Sukanta Maity

Estimation of distribution coefficient of natural radionuclides in soil around uranium mines and its effect with ionic strength of water

The distribution coefficient, K(d) in soil is an important parameter to predict the migration of contaminants. In this study, uranium (U) and its decay products thorium (Th), radium (Ra), bismuth (Bi), lead (Pb) and polonium (Po), which may contaminate the soil and ground water around uranium mining areas, have been considered. Soil and ground water samples were collected from a proposed uranium mining site in India. The soil samples were characterised for different parameters affecting the K(d) values. The batch sorption method was employed to measure the K(d) of different radionuclides. The important factors affecting the batch method for K(d) estimation were identified and optimised. The variation of K(d) was observed with different ionic strength water samples. Results showed high K(d) values for Th(IV), Po(IV) and Pb(II) (log K(d) ∼4) and low K(d) (log K(d) ∼2-3) for U(VI), Ra(II) and Bi(III) in all three types of water with different ionic strength.

Method for determination of radium in seawater using MnO 2 co-precipitation technique

Radium is considered to be a useful tracer for studying various physical processes of seawater. There are several methods for analysis of radium; however, analysis of radium in seawater by those analytical techniques is a tedious job. Thus a new methodology was optimized for analysis of radium in sea water using MnO2 co-precipitation followed by gamma spectrometry. The method produced good yield which ranged from 85–98%. The method is simple and requires less amounts of chemicals and no use of acids. Seawater from different western Indian coastal environments viz. Tarapur, Mumbai and Goa were collected and analysed for 226Ra and 228Ra using this method.

Determination of Heavy Metals and Their Distribution In Different Size Fractionated Sediment Samples Using Different Analytical Techniques

Abstract Distribution of heavy metals (Pb, Cu and Cd) in different size-fractionated sediment samples was studied using different analytical techniques such as flame atomic absorption spectrometry (FAAS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and differential pulse anodic stripping voltammetry (DPASV). Pb and Cu concentrations were found to have respective variations of 6.58% and 9.45% from FAAS, ICP-AES and DPASV analysis. Cadmium was detectable only by DPASV because of its lower abundance in different size fractions. The percentage distribution of total organic carbon (TOC) and heavy metals increased with decrease in particle size. Metal concentrations increase with increasing TOC content in different size-fractionated sediment samples studied. Although the smallest fractions (< 53 μm) of sediment contributed only 3.4–17.8%, they had the highest mean distribution factor of 1.08 for Pb, 1.04 for Cu and 1.06 for Cd, respectively. Pb, Cu and Cd were correlated positively with organic carbon content in the sediment samples.

Distribution coefficients of radionuclides around uranium mining area and effect of different analytical parameters on their determination

Macroscopic batch sorption study has been carried out to measure distribution coefficient (Kd) of uranium, thorium and their daughter products, radium and polonium, on soil samples collected from a proposed uranium mining site in India. Results showed high Kd values for Th(IV) and Po(IV) (log Kd ~4), while lower Kd values were obtained for U(VI) with the site ground water as aqueous medium compared to the synthetic water. Ra(II)–Kd has been found dependent on soluble Ca(II) content of the water samples. Determination of Kd values in an inter-comparison manner involving different estimation methodology produced a consistent data set.

Estimation of Distribution Coefficient of Uranium and Its Correlation with Soil Parameters Around Uranium Mining Site

Distribution coefficient of uranium and its daughter products are very important for migration study around uranium mining sites. Since the distribution coefficient depends very much on the soil chemistry, generation of site specific Kd is very important. The present study emphasizes on the estimation of distribution coefficient for uranium and its correlation with various soil parameters. The distribution coefficient of uranium in top and one meter depth soil samples from above locations were estimated using laboratory batch method. The distribution coefficient of uranium varies from 69 to 5524 l/kg. No significant difference in uranium Kd values was observed for top and one meter depth soil samples. A good correlation was observed between distribution coefficient of uranium and soil parameters like pH and concentration of CaCO3.

Trace metals distribution and their dependence on some physico-chemical parameters in creek sediment

ABSTRACT The concentrations of the trace metals Mn, Zn, Cr, V, Co, Ni, Ba, Pb, Cu, Cd, As and Hg, their spatial distribution, and their correlation as a function of physico-chemical parameters were investigated for grab sediment samples collected from different locations across the Thane Creek, Mumbai, India. Hydride generation atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, and differential pulse anodic stripping voltammetry were adopted for chemical analyses. Various geochemical indices were evaluated. The studied metal/metalloids were compared with sediment quality guideline values. Besides, the role of different physico-chemical parameters of the sediments such as pH, CaCO3, cation exchange capacity, total carbon, and of the relative composition in respect to very coarse, coarse and medium sand, fine sand and very fine sand, silt and clay fraction were also critically investigated. Positive one-to-one correlations between fine sand and very fine sand, silt and clay, and total carbon with sediment metal concentrations have been noticed. Multiple regression analysis reveals strong positive correlations between sediment metal concentrations and total carbon content only.

Multi-element detection in sea water using preconcentration procedure and EDXRF technique

A method was optimized for detecting trace elements in sea water using Energy dispersive X-ray fluorescence (EDXRF) technique. Sea water samples were pre-concentrated using ammonium pyrrolidinedithiocarbamate (APDC) as chelating agent and methyl isobutyl ketone (MIBK) as organic phase. The preconcentrated samples were dried to form thin films on mylar substrate and analysed using EDXRF spectrometer. The multi-element standard samples prepared in synthetic sea water were used for EDXRF instrument calibration. The instrument was calibrated for 11 elements namely As, Cd, Co, Cr, Fe, Ga, Pb, Se, Sc, V and Zn using linear regression method for concentration up to 200 ppb. The detection limits achieved for As, Cd, Co, Cr, Fe, Ga, Pb, Se, Sc, V and Zn were 13, 70, 5.1, 36, 15, 36, 23, 11, 20, 13 and 40 ppb respectively. The optimized method was used for determination of elements in sea water collected from the Thane creek, Mumbai, India. The results were checked for accuracy by comparing it with inductively coupled plasma atomic emission spectroscopy (ICP AES) technique. The comparison showed the discrepancy of results to be insignificant at 95% confidence level.

Distribution of pollutants in ground water samples collected from uranium mining area

Environmental pollution by chemical pollutants such as heavy metals, radionuclides, and anionic constituents such as sulfate and nitrate originated from mines and mining operations can become a very important source of contamination in water. Pollutants mainly present in the chemical industrial wastes as well as in the low level liquid releases from the nuclear fuel cycle. The solid hazardous radioactive wastes arising are usually disposed of in near surface/shallow land burial facilities. The heavy metals components of these solid wastes (radioactive and stable) could find their way either into the ground water through infiltrating water or to the soil by runoff. In this study, an approach is made for distribution of pollutants in ground water collected from seven locations around the premises of a uranium mining site, Turamdih located at Jharkhand state of India. Major and trace elements such as Na, K, Zn, Ni, Mn, Fe, Pb, Cu, Al, Ba, Mo, and U, etc., were analyzed using inductively coupled plasma-atomic emission spectrometry and differential pulse adsorptive stripping voltammetry. Sulfate, nitrate, chloride, and fluoride were analyzed using ion chromatogram. Bicarbonate was analyzed by titration method.