Browsing by Author "Mrigank Mauli Dwivedi"

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Assessment of topsoil contamination in an urbanized interfluve region of Indo-Gangetic Plains (IGP) using magnetic measurements and spectroscopic techniques
(Springer International Publishing, 2019) Abhishek Kumar Rai; Anuj Kumar Singh; Jayanta Kumar Pati; Shubham Gupta; Munmun Chakarvorty; Ambalika Niyogi; Anamika Pandey; Mrigank Mauli Dwivedi; Kamlesh Pandey; Kuldeep Prakash
The magnetic susceptibility (MS) measurements are used for rapid and cost-effective soil surveys and for accessing heavy metal contamination worldwide. In the sub-Himalayan plains of India, nearly 6.05 × 104 km2 area of most the fertile land occurs as interfluve of Late Quaternary age between the two major glacier-fed rivers (Ganga and Yamuna). The vast areal expanse of interfluve terminates at the rivers’ confluence in Sangam (25°25′13″N-81°53′22″E), Allahabad. This is the first study of MS soil survey of the interfluve region at the confluence comprising 490 samples from 49 locations. The MS values are between 8.84 and 261.25 × 10−8 m3 kg−1 and the change is more pronounced (8.84–312.65 × 10−8 m3 kg−1) with increasing depth. A sudden increase in the MS between 12- (11.28–303.32 × 10−8 m3 kg−1) and 14-cm (11.21–238.45 × 10−8 m3 kg−1) depth is observed similar to observations worldwide. The high MS hotspots are aligned parallel to major traffic networks of the city suggesting a major contribution emanating from the anthropogenic load. A significant difference has been noted in the MS values of present-day mid-channel bar sediments of Ganga (25.24 × 10−8 m3 kg−1) and Yamuna (116.47 × 10−8 m3 kg−1) Rivers. The laser-induced breakdown spectroscopy (LIBS) data showed the presence of heavy (Fe, Ti, Cr, Cu, Cd, Zn, and Pb) and light (H, C, N, and O) elements supporting MS data. The concentration of toxic elements predicted by partial least squares regression (PLSR) approach concurs with magnetic measurements. The topsoil MS values increase up to a depth of ~ 6.25 cm suggesting the dominant role of anthropogenic source for the increased heavy metal concentration compared with basement contributions. © 2019, Springer Nature Switzerland AG.
Characterization of Ash Samples from the Kelud (Indonesia) Volcanic Eruption of 2014 and its Environmental Implications
(Springer, 2023) Sujesh Sahay; Jayanta Kumar Pati; Anuj Kumar Singh; Ambalika Niyogi; Munmun Chakarvorty; Kuldeep Prakash; Mrigank Mauli Dwivedi
The eruptions from Kelud (Kelut) volcano, Indonesia on 13 to 14 February, 2014 ejected huge amount of volcanic ash to an altitude of more than 26 km and spread to >700 km, leading to the disruption of flights, collapse of man-made structures, traffic accidents, and large-scale evacuations while leaving indelible signs of ecosystem degradation. To better comprehend the physical and chemical characters and possible environmental implications of Kelud eruption, three unconsolidated poorly-sorted ash samples were collected on February 24, 2014 from roof tops in Yogyakarta, Indonesia and analyzed for their size (0.3 to 300 µm), shape (irregular, columnar and tabular), texture (vesicular with shards and Pele’s hair), mineralogy (andesine + diopside + enstatite + cristobalite + magnetite + glass) and geochemistry (basaltic andesite — andesite). The trace element concentrations, marginally fractionated REE pattern, and the basaltic andesite to andesite affinity of all Kelud ash samples infer their genetic linkage with island arc environment. The fine-grained particulate matter in the inhalable size range, presence of crystalline silica (cristobalite) and chemical toxicity of ash, observed during the present study, shall be useful for disaster preparedness and to create environmental safeguards for similar volcanic eruptions in future. © 2023, Geological Society of India, Bengaluru, India.
Experimental Synthesis of Coloured Soda-lime-silica (SLS) Glasses using Untreated Silica Sand of Shankargarh Area (Prayagraj District, Uttar Pradesh, India) and its Ramifications
(Springer, 2022) Anuj Kumar Singh; Pawan Kumar Rajak; Jayanta Kumar Pati; Mrigank Mauli Dwivedi; Kamlesh Pandey; Kuldeep Prakash; Abhishek Kumar Rai; Shivanshu Dwivedi
The physical, mechanical and chemical processing of silica sand, the main ingredient of silicate glass, are routinely carried out in glass and ceramic industries worldwide to enhance the silica content and to reduce the concentration of ferromagnesian impurities. The processing of silica sand prior to glass synthesis generally involves washing with water, physical screening (size and magnetic separation) and chemical treatments. The silica sand mining, in parts of Prayagraj (earlier known as Allahabad) district, Uttar Pradesh, is continuing for more than six decades and yet meager peer-reviewed published scientific data is available hitherto. On the other hand, the continued rampant water cleaning of silica sand for more than six decades has led to the accumulation of toxic sludge in the vicinity and also causing ground water depletion in the area. In order to find an amicable balance amongst silica sand processing, ground water depletion and environmental degradation, an attempt has been made to use untreated/raw silica sand of Prayagraj district, mainly from the Shankargarh area, to synthesize soda-lime-silica (SLS) glass. Following this objective, thirty five silica sand samples are collected from different washeries and grouped into seven classes based on their magnetic susceptibility values (30.23 to −0.71 × 10−8 m3kg−1). Representative silica sand samples from these seven groups are mixed with sodium carbonate (Na2CO3) and calcium carbonate (CaCO3) in a ratio of 75:15:10 and melted at 1300°C under one atmospheric pressure for a run duration of 90 minutes. Transparent to translucent SLS glasses of various hues and variable refractive indices (1.504–1.547) are formed. The glasses, thus analyzed by the electron probe micro analyzer (EPMA), comprise SiO2 (80.56–85.79 wt%), Na2O (9.70–12.69 wt%), CaO (4.80–6.51 wt%), Al2O3 (0.51–1.46 wt%), FeOT (0.15–0.95 wt%) and TiO2 (0.12–0.29 wt%), similar to the commercial SLS glasses manufactured worldwide. The present study suggests that the raw silica sand from Shankargarh area can be used to synthesize coloured SLS glasses even without washing with water and as a consequence the water resources and geo-environment of the area shall remain protected from further degradation. © 2022, Geological Society of India, Bengaluru, India.
Silicon bioavailability in exocarp of Cucumis sativus Linn
(Springer Verlag, 2017) Deepika Tripathi; Mrigank Mauli Dwivedi; Durgesh Kumar Tripathi; Devendra Kumar Chauhan
Scanning electron microscopy (SEM) and electron probe micro-analyzer (EPMA) techniques have been used to detect the silicon bioavailability in the exocarp of warty cucumber surface. Warts appear at the time of anthesis and are remnant part of spines/trichomes which on further fruit maturation abscised from the exocarp. Results of EPMA and phytolith analysis clearly revealed that the surface of exocarp (fruit) of Cucumis sativus Linn. containing warts has greater quantity of silicon as compared to the other part of the fruit. Besides silicon, some other elements were also found, on the fruit exocarp and its surrounding area. The other elements are magnesium (Mg), aluminum (Al), phosphorus (P), sulfur (S), potassium (K), calcium (Ca), iron (Fe), nickel (Ni), copper (Cu), and sodium. The percentage of silica is highest followed by Ni, Ca, Al, P, Mg, Fe, S, Cu, K, and Cl. Thus, this study clearly demonstrates that Cucumis sativus Linn. fruits which are used as salads and appetizers on daily basis are loaded with silicon and other useful elements and possess numerous health benefits. © 2017, Springer-Verlag GmbH Germany.