ABSTRACT
Carbon isotope fractionation associated with the aerobic consumption of propane (C3) were determined using Rhodococcus rhodochrous MTCC 291 bacterial strain to estimate the amount of hydrocarbon oxidized using GC, fractionation of δ13C carbon isotopes of propane and CO2 using GC-C-IRMS and growth of bacteria by UV-Visible Spectrophotometer. The initial δ13C isotopic value of propane was -34 ‰ and after incubation the changes of the isotopic values have been determined on 6th, 10th, 14th, and 17th days. The propane isotopic fractionation value was found to be maximum of -38.0 ‰ with an average value of -36.5 ‰ and a standard deviation of -1.22 ‰. The initial δ13C isotopic value of CO2 was -19.601 ‰. The CO2 isotopic fractionation value was found to be maximum of -29.153 ‰ with an average value of -26.859 ‰ and a standard deviation of -28.338 ‰. The consumption of propane gas was estimated using Gas Chromatograph. The initial concentration of propane in control was found to be 53 ppm. On incubation, the consumption of the propane gas was observed to be of 26 ppm. The carbon isotope fractionation presented here may be applied to estimate the extent of C1-C4 oxidation in natural gas samples, and should prove useful in further studying the microbial oxidation of these compounds in the natural environment.
ABSTRACT
Reconnaissance hydrochemical survey was conducted in some villages of Adilabad district, Andhra Pradesh to assess the quality of groundwater, which is mainly used for drinking purpose. The study consists of the determination of physico-chemical properties, trace metals, heavy metals and rare earth elements in water samples. The data showed the variation of the investigated parameters in samples as follows: pH 6.92 to 8.32, EC 192 to 2706 µS cm-1, TDS 129.18 to 1813.02 ppm. The pH of the waters was within the permissible limits whereas EC and TDS were above the permissible limits of World Health Organization (WHO). Total 27 elements (Li, Be, B, Na, Mg, Al, Si, K, Ca, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Ba and Pb) were analyzed using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The concentration of elements in water samples ranged between 0.063 to 0.611 mg l-1 for B, 11.273 to 392 mg l-1 for Na, 5.871 to 77.475 mg l-1 for Mg, 0.035 to 1.905 mg l-1 for Al, 0.752 to 227.893 mg l-1 for K, 11.556 to 121.655 mg l-1 for Ca and 0.076 to 0.669 mg l-1 for Fe respectively. The concentrations of Na, Mg, Al, K, Ca, and Fe exceeded the permissible limits of WHO and BIS guidelines for drinking water quality. In the present study, Bhimavaram, Kazipalli, Kannepalli and Chennur areas of the Adilabad are especially prone to geogenic contamination. Overall water quality was found unsatisfactory for drinking purposes.
ABSTRACT
Several techniques are used for the exploration of hydrocarbons, of which; the geochemical techniques involving the microbiological technique use the principle of detecting the light hydrocarbon seepage activities for indication of sub-surface petroleum accumulations. A survey was carried out to characterize the light gaseous hydrocarbons seeping in oil and gas fields of Krishna-Godavari basin of Andhra Pradesh. A set of 50 sub-soil samples were collected at depths of about 3 m for geochemical analyses and 1m for microbiological analysis. The microbial prospecting studies showed the presence of high bacterial population for methane 2.5 x 102 to 6.0 x 106 cfu g-1, propane 1x102 to 8.0 x 106 cfu g-1 in soil samples. The adsorbed soil gas analysis showed the presence of moderate to low concentrations of methane (26 to 139 ppb), ethane (0 to 17 ppb), propane (0 to 8 ppb), butane (0 to 5 ppb) and pentane (0 to 2 ppb) in the soil samples of the study area. Carbon isotope analysis for methane (´13C1) ranging from -36.6 to -22.7‰ Pee Dee Belemnite (PDB) suggests these gases are of thermogenic origin. Geo-microbial prospecting method coupled with adsorbed soil gas and carbon isotope ratio analysis have thus shown good correlation with existing oil/ gas fields of Krishna-Godavari basin.