R. Ravisankar

Spatial distribution of physico-chemical properties and function of heavy metals in soils of Yelagiri hills, Tamilnadu by energy dispersive X-ray florescence spectroscopy (EDXRF) with statistical approach

Soil physico-chemical properties were thought to be important factors in obscuring clear identification of pollutant sources. In the present study physicochemical properties such as, pH, electrical conductivity, bulk density, porosity density, soil texture and color were determined to identify the pollution status using different conventional analytical methods in soils of Yelagiri Hills, Tamilnadu. Soil pH ranges from 5.39 to 8.43 which indicate that the soils are acidic to alkaline in nature. The concentrations of selected heavy metals were determined using energy dispersive X-ray florescence spectroscopy (EDXRF) technique. In all the locations Al is the most abundant metal and Co is the least amount in soil. The relationship between the physico-chemical properties and heavy metals were studied by Pearson correlation. The statistical technique shows that strong significant correlation among the heavy metals. The Chemometric approaches namely: principal component analyses (PCA), hierarchical cluster analysis (HCA), were used for identify the soil pollutant. Spatial distribution of physico-chemical properties of soil such as pH, soil texture (sand, silt, clay) electrical conductivity was studied by geo-statistical methods such as kriging identified areas. The heavy metal mapping also attempted to know the distribution pattern in soils.

Assessment of natural radioactivity and function of minerals in soils of Yelagiri hills, Tamilnadu, India by Gamma Ray spectroscopic and Fourier Transform Infrared (FTIR) techniques with statistical approach

Gamma Ray and Fourier Transform Infrared (FTIR) spectroscopic techniques were used to evaluate the natural radioactivity due to natural radionuclides and mineralogical characterization in soils of Yelagiri hills, Tamilnadu, India. Various radiological parameters were calculated to assess the radiation hazards associated with the soil. The distribution pattern of activity due to natural radionuclides is explained by Kriging method of mapping. Using FTIR spectroscopic technique the minerals such as quartz, microcline feldspar, orthoclase feldspar, kaolinite, montmorillonite, illite, and organic carbon were identified and characterized. The extinction coefficient values were calculated to know the relative distribution of major minerals such as quartz, microcline feldspar, orthoclase feldspar and kaolinite. The calculated values indicate that the amount of quartz is higher than orthoclase feldspar, microcline feldspar and much higher than kaolinite. Crystallinity index was calculated to know the crystalline nature of quartz. The result indicates that the presence of disordered crystalline quartz in soils. The relation between minerals and radioactivity was assessed by multivariate statistical analysis (Pearsons correlation and cluster analysis). The statistical analysis confirms that the clay mineral kaolinite and non-clay mineral quartz is the major factor than other major minerals to induce the important radioactivity variables and concentrations of uranium and thorium.

Assessment of Heavy Metal Contamination in Marine Sediments of East Coast of Tamil Nadu Affected by Different Pollution Sources

The aim of this study was to determine the concentration of heavy metals in the sediments of Periyakalapet to Parangipettai coast, east coast of Tamil Nadu, by using energy-dispersive X-ray fluorescence (EDXRF) technique. The average heavy metal concentrations in the sediment samples were found in the order Al>Fe>Ca>Ti>K>Mg>Mn>Ba>V>Cr>Zn>La>Ni>Pb>Co>Cd>Cu. The average heavy metal concentrations were below the world crustal average. The degree of contamination by heavy metals was evaluated using pollution indices. The results of pollution indices revealed that titanium (Ti) and cadmium (Cd) were significantly enriched in sediments. Pearson correlation analysis was performed among heavy metal concentrations to know the existing relationship between them. Multivariate statistical technique was employed to identify the heavy metal pollution sources.

Assessment of natural radioactivity and radiological hazards in building materials used in the Tiruvannamalai District, Tamilnadu, India, using a statistical approach

Abstract One-hundred-fifty-one samples of six types of building materials were collected from different locations of the Tiruvannamalai District, Tamilnadu, and were analyzed using a gamma ray spectroscopy system. From the results, the highest values observed in the specific activities of 226Ra, 232Th and 40K were 116.1 (soil) 106.67 (sand) and 527.533 (tiles) in Bq kg−1, while the lowest values observed in the specific activities of the same radionuclides were 35.73, 37.75 and 159.83 for cement in Bq kg−1, respectively. The potential radiological hazards were assessed by calculating the radium equivalent activity (Raeq), the indoor absorbed gamma dose rate (DR), the annual effective dose rate (HR), the activity utilization index (I), the alpha index (Iα), the gamma index (Iγ), and the external hazard (Hex) and internal hazard (Hin) indices. The estimated mean value of the absorbed dose rate of 148.35 nGy h−1 is slightly higher than the world average value of 84 nGy h−1, and the annual effective dose in the studied samples is 0.1824 mSv y−1, which is lower than the recommended limit. Multivariate statistical methods are applied to determine the existing relationship between radionuclides and radiological health hazard parameters and to identify the maximum contribution of radionuclide in radioactivity. The values of the hazard indices were below the recommended levels; therefore, it is concluded that the buildings constructed from such materials are safe for the inhabitants. The findings from this research will be useful to assess the radiation hazards of building materials in humans.

Synthesis, growth, and structural, optical, mechanical, electrical properties of a new inorganic nonlinear optical crystal: Sodium manganese tetrachloride (SMTC)

Abstract A new inorganic nonlinear optical single crystal of sodium manganese tetrachloride (SMTC) has been successfully grown from aqueous solution using the slow evaporation technique at room temperature. The crystals obtained using the aforementioned method were characterized using different techniques. The crystalline nature of the as-grown crystal of SMTC was analyzed using powder X-ray diffraction. Single-crystal X-ray diffraction revealed that the crystal belongs to an orthorhombic system with non-centrosymmetric space group Pbam. The optical transmission study of the SMTC crystal revealed high transmittance in the entire UV–vis region, and the lower cut-off wavelength was determined to be 240 nm. The mechanical strength of the as-grown crystal was estimated using the Vickers microhardness test. The second harmonic generation (SHG) efficiency of the crystal was measured using Kurtzs powder technique, which indicated that the crystal has a nonlinear optical (NLO) efficiency that is 1.32 times greater than that of KDP. The dielectric constant and dielectric loss of the compound were measured at different temperatures with varying frequencies. The photoconductivity study confirmed that the title compound possesses a negative photoconducting nature. The growth mechanism and surface features of the as-grown crystals were investigated using chemical etching analysis.

Data on the radiometric survey over a kaolinitic terrain in Dahomey Basin, Nigeria

This article consists the in situ data sets of activity concentrations of radionuclides (K-40, Th-232 and U-238) and gamma radiation dose rates measured about 1 m above a kaolinitic terrain in Ifonyintedo, Dahomey Basin, SW Nigeria. Nineteen (19) data points were randomly occupied at the lower axis of the kaolin field using a hand-held detector known as Super-Spec (RS 125). At each data point, the measurements were taken four times, while their averages and standard deviations were estimated in order to ensure accuracy. The radiometric survey was carried out between December, 2017 and January, 2018. The data sets were processed and analyzed via a descriptive statistics. The data can be explored further by estimating the radiological risks to the miners on the field, and to correlate the activity concentrations of the data with the activity concentrations of the tiles that are produced from the kaolin deposits in Ifonyintedo. Furthermore, the data from this article could be compared with other data acquired over a kaolinitic terrain across the globe.

Dataset on elemental concentration and group identification of ancient potteries from Tamil Nadu, India

The dataset contains concentration of major and trace elements of ancient potteries from Tamilnadu and grouping different potteries from the statistical techniques of factor and cluster analysis (Figs. 2, 3 and 4). The major and trace elemental concentration data generated using energy dispersive X-ray fluorescence technique (EDXRF) and factor and cluster analysis data obtained using STATISTICA (10.0 version) software. The concentration of major and trace elements determines the type of clay minerals (Calcareous/Non-Calcareous and either low or high refractory) and firing atmosphere adopted by the artisans at the time of manufacture. The statistical tool examined graphically the grouping pattern of the samples in terms of chemical composition and extract information about their provenance. The compilation of this data provides a resource for the wider research community in archeology.

Analysis of beach rock samples of Andaman Island, India by spectroscopic techniques

Abstract Beach rock is a peculiar formation when compared to other types of rock formations. One such formation is found in Andaman and Nicobar Island of India. It needs intensive and extensive investigation on its formation. The present work aimed to collect the beach rock samples along the Coast of Andaman Island and subjected to mineral and multi-elemental analysis using spectroscopic techniques. The presence of mineral in beach rock samples is identified by FT-IR spectroscopic technique. The constituents of minerals present in the beach rocks are further confirmed by XRD technique. Elemental concentrations of beach rock samples have been analyzed using non-destructive technique of energy dispersive X-ray fluorescence (EDXRF) spectrometry. The concentrations of Al, Ca, K, Fe, Ti, Si, V, Co, Cu, Ba, Zn, Pb, Cd & Mn are determined. The geochemical behavior of elements in the region is discussed. The spectroscopic techniques reveal the cementing minerals and elemental compositions of beach rocks of Andaman Island, India. Results are discussed and the conclusions are drawn.

Assessment of gamma radiation and associated radiation hazards in coastal sediments of south east coast of Tamilnadu, India with statistical approach

Gamma spectroscopy was performed to determine the concentrations of 226Ra, 232Th and 40K in sediment samples collected from Periyakalapet to Parangaipettai, East coast of Tamilnadu. The activity concentrations were determined by direct counting using a hyper pure germanium (HPGe) detector inter phased with a multi channel analyzer (MCA). The average activity concentrations of the corresponding nuclides were 30.81 Bq kg-1 for 226Ra, 85.67 Bq kg-1 for 232Th and 425.72 Bq kg-1 for 40K. The average activity concentration of 232Th and 40K are slightly higher and 226Ra is lower than world average values. The radiation hazard indices namely Radium Equivalent Activity (Raeq) Absorbed Gamma Dose Rate (DR), Annual Effective Dose Rate (HR), Representative Level Index (RLI), Annual Gonadal Dose Equivalent (AGDE), Internal Hazard Index (Hin) and External Hazard index (Hex) are calculated and compared with the previously reported data. The extracted values are comparable to the recommended values and they all fall within the safety limits. Hence harmful radiation effects are not posed to the public and tourists going to the beaches for recreation or to the fishermen involved in their activities in the area as a result of the natural radioactivity of sediments. Multivariate Statistical analyses were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclides.

Data on natural radioactivity and associated radiation hazards in coastal sediment of Chennai Coast, Tamilnadu, India using gamma ray spectrometry

This article contains data on the activity concentration of natural radionuclides in coastal sediment samples collected from Pulicat Lake to Vadanemmeli, East coast of Tamil Nadu using NaI(Tl) detector based γ-spectrometry. As marine sediments are found to be the repository of many radioactive pollutants, studied the objectives like (i) determine natural radionuclide activity concentrations in sediment samples in and around Chennai coast (ii) evaluate the radiological hazards due to natural radioactivity associated with coastal sediments and (iii) identify areas which may be radiological hazardous for the public along the study area. The average activity concentration of 238U, 232Th and 40K in the present study is lower than world median value. The radiological hazard indices such as External hazard index (Hex) and Gamma representative level index, (Iγ) were evaluated to assess radiation hazard associated with the sediments. The simulated results show sediments do not pose any significant radiation hazards due to concentration of natural radionuclides.