Metal contaminations in sediment and associated ecological risk assessment of river Mahanadi, India.

Mahanadi is one of the major rivers of peninsular India. Like other Indian rivers, it is contaminated with sewages, industrial discharges, and agricultural runoff. Thus, necessity was felt to monitor its pollution status. Present work was part of that program and aimed to assess the sediment contamination due to the trace metals Cd, Cr, Cu, Mn, Pb, and Zn during 2012-2015. Sediment pollution status and ecological risks were evaluated calculating contamination factor (CF), geo-accumulation (Igeo), pollution load index (PLI), potential ecological risk (EiR), etc. The recorded metal concentrations were Cd BDL of flame mode of AAS; Cr BDL - 73.9; Cu BDL - 44.4; Mn 37.2 - 1887.0; Pb BDL - 29.5; and Zn BDL - 92.5 mg kg-1. As per US EPA guidelines, Cr concentrations at many locations were in the moderately polluted range. Igeo, CF, mCd, PLI, and EiR indicated low pollution levels and low ecological risks due to the trace metals assessed. The sediment quality guidelines (SQGs) indicated that Cr and Cu concentrations exceeded (16% sample) the threshold effect concentrations and may occasionally exhibit adverse biological effects. The association of sediment organic matter, conductivity and content of Cu, and their grouping in component 1 of PCA revealed that the anthropogenic input was dominant and so also the component 2 where Cr exhibited moderately good correlation with organic matter. Cluster analysis of the sampling sites based on pollution status yielded 3 groups: relatively uncontaminated (S3, S4), low to moderately contaminated (S2), and moderately contaminated (S1, S5, S6) stretches.

Fabrication and characterization of carbon-backed thin 208Pb targets.

Thin carbon-backed isotopically enriched 208Pb targets were required for our experiment aimed to study the reaction dynamics for 48Ti + 208Pb system, populating the near super-heavy nucleus 256Rf, through mass-energy correlation of the fission fragments. Purity and thickness of the targets are of utmost importance in such studies as these factors have strong influence on the measurement accuracy of mass and energy distribution of fission fragments. 208Pb targets with thickness ranging from 60 µg/cm2 to 250 µg/cm2 have been fabricated in high vacuum environment using physical vapor deposition method. Important points in the method are as follows: •208Pb was deposited using resistive heating method, whereas carbon (backing foil) deposition was performed by using the electron beam bombardment technique.•Different characterization techniques such as Particle Induced X-ray Emission (PIXE), Energy Dispersive X-Ray Fluorescence (EDXRF) and Rutherford Backscattering Spectrometry (RBS) were used to assert the purity and thickness of the targets.•These targets have successfully been used to accomplish our experimental objectives.

Structure, spectra and antioxidant action of ascorbic acid studied by density functional theory, Raman spectroscopic and nuclear magnetic resonance techniques.

Structure, vibrational and nuclear magnetic resonance spectra, and antioxidant action of ascorbic acid towards hydroxyl radicals have been studied computationally and in vitro by ultraviolet-visible, nuclear magnetic resonance and vibrational spectroscopic techniques. Time dependant density functional theory calculations have been employed to specify various electronic transitions in ultraviolet-visible spectra. Observed chemical shifts and vibrational bands in nuclear magnetic resonance and vibrational spectra, respectively have been assigned with the help of calculations. Changes in the structure of ascorbic acid in aqueous phase have been examined computationally and experimentally by recording Raman spectra in aqueous medium. Theoretical calculations of the interaction between ascorbic acid molecule and hydroxyl radical predicted the formation of dehydroascorbic acid as first product, which has been confirmed by comparing its simulated spectra with the corresponding spectra of ascorbic acid in presence of hydrogen peroxide.

Uncertainty in dual permeability model parameters for structured soils.

Successful application of dual permeability models (DPM) to predict contaminant transport is contingent upon measured or inversely estimated soil hydraulic and solute transport parameters. The difficulty in unique identification of parameters for the additional macropore- and matrix-macropore interface regions, and knowledge about requisite experimental data for DPM has not been resolved to date. Therefore, this study quantifies uncertainty in dual permeability model parameters of experimental soil columns with different macropore distributions (single macropore, and low- and high-density multiple macropores). Uncertainty evaluation is conducted using adaptive Markov chain Monte Carlo (AMCMC) and conventional Metropolis-Hastings (MH) algorithms while assuming 10 out of 17 parameters to be uncertain or random. Results indicate that AMCMC resolves parameter correlations and exhibits fast convergence for all DPM parameters while MH displays large posterior correlations for various parameters. This study demonstrates that the choice of parameter sampling algorithms is paramount in obtaining unique DPM parameters when information on covariance structure is lacking, or else additional information on parameter correlations must be supplied to resolve the problem of equifinality of DPM parameters. This study also highlights the placement and significance of matrix-macropore interface in flow experiments of soil columns with different macropore densities. Histograms for certain soil hydraulic parameters display tri-modal characteristics implying that macropores are drained first followed by the interface region and then by pores of the matrix domain in drainage experiments. Results indicate that hydraulic properties and behavior of the matrix-macropore interface is not only a function of saturated hydraulic conductivity of the macroporematrix interface (Ksa ) and macropore tortuosity (lf ) but also of other parameters of the matrix and macropore domains.

Determination of processes affecting groundwater quality in the coastal aquifer beneath Puri city, India: a multivariate statistical approach.

Variability of groundwater quality parameters is linked to various processes such as weathering, organic matter degradation, aerobic respiration, iron reduction, mineral dissolution and precipitation, cation exchange and mixing of salt water with fresh water. Multivariate statistical analyses such as principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied to the standardized data set of eleven groundwater quality parameters (i.e. pH, Ca2+, Mg2+, Na+, K+, Fe3+, alkalinity, NO3-, Cl-, SO4(2-), TDS) collected during the post-monsoon and the summer seasons in order to elicit hydrologic and biogeochemical processes affecting water quality in the unconfined aquifer beneath Puri city in eastern India. The application of PCA resulted in four factors explaining 73% variance in post-monsoon and 81% variance in summer. The HCA using Ward's method and squared Euclidean distance measure classified the parameters into four clusters based on their similarities. PCA and HCA allowed interpretation of processes. During both post-monsoon and summer seasons, anthropogenic pollution and organic matter degradation/Fe(III) reduction were found dominant due to contribution from on-site sanitation in septic tanks and soak pits in the city. Cation exchange and mineral precipitation were possible causes for increase in Na+ and decrease in Ca2+ concentration in summer. Fresh water recharge during monsoon and Sea water intrusion in summer are attributed as significant hydrologic processes to variations of the groundwater quality at the study site.

Secretion of testicular steroids and gonadotrophins in hypothyroidism.

Inconsistent alterations in gonadal steroidogenesis and pituitary functions have been reported in hypothyroid males. We have compared the lipid and endocrine profiles of the euthyroid and hypothyroid [thyroid-stimulating hormone (TSH) >100 mIU l(-1)] males. Hypothyroidism was found to be associated with an increase in the circulating level of total cholesterol and LDL-cholesterol (LDL-C) and a reduction in the levels of progesterone and testosterone, without any change in the serum levels of oestradiol and gonadotrophins. The failure of gonadotrophins to rise could be accounted by a normal level of serum oestradiol in the hypothyroid male. A mild hyperprolactinaemia was also noted in the hypothyroid patients. The reduction in serum testosterone level could be explained by (i) a reduced uptake of LDL-C by the Leydig cells and thereby a reduction in the synthesis of progesterone and consequentially testosterone, (ii) a further reduction in the rate of conversion of progesterone to testosterone, (iii) a higher rate of conversion of testosterone to oestradiol, (iv) a decrease in serum triiodothyronine and (v) hyperprolactinaemia. Rise in TSH needs to be investigated as a cause of the suppression of gonadal steroidogenesis.

A p53-like protein from a freshwater mollusc Lamellidens corrianus.

p53 is the most frequently mutated protein in human cancers and the accumulation of its high levels is a potential novel marker for malignancy. Recently, its homologues such as p63 and p73 have been reported in human, mice and fish. Environmentally induced alterations in p53 protein have been reported to contribute to pathogenesis of leukemia in soft-shell clam Mya arenaria inhabiting polluted water, suggesting that p53 proteins can also be used as pollution markers. In the present study, the presence of p53 protein or its homologues was investigated in tissues of bivalve molluscs Lamellidens corrianus that are predominant in the freshwater riverine environment and are well suited to act as test organisms for evaluation of habitat degradation. The molluscs were collected live from the river Ganga at three sampling sites viz., Kanpur, Allahabad and Varanasi and different tissues (foot, gill and mantle) were collected. Proteins were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). On immunoblot analysis, a 45 kDa protein (p45) was recognized by the monoclonal anti-p53 antibody in the molluscan tissues. The p45 showed immunoreactivity in all the three tissues of molluscs collected at Kanpur, in foot and gill tissues in those collected at Allahabad, and in foot tissue only, in those collected at Varanasi. Since monoclonal anti-p53 recognizes a denaturation-resistant epitope on the p53 (53 kDa) nuclear protein and does not react with other cellular proteins, the molluscan p45 is a p53-homologue or p53-like protein. Further, the differential expression of p45 in the different organs might serve as a useful biomarker that would help in establishing pollution gradient for environmental monitoring in the large aquatic ecosystems.

Genetic diversity in cultivars and landraces of Oryza sativa subsp. indica as revealed by AFLP markers.

Genetic diversity among 49 Indian accessions of rice (Oryza sativa subsp. indica), including 29 landraces from Jeypore, 12 modern cultivars, and 8 traditional cultivars from Tamil Nadu, was investigated using AFLP markers. In total, nine primer combinations revealed 664 AFLPs, 408 of which were found to be polymorphic. The percentage of polymorphic AFLPs was approximately the same within the cultivars and landraces. Similar results were obtained when genetic diversity values were estimated using the Shannon-Weiner index of diversity. Genetic diversity was slightly higher in the modern cultivars than in the traditional cultivars from Tamil Nadu. Among the landraces from Jeypore, the lowland landraces showed the highest diversity. The present study showed that the process of breeding modern cultivars did not appear to cause significant genetic erosion in rice. Cluster analysis and the first component of principle component analysis (PCA) both showed a clear demarcation between the cultivars and landraces as separate groups, although the genetic distance between them was narrow. The modern cultivars were positioned between the landraces from Jeypore and the traditional cultivars from Tamil Nadu. The second component of PCA further separated medium and upland landraces from lowland landraces, with the lowland landraces found closest to the traditional and modern cultivars.