Water quality is the critical environmental determinant that influences the agricultural production and therefore, the economy that solely depends on its agricultural productions. Batiaghata Upazilla is one of the maj...Water quality is the critical environmental determinant that influences the agricultural production and therefore, the economy that solely depends on its agricultural productions. Batiaghata Upazilla is one of the major crop productive areas of Khulna region and the agricultural production here largely depends on the natural water of the Shailmari River system around it. The present study was conducted to assess the suitability of this coastal river water for irrigational use. 66 water samples were collected during this study in three consecutive agricultural seasons, viz., pre-monsoon (22), monsoon (22) and post-monsoon (22) from 11 sampling stations within the river system considering the high (11) and ebb (11) tides for each station. Standard methods were followed throughout the study period for the collection of the samples and analysis of major physicochemical parameters (pH, EC, TDS, salinity, Na, K, Ca, Mg, Cl, HCO<sub>3</sub>, SO<sub>4</sub>, NO<sub>3</sub> and PO<sub>4</sub>). Hydrocehmical characterization using Piper trilinear diagram shows that the water of the river system is Na-Cl dominated saline water type in pre-monsoon, whilst most of the samples of the river and the connected channel are characterized as fresh water of Ca-Mg-Na-HCO<sub>3</sub> and Ca-Na-Mg-HCO<sub>3</sub> types in monsoon and post-monsoon respectively. The calculated values of chemical indices like SAR, %Na, KI, PI and MH using the results of the analysed parameters indicate that the river water is chemically unsuitable for use in irrigation during pre-monsoon, while in the monsoon and post-monsoon the river water is within good to permissible limit for the use in the agricultural fields. However, high %Na, KI and MH values with high salinity of the channel water limit its use in agricultural applications in monsoon and post-monsoon. The USSL (United States Salinity Laboratory) diagram depicts that the river water is C4-S4 type with very high salinity and sodium content in pre-monsoon, while in other seasons the water is mostly C1-S1, C2-S1 or C2-S2 types (low to moderate salinity and sodium) in the river. Wilcox diagram shows that the river water is “suitable” for irrigation during monsoon and post-monsoon as the most of the samples range within “Excellent to Good” and “Good to permissible” categories, while it is “unsuitable” for crop irrigation during pre-monsoon when SAR (Sodium Adsorption Ratio) and EC (Electrical Conductivity) values of the water reach to their peaks.展开更多
Surface water has become one of the most vulnerable resources on the earth due to deterioration of its quality from diverse sources of pollution. Understanding of the spatiotemporal distribution of pollutants and iden...Surface water has become one of the most vulnerable resources on the earth due to deterioration of its quality from diverse sources of pollution. Understanding of the spatiotemporal distribution of pollutants and identification of the sources in the river systems is a prerequisite for the protection and sustainable utilization of the water resources. Multivariate statistical techniques such as Principal Component Analysis (PCA) and Factor Analysis (FA) were applied in this study to investigate the temporal and spatial variations of water quality and appoint the major factors of pollution in the Shailmari River system. Water quality data for 14 physicochemical parameters from 11 monitoring sites over the year of 2014 in three sampling seasons were collected and analyzed for this study. Kruskal-Wallis test showed significant (p < 0.01) temporal and spatial variations in all of the water quality parameters of the river water. Principal component analysis (PCA) allowed extracting the contributing parameters affecting the seasonal water quality in the river system. Scatter plots of the PCs showed the tidal and spatial variation within river system and identified parameters controlling the behavior in each case. Factor analysis (FA) further reduced the data and extracted factors which are significantly responsible for water quality variation in the river. The results indicate that the parameters controlling the water quality in different seasons are related with salinity, anthropogenic pollution (sewage disposal, effluents) and agricultural runoff in pre-monsoon;precipitation induced surface runoff in monsoon;and erosion, oxidation or organic pollution (point and non-point sources) in post-monsoon. Therefore, the study reveals the applicability and usefulness of the multivariate statistical methods in assessing water quality of river by identifying the potential environmental factors controlling the water quality in different seasons which might help to better understand, monitor and manage the quality of the water resources.展开更多
Narail Sadar Upazilla is a major agricultural productive region of Narail District, Bangladesh. The crop production here significantly depends on the Chitra River water for irrigation. The present study was undertaken...Narail Sadar Upazilla is a major agricultural productive region of Narail District, Bangladesh. The crop production here significantly depends on the Chitra River water for irrigation. The present study was undertaken with an aim to evaluate the usability of this river water for irrigation purpose during pre-monsoon, monsoon and post-monsoon. Sampling was conducted three times in each season both in high tide and low tide. The collected samples were analyzed for some physicochemical parameters including pH, electrical conductivity (EC), total dissolved solid (TDS), major cations (Na+, K+, Ca2+ and Mg2+) and major anions (HCO3?, PO43?, SO42?, Cl? and NO3?). The calculated chemical indices’ values for the collected water samples during pre-monsoon indicate that this river water is chemically suitable for irrigation during pre-monsoon with respect to sodium adsorption ratio (SAR), residual sodium carbonate (RSC) and permeability index (PI). The values of all chemical indices declare this river water fitness for use in irrigation both in monsoon and post-monsoon. According to Wilcox diagram, all of the water samples irrespective of tide and sampling stations fall within “permissible to doubtful” category during pre-monsoon while the water samples collected in both tide from all stations fall within “excellent to good” category during monsoon and post-monsoon. The United States Salinity Laboratory (USSL) diagram certifies this river water as C1-S1 (low salinity along with low sodium level) type during monsoon and post-monsoon which makes the river water suitable for use in irrigation in these two seasons while the water is mostly C3-S1, C3-S2 and C3-S3 (high salinity along with low to high sodium level) type in pre-monsoon which makes the river water restricted for use in irrigation in this season.展开更多
At Shailmari River basin, located in the central Ganges Delta and the southwestern coastal Bangladesh, groundwater is the only potable source for water supply due to incompatible surface water sources. However, salini...At Shailmari River basin, located in the central Ganges Delta and the southwestern coastal Bangladesh, groundwater is the only potable source for water supply due to incompatible surface water sources. However, salinity degradation along with arsenic and iron contamination poses a serious health threat to the basin community. Considering this, an investigation was carried out along both banks of the river to assess groundwater vulnerability and its quality for drinking by conducting multi-seasonal water sampling campaigns from 20 domestic wells and analyses (both in-situ and laboratory) for several physico-chemical (pH, EC, TDS and major ions) and biological (coliforms) parameters. The results show slightly alkaline groundwater in the study area with largely variable chemical composition, i.e. EC varies from around 1900 to 2700 μS/cm. The abundance of major ions indicates as Na+ > Ca2+ > Mg2+ > K+ for cations and ?> Cl- > ?> ?> ?for anions. As per the Canadian water quality index (CCMEWQI), almost all groundwater samples concentrate in the marginal category meaning that groundwater is frequently threatened. Besides, it is not fully safe for drinking as revealed from comparison of geochemical data with national and WHO water quality standards.展开更多
This review summarizes the utilization of supported noble metal nanoparticles (such as Au/TiO2, Au/ZrO2, Ag/AgCl) as efficient photo/sono-catalysts for the selective synthesis of chemicals and degradation of environme...This review summarizes the utilization of supported noble metal nanoparticles (such as Au/TiO2, Au/ZrO2, Ag/AgCl) as efficient photo/sono-catalysts for the selective synthesis of chemicals and degradation of environmental pollutants. Supported noble metal nanoparticles could efficiently catalyze the conversion of solar energy into chemical energy. Under UV/visible light irradiation, important chemical transformations such as the oxidation of alcohols to carbonyl compounds, the oxidation of thiol to disulfide, the oxidation of benzene to phenol, and the reduction of nitroaromatic compounds to form aromatic azo compounds, are effectively achieved by supported noble metal nanoparticles. Under ultrasound irradiation, supported noble metal nanoparticles could efficiently catalyze the production of hydrogen from water. Moreover, various pollutants, including aldehydes, alcohols, acids, phenolic compounds, and dyes, can be effectively decomposed over supported noble metal nanoparticles under UV/visible light irradiation. Under ultrasound irradiation, pollutant molecules can also be completely degraded with supported noble metal nanoparticles as catalysts.展开更多
The host-vip relationship between cucurbit[8]uril,phenanthrolines and some methyl substituted 1,10-phenanthrolines has been investigated by using 1H NMR spectroscopy and fluorescence spectroscopy.The results showed ...The host-vip relationship between cucurbit[8]uril,phenanthrolines and some methyl substituted 1,10-phenanthrolines has been investigated by using 1H NMR spectroscopy and fluorescence spectroscopy.The results showed that phenanthrolines as molecular vips bind in the cavity and portal of cucurbit[8]uril in a ratio of 2:1 (vip to host).The phenanthroline isomers 1,10-,1,7-and 4,7-showed red shifts between 47 and 108 nm and pronounced in-creases in fluorescent intensity.These same isomers produced inclusion complexes with cucur-bit[8]uril which had moderate to fast exchange rates on the 1H NMR time scale.The methyl substituted 1,10-phenanthrolines studied gave stable inclusion complexes in a ratio of 2:1 which showed slow exchange rates.These vips formed p-p stacked pairs which were cavity bound but also partly protruded from only one portal forming unsymmetrical host-vip complexes.In addition,these p-p stacked pairs formed orientation isomers within the confines of the cucur-bit[8]uril cavity.展开更多
TiO_(2) spheres assembled by nanorods,nanoplates and nanosheets were fabricated by facile hydrothermal/solvothermal methods.The three samples were thoroughly characterised by scanning electron microscopy,X-ray diffrac...TiO_(2) spheres assembled by nanorods,nanoplates and nanosheets were fabricated by facile hydrothermal/solvothermal methods.The three samples were thoroughly characterised by scanning electron microscopy,X-ray diffraction,the Brunauer-Emmett-Teller method and UV spectroscopy.The surface area of spheres assembled by nanosheets was 83.9 m^(2)g^(-1),which is larger than that obtained for nanorods(10.8 m2g-1)and nanoplates(6.31 m^(2)g^(-1)).Their photocatalytic performance was evaluated in terms of the decomposition rate of methyl orange in these three samples under UV irradiation.The best photoactivity was observed in the samples constructed from nanosheets.展开更多
文摘Water quality is the critical environmental determinant that influences the agricultural production and therefore, the economy that solely depends on its agricultural productions. Batiaghata Upazilla is one of the major crop productive areas of Khulna region and the agricultural production here largely depends on the natural water of the Shailmari River system around it. The present study was conducted to assess the suitability of this coastal river water for irrigational use. 66 water samples were collected during this study in three consecutive agricultural seasons, viz., pre-monsoon (22), monsoon (22) and post-monsoon (22) from 11 sampling stations within the river system considering the high (11) and ebb (11) tides for each station. Standard methods were followed throughout the study period for the collection of the samples and analysis of major physicochemical parameters (pH, EC, TDS, salinity, Na, K, Ca, Mg, Cl, HCO<sub>3</sub>, SO<sub>4</sub>, NO<sub>3</sub> and PO<sub>4</sub>). Hydrocehmical characterization using Piper trilinear diagram shows that the water of the river system is Na-Cl dominated saline water type in pre-monsoon, whilst most of the samples of the river and the connected channel are characterized as fresh water of Ca-Mg-Na-HCO<sub>3</sub> and Ca-Na-Mg-HCO<sub>3</sub> types in monsoon and post-monsoon respectively. The calculated values of chemical indices like SAR, %Na, KI, PI and MH using the results of the analysed parameters indicate that the river water is chemically unsuitable for use in irrigation during pre-monsoon, while in the monsoon and post-monsoon the river water is within good to permissible limit for the use in the agricultural fields. However, high %Na, KI and MH values with high salinity of the channel water limit its use in agricultural applications in monsoon and post-monsoon. The USSL (United States Salinity Laboratory) diagram depicts that the river water is C4-S4 type with very high salinity and sodium content in pre-monsoon, while in other seasons the water is mostly C1-S1, C2-S1 or C2-S2 types (low to moderate salinity and sodium) in the river. Wilcox diagram shows that the river water is “suitable” for irrigation during monsoon and post-monsoon as the most of the samples range within “Excellent to Good” and “Good to permissible” categories, while it is “unsuitable” for crop irrigation during pre-monsoon when SAR (Sodium Adsorption Ratio) and EC (Electrical Conductivity) values of the water reach to their peaks.
文摘Surface water has become one of the most vulnerable resources on the earth due to deterioration of its quality from diverse sources of pollution. Understanding of the spatiotemporal distribution of pollutants and identification of the sources in the river systems is a prerequisite for the protection and sustainable utilization of the water resources. Multivariate statistical techniques such as Principal Component Analysis (PCA) and Factor Analysis (FA) were applied in this study to investigate the temporal and spatial variations of water quality and appoint the major factors of pollution in the Shailmari River system. Water quality data for 14 physicochemical parameters from 11 monitoring sites over the year of 2014 in three sampling seasons were collected and analyzed for this study. Kruskal-Wallis test showed significant (p < 0.01) temporal and spatial variations in all of the water quality parameters of the river water. Principal component analysis (PCA) allowed extracting the contributing parameters affecting the seasonal water quality in the river system. Scatter plots of the PCs showed the tidal and spatial variation within river system and identified parameters controlling the behavior in each case. Factor analysis (FA) further reduced the data and extracted factors which are significantly responsible for water quality variation in the river. The results indicate that the parameters controlling the water quality in different seasons are related with salinity, anthropogenic pollution (sewage disposal, effluents) and agricultural runoff in pre-monsoon;precipitation induced surface runoff in monsoon;and erosion, oxidation or organic pollution (point and non-point sources) in post-monsoon. Therefore, the study reveals the applicability and usefulness of the multivariate statistical methods in assessing water quality of river by identifying the potential environmental factors controlling the water quality in different seasons which might help to better understand, monitor and manage the quality of the water resources.
文摘Narail Sadar Upazilla is a major agricultural productive region of Narail District, Bangladesh. The crop production here significantly depends on the Chitra River water for irrigation. The present study was undertaken with an aim to evaluate the usability of this river water for irrigation purpose during pre-monsoon, monsoon and post-monsoon. Sampling was conducted three times in each season both in high tide and low tide. The collected samples were analyzed for some physicochemical parameters including pH, electrical conductivity (EC), total dissolved solid (TDS), major cations (Na+, K+, Ca2+ and Mg2+) and major anions (HCO3?, PO43?, SO42?, Cl? and NO3?). The calculated chemical indices’ values for the collected water samples during pre-monsoon indicate that this river water is chemically suitable for irrigation during pre-monsoon with respect to sodium adsorption ratio (SAR), residual sodium carbonate (RSC) and permeability index (PI). The values of all chemical indices declare this river water fitness for use in irrigation both in monsoon and post-monsoon. According to Wilcox diagram, all of the water samples irrespective of tide and sampling stations fall within “permissible to doubtful” category during pre-monsoon while the water samples collected in both tide from all stations fall within “excellent to good” category during monsoon and post-monsoon. The United States Salinity Laboratory (USSL) diagram certifies this river water as C1-S1 (low salinity along with low sodium level) type during monsoon and post-monsoon which makes the river water suitable for use in irrigation in these two seasons while the water is mostly C3-S1, C3-S2 and C3-S3 (high salinity along with low to high sodium level) type in pre-monsoon which makes the river water restricted for use in irrigation in this season.
文摘At Shailmari River basin, located in the central Ganges Delta and the southwestern coastal Bangladesh, groundwater is the only potable source for water supply due to incompatible surface water sources. However, salinity degradation along with arsenic and iron contamination poses a serious health threat to the basin community. Considering this, an investigation was carried out along both banks of the river to assess groundwater vulnerability and its quality for drinking by conducting multi-seasonal water sampling campaigns from 20 domestic wells and analyses (both in-situ and laboratory) for several physico-chemical (pH, EC, TDS and major ions) and biological (coliforms) parameters. The results show slightly alkaline groundwater in the study area with largely variable chemical composition, i.e. EC varies from around 1900 to 2700 μS/cm. The abundance of major ions indicates as Na+ > Ca2+ > Mg2+ > K+ for cations and ?> Cl- > ?> ?> ?for anions. As per the Canadian water quality index (CCMEWQI), almost all groundwater samples concentrate in the marginal category meaning that groundwater is frequently threatened. Besides, it is not fully safe for drinking as revealed from comparison of geochemical data with national and WHO water quality standards.
文摘This review summarizes the utilization of supported noble metal nanoparticles (such as Au/TiO2, Au/ZrO2, Ag/AgCl) as efficient photo/sono-catalysts for the selective synthesis of chemicals and degradation of environmental pollutants. Supported noble metal nanoparticles could efficiently catalyze the conversion of solar energy into chemical energy. Under UV/visible light irradiation, important chemical transformations such as the oxidation of alcohols to carbonyl compounds, the oxidation of thiol to disulfide, the oxidation of benzene to phenol, and the reduction of nitroaromatic compounds to form aromatic azo compounds, are effectively achieved by supported noble metal nanoparticles. Under ultrasound irradiation, supported noble metal nanoparticles could efficiently catalyze the production of hydrogen from water. Moreover, various pollutants, including aldehydes, alcohols, acids, phenolic compounds, and dyes, can be effectively decomposed over supported noble metal nanoparticles under UV/visible light irradiation. Under ultrasound irradiation, pollutant molecules can also be completely degraded with supported noble metal nanoparticles as catalysts.
基金the National Natural Science Foundation of China(Grant Nos.20261002&20362003)the International Collaborative Project of the Minist ry of Science and Technology(Grant No.2003DF000030)+2 种基金the Foundation of the Governor of Guizhou Provincethe Key Project of Natural Science Foundat ion of Guizhou Province(Grant No.20023004) the Foundation for the Qualified Scient ist Program of Guizhou Province(Grant No.20020204).
文摘The host-vip relationship between cucurbit[8]uril,phenanthrolines and some methyl substituted 1,10-phenanthrolines has been investigated by using 1H NMR spectroscopy and fluorescence spectroscopy.The results showed that phenanthrolines as molecular vips bind in the cavity and portal of cucurbit[8]uril in a ratio of 2:1 (vip to host).The phenanthroline isomers 1,10-,1,7-and 4,7-showed red shifts between 47 and 108 nm and pronounced in-creases in fluorescent intensity.These same isomers produced inclusion complexes with cucur-bit[8]uril which had moderate to fast exchange rates on the 1H NMR time scale.The methyl substituted 1,10-phenanthrolines studied gave stable inclusion complexes in a ratio of 2:1 which showed slow exchange rates.These vips formed p-p stacked pairs which were cavity bound but also partly protruded from only one portal forming unsymmetrical host-vip complexes.In addition,these p-p stacked pairs formed orientation isomers within the confines of the cucur-bit[8]uril cavity.
文摘TiO_(2) spheres assembled by nanorods,nanoplates and nanosheets were fabricated by facile hydrothermal/solvothermal methods.The three samples were thoroughly characterised by scanning electron microscopy,X-ray diffraction,the Brunauer-Emmett-Teller method and UV spectroscopy.The surface area of spheres assembled by nanosheets was 83.9 m^(2)g^(-1),which is larger than that obtained for nanorods(10.8 m2g-1)and nanoplates(6.31 m^(2)g^(-1)).Their photocatalytic performance was evaluated in terms of the decomposition rate of methyl orange in these three samples under UV irradiation.The best photoactivity was observed in the samples constructed from nanosheets.
