 308.15, 313.15, 318.15, and 323.15) K and at the atmospheric pressure. The excess molar volumes were derived from the experimental data and were fitted with the Redlich-Kister equation to obtain their coefficients and standard deviations. The Grunberg-Nissan equation was used to correlate the viscosity data. Furthermore, kinematic viscosities were compared with those predicted by the UNIFAC-VISCO model. The cause of relatively large deviations between the experimental and predicted kinematic viscosities was explored by comparing the combinatorial and residual terms of the UNIFAC-VISCO model. © 2011 American Chemical Society.
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| 5.
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Rahman, Ismail M. M. ; Furusho, Yoshiaki ; Begum, Zinnat A. ; Sabarudin, Akhmad ; Motomizu, Shoji ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
A simple flow-based method was developed for the simultaneous separation of certain transition metal ions (Co, Ni, Cu, Z
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n, Cd) from aqueous systems, which ions show ecotoxic effects when present at elevated concentrations. A silica-gel-bonded macrocycle system, commonly known as molecular recognition technology (MRT) gel, was used for solid phase extraction (SPE) of the target analytes. The collection behavior of the MRT-SPE system was studied based on pH. Fortified deionized water samples containing 250 μg L-1 of each of the elements were treated at the flow rate of 1 mL min-1. The collected analytes were then eluted by 3 M HNO3 and analyzed using inductively coupled plasma spectrometry. Detection limits of the proposed technique were in the range of 0.004-0.040 μg L-1 for the studied metal ions. The validity of this separation technique was checked with spiked 'real' water samples, which produced satisfactory recoveries of 96-102%. The non-destructive nature and highly selective ion-extraction capability of the SPE material are the most important aspects of the proposed method and they are the main focus of this paper. © 2011 © Versita Warsaw and Springer-Verlag Wien.
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| 6.
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Hasegawa, Hiroshi ; Rahman, Ismail M. M. ; Nakano, Masayoshi ; Begum, Zinnat A. ; Egawa, Yuji ; Maki, Teruya ; Furusho, Yoshiaki ; Mizutani, Satoshi
概要:
Aminopolycarboxylate chelants (APCs) are extremely useful for a variety of industrial applications, including the treatm
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ent of toxic metal-contaminated solid waste materials. Because non-toxic matrix elements compete with toxic metals for the binding sites of APCs, an excess of chelant is commonly added to ensure the adequate sequestration of toxic metal contaminants during waste treatment operations. The major environmental impacts of APCs are related to their ability to solubilize toxic heavy metals. If APCs are not sufficiently eliminated from the effluent, the aqueous transport of metals can occur through the introduction of APCs into the natural environment, increasing the magnitude of associated toxicity. Although several techniques that focus primarily on the degradation of APCs at the pre-release step have been proposed, methods that recycle not only the processed water, but also provide the option to recover and reuse the metals, might be economically feasible, considering the high costs involved due to the chelants used in metal ion sequestration. In this paper, we propose a separation process for the recovery of metals from effluents that contain an excess of APCs. Additionally, the option of recycling the processed water using a solid phase extraction (SPE) system with an ion-selective immobilized macrocyclic material, commonly known as a molecular recognition technology (MRT) gel, is presented. Simulated effluents containing As(V), Cd(II), Cr(III), Pb(II) or Se(IV) in the presence of APCs at molar ratios of 1:50 in H2O were studied with a flow rate of 0.2mL min-1. The 'captured' ions in the SPE system were quantitatively eluted with HNO3. The effects of solution pH, metal-chelant stability constants and matrix elements were assessed. Better separation performance for the metals was achieved with the MRT-SPE compared to other SPE materials. Our proposed technique offers the advantage of a non-destructive separation of both metal ions and chelants compared to conventional treatment options for such effluents. © 2011 Elsevier Ltd.
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| 7.
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Hasegawa, Hiroshi ; Rahman, Ismail M.M. ; Nakano, Masayoshi ; Begum, Zinnat A. ; Egawa, Yuji ; Maki, Teruya ; Furusho, Yoshiaki ; Mizutani, Satoshi
概要:
Aminopolycarboxylate chelants (APCs) are extremely useful for a variety of industrial applications, including the treatm
…
ent of toxic metal-contaminated solid waste materials. Because non-toxic matrix elements compete with toxic metals for the binding sites of APCs, an excess of chelant is commonly added to ensure the adequate sequestration of toxic metal contaminants during waste treatment operations. The major environmental impacts of APCs are related to their ability to solubilize toxic heavy metals. If APCs are not sufficiently eliminated from the effluent, the aqueous transport of metals can occur through the introduction of APCs into the natural environment, increasing the magnitude of associated toxicity. Although several techniques that focus primarily on the degradation of APCs at the pre-release step have been proposed, methods that recycle not only the processed water, but also provide the option to recover and reuse the metals, might be economically feasible, considering the high costs involved due to the chelants used in metal ion sequestration. In this paper, we propose a separation process for the recovery of metals from effluents that contain an excess of APCs. Additionally, the option of recycling the processed water using a solid phase extraction (SPE) system with an ion-selective immobilized macrocyclic material, commonly known as a molecular recognition technology (MRT) gel, is presented. Simulated effluents containing As(V), Cd(II), Cr(III), Pb(II) or Se(IV) in the presence of APCs at molar ratios of 1:50 in H2O were studied with a flow rate of 0.2mL min-1. The 'captured' ions in the SPE system were quantitatively eluted with HNO3. The effects of solution pH, metal-chelant stability constants and matrix elements were assessed. Better separation performance for the metals was achieved with the MRT-SPE compared to other SPE materials. Our proposed technique offers the advantage of a non-destructive separation of both metal ions and chelants compared to conventional treatment options for such effluents. © 2011 Elsevier Ltd.
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| 8.
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Rahman, M. Azizur ; Hasegawa, Hiroshi
概要:
Rice is the staple food for the people of arsenic endemic South (S) and South-East (SE) Asian countries. In this region,
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arsenic contaminated groundwater has been used not only for drinking and cooking purposes but also for rice cultivation during dry season. Irrigation of arsenic-contaminated groundwater for rice cultivation has resulted high deposition of arsenic in topsoil and uptake in rice grain posing a serious threat to the sustainable agriculture in this region. In addition, cooking rice with arsenic-contaminated water also increases arsenic burden in cooked rice. Inorganic arsenic is the main species of S and SE Asian rice (80 to 91% of the total arsenic), and the concentration of this toxic species is increased in cooked rice from inorganic arsenic-rich cooking water. The people of Bangladesh and West Bengal (India), the arsenic hot spots in the world, eat an average of 450. g rice a day. Therefore, in addition to drinking water, dietary intake of arsenic from rice is supposed to be another potential source of exposure, and to be a new disaster for the population of S and SE Asian countries. Arsenic speciation in raw and cooked rice, its bioavailability and the possible health hazard of inorganic arsenic in rice for the population of S and SE Asia have been discussed in this review. © 2011 Elsevier B.V.
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| 9.
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Rahman, Ismail M. M. ; Furusho, Yoshiaki ; Begum, Zinnat A. ; Sabarudin, Akhmad ; Motomizu, Shoji ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
A simple flow-based method was developed for the simultaneous separation of certain transition metal ions (Co, Ni, Cu, Z
…
n, Cd) from aqueous systems, which ions show ecotoxic effects when present at elevated concentrations. A silica-gel-bonded macrocycle system, commonly known as molecular recognition technology (MRT) gel, was used for solid phase extraction (SPE) of the target analytes. The collection behavior of the MRT-SPE system was studied based on pH. Fortified deionized water samples containing 250 ìg L-1 of each of the elements were treated at the flow rate of 1 mL min-1. The collected analytes were then eluted by 3 M HNO3 and analyzed using inductively coupled plasma spectrometry. Detection limits of the proposed technique were in the range of 0.004-0.040 ìg L-1 for the studied metal ions. The validity of this separation technique was checked with spiked 'real' water samples, which produced satisfactory recoveries of 96-102%. The non-destructive nature and highly selective ion-extraction capability of the SPE material are the most important aspects of the proposed method and they are the main focus of this paper. © Versita Sp. z o.o.
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| 10.
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Maki, Teruya ; Aoki, Kazuma ; Kobayashi, Fumihisa ; Kakikawa, Makiko ; Tobo, Yutaka ; Matsuki, Atsushi ; Hasegawa, Hiroshi ; Iwasaka, Yasunobu
概要:
金沢大学理工研究域物質化学系<br />Microbial particles transported by Asian desert dust (KOSA) possibly impact ecosystems and human hea
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lth in downwind environments and are commonly called "bioaerosols." The microbial communities associated with KOSA mineral particles (KOSA bioaerosol), which were collected from the snow cover on Mt. Tateyama, were investigated by means of a culture-amendment technique combined with denaturing gradient gel electrophoresis (DGGE) analysis using 16S rRNA genes. After the stratigraphy of the snow layer formed on the walls of a snow pit on Mt. Tateyama, samples were collected from 2 layers, which included KOSA particles and one which did not. The snow samples with KOSA particles indicated microbial growth in the 100 and 10-1 dilution media and in the medium with NaCl below 10%, while the snow sample without KOSA particles showed no microbial growth in the culture media. The PCR-DGGE analysis revealed that the bacterial compositions in the snow samples including KOSA mineral particles were mainly composed of the members of the phyla Actinobacteria, Firmicutus, and Proteobacteria. In particular, the 2 phylotypes appeared in the microbial cultures were similar to the members of the B. subtilis group, which has been detected in bioaerosol samples collected from the atmosphere over KOSA arrival (Suzu City) and source (Dunhuang City) regions. Presumably, halotolerant and oligotrophic bacterial communities are associated with the KOSA particles that descend to the snow cover on Mt. Tateyama. © 2011 Springer Science+Business Media B.V.
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| 11.
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Rahman, Ismail M. M. ; Islam, M. Monirul ; Hossain, M. Mosharraf ; Hossain, M. Shahadat ; Begum, Zinnat A. ; Chowdhury, Didarul A. ; Chakraborty, Milan K. ; Rahman, M. Azizur ; Nazimuddin, Mohammad ; Hasegawa, Hiroshi
概要:
金沢大学理工研究域物質化学系<br />The concern over ensuing freshwater scarcity has forced the developing countries to delve for altern
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ative water resources. In this study, we examined the potential of stagnant surface water bodies (SSWBs) as alternative freshwater resources in the densely populated Chittagong metropolitan area (CMPA) of Bangladesh-where there is an acute shortage of urban freshwater supply. Water samples were collected at 1-month intervals for a period of 1 year from 12 stations distributed over the whole metropolis. Samples were analyzed for pH, water temperature (WTemp), turbidity, electrical conductivity (EC), total dissolved solids, total solids, total hardness, dissolved oxygen (DO), chloride, orthophosphates, ammonia, total coliforms (TC), and trace metal (Cd, Cr, Cu, Pb, As, and Fe) concentrations. Based on these parameters, different types of water quality indices (WQIs) were deduced. WQIs showed most of CMPA-SSWBs as good or medium quality water bodies, while none were categorized as bad. Moreover, it was observed that the minimal water quality index (WQIm), computed using five parameters: WTemp, pH, DO, EC, and turbidity, gave a reliable estimate of water quality. The WQIm gave similar results in 72% of the cases compared with other WQIs that were based on larger set of parameters. Based on our finding, we suggest the wider use WQIm in developing countries for assessing health of SSWBs, as it will minimize the analytical cost to overcome the budget constraints involved in this kind of evaluations. It was observed that except turbidity and TC content, all other quality parameters fluctuated within the limit of the World Health Organization suggested standards for drinking water. From our findings, we concluded that if the turbidity and TC content of water from SSWBs in CMPA are taken care of, they will become good candidates as alternative water resources all round the year. © 2010 Springer Science+Business Media B.V.
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| 12.
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Rahman, M.A. ; Kadohashi, K. ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
金沢大学理工研究域物質化学系<br />Arsenate (As(V)) transport into plant cells has been well studied. A study on rice (Oryza sativa L.)
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showed that arsenite is transported across the plasma membrane via glycerol transporting channels. Previous studies reported that the dimethylarsinic acid (DMAA) and monomethylarsonic acid (MMAA) uptake in duckweed (Spirodela polyrhiza L.) differed from that of As(V), and was unaffected by phosphate (H2PO4). This article reports the transport mechanisms of DMAA and MMAA in rice roots. Linear regression analysis showed that the DMAA and MMAA uptake in rice roots increased significantly (p ≤ 0.0002 and ≤0.0001 for DMAA and MMAA, respectively) with the increase of exposure time. Concentration-dependent influx of DMAA and MMAA showed that the uptake data were well described by Michaelis-Menten kinetics. The MMAA influx was higher than that of DMAA. The DMAA and MMAA uptake in rice roots were decreased significantly (p ≤ 0.0001 and ≤0.0077 for DMAA and MMAA, respectively) with the increase of glycerol concentration indicating that DMAA and MMAA were transported into rice roots using the same mechanisms of glycerol. Glycerol is transported into plant cells by aquaporins, and DMAA and MMAA are transported in a dose-dependent manner of glycerol which reveals that DMAA and MMAA are transported into rice roots through glycerol transporting channels. The DMAA and MMAA concentration in the solution did not affect the inhibition of their uptake rate by glycerol. © 2010.
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| 13.
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Rahman, Ismail M. M. ; Uddin, M. Ashraf ; Iwakabe Koichi ; Adhikhari, Anath B. ; Majid, M. Abdul ; Hasegawa, Hiroshi
概要:
金沢大学理工研究域物質化学系<br />Viscosities of binary liquid mixtures of butan-2-one with benzene were measured at a number of mole
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fractions at T = (303.15, 313.15, and 323.15) K and atmospheric pressure. The viscometric behavior is discussed on the basis of structural and geometrical effects between the components. In addition, kinematic viscosities were calculated using the UNIFAC-VISCO model. The predicted kinematic viscosities are in good agreement with the experimental ones. © 2011 American Chemical Society.
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| 14.
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Rahman, Ismail M. M. ; Islam, M. Monirul ; Hossain, M. Mosharraf ; Hossain, M. Shahadat ; Begum, Zinnat A. ; Chowdhury, Didarul A. ; Chakraborty, Milan K. ; Rahman, M. Azizur ; Nazimuddin, M. ; Hasegawa, Hiroshi
概要:
金沢大学理工研究域物質化学系<br />The concern over ensuing freshwater scarcity has forced the developing countries to delve for altern
…
ative water resources. In this study, we examined the potential of stagnant surface water bodies (SSWBs) as alternative freshwater resources in the densely populated Chittagong metropolitan area (CMPA) of Bangladesh-where there is an acute shortage of urban freshwater supply. Water samples were collected at 1-month intervals for a period of 1 year from 12 stations distributed over the whole metropolis. Samples were analyzed for pH, water temperature (WTemp), turbidity, electrical conductivity (EC), total dissolved solids, total solids, total hardness, dissolved oxygen (DO), chloride, orthophosphates, ammonia, total coliforms (TC), and trace metal (Cd, Cr, Cu, Pb, As, and Fe) concentrations. Based on these parameters, different types of water quality indices (WQIs) were deduced. WQIs showed most of CMPA-SSWBs as good or medium quality water bodies, while none were categorized as bad. Moreover, it was observed that the minimal water quality index (WQI m), computed using five parameters: WTemp, pH, DO, EC, and turbidity, gave a reliable estimate of water quality. The WQIm gave similar results in 72% of the cases compared with other WQIs that were based on larger set of parameters. Based on our finding, we suggest the wider use WQI m in developing countries for assessing health of SSWBs, as it will minimize the analytical cost to overcome the budget constraints involved in this kind of evaluations. It was observed that except turbidity and TC content, all other quality parameters fluctuated within the limit of the World Health Organization suggested standards for drinking water. From our findings, we concluded that if the turbidity and TC content of water from SSWBs in CMPA are taken care of, they will become good candidates as alternative water resources all round the year. © 2010 Springer Science+Business Media B.V.
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| 15.
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論文
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Maki, Teruya ; Hirota, Wakana ; Motojima, Hiroyuki ; Hasegawa, Hiroshi ; Rahman, Mohammad Azizur
概要:
金沢大学理工研究域物質化学系<br />Aquatic arsenic cycles mainly depend on microbial activities that change the arsenic chemical forms
…
and influence human health and organism activities. The microbial aggregates degrading organic matter are significantly related to the turnover between inorganic arsenic and organoarsenic compounds. We investigated the effects of microbial aggregates on organoarsenic mineralization in Lake Kahokugata using lake water samples spiked with dimethylarsinic acid (DMA). The lake water samples converted 1 μmol L-1 of DMA to inorganic arsenic for 28 d only under anaerobic and dark conditions in the presence of microbial activities. During the DMA mineralization process, organic aggregates >5.0 μm with bacterial colonization increased the densities. When the organic aggregates >5.0 μm were eliminated from the lake water samples using filters, the degradation activities were reduced. DMA in the lake water would be mineralized by the microbial aggregates under anaerobic and dark conditions. Moreover, DMA amendment enhanced the degradation activities in the lake water samples, which mineralized 50 μmol L-1 of DMA. The DMA-amended aggregates >5.0 μm completely degraded 1 μmol L-1 of DMA with a shorter incubation time of 7 d. The supplement of KNO3 and NaHCO3 to lake water samples also shortened the DMA-degradation period. Presumably, the bacterial aggregates involved in the chemical heterotrophic process would contribute to the DMA-biodegradation process in Lake Kahokugata, which is induced by the DMA amendment. © 2011 Elsevier Ltd. All rights reserved.
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| 16.
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Hasegawa, Hiroshi ; Rahman, Ismail M. M. ; Kinoshita, Sanae ; Maki, Teruya ; Furusho, Yoshiaki
概要:
金沢大学理工研究域物質化学系<br />A new technique for the separation and pre-concentration of dissolved Fe(III) from the ligand-rich a
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queous system is proposed. A solid phase extraction (SPE) system with an immobilized macrocyclic material, commonly known as molecular recognition technology (MRT) gel and available commercially, was used. Synthetic Fe(III) solution in aqueous matrices spiked with a 100-fold concentration of EDTA was used. Dissolved iron that was 'captured' by the MRT gel was eluted using hydrochloric acid and subsequently determined by graphite furnace atomic absorption spectrometry. The effect of different variables, such as pH, reagent concentration, flow rate and interfering ions, on the recovery of analyte was investigated. Quantitative maximum separation (~100%) of the dissolved Fe(III) from synthetic aqueous solutions at a natural pH range was observed at a flow rate of 0.2mLmin-1. The extraction efficiency of the MRT gel is largely unaltered by the coexisting ions commonly found in natural water. When compared with different SPE materials, the separation performance of MRT gel is also much higher. © 2010 Elsevier Ltd.
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| 17.
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Hasegawa, Hiroshi ; Rahman, M.A. ; Saitou, K. ; Kobayashi, M. ; Okumura, C.
概要:
金沢大学理工研究域物質化学系<br />In this study, the effects of chelating ligands on iron movement in growth medium, iron bioavailabil
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ity, and growth of radish sprouts (Raphanus sativus) were investigated. Iron is an important nutrient for plant growth, yet the insoluble state of iron hydroxides in alkaline conditions decreases its bioavailability. Iron chelates increase iron uptake and have been used in agriculture to correct iron chlorosis. While previous studies have reported the effects of chelating ligands on iron solubility and bioavailability, the present study elucidates the pattern of iron movement by chelating ligands in plant growth medium. The apparent mobility of iron in growth medium was calculated using a '4-box' model. Ethylenediaminedisuccinic acid (EDDS) and hydroxy-iminodisuccinic acid (HIDS) produced the highest apparent mobility of iron from the bottom layer of the medium (initially 10-4M Fe(III)) to the upper layer (no iron), followed by glutamatediacetic acid (GLDA), ethylenediaminetetraacetic acid (EDTA), methylglycinediacetic acid (MGDA), and iminodisuccinic acid (IDS). Iron movement in the growth medium was influenced by the chelating ligand species, pH, and ligand exposure time. The iron uptake and growth of radish sprouts were related to the iron mobility produced by the chelating ligands. These results suggest that, in alkaline media, chelating ligands dissolve the hardly soluble iron hydroxide species, thus increasing iron mobility, iron uptake, and plant growth. HIDS, which is biodegradable, was one of the most effective ligands studied; therefore, this compound would be a good alternative to other environmentally persistent chelating ligands. © 2011 Elsevier B.V.<br />2011年8月より全文公開.
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| 18.
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Hasegawa, Hiroshi ; Rahman, M. Azizur ; Saitou, K. ; Kobayashi, M. ; Okumura, Chikako
概要:
In this study, the effects of chelating ligands on iron movement in growth medium, iron bioavailability, and growth of r
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adish sprouts (Raphanus sativus) were investigated. Iron is an important nutrient for plant growth, yet the insoluble state of iron hydroxides in alkaline conditions decreases its bioavailability. Iron chelates increase iron uptake and have been used in agriculture to correct iron chlorosis. While previous studies have reported the effects of chelating ligands on iron solubility and bioavailability, the present study elucidates the pattern of iron movement by chelating ligands in plant growth medium. The apparent mobility of iron in growth medium was calculated using a '4-box' model. Ethylenediaminedisuccinic acid (EDDS) and hydroxy-iminodisuccinic acid (HIDS) produced the highest apparent mobility of iron from the bottom layer of the medium (initially 10-4M Fe(III)) to the upper layer (no iron), followed by glutamatediacetic acid (GLDA), ethylenediaminetetraacetic acid (EDTA), methylglycinediacetic acid (MGDA), and iminodisuccinic acid (IDS). Iron movement in the growth medium was influenced by the chelating ligand species, pH, and ligand exposure time. The iron uptake and growth of radish sprouts were related to the iron mobility produced by the chelating ligands. These results suggest that, in alkaline media, chelating ligands dissolve the hardly soluble iron hydroxide species, thus increasing iron mobility, iron uptake, and plant growth. HIDS, which is biodegradable, was one of the most effective ligands studied; therefore, this compound would be a good alternative to other environmentally persistent chelating ligands. © 2011 Elsevier B.V.
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| 19.
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Azizur Rahman, Mohammad ; Kadohashi, K. ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
Arsenate (As(V)) transport into plant cells has been well studied. A study on rice (Oryza sativa L.) showed that arsenit
…
e is transported across the plasma membrane via glycerol transporting channels. Previous studies reported that the dimethylarsinic acid (DMAA) and monomethylarsonic acid (MMAA) uptake in duckweed (Spirodela polyrhiza L.) differed from that of As(V), and was unaffected by phosphate (H2PO4). This article reports the transport mechanisms of DMAA and MMAA in rice roots. Linear regression analysis showed that the DMAA and MMAA uptake in rice roots increased significantly (p竕､0.0002 and 竕､0.0001 for DMAA and MMAA, respectively) with the increase of exposure time. Concentration-dependent influx of DMAA and MMAA showed that the uptake data were well described by Michaelis-Menten kinetics. The MMAA influx was higher than that of DMAA. The DMAA and MMAA uptake in rice roots were decreased significantly (p竕､0.0001 and 竕､0.0077 for DMAA and MMAA, respectively) with the increase of glycerol concentration indicating that DMAA and MMAA were transported into rice roots using the same mechanisms of glycerol. Glycerol is transported into plant cells by aquaporins, and DMAA and MMAA are transported in a dose-dependent manner of glycerol which reveals that DMAA and MMAA are transported into rice roots through glycerol transporting channels. The DMAA and MMAA concentration in the solution did not affect the inhibition of their uptake rate by glycerol.. © 2010 Elsevier B.V.
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| 20.
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Rahman, Ismail M. M. ; Islam, M. Monirul ; Hossain, M. Mosharraf ; Hossain, M. Shahadat ; Begum, Zinnat A. ; Chowdhury, Didarul A. ; Chakraborty, Milan K. ; Rahman, M. Azizur ; Nazimuddin, M. ; Hasegawa, Hiroshi
概要:
金沢大学理工研究域物質化学系<br />The concern over ensuing freshwater scarcity has forced the developing countries to delve for altern
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ative water resources. In this study, we examined the potential of stagnant surface water bodies (SSWBs) as alternative freshwater resources in the densely populated Chittagong metropolitan area (CMPA) of Bangladesh-where there is an acute shortage of urban freshwater supply. Water samples were collected at 1-month intervals for a period of 1 year from 12 stations distributed over the whole metropolis. Samples were analyzed for pH, water temperature (WTemp), turbidity, electrical conductivity (EC), total dissolved solids, total solids, total hardness, dissolved oxygen (DO), chloride, orthophosphates, ammonia, total coliforms (TC), and trace metal (Cd, Cr, Cu, Pb, As, and Fe) concentrations. Based on these parameters, different types of water quality indices (WQIs) were deduced. WQIs showed most of CMPA-SSWBs as good or medium quality water bodies, while none were categorized as bad. Moreover, it was observed that the minimal water quality index (WQI m), computed using five parameters: WTemp, pH, DO, EC, and turbidity, gave a reliable estimate of water quality. The WQIm gave similar results in 72% of the cases compared with other WQIs that were based on larger set of parameters. Based on our finding, we suggest the wider use WQI m in developing countries for assessing health of SSWBs, as it will minimize the analytical cost to overcome the budget constraints involved in this kind of evaluations. It was observed that except turbidity and TC content, all other quality parameters fluctuated within the limit of the World Health Organization suggested standards for drinking water. From our findings, we concluded that if the turbidity and TC content of water from SSWBs in CMPA are taken care of, they will become good candidates as alternative water resources all round the year. © 2010 Springer Science+Business Media B.V.
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| 21.
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論文
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Rahman, Ismail M. M. ; Furusho, Yoshiaki ; Begum, Zinnat A. ; Ronald, Neil Izatt ; Akhmad Sabarudin, Bruening ; Hasegawa, Hiroshi
概要:
金沢大学理工研究域物質化学系<br />Separation of trace levels of lead from concentrated-matrix electroless nickel plating (ENP) waste s
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olutions is required to meet the increasingly stringent environmental regulations. A solid phase extraction (SPE) system using a molecular recognition technology (MRT) gel was used for the selective separation of trace levels of lead (Pb) from the waste discharge of ENP operations, followed by subsequent analysis with inductively coupled plasma optical emission spectrometry (ICP-OES). Two SPE-MRTs, AnaLig® Pb-01 and AnaLig® Pb-02, packed in 3 mL polypropylene cartridges were used to treat the synthetic metal-waste solutions that were used to simulate the typical metal mixture in ENP bath waste. The fortified solutions contained 100-1000 μg L- 1 of Pb in an HNO3 matrix with pre-added Ni, Cu and other interfering elements (1000 mg L- 1). After the sample treatment, the SPE-MRT cartridges were washed with water and 0.1 M nitric acid, followed by elution with 0.03 M EDTA. The matrix elements (e.g., Ni, Cu) were completely removed at the washing step, while the 'captured' Pb was quantitatively eluted, as determined by ICP-OES measurements. The detection limit of the proposed method was 2.6 μg L- 1. 'Real' samples from commercial ENP operations were used to assess the validity of this method, and almost quantitative Pb recovery was observed. The excellent Pb selectivity of the SPE-MRT system indicates the potential of the proposed technique for trace-level Pb separation from the Pb-containing high matrix aqueous waste discharge. © 2010 Elsevier B.V. All rights reserved.
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| 22.
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Hasegawa, Hiroshi ; Rahman, Ismail M. M. ; Kinoshita, Sanae ; Maki, Teruya ; Furusho, Yoshiaki
概要:
金沢大学理工研究域物質化学系<br />A new technique for the separation and pre-concentration of dissolved Fe(III) from the ligand-rich a
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queous system is proposed. A solid phase extraction (SPE) system with an immobilized macrocyclic material, commonly known as molecular recognition technology (MRT) gel and available commercially, was used. Synthetic Fe(III) solution in aqueous matrices spiked with a 100-fold concentration of EDTA was used. Dissolved iron that was 'captured' by the MRT gel was eluted using hydrochloric acid and subsequently determined by graphite furnace atomic absorption spectrometry. The effect of different variables, such as pH, reagent concentration, flow rate and interfering ions, on the recovery of analyte was investigated. Quantitative maximum separation (~100%) of the dissolved Fe(III) from synthetic aqueous solutions at a natural pH range was observed at a flow rate of 0.2mLmin-1. The extraction efficiency of the MRT gel is largely unaltered by the coexisting ions commonly found in natural water. When compared with different SPE materials, the separation performance of MRT gel is also much higher. © 2010 Elsevier Ltd.
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| 23.
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論文
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Rahman, Ismail M. M. ; Begum, Zinnat A. ; Nakano, Masayoshi ; Furusho, Yoshiaki ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
金沢大学理工研究域物質化学系<br />A combination of solid phase extraction (SPE) columns was used for selective separation of water-sol
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uble arsenic species: arsenite, arsenate, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). The SPE columns, namely AnaLig TE-01 (TE-01), AnaLig AN-01 Si (AN-01) and AnaLig As-01 PA (As-01), contain immobilized macrocyclic material as the sorbent and commonly known as molecular recognition technology (MRT) gel. The retention, extraction and recovery behavior of the MRT gel SPE columns were studied at pH 4-10. Fortified deionized water spiked with 100μM of arsenic species were treated at the flow rate of 0.2mLmin-1. HNO3 (1.0 and 6.0M) was used as eluent to recover the retained arsenic species from TE-01 and AN-01 SPE columns. Arsenic species retained in the As-01 column were eluted with HNO3 (0.1M) followed by NaOH (2.0M). Likely interference from the various coexisting ions (Na+, K+, Ca2+, Mg2+, Cl-, NO3-, CH3COO-, PO43-, SO42-, ClO4-) (10mM) were negligible. Quantitative separation of As(III), As(V), MMA and DMA was achieved based on the differences in extraction and recovery behavior of the MRT gel SPE columns with pH for different arsenic species. Complexation between arsenic species and MRT gel is the core phenomenon of the proposed technique as the complexation of MRT gels is expected to be stronger than the resin-based separation processes. MRT gel SPE columns are advantageous as compared with other reported SPE columns in terms of its performance with As(III). Effortless regeneration and unaltered separation performance of the sorbent materials for more than 100 loading and elution cycles are other sturdy characteristics to consider the MRT gel SPE columns for sensitive and selective arsenic species separation. © 2010 Elsevier Ltd.
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| 24.
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論文
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Hasegawa, Hiroshi ; Rahman, Ismail M. M. ; Kinoshita, Sanae ; Maki, Teruya ; Furusho, Yoshiaki
概要:
金沢大学理工研究域物質化学系<br />A new technique for the separation and pre-concentration of dissolved Fe(III) from the ligand-rich a
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queous system is proposed. A solid phase extraction (SPE) system with an immobilized macrocyclic material, commonly known as molecular recognition technology (MRT) gel and available commercially, was used. Synthetic Fe(III) solution in aqueous matrices spiked with a 100-fold concentration of EDTA was used. Dissolved iron that was 'captured' by the MRT gel was eluted using hydrochloric acid and subsequently determined by graphite furnace atomic absorption spectrometry. The effect of different variables, such as pH, reagent concentration, flow rate and interfering ions, on the recovery of analyte was investigated. Quantitative maximum separation (~100%) of the dissolved Fe(III) from synthetic aqueous solutions at a natural pH range was observed at a flow rate of 0.2mLmin-1. The extraction efficiency of the MRT gel is largely unaltered by the coexisting ions commonly found in natural water. When compared with different SPE materials, the separation performance of MRT gel is also much higher. © 2010 Elsevier Ltd.
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| 25.
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論文
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Rahman, Ismail M.M. ; Begum, Zinnat A. ; Nakano, Masayoshi ; Furusho, Yoshiaki ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
金沢大学理工研究域物質化学系<br />A combination of solid phase extraction (SPE) columns was used for selective separation of water-sol
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uble arsenic species: arsenite, arsenate, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). The SPE columns, namely AnaLig TE-01 (TE-01), AnaLig AN-01 Si (AN-01) and AnaLig As-01 PA (As-01), contain immobilized macrocyclic material as the sorbent and commonly known as molecular recognition technology (MRT) gel. The retention, extraction and recovery behavior of the MRT gel SPE columns were studied at pH 4-10. Fortified deionized water spiked with 100 μM of arsenic species were treated at the flow rate of 0.2 mL min-1. HNO3 (1.0 and 6.0 M) was used as eluent to recover the retained arsenic species from TE-01 and AN-01 SPE columns. Arsenic species retained in the As-01 column were eluted with HNO3 (0.1 M) followed by NaOH (2.0 M). Likely interference from the various coexisting ions (Na+, K+, Ca2+, Mg2+, Cl-, NO3-, CH3COO-, PO43 -, SO42 -, ClO4-) (10 mM) were negligible. Quantitative separation of As(III), As(V), MMA and DMA was achieved based on the differences in extraction and recovery behavior of the MRT gel SPE columns with pH for different arsenic species. Complexation between arsenic species and MRT gel is the core phenomenon of the proposed technique as the complexation of MRT gels is expected to be stronger than the resin-based separation processes. MRT gel SPE columns are advantageous as compared with other reported SPE columns in terms of its performance with As(III). Effortless regeneration and unaltered separation performance of the sorbent materials for more than 100 loading and elution cycles are other sturdy characteristics to consider the MRT gel SPE columns for sensitive and selective arsenic species separation. © 2010 Elsevier Ltd. All rights reserved.
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