Sukumar Basu Mallik

Jadavpur University, Kolkata, Bengal, India

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Publications (12)16.21 Total impact

  • Applied Geochemistry 01/2009; 24(1):186-187. · 1.71 Impact Factor
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    ABSTRACT: The present study demonstrates the importance of hydrogeochemical characteristics (groundwater flow and recharge) of an aquifer in the release of As to groundwater. The study area (∼20 km2) is located in Chakdaha block, Nadia district, West Bengal, which hosts groundwaters of variable As content. The spatial distribution pattern of As is patchy with areas containing groundwater that is high in As (>200 μg L−1) found in close vicinity to low As (<50 μg L−1) groundwaters (within 100 m). The concentration of groundwater As is found to decrease with depth. In addition, the data shows that there is no conspicuous relationship between high groundwater As concentration and high groundwater abstraction, although the central cone of depression has enlarged over 2 a and is extending towards the SE of the study area. The river Hooghly, which forms the NW boundary of the study site, shows dual behaviour (effluent and influent during pre- and post-monsoon periods, respectively), complicating the site hydrogeology. The observed groundwater flow lines tend to be deflected away from the high As portion of the aquifer, indicating that groundwater movement is very sluggish in the As-rich area. This leads to a high residence time for this groundwater package, prolonging sediment–water interaction, and hence facilitating groundwater As release.
    Applied Geochemistry 01/2008; 23(5):977-995. · 1.71 Impact Factor
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    ABSTRACT: Aquifer sediments from areas of low- and high-As groundwater were characterized mineralogically and geochemically at a field site in the Nadia district of West Bengal, India. Leaching experiments and selective extraction of the sediments were also carried out to understand the release mechanism of As in the sub-surface. The correlation between measured elements (major, minor and trace) from low- and high-As groundwater areas are only significant for As, Fe and Mn. The borehole lithology and percentage of silt and clay fraction demonstrates the dominance of finer sediments in the high-As aquifer. Multivariate analysis of the geochemical parameters showed the presence of four different mineral phases (heavy-mineral fraction, phyllosilicates/biotite/Fe-oxyhydroxides, carbonates and sulphides) in the sediments. Selective extraction of sediment reveals that amorphous Fe-oxyhydroxide acts as a potential sink for As in the sub-surface. The result is consistent with microbially mediated redox reactions, which are controlled in part by the presence of natural organic matter within the aquifer sediments. The occurrences of As-bearing redox traps, primarily formed of Fe- and Mn-oxides/hydroxides, are also important factors that control the release of As into groundwater at the study site.
    Applied Geochemistry 01/2008; 23(5):996-1011. · 1.71 Impact Factor
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    ABSTRACT: The origin of the spatial variability of dissolved As concentrations in shallow aquifers of the Bengal Basin remains poorly understood. To address this, we compare here transects of simultaneously-collected groundwater and aquifer solids perpendicular to the banks of the Hooghly River in Chakdaha, India, and the Old Brahmaputra River in Araihazar, Bangladesh. Variations in surface geomorphology mapped by electromagnetic conductivity indicate that permeable sandy soils are associated with underlying aquifers that are moderately reducing to a depth of 10-30 m, as indicated by acid-leachable Fe(II)/Fe ratios <0.6 in the solid phase and concentrations of dissolved sulfate >5 mg L(-1). More reducing aquifers are typically capped with finer-grained soils. The patterns suggest that vertical recharge through permeable soils is associated with a flux of oxidants on the banks of the Hooghly River and, further inland, in both Chakdaha and Araihazar. Moderately reducing conditions maintained by local recharge are generally associated with low As concentrations in Araihazar, but not systematically so in Chakdaha. Unlike Araihazar, there is also little correspondence in Chakdaha between dissolved As concentrations in groundwater and the P-extractable As content of aquifer particles, averaging 191 +/- 122 microg As/L, 1.1 +/- 1.5 mg As kg(-1) (n = 43) and 108 +/- 31 microg As/L, 3.1 +/- 6.5 mg As kg(-1) (n = 60), respectively. We tentatively attribute these differences to a combination of younger floodplain sediments, and therefore possibly more than one mechanism of As release, as well as less reducing conditions in Chakdaha compared to Araihazar. Systematic dating of groundwater and sediment, combined with detailed mapping of the composition of aquifer solids and groundwater, will be needed to identify the various mechanisms underlying the complex distribution of As in aquifers of the Bengal Basin.
    Geochemical Transactions 01/2008; 9:1. · 1.50 Impact Factor
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    ABSTRACT: Extremely high As concentrations in drinking water of the Ganges Delta (West Bengal and Bangladesh) has emerged as an issue of great concern in the past decade because of its serious impact on the health of millions of people. The distribution pattern of As concentrations in the Ganges Delta region is patchy and there are numerous As “hotspots”. The present study is perhaps the first attempt in West Bengal to characterize such a hotspot by geophysical and geochemical methods, and to model the transport of the enrichment plume using a 1D reactive transport model (PHREEQC). The study site is located along the Hooghly River, 60 km north of Kolkota City, near the city of Chakdaha. Total As concentrations in the groundwater range from 0.5 to more than 6 μmol L−1; the WHO recommended maximum drinking water concentration is 0.13 μmol L−1 (i.e. 10 μg L−1). Results show groundwater is in chemical equilibrium with siderite and calcite, a mineral phase previously shown to be an efficient trap for As(III). Groundwater redox potential is controlled by the Fe(OH)3(am)/Fe2+ couple. The As(III) versus As(V) distribution (42% As(III) and 58% As(V), on average) is not at equilibrium with measured Eh values. No evidence of sulfide solid phases, such as As rich pyrite or arsenopyrite, was found. Although amorphous Fe dissolution is confirmed to play an important role in the release of As, selective dissolution extractions indicate that adsorption of As on carbonates and micas may also be an important component of As cycling in the sediment. Modelling results demonstrate the role of and Fe(II) in mobilizing the As plume, thereby increasing the threat to the 75,000 inhabitants of Chakdaha.
    Applied Geochemistry 01/2007; 22(7):1273-1292. · 1.71 Impact Factor
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    ABSTRACT: Possible relationships between groundwater arsenic concentration and alluvial sediment characteristics in a ~19 km2 area in West Bengal have been investigated using a combination of hydrogeochemical, lithogeochemical and geophysical techniques. Arsenic hotspots, typically associated with elevated groundwater Fe and Mn, were found to be correlated to some extent with old river channels (abandoned meanders, oxbow lakes), where sandy aquifers included intercalated fine-grained overbank deposits, rich in As, Fe, Mn and Corg. Otherwise no demonstrably significant overall differences in any of lithology, grain-size distribution, mineral composition or Fe, Mn and organic C content of the sediments were found between two representative sites with contrastingly low (<50 μg l−1) and high (>200 μg l−1) As groundwater contents. Our results are consistent with microbially mediated redox reactions controlled by the presence of natural organic matter within the aquifer and the occurrence of As-bearing redox traps, primarily formed by Fe and Mn oxides/hydroxides, being the most important factors which control the release of As into shallow groundwaters at the study site.
    Mineralogical Magazine 01/2005; 69(5):841-854. · 2.21 Impact Factor
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    ABSTRACT: Groundwater of the arsenic affected areas demonstrates that the water is Ca-bocarbonate type and typical anoxie in nature. High arsenic groundwater is distributed in patches and ``hot spots'' are identifie in palaeo-meander belt. Iron rich arsenic traps undergo reduction and release redox sensitive species (As and Fe) under local reducing conditions. Releases of redox species are often depends on land-use pattern and the abundance of bio-available fonns of iron oxides/minerals.
    Journal de Physique IV (Proceedings) 01/2003; 107:293-296. · 0.29 Impact Factor
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    ABSTRACT: Arsenic contamination in drinking water is a problem of great concern in Ganges delta region, and could be one of the largest natural calamity in the world. In the present study, a contamination plume located in the Lalpur area (Chakdaha Block, Nadia District, West Bengal, India) was studied. A coupled geochemical and geophysical approach was employed to understand the mechanism of arsenic mobilisation from the sediments to groundwater, as a first step towards a global explanation of the phenomenon for other contaminated areas in the Ganges delta. The groundwater As concentration, in the 10 km x 10 km studied area, ranges from 10 to 500 ppb. In situ chemical speciation of arsenic was carried out and various geochemical parameters were measured in representative contaminated wells to interpret the mobilization mechanism in terms of redox kinetics. Through geophysical investigations, subsurface lithology, sediment depositional and geomorphological characteristics were determined and correlated with the arsenic contamination processes. From a geomorphological viewpoint, the contaminated area is located in an abandoned paleochannel of the Hooghly river, interpreted as the active site of deposition of fine sediments which were preserved as clay pockets at certain depths. These clay pockets are rich in organic matter, which may be the driving force for redox potential change and thus, may have driven the mobilisation of arsenic in groundwater. The clay pockets rich in organic matter presumably represent the major reservoir where arsenic is sitting and getting released due to redox mechanism. They are sampled at present. A piezometric depression cone characterized by a radial groundwater flow is located underneath the highly populated Lalpur area. The arsenic plume appears to migrate from the Hooghly river towards the cone of depression following the water flowpath, and this shall be verified in forthcoming field campaigns. As (III) constitutes 42 % of the total As concentration. It is several times more toxic than As (V). The As (III) / As (V) and S (-II) / S (VI) ratios are not at equilibrium with the Eh measured in groundwater. The groundwater is at equilibrium with Ba(II) and Fe(II) arsenate minerals, barite and siderite. The reactive transport modeling of the data is explored.
    AGU Spring Meeting Abstracts. 05/2001;
  • Sukumar Basu Mallik
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    ABSTRACT: Proceeding from the equations of electromagnetism (Maxwell) and those of mechanical motions, this investigation has been carried in a layered media, comprising of a liquid and a solid (Fener type) layers to determine the mechanical deformation. It is found that the disturbances owing to the coupling effect of the transversely acting magnetic field and the tangential force along the inference, are predominantly transient in character for both ranges of time, but being damped more in case of larger values.
    Pure and Applied Geophysics 11/1973; 104(1):460-466. · 1.62 Impact Factor
  • Sukumar Basu Mallik
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    ABSTRACT: The propagation of disturbances in a composite viscoelastic layer when subjected to an impulsive force in the presence of a primary magnetic field, has been investigated in this note. The mechanical displacement has been derived from the electro-magnetic equations of Maxwell, the equation of motion and the stress-strain relations of the materials considered and has been computed for small values of time.
    Pure and Applied Geophysics 11/1972; 96(1):52-60. · 1.62 Impact Factor
  • TAPAS ACHARYA, SUKUMAR BASU MALLIK
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    ABSTRACT: Addressing the geologic significance of lineaments and their correlation with joints/fractures is still unclear. The present study attempts to analyse the lineament swarms developed in a Precambrian metamorphic terrain in India using both unfiltered and filtered techniques. The unfiltered analysis technique shows that the major lineament and fracture trends are oriented along EW and NS directions respectively, thus failing to provide any correlation between them. The application of domain-based filtering techniques identifies a highly predominant fracture-correlated lineaments in mica schist constituting the EW trending shear zone in the area. This correlation is not evident in the areas north and south of the shear zone, where the lineaments are consistently oriented along the foliation planes of the rocks and are designated as ‘foliation correlated’. The present analysis indicates that the fracture frequency and the strain history may have played significant roles for the formation of fracture-correlated lineaments in the metamorphic terrain.
    Journal of Earth System Science 121(2). · 0.70 Impact Factor
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    ABSTRACT: This study aims at finding out possible relation between lithology and spatial pattern of dissolved arsenic (As) in groundwater around Chakdaha municipality, West Bengal, India. Satellite image, coupled with electrical resistivity survey and borehole drilling helps to delineate surface and sub-surface lithological framework of the As affected alluvial aquifers. The satellite imagery demonstrate that the high As area are presumably under active flood plain environment (low-lying areas), that constantly receive organics due to periodic flooding. Thick low resistive (fine-grained) layer was observed at the top around the high As areas, which, however, not found in low As areas. The result suggests that hydraulic properties of the surface/sub-surface soil/sediment have an important control on the fate and transport of As in the aquifer. This study demonstrates that electrical resistivity tools can be effectively used for the reconnaissance survey in characterizing the plausible lithological framework of an alluvial aquifer containing As. KeywordsBengal Delta Plain-Groundwater-Arsenic-Geomorphology-Electrical resistivity
    Environmental earth sciences 60(4):873-884. · 1.45 Impact Factor