Dendrogram shows cluster of variables. Cluster I confirms that the clay and organic matter content plays an important role to raise the level of heavy metal contents as well as PLI and PER (level of ...toxicity). Display omitted
•Distributions of heavy metals were measured for surface sediments of the Vaigai river.•Average values of PLI and PER show that sediments have moderate toxicity level.•Content of clay and organic matter raise the level of heavy metal and their toxicity.•Metal contents and their toxicity decreases in sand sized sediment samples.
The distributions of the metals (Al, Fe, Mg, Cd, Cr, Cu, Ni, Pb and Zn) were measured for the surface sediments of the Vaigai river, Tamilnadu, India. These values are compared with different standard values to assess the level of toxicity of the heavy metals in the sediments. Risk indices (CF, PLI and PER) are also calculated to understand the level of toxicity of the metals. Multivariate statistical analyses (Pearson’s correlation analysis, cluster analysis and factor analysis) are carried out to know the inter-relationship between sediment characteristics and the heavy metals. From this analysis, it is confirmed that the contents of clay and organic matter play an important role to raise the level of heavy metal contents as well as PLI and PER (level of toxicity). Heavy metal concentrations of the samples (after removing silt and clay fractions from bulk samples) show decrease in their concentrations and risk indices compared to the level of bulk samples.
Graphical representation shows that concentrations of Cd and Pb and all the calculated indexes might have been influenced by the amount of total organic content and the Ni and Zn concentrations might ...have been influenced by sediment grain size (silt and clay). Display omitted
•Most of the metals are higher in S1 and other higher values are erratically distributed.•Moderate and severe degree of ecological risk is observed in different layers.•Surface and first feet samples had 21%, third feet samples had 49% of probability of toxicity.•Most of the studied metals and all calculated indexes are higher in third feet samples.•The calculated indexes might have been influenced by amount of total organic content.
The spatial and vertical distribution of heavy metals and the sediment characteristics of beaches in Kerala, India (the upper surface sediments and the first, second and third one-foot-thick strata) were assessed in this study. The concentrations of most of the studied metals were highest at sampling site S1 (Cochin). The measured concentrations were compared with background and toxicological reference values. The results show that definite adverse biological effects are possible at most of the sampling sites due to the high Pb levels. Three different indexes were calculated to investigate the potential toxicity level. Most of the studied metals and all calculated indexes were highest in the third foot of sediment. Multivariate statistical analyses were performed and suggested that particular heavy metals, e.g., Pb, Cd, Cr and Ni, may represent contamination from a common source. The Cd and Pb concentrations and all the calculated index values show a relationship with the content of organic matter. The results of the present study suggest the recommendation that a systematic analysis is needed to monitor heavy metal levels in the studied area.
The spatial distributions of heavy metals, magnetic susceptibility and granulometric contents have been assessed for beach and intertidal sectors of North-East coast of Tamilnadu, India. Metal ...concentrations and magnetic susceptibility are high, moderate and low in WER, MER and LER respectively. The measured concentrations are compared with background and toxicological reference values, results insist that in both sectors adverse biological effect is possible in some sites due to the excess Ni and Pb. Calculated three different indexes (PLI, PER and mERM-Q) indicate that in beach and intertidal samples shows moderate and low degree of potential ecological risk respectively. The studied metals might have 21% probability of being toxic in both sectors. Studied metal concentrations, calculated indexes, magnetic susceptibility and clay content are low in intertidal sector. Dominant factors for calculated indexes have been assessed in both sectors. In both cases, all the calculated indexes are positively (low) correlated with magnetic susceptibility and clay.
Satellite imagery is categorized into three distinct types: Panchromatic (PAN), Multi-spectral (MS), and Hyperspectral (HS). PAN images possess high spatial resolution, while MS images excel in ...spectral resolution, and HS images excel in very high spectral resolution. The field of remote sensing has a pivotal role in diverse fields such as environmental protection, safety, hazard prevention through geological surveys, smart agriculture, and defense security. These applications demand a combined high level of spatial and spectral resolution within a single image. By utilizing novel image fusion techniques, PAN and MS images can be merged to yield high-quality composite images. The fusion process employs a new approach involving weighted guided image filtering in conjunction with Particle Swarm Optimization (PSO) segmentation. Image segmentation plays a crucial role in image enhancement. This study applies various segmentation algorithms to the source images before fusion. The objective of this work is to transcend the limitations of conventional fusion methods by introducing a novel model for remote-sensing image fusion. Performance evaluation includes an analysis of multiple segmentation methods, and their results with the following performance metrics, Peak Signal-to-Noise Ratio (PSNR), Mean Squared Error (MSE), Structural Similarity Index Measure (SSIM), Average Difference (AD), Structural Content (SC), Normalized Cross Correlation (NCC), and Normalized Absolute Error (NAE). Empirical investigations are conducted using images from the Ikonos and Quikbird sensors. The proposed methodology, featuring modified PSO segmentation, yields high-quality fused images with PSNR values of 23.34 for the Ikonos image and 24.54 for the Quickbird image, surpassing the performance of traditional approaches.
Horizontal and vertical distributions of heavy metals (Al, Fe, Mg, Cd, Cr, Cu, Ni, Pb and Zn) and magnetic susceptibility of Vaigai river sediment have been assessed to know the heavy metal toxicity ...and magnetic behavior of the sediment. The present study intentionally shows the magnetic susceptibility as proxy for metal concentrations and their risk levels of sediment. Univariate statistical analysis is carried out to confirm the spatial distribution of the heavy metals. The metal concentrations in present sediment are compared with iportant toxic reference values such as TEL, PEL, ERL, ERM and TRV to predict the toxicity of metals. The result shows that the frequent biological effect can be possible due to Cd, Cr, Cu, Pb and Zn in all feet sediments. Some interesting pollution factors such as PLI, PER and mPEC-Q are calculated to know the pollution status of the river. High magnetic susceptibility values in S
16
, S
18
and S
25
indicate the presence of various magnetic minerals. Principal Component Analysis (PCA) is carried out to show magnetic susceptibility as proxy for measuring heavy metals and their risk levels. Since magnetic susceptibility is strongly associated with heavy metals and their risk levels, this may be proxy for determining heavy metals and their risk levels.
The concentration and distribution of the natural radionuclides (238U, 232Th and 40K) have been analyzed for the beach sediments of Kerala with an aim of evaluating the radiation hazards. The ranges ...of activity concentrations of 238U, 232Th and 40K are BDL—1187±21.7Bq/kg, BDL—5328±23.2Bq/kg and BDL—693±31.2Bq/kg respectively. Radiological parameters such as absorbed dose rate, annual effective dose equivalent, annual gonadal dose equivalent, radium equivalent, hazard index, gamma Index, activity utilization index and excess lifetime cancer risk are calculated to know the complete radiological hazardous nature. Concentration of radionuclides (238U and 232Th) and all the calculated radiological parameters are higher in site number S23 (Chavara beach) due to the presence of rich deposits of black sands. Average concentrations of radionuclides (238U and 232Th) and all calculated radiological parameters are higher than the recommended level. Both univariate and multivariate statistical analyses were applied effectively to assess the distribution of the radionuclides. Univariate statistical analysis shows that the confirmation of infrequent extreme deviations of all radioactive variables. Cluster analysis shows that light minerals play a role in cluster I sampling sites and heavy minerals may be played in sampling sites of other clusters. Calculated activity ratio confirmed the presence of light and heavy minerals in above mentioned sampling sites. The Kerala beach sediments pose significant radiological threat to the people living in the area and tourists going to the beaches for recreation or to the sailors and fishermen involved in their activities in the study area.
► The concentration and distribution of the natural radionuclides have been analyzed for the Kerala beach sediments. ► Average concentrations of 238U and 232Th, and all calculated radiological parameters are higher than the recommended level. ► Univariate statistical analysis shows the confirmation of infrequent extreme deviations of all radioactive variables. ► Cluster analysis shows the role of light and heavy minerals. ► The present sediments pose significant radiological threat to the peoples.
Quasimagic rectangles Froncek, D.; Paramasivam, K.; Prajeesh, A. V.
Journal of combinatorial designs,
March 2022, Letnik:
30, Številka:
3
Journal Article
Recenzirano
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The present study is aimed to show that the mineral and magnetic parameters are proxies for radioactivity level of Vaigai river sediment. In order to show the usefulness of above said parameters as ...proxies for radioactivity level of the river, elaborate analyses along with radioactivity level need to be analyzed in horizontal (different locations) and vertical (upper, first, second and third feet) views of the river. The radioactivity analysis shows that average concentrations of 238U, 232Th and calculated absorbed dose rate are within the recommended safety level in all depth samples. Eleven minerals have been identified and characterized by FTIR, and are confirmed by XRD techniques. Based on the calculated results of extinction co-efficient, the amount of major minerals are decreased in the order of quartz > microcline feldspar > orthoclase feldspar > kaolinite in all depth samples. The presence of ordered crystalline quartz in all depth samples have been assessed by the calculated crystallinity index values. These observations are matched with XRD results. Magnetic susceptibility measurement was carried out in horizontal and vertical views which show the presence of dia, ferri, antiferri and ferrihydrate magnetic minerals in present sediments. Studied characteristics and their distributions are almost similar in all the depths. Multivariate statistical analyses include cluster analysis (CA), Factor analysis (FA) and Principal component analysis (PCA) are effective tool to show the above said parameters as proxy and the analyses are carried out. Relevant justification is also given for explaining the parameters as proxy. In the clay mineral, high adsorption of radionuclides and magnetic minerals occurs in lattice defects or onto crystal and grain boundaries due to the high cation exchange capacity. Since, the parameters such as content of clay, magnetic susceptibility and amount of kaolinite (clay) in all depth samples are strongly associated with radioactivity variables, one can say that above said parameters may be proxies for determining the level of radioactivity in Vaigai river sediment.
•The present study is focused to show the mineral and magnetic parameters as proxies for radioactivity level.•Radiological parameters are within the recommended safety level in all depth samples.•Justification is also given for explaining the parameters as proxy.•High adsorption of radionuclides and magnetic minerals occurs in lattice defects or onto crystal of the clay.•Above parameters may be proxies for determining the level of radioactivity in Vaigai river sediment.
Dendrogram shows cluster of variables. Cluster I shows that the total radioactivity mainly depends upon concentration of 238U and 232Th and content of kaolinite. The cluster III shows that the other ...major minerals are not significant for the total radioactivity.
•Vaigai River radioactivity level and mineralogy studied by spectroscopic techniques.•Some sites are having higher radioactivity values than the recommended safety limit.•Relative distributions of minerals are studied by extinction coefficient calculation.•Crystallinity index calculation shows the presence of well ordered crystalline quartz.•The kaolinite has a great influence on radionuclides concentrations in river sediment.
Using Gamma ray and Fourier Transform Infrared (FTIR) spectroscopic techniques, level of natural radioactivity (238U, 232Th and 40K) and mineralogical characterization of Vaigai River sediments have been analyzed with the view of evaluating the radiation risk and its relation to available minerals. Different radiological parameters are calculated to know the entire radiological characterization. The average of activity concentrations and all radiological parameters are lower than the recommended safety limit. However, some sites are having higher radioactivity values than the safety limit. From the FTIR spectroscopic technique, the minerals such as quartz, microcline feldspar, orthoclase feldspar, kaolinite, gibbsite, calcite, montmorillonite and organic carbon are identified and they are characterized. The extinction co-efficient values are 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 is calculated to know the crystalline nature of quartz and the result indicates that the presence of ordered crystalline quartz in the present sediment. The role of minerals in the level of radioactivity is assessed by multivariate statistical analysis (Pearson’s correlation and Cluster analysis). The statistical analysis confirms that the clay mineral kaolinite is the major factor than other major minerals to induce the important radioactivity variables such as absorbed dose rate and concentrations of 232Th and 238U.
Natural radionuclides (238U, 232Th and 40K) concentrations and eight different radiological parameters have been analyzed for the beach sediments of Kerala with an aim of evaluating the radiation ...hazards. Activity concentrations (238U and 232Th) and all the radiological parameters in most of the sites have higher values than recommended values. The Kerala beach sediments pose significant radiological threat to the people living in the area and tourists going to the beaches for recreation or to the sailors and fishermen involved in their activities in the study area. In order to know the light mineral characterization of the present sediments, mineralogical analysis has been carried out using Fourier transform infrared (FTIR) spectroscopic technique. The eight different minerals are identified and they are characterized. Among the various observed minerals, the minerals such as quartz, microcline feldspar, kaolinite and calcite are major minerals. The relative distribution of major minerals is determined by calculating extinction co-efficient and the values show that the amount of quartz is higher than calcite and much higher than microcline feldspar. Crystallinity index is calculated to know the crystalline nature of quartz present in the sediments. Heavy mineral separation analysis has been carried out to know the total heavy mineral (THM) percentage. This analysis revealed the presence of nine heavy minerals. The minerals such as monazite, zircon, magnetite and illmenite are predominant. Due to the rapid and extreme changes occur in highly dynamic environments of sandy beaches, quantities of major light and heavy minerals are widely varied from site to site. Granulometric analysis shows that the sand is major content. Multivariate statistical (Pearson correlation, cluster and factor) analysis has been carried out to know the effect of mineralogy on radionuclide concentrations. The present study concluded that heavy minerals induce the 238U and 232Th concentrations. Whereas, light mineral (calcite) controls the 40K concentration. In addition to the heavy minerals, clay content also induces the important radioactive variables.
•Due to the higher activity concentrations, the present sediments pose significant radiological threat to the peoples.•Light mineral characterization shows the presence of eight light minerals.•Heavy mineral separation analysis revealed the presence of nine heavy minerals.•Multivariate statistical analysis gives an idea about the role of mineralogy on radionuclide concentrations.•Along with clay content, the heavy minerals induce the 238U and 232Th concentrations and light mineral calcite controls the 40K concentration.
