Publications by authors named "Tapan Adhikari"

4 Publications

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Ecotoxicological effect of TiO nano particles on different soil enzymes and microbial community.

Ecotoxicology 2021 May 1;30(4):719-732. Epub 2021 Apr 1.

ICAR- Indian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal, 462038, India.

TiO nano particles (NPs) are one of the most produced nanoparticles in the world which are increasingly being released in to the soil. Soils are exposed to various level of concentration of TiO NPs, which has raised concern over the adverse influence on soil microbial community, in turn on ecosystem functions. Although, increasing number of studies on ecotoxicological effect of TiO NPs are coming up recently, however, a common conscience has yet to be reached regarding the impact of TiO NPs on soil microbial community and processes. Moreover, very few studies have targeted soil enzymes which are being considered as sensitive indicator of soil health. Therefore, the present study has been carried out to estimate the ecotoxicological effect of various doses of TiO NPs (5, 10, 20, 40, 80, 100 mg kg soil) on different soil enzymes and microbial community structure. Results revealed that soil enzyme activities and microbial biomass had a uniform trend where the value increased up to the dose of 20 mg TiO NPs kg soil and there onwards reduced drastically up to 100 mg TiO NPs kg soil dose. On the contrary, soil respiration and metabolic quotient kept increasing up to 100 mg TiO NPs kg soil dose indicating sub-lethal stress on microbial community. Nevertheless, the structure of microbial community had slightly different trend where the biomass of total phospho lipid fatty acid (PLFA), Gram positive, Gram negative bacteria, fungi, actinomyctetes and anaerobes were found to be increased up to dose of 80 mg TiO NPs kg soil, but, significantly declined at 100 mg TiO NPs kg soil dose. Furthermore, temperature effect on TiO NPs toxicity had exhibited a less negative impact at 40 °C rather than at 25 °C. In addition alteration index (AI3), an integrated indicator of C, N, P cycling of soils as well as a well-documented indicator of soil pollution, has been found to be regulated by soil respiration, clay content, anaerobe and eukaryote for AI3-Acid Phos. and by fungi to bacteria ratio, soil respiration, microbial biomass and Gram positive bacteria for AI3-Alk. Phos. Overall, the study provided valuable information regarding ecotoxicological impact of environmentally relevant concentrations of TiO NPs in clay loam soils as well as improved our perception regarding the impact of NPs on soil functioning.
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http://dx.doi.org/10.1007/s10646-021-02398-2DOI Listing
May 2021

Fe-exchanged nano-bentonite outperforms FeO nanoparticles in removing nitrate and bicarbonate from wastewater.

J Hazard Mater 2019 08 13;376:141-152. Epub 2019 May 13.

ICAR-Central Soil Salinity Research Institute, Karnal 132001, India.

Nitrate (NO) and bicarbonate (HCO) are harmful for the water quality and can potentially create negative impacts to aquatic organisms, crops and humans. This study deals with the removal of NO and HCO from contaminated wastewater using Fe-exchanged nano-bentonite and FeO nanoparticles. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, surface area measurement and particle size analysis revealed that the adsorbents fall under the nano-scale size range with high specific surface area, and Fe was successfully exchanged in the nano-bentonite clay. The kinetics of adsorption was well defined by pseudo-first order and pseudo-second order kinetic models for both NO and HCO. The Fe-exchanged nano-bentonite was a better performing adsorbent of the oxyanions than FeO nanoparticles. According to the Sips isothermal model, the Fe-exchanged nano-bentonite exhibited the highest NO and HCO adsorption potential of 64.76 mg g and 9.73 meq g, respectively, while the respective values for FeO nanoparticles were 49.90 mg g and 3.07 meq g. Thus, inexpensiveness and easy preparation process of Fe-exchanged nano-bentonite make it attractive for NO and HCO removal from contaminated wastewater with significant environmental and economic benefits.
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http://dx.doi.org/10.1016/j.jhazmat.2019.05.025DOI Listing
August 2019

Effect of Soil Amendments on Microbial Resilience Capacity of Acid Soil Under Copper Stress.

Bull Environ Contam Toxicol 2017 Nov 9;99(5):625-632. Epub 2017 Sep 9.

ICAR-Indian Institute of Soil Science, Nabibagh, Berasia Road, Bhopal, 462038, India.

An incubation study was undertaken to study microbial resilience capacity of acid soil amended with farmyard manure (FYM), charcoal and lime under copper (Cu) perturbation. Copper stress significantly reduced enzymatic activities and microbial biomass carbon (MBC) in soil. Percent reduction in microbial activity of soil due to Cu stress was 74.7% in dehydrogenase activity, 59.9% in MBC, 48.2% in alkaline phosphatase activity and 15.1% in acid phosphatase activity. Soil treated with FYM + charcoal showed highest resistance index for enzymatic activities and MBC. Similarly, the highest resilience index for acid phosphatase activity was observed in soil amended with FYM (0.40), whereas FYM + charcoal-treated soil showed the highest resilience indices for alkaline, dehydrogenase activity and MBC: 0.50, 0.22 and 0.25, respectively. This investigation showed that FYM and charcoal application, either alone or in combination, proved to be better than lime with respect to microbial functional resistance and resilience of acid soil under Cu perturbation.
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http://dx.doi.org/10.1007/s00128-017-2173-8DOI Listing
November 2017

Phytoaccumulation and tolerance of Riccinus communis L. to nickel.

Int J Phytoremediation 2012 May-Jun;14(5):481-92

Indian Institute of Soil Science, Nabiabagh, Madhya Pradesh, India.

The phytotoxicity due to nickel (Ni) and its accumulation in castor (Ricinus communis L.) plant of Euphorbiaceae family resulting from its addition from low to very high levels to a swell-shrink clayey soil (Haplustert) was studied in a pot culture experiment. Nine levels of Ni (0, 10, 40, 80, 120, 160, 180, 200, 250 mg Ni kg(-1) soil) were applied. Crop was harvested at 45 days after sowing. At the higher Ni levels, beyond 200 mg Ni kg(-1) soil, reduced growth symptom was recorded. The concentration of Ni in plant parts increased with increasing dose of applied Ni. Nickel concentration in castor root ranged from traces (control) to 455 mg kg(-1) and was directly related to soil Ni concentration. At 200 mg Ni kg(-1) soil, dry matter yield of castor reduced to 10% of control plant. Significant changes were observed in the roots of castor treated with higher levels of Ni against control. The roots treated with Ni showed a decrease in number of cells in the cortex region. It also appeared that the cortex region consisted of elongated parenchymatous cells instead of the normal parenchymatous tissue as in the control plant. Regarding Ni accumulation capacity, castor plant was recorded as an accumulator (alpha = 0.11 and beta = 1.10). A laboratory study was also conducted in the experimental soil to know the different operationally defined fractions of Ni, which control the availability of Ni to castor. Different fractions of Ni present in this soil followed this order: Residual > Fe-Mn oxides > carbonate > organic > exchangeable > water soluble. Overall results depict that castor is a promising species which can be used as a potential plant for phytoremediation of contaminated soils and to improve soil quality and provide economical benefits.
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http://dx.doi.org/10.1080/15226514.2011.604688DOI Listing
May 2014
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