I am originally from Calcutta, India. I completed my BS (Honors) in Chemistry in 2004 and MS in Environmental Chemistry in 2007 from University of Calcutta. I moved to The Pennsylvania State University in United States for my PhD in August, 2008. Dr. Carmen Enid Martinez was my PhD advisor. After successfully finishing my PhD in December, 2012 I moved to Colorado in March, 2013 to do my postdoctoral research with Dr. Thomas Borch at Colorado State University in Fort Collins. As a postdoctoral fellow here at CSU I work in the research project described below.
Postdoctoral Project: Geochemical Characterization of Uranium from Baseline- and Post-Mining Site Conditions at an In-situ Recovery Uranium Mine
In-situ recovery (ISR) uranium (U) mine restoration is generally based upon a return of the site to baseline conditions. Little or no scientific information is used to justify utilizing baseline conditions for regulatory compliance and the constituents monitored for compliance have not been evaluated to ensure they are proper indicators of restoration. Our study examines, for the first time, the pre-existing aquifer parameters, thereby allowing a complete scientific evaluation of the changes that occur during mining, so that specific recommendations can be made on how best to accomplish restoration of those constituents that most impact human and environmental health.
The chemical speciation, bioavailability, toxicity, and mobility of U in the subsurface environments are directly affected by reduction and oxidation. U remediation approaches focus on converting and maintaining U in its tetravalent oxidation state because of the formation of sparingly soluble, immobile U(IV) mineral phases, such as uraninite. Therefore it is critical to determine the speciation of U in order to understand the chemistry governing their retention and transport in these environmental systems before effective remediation strategies can be developed to prevent groundwater contamination. We focus on geochemical characterization of U from baseline conditions and compare it to a mined site to help evaluate the impact of mining and the potential for natural attenuation of contaminants. For my postdoctoral research I attempt to identify the different U species formed in ore bodies under different redox and hydrological gradients, thereby optimizing water management procedures to reduce aquifer impacts and wastewater volumes using traditional wet chemical techniques as well as synchrotron extended x-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectroscopy. This work will advance understanding of the redox processes associated with the reductive sequestration of U from groundwater and will provide regulators with sound scientific evidence for optimizing remediation goals.
This project is in collaboration with Cameco, Los Alamos National Laboratory and USGS.
PhD project: Redox Interactions of Iron with Natural Organic Matter
Natural organic matter (NOM) exerts a significant control on the oxidation state and coordination environment of Fe. Iron (Fe) complexes with organic matter (OM) represent an important class of structures whose chemistry and reactivity require further understanding under different environmental conditions since Fe speciation and mobility affect the availability, cycling, and transport of metals, OM and nutrients. I studied the Fe speciation in peat soils under varying redox conditions and the various factors stabilizing Fe(II) and Fe(III) under oxic and anoxic conditions respectively.Furthermore, electron exchange interactions between the redox active metal (Fe) center and the different functional groups present in NOM (carboxylic, amine and thiol) were studied in model Fe-organic complexes to explore the electron shuttling capabilities of Fe and the various functional groups in NOM. For my research, I have used a combination of traditional wet chemical methods as well as sophisticated synchrotron X-ray absorption spectroscopy (XAS) techniques and molecular multiplet calculations to elucidate the Fe speciation in soils where Fe-organic complexes are abundant.
For more details about the research conducted in the Borch group please click here.
Bhattacharyya, A., Dvorak, J., Stavitski, E. and Martínez, C.E. 2013. Redox interactions between Fe and cysteine: Spectroscopic studies and multiplet calculations. Geochimica et Cosmochimica Acta, 122, 89-100.
Bhattacharyya, A., Dvorak, J., Stavitski, E. and Martínez, C.E. 2012. Binding of Fe to Low Molecular Weight N-containing Amino Acids: Spectroscopic Studies and Multiplet Calculations. (soon to be submitted to Environmental Science &Technology)
For more publications in the Borch group please click here.
Dr. Kate Campbell (USGS)
Dr. Paul Reimus (Los Alamos National Laboratory)
Dr. Jim Stone (South Dakota School of Mines and Technology)
Dr. Stefan Weyer (Leibniz-Universität Hannover)
PhD: Department of Ecosystem Science and Management, The Pennsylvania State University
MS: University of Calcutta, India
BS: University of Calcutta, India