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Extreme exposure of fluoride and arsenic contamination in shallow coastal aquifers of the Ganges delta,transboundary of the Indo-Bangladesh region

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Geoscience Frontiers 2024年第1期15卷 286-303页

作者： dipankar Ruidas Subodh Chandra Pal Tanmoy Biswas Asish saha Abu Reza Md.Towfiqul Islam Department of Geography The University of BurdwanPurba BardhamanWest Bengal 713104India Department of Disaster Management Begum Rokeya UniversityRangpur 5400Bangladesh Department of Development Studies Daffodil International UniversityDhaka 1216Bangladesh

Globally,shallow aquifer groundwater(GW)has been severely affected in recent decades for both geogenic and anthropogenic reasons.The hydro-geochemical characteristics of the GW change inconsistently with the addition of unwanted inorganic trace elements into the GW aquifer of the Indo-Bangladesh delta region(IBDR),such as arsenic(As)along with fluoride(F-)contamination.Contaminated GW can have a negative impact on drinking water supplies and agricultural output.GW pollution can have serious adverse effects on the environment and human health.Thus,the GW quality of this region is deteriorating progressively,and human health threatening by various life-threatening disorders.Hence,the current study concentrated on the GW quality evaluation and prediction of possible health issues in the IBDR due to elevated contamination of As along with F-within GW aquifers by considering sixteen causative.Field survey-based statistical methods such as entropy quality index(EWQI)combined with health risk index(HRI)was implemented for evaluating the As and F-sensitivity with the help of correlation testing and principal component analysis.The study's outcome explains that a substantial portion of the IBDR has been vastly experiencing inferior GW quality,environmental issues,and health-related problems in dry and wet seasons,correspondingly for As and F-exposure.Piper diagram verified the suitability of water that almost 55%of GW across the study area’s aquifers are unfit for drinking as well as cultivation of crops.Sensitivity analysis and the Monte Carlo simulation method were also applied to assess the contaminant's concentration level and probable health risk appraisal.The present study concludes that the elevated exposure of As and F-pollution has to be monitored regularly and prevent unwanted GW contamination through implementing sustainable approaches and policies to fulfil the sustainable development goal 6(SDG-6)till 2030,ensuring the most basic human right of clean,safe,and hygienic water.

关键词： Indo-Bangladesh delta Entropy quality index Health risk index Monte Carlo simulation SDG-6

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Assessment of surface and subsurface waterlogging, water level fluctuations, and lithological variations for evaluating groundwater resources in Ganga Plains

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International Journal of Digital Earth 2013年第3期6卷 276-296页

作者： Arvind Chandra Pandey Suraj Kumar Singh M.S.Nathawat Dipankar SAHA Department of Remote Sensing Birla Institute of TechnologyMesraRanchiIndia Central Ground Water Board Ministry of Water ResourcesPatnaIndia

In the present study,the multi-temporal satellite images of IRS P6 LISS III were used to map waterlogging dynamics over different seasons.An area of 594.36 km2(6.75%)and 4.17 km^(2)(0.04%)was affected by surface waterlogging during pre and postmonsoon season,respectively.The average annual groundwater level fluctuations were calculated using 18 years(1990-2007)pre and postmonsoon groundwater level data to identify the areas which are under groundwater induced waterlogging conditions.The soil map clearly indicates that salinity and sodicity exhibit the highest severity and occur in areas with shallow groundwater levels.The hydrogeomorphical units mapped using IRS P6 LISS III satellite images are flood plain,alluvial plain,paleochannels,and oxbow lakes.The study revealed that 44.65%areas have very good to excellent groundwater resources.The litholog data clearly indicate an alternating sequence of clay and sand in which deep aquifers made up of coarse sand would be best suited for adequate water supply and good groundwater quality.The integrated study utilizing digital spatial data pertaining to waterlogging,soil salinity,water level fluctuation,and lithological variation proved that planning of any surface and subsurface water resources development activity should be taken up after assessments of said parameters.

关键词： waterlogging salinity Ganga plain digital earth groundwater resources digital data

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Synthetic Detergents (Surfactants) and Organochlorine Pesticide Signatures in Surface Water and Groundwater of Greater Kolkata, India

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Journal of Water Resource and Protection 2009年第4期1卷 290-298页

作者： Naresh C. GHOSE Dipankar SAHA Anjali GUPTA 不详

An assessment on the concentration of surfactants and pesticides of chlorinated hydrocarbon group in surface and groundwater, is made from Greater Kolkata located in the Western Ganga Delta, one of the largest urban agglomerate in Asia. Concentration of both anionic synthetic detergents and organochlorine pesticide resi-dues analysed from 54 and 19 sampling stations covering groundwater and surface water sources respec-tively, are generally found to be within the tolerance limit for human consumption. The concentration of synthetic detergent ranges from 0.084 to 0.425mg/l. Residues of organochlorine pesticides are analysed from different sources like tanks, lakes, rivers and groundwater. Lindane (0.01-0.43μg/l) and DDT (0.03-0.65 μg/l) are the most widely detected pesticide residues. Howerer, the two have not exceeded the limits for drinking anywhere. High value of aldrin and dieldrin (0.9μg/l) is obtained in the river Hugli at Barakpur-Seoraphuli, 20 km north of Kolkata. Likewise high value of Heptachloreis detected in a canal water sample at Palta (0.05 μg/l), a suburban area. Seasonally, the pesticide concentration in surface water is maximum during winter due to their higher application and minimum during monsoon. In groundwater, however, this relationship is reverse due to higher infiltration of surface water during monsoon.

关键词： Kolkata Ganga Delta Surface Water Groundwater Surfactants Organochlorine Pesticides

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Comparative evaluation of physico-chemical characteristics of biopolyesters P（3HB） and P（3HB-co-3HV） produced by endophytic Bacillus cereus RCL 02

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Frontiers in Biology 2018年第4期13卷 297-308页

作者： Ritupama Das Nayan Ranjan saha Arundhati Pal dipankar Chattopadhyay Amal Kanti Paul Microbiology Laboratory Department of Botany University of Calcutta 35 Ballygunge Circular Road Kolkata 700019 West Bengal India Department of Polymer Science and Technology University of Calcutta 92 A. P. C. Road KoIkata 700009 West Bengal India Department of Botany Serampore College 9 William Carey Road Serampore Hooghly 712201 West Bengal India

BACKGROUND： Bacteria endogenously residing within the plant tissues have attracted significant attention for production of biopolyester, polyhydroxyalkanoates （PHAs）. Bacillus cereus RCL 02 （MCC 3436）, a leaf endophyte of oleaginous plant Ricinus communis L. accumulates 81% poly（3-hydroxybutyrate） [P（3HB）] of its cell dry biomass when grown in mineral salts （MS） medium. METHODS： The copolymer production efficiency of B. cereus RCL 02 was evaluated in valeric acid supplemented MS medium under biphasic cultivation condition. The copolymer so produced has been compared with the P（3HB） isolated from RCL 02 in terms of thermal, mechanical and chemical properties. RESULTS： Valeric acid supplementation as co-substrate in the medium has led to the production of copolymer of 3- hydroxybutyrate （3HB） and 3-hydroxyvalerate （3HV） [P（3HB-co-3HV）] with 14.6 mol% 3HV. The identity of the polymers has been confirmed by X-ray diffraction （XRD） analysis, Fourier transform infrared （FTIR） and nuclear magnetic resonance （NMR） spectroscopic studies. Thermogravimetric analysis （TGA） revealed that P（3HB） and P（3HB-co-3HV） films degraded at 278.66℃ and 273.49℃, respectively. The P（3HB-co-3HV） showed lower melting temperature （165.03℃） compared to P （3HB）（170.74℃） according to differential scanning calorimetry （DSC）. Incorporation of 3HV monomers decreased the tensile strength （21.52 MPa）, tensile modulus （0.93 GPa）, storage modulus （E＇）（0.99 GPa） and increased % elongation at break （12.2%） of the copolyester. However, P（3HB） showed better barrier properties with lower water vapor transmission rate （WVTR） of 0.55 g-mil/100 in2/24 h. CONCLUSION： These findings emphasized exploration of endophytic bacterial strain （RCL 02） to produce biodegradable polyesters which might have significant potential for industrial application.

关键词： poly（3-hydroxybutyrate） poly（3-hydroxybutyrate-co-3-hydroxyvalerate） biodegradable polyester Bacillus cereus endophytic bacteria

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Sensing Behaviour of Some Nanocomposite Systems

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Soft Nanoscience Letters 2013年第4期3卷 12-15页

作者： dipankar Chakravorty Bhola Nath Pal Shilpi Banerjee Amrita Mandal Sreemanta Mitra Dhriti Ranjan saha Department of Physics University of Calcutta Kolkata India. MLS Prof. Unit Indian Association for the Cultivation of Science Jadavpur Kolkata India MLS Prof. Unit Indian Association for the Cultivation of Science Jadavpur Kolkata India

Silver nanoparticles of diameters 3.4 to 13.2 nm grown at the interfaces between silicate glass and some oxide crystallites exhibited about six orders of magnitude reduction in resistivity for a relative humidity change from 25% to 80%. Sn-SnO2 nano core-shell structure prepared within a gel-derived silica glass film by electrodeposition technique followed by heat treatment showed large change in resistivity as a function of humidity. The resistivity also changed due to gas flow of CO2, C2H5OH and NO2, respectively. The latter arose because of reduction/oxidation of Sn4+/Sn2+ species present at the shell layer of the nanostructures. Nickel nanosheets of thickness ~0.6 nm grown within the interlayer spaces of Na-4 mica crystallites showed a change of dielectric permittivity (5%) for an applied magnetic field of 1.2 Tesla. An inhomogeneous model was used to explain this behavior. Two dimensional CuO phase was grown within the channels of diameter ~5 nm of mesoporous SiO2 structure. A magnetodielectric (MD) parameter M.D. of 4.4% was obtained in this case. BaTiO3 nanoparticles of diameter ~25 nm having pores with diameter 10 nm showed multiferroic behavior which arose due to the presence of oxygen vacancies as a result of large surface area present. An M.D. parameter of 11% was found. Similarly mesoporous LiNbO3 of 10 nm diameter showed an M.D. parameter of ~4.5% at a magnetic field 1 Tesla. A giant magnetocapacitance effect with a value of 44% at 1.5 T was observed in nickel zinc ferrite (NZF) impregnated mesoporous silica. A magnetocapacitance of 51% at magnetic field 1.7 T was found in the case of nanocomposites comprising of iron ion containing silica based nanoglass and mesoporous silica. In the last two examples the behavior was explained on the basis of Catalan model of space-charge polarization with extracted values of magnetoresistance of the NZF and nanoglass phases being 58%.

关键词： Nanocomposites Na-4 Mica Mesoporous Silica BaTiO3+LiNbO3 Magneto Dielectric Effect

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