Papers by Bhaskar Sengupta
Environmental Science and Pollution Research, Jan 16, 2022
In this study we simulate the irrigation of tomato plants with As contaminated water (from 0 to 3... more In this study we simulate the irrigation of tomato plants with As contaminated water (from 0 to 3.2 mg L - 1 ) and investigate the effect of the application of silicon nanoparticle (Si NPs) in form of silicon dioxide (0, 250 and 1000 mg L -1 ) on As uptake and stress. Arsenics concentrations were determined in substrate and plant tissue at three different stratums. Phytotoxicity, As accumulation and translocation, photosynthetic pigments and antioxidant activity of enzymatic and non-enzymatic compounds were also determined. Irrigation of tomato plants with As contaminated water caused As substrate enrichment and As bioaccumulation (roots > leaves > steam) showing that the higher the concentration in irrigation water, the farther the contaminant owed and translocated through the different tomato stratums. Phytotoxicity was observed at low concentrations of As, while tomato yield increases increased at high concentrations. Application of Si NPs decreases As translocation, tomato yield, and root biomass. Increased production of photosynthetic pigments and improved enzymatic activity (CAT and APX) suggested tomato plant adaptation at high As concentrations in the presence of Si NPs. Our results reveal likely impacts of As and nanoparticles on tomato production in places where As in groundwater is common and might represent a risk.
IOCAG 2022
Toxic metal pollution in soil and the associated health risk is a global problem, with the majori... more Toxic metal pollution in soil and the associated health risk is a global problem, with the majority of cases occurring in developing nations. The current work focuses on a contaminated site in Mexico which is used for recreational purposes. The contaminated site in Cerrito Blanco in San Luis Potosi, Mexico is close to an abandoned mining area surrounded by non-cultivated farmland. Analyses of topsoil samples indicated the presence of arsenic (As), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn). This work has estimated the potential harmful impacts of toxic metals by using the Contamination factor (C f ), Ecological risk factor (E r ), and Potential ecological risk index (RI) by Hakanson's method. The results indicated that the soil contamination factors (C f ) of toxic metals were: As > Zn > Cu > Pb > Ni. It is concluded that Cu, Pb, and Zn have been found in the soil samples because of past mining activities. The highest contamination factor (C f ) of As (11.94 mg/kg) in the soil was in the extremely high contamination category. It is also believed that the As concentration in the soil was high because arsenic-contaminated water was regularly used to irrigate the land. The Ecological risk factors (E r ) for toxic metals were: As > Cu > Pb > Zn > Ni. In the surface soils of this region, As was a considerable ecological concern and contributed the most to potential ecological risk indices (RI). It is also acknowledged that various anthropogenic factors contributed significantly to the potential ecological risk index (RI). The spatial distribution of toxic metal contamination in the soil was also mapped using a Geographic Information System (GIS). This study concludes that a regular assessment is needed to estimate the risk level of toxic metal contamination in soil.
Soil Systems, 2022
Toxic heavy metals in soil negatively impact soil’s physical, biological, and chemical characteri... more Toxic heavy metals in soil negatively impact soil’s physical, biological, and chemical characteristics, and also human wellbeing. The traditional approach of chemical analysis procedures for assessing soil toxicant element concentration is time-consuming and expensive. Due to accessibility, reliability, and rapidity at a high temporal and spatial resolution, hyperspectral remote sensing within the Vis-NIR region is an indispensable and widely used approach in today’s world for monitoring broad regions and controlling soil arsenic (As) pollution in agricultural land. This study investigates the effectiveness of hyperspectral reflectance approaches in different regions for assessing soil As pollutants, as well as a basic review of space-borne earth observation hyperspectral sensors. Multivariate and various regression models were developed to avoid collinearity and improve prediction capabilities using spectral bands with the perfect correlation coefficients to access the soil As cont...
In this study we simulate the irrigation of tomato plants with As contaminated water (from 0 to 3... more In this study we simulate the irrigation of tomato plants with As contaminated water (from 0 to 3.2 mg L-1) and investigate the effect of the application of silicon nanoparticle (Si NPs) in form of silicon dioxide (0, 250 and 1000 mg L-1) on As uptake and stress. Arsenics concentrations were determined in substrate and plant tissue at three different stratums. Phytotoxicity, As accumulation and translocation, photosynthetic pigments and antioxidant activity of enzymatic and non-enzymatic compounds were also determined. Irrigation of tomato plants with As contaminated water caused As substrate enrichment and As bioaccumulation (roots > leaves > steam) showing that the higher the concentration in irrigation water, the farther the contaminant flowed and translocated through the different tomato stratums. Phytotoxicity was observed at low concentrations of As, while tomato yield increases increased at high concentrations. Application of Si NPs decreases As translocation, tomato yi...
Journal of Ecological Engineering, 2021
Eco-friendly saponin from soapnut was studied for the remediation of the soils contaminated by le... more Eco-friendly saponin from soapnut was studied for the remediation of the soils contaminated by lead. This study applied a full factorial design of the experiment with 3-factors in 3-level (3×3 factors) to evaluate the effect and interactions of the washing parameters on the lead removal by soapnut in a batch experiment. The parameters studied include: soil-solution ratio, surfactant concentrations by mass, and pH of the washing solution. Two soil samples representing low lead concentration (C1) and high lead concentration (C2) were investigated. The findings indicate that the removal efficiency obtained, increases along with the soil-solution ratio and surfactant concentration, but decreases with an increase in the pH of washing solution. Polynomial models were developed to predict the experimental response and optimal conditions. The model predicted a maximum of 50.54% and 47.44% lead removal from the contaminated soil C1 and C2, respectively. Multiple washing was investigated using the higher values of the parameters; the responses obtained significantly increased the percentage of lead removed and achieved 79.98% removal for C1 and 77.49% removal for C2. The effective performance of the soil washing process demonstrates the potential usage of soapnut saponin in the remediation of contaminated soil. Saponin from soapnut is cheap and environment-friendly.
International Journal of Environmental Science and Development, 2019
Journal of Water Process Engineering, 2020
Performance of rotating packed bed (RPB) contactor in the removal of nickel from water was invest... more Performance of rotating packed bed (RPB) contactor in the removal of nickel from water was investigated from two aspects: i) effect of operating parameters, and ii) effect of mode of operation. The results showed that the performance of RPB was highly governed by the rotational speed and activated carbon dosage. The increase in centrifugal force generated by the RPB from 200 rpm -875 rpm was found to displace the activated carbon to the outer side of the RPB, which reduced the liquid flow path length and contact time between the packed bed and Ni solution and this reduced the removal efficiency. Nevertheless, a further increase in rotational speed from 875 rpm to 1200 rpm improved the removal efficiency as the enhancement in mass transfer process had outperformed the effect given by reduced path length. Higher activated carbon dosage also improved RPB performance by providing higher number of adsorption sites, as well as improving the packing density of the packed bed which minimized the reduced path length effect. The study also revealed that the mode of operation for a RPB contactor has crucial impact on the nickel adsorption. The removal efficiency was found to follow the sequence of multiple cycle mode operation > batch mode operation > continuous mode operation, as a result of better contact time and consistent contact between the solution and the packed bed.
Science of The Total Environment, 2020
Alluvial and gypsum karst geological transition favors spreading arsenic contamination in Matehua... more Alluvial and gypsum karst geological transition favors spreading arsenic contamination in Matehuala, Mexico,
E3S Web of Conferences, 2019
Large attenuation of arsenic is observed in a shallow aquifer in central Mexico, where the concen... more Large attenuation of arsenic is observed in a shallow aquifer in central Mexico, where the concentration decreases from 91.5 to 11.3 mg/L, over 1.3 km horizontal distance. To investigate possible mechanisms of attenuation of this pollutant, we dug a pit between the surface and the saturated zone. We then described the soil profile and determined arsenic and iron concentrations in soil samples as a function of depth. Next, we determined particle size distribution, bulk density, particle density, soil moisture and porosity of the soil material. We also analyzed arsenic concentration in the groundwater. The 2.2 m deep profile intersected 4 soil horizons (A, AB, B1 and B2). We found arsenic accumulation in the B2 horizon, directly overlying the saturated zone. These accumulations coincide with the thickness of the capillary fringe, revealing that arsenic is drawn up in the soil profile by capillary rise of arsenic-contaminated groundwater. Furthermore, arsenic accumulation showed a dire...
Journal of Water Process Engineering, 2018
High gravimetric technology or HIGEE is a novel technique which uses centrifugal force in a rotat... more High gravimetric technology or HIGEE is a novel technique which uses centrifugal force in a rotating packed bed (RPB) contactor. In RPB, a doughnut shaped bed is spun at high speed to allow fluid to flow through an adsorbent bed at a high velocity. Centrifugal force enhances the adsorption process with increased mass transfer coefficient. In this study, the optimum condition of the working parameters of a RPB contactor for arsenic removal by activated carbon was investigated and optimized by Taguchi method. Five parameters, namely rotating speed, feed rate, packing density, initial concentration and initial solution pH were considered in determining the initial optimal condition in a L16 orthogonal array. According to the signal to noise ratio (S/N), the optimum condition obtained from the L16 experiments are rotating speed of 1600 rpm, feed rate of 50 L/h, packing density of 510 kg/m 3 , initial concentration of 150 mg/L and pH of 3. Depending upon the delta value, which is the difference between the highest and lowest S/N ratio, it was found that the initial concentration was the least affecting factor and pH could be fixed at 3 for practical purposes.
Healthcare, 2019
Fuller’s earth spherical beads using chitosan as a binder were prepared for the removal of stront... more Fuller’s earth spherical beads using chitosan as a binder were prepared for the removal of strontium ions from aqueous solution. The adsorbents were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed the porous nature of the beads. The Brunauer–Emmett–Teller (BET) surface area of the beads was found to be 48.5 m2/g. The adsorption capacities of the beads were evaluated under both batch and dynamic conditions. The adsorption capacity was found to be ~29 mg/g of adsorbent at 298 K when the equilibrium concentration of strontium in the solution was 925 mg/L at pH 6.5. The X-ray photoelectron spectroscopy (XPS) data suggest that strontium uptake by the beads occurs mainly through an ion-exchange process. Kinetic data indicate that the sorption of strontium onto the beads follows anomalous diffusion. Thermodynamic data suggest that the ion-exchange of Sr2+ on the bead surface was feasible, spontaneous and endothermic in nature.
Journal of hazardous materials, Jan 21, 2017
Mobility of Arsenic (As) from metallurgical wastes in Matehuala, Mexico has been accounted for ul... more Mobility of Arsenic (As) from metallurgical wastes in Matehuala, Mexico has been accounted for ultra-high concentration of As in water (4.8-158mg/L) that is used for recreational purposes as well as cultivation of maize. In this study, we (i) measured As concentrations in soils irrigated with this water, (ii) investigated the geochemical controls of available As, and (iii) measured bioaccumulation of As in maize. Water, soil, and maize plant samples were collected from 3 different plots to determine As in environmental matrices as well as water soluble As in soils. Soil mineralogy was determined by X-ray diffraction analysis. Bioaccumulation of As in maize plants was estimated from the bioconcentration and translocation factors. We recorded As built-up in agricultural soils to the extent of 172mg/kg, and noted that this As is highly soluble in water (30% on average). Maize crops presented high bioaccumulation, up to 2.5 times of bioconcentration and 45% of translocation. Furthermore...
Bulletin of environmental contamination and toxicology, Jan 13, 2016
Phosphate and colloidal gas aphrons (CGAs) generated from saponin extracted from Sapindus mukoros... more Phosphate and colloidal gas aphrons (CGAs) generated from saponin extracted from Sapindus mukorossi fruit, were evaluated for washing low levels of arsenic from an iron rich soil. Phosphate is one of the most commonly dispersed chemicals that increases arsenic mobility in soil due to their structural similarities, making it an important factor in arsenic removal process. Column washing experiments were performed with CGAs in down flow and up flow modes on soil of pH 5 and 6. Soapnut CGAs, when paired with phosphate removed up to 95 % arsenic while soapnut CGAs alone could only remove up to 70 % arsenic. The presence of phosphate improved efficiency of soapnut solution by up to 35 %. SEM image of washed soil revealed minor corrosion of soil surface while using phosphate with soapnut. Therefore, the addition of phosphates would have positive impact on soil washing using soapnut saponin.
Chemical Engineering Journal, 2016
Ammonium-based deep eutectic solvents as novel soil washing agent for lead removal, Chemical
RSC Advances, 2015
Optimization of process variables in activated carbon preparation by microwave heating for reduct... more Optimization of process variables in activated carbon preparation by microwave heating for reduction of energy use aiding sustainable development.
The Science of the total environment, Jan 15, 2015
A former silver mine in Tynagh, Co. Galway, Ireland is one of the most contaminated mine sites in... more A former silver mine in Tynagh, Co. Galway, Ireland is one of the most contaminated mine sites in Europe with maximum concentrations of Zn, As, Pb, Mn, Ni, Cu, and Cd far exceeding guideline values for water and sediment. The aims of this research were to 1) further assess the contamination, particularly metals, in surface water and sediment around the site, and 2) determine if the contamination has increased 10years after the Environmental Protection Agency Ireland (EPAI) identified off-site contamination. Site pH is alkaline to neutral because CaCO3-rich sediment and rock material buffer the exposed acid generating sulphide-rich ore. When this study was compared to the previous EPAI study conducted 10years earlier, it appeared that further weathering of exposed surface sediment had increased concentrations of As and other potentially toxic elements. Water samples from the tailings ponds and adjacent Barnacullia Stream had concentrations of Al, Cd, Mn, Zn and Pb above guideline val...
Science of The Total Environment, 2014
The use of seaweed fertilisers in sports green maintenance has become a common practice across th... more The use of seaweed fertilisers in sports green maintenance has become a common practice across the globe due to its image as an "eco-friendly" alternative to chemical fertilisers. The aim of this study was to characterise the risk of human exposure to arsenic (As), via dermal absorption, from golfing activities on a private golf course in the UK, where As contaminated seaweed fertiliser (~100 mg/kgd.wt.) is applied. This was fulfilled by, 1) determining As concentrations in shallow soils with GIS geo-statistical analysis, 2) measuring As concentrations from an on-site borehole groundwater well, and (3) developing a risk assessment calculation for golfing activities based on field and questionnaire data. Total As concentrations in shallow soils were less than the UK threshold for domestic soils, however, frequent and sustained dermal contact between site-users and surface soil attributed to a maximum carcinogenic risk value of 2.75 x 10 -4 , which is in the upper limit of the acceptable risk range. Arsenic concentrations in underlying groundwater exceeded the WHO's permissible drinking water standard, demonstrating the risk of groundwater contamination following the application of seaweed fertiliser to golf course soils. This is the first risk study on dermal As absorption via application of a seaweed fertiliser.
Electrochimica Acta, 2014
The study explores the application of a two-stage electrokinetic washing system on remediation of... more The study explores the application of a two-stage electrokinetic washing system on remediation of lead (Pb) contaminated soil. The process involved an initial soil washing, followed by an electrokinetic process. The use of electrokinetic process in soil washing not only provided additional driving force for transporting the desorbed Pb away from the soil but also reduced the high usage of wash solution. In this study, the effect of NaNO 3 , HNO 3 , citric acid and EDTA as wash solutions on two-stage electrokinetic washing system were evaluated. The results revealed that a two-stage electrokinetic washing process enhanced Pb removal efficiency by 2.52-9.08% and 4.98-20.45% in comparison to a normal electrokinetic process and normal washing process, respectively. Low pH and adequate current were the most important criteria in the removal process as they provided superior desorption and transport properties. The effect of chelating by EDTA was less dominant as it delayed the removal process by forming a transport loop in anode region between Pb ion and complexes. HNO 3 was not suitable as wash solution in electrokinetic washing in spite of offering highest removal efficiency as it caused pH fluctuation in the cathode chamber, corroded graphite anode and showed high power consumption. In contrast, citric acid not only yielded high Pb removal efficiency with low power consumption but also maintained a low soil: solution ratio of 1g: <1mL, stable pH and electrode integrity. Possible transport mechanisms for Pb under each wash solution are also discussed in this work.
Journal of Environmental Sciences, 2014
Recovery of cellulose fibres from paper mill effluent has been studied using common polysaccharid... more Recovery of cellulose fibres from paper mill effluent has been studied using common polysaccharides or biopolymers such as Guar gum, Xanthan gum and Locust bean gum as flocculent. Guar gum is commonly used in sizing paper and routinely used in paper making. The results have been compared with the performance of alum, which is a common coagulant and a key ingredient of the paper industry. Guar gum recovered about 3.86 mg/L of fibre and was most effective among the biopolymers. Settling velocity distribution curves demonstrated that Guar gum was able to settle the fibres faster than the other biopolymers; however, alum displayed highest particle removal rate than all the biopolymers at any of the settling velocities. Alum, Guar gum, Xanthan gum and Locust bean gum removed 97.46%, 94.68%, 92.39% and 92.46% turbidity of raw effluent at a settling velocity of 0.5 cm/min, respectively. The conditions for obtaining the lowest sludge volume index such as pH, dose and mixing speed were optimised for guar gum which was
Critical Reviews in Environmental Science and Technology, 2014
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Papers by Bhaskar Sengupta