Assessment of Soil Contamination in Patancheru Industrial Area

Abstract: Toxic trace metals concentrations in soil exert a decisive impact on soil quality and its use in food production particularly in an industrial area. An attempt is made here to study toxic metals such as Cr, Cu, Ni, Pb, Zn, including Ba, Co and V in representative soil samples from Patancheru industrial area near Hyderabad, Andhra Pradesh. It is a known polluted area and is one of the most contaminated regions where about 260 small and large-scale manufacturers of pharmaceuticals, paints, pesticides, chemicals, steel and metallic products have been functioning for over several decades. Toxic trace metal geochemical studies were carried out in fifteen representative soil samples collected from residential and agricultural area, to understand the spatial distribution and to assess the level of contamination on the basis of index of geoaccummulation, enrichment factor, contamination factor and degree of contamination. The various indices show that residential soils are contaminated with Cr, Ni and Pb (Cu to some extent). The agricultural area, although were invariably enriched in these toxic metals, showed comparatively less contamination possibly due to uptake by plants

Directly photoexcited Dirac and Weyl fermions in ZrSiS and NbAs

We report ultrafast optical measurements of the Dirac line-node semimetal ZrSiS and the Weyl semimetal NbAs, using mid-infrared pump photons from 86 meV to 500 meV to directly excite Dirac and Weyl fermions within the linearly dispersing bands. In NbAs, the photoexcited Weyl fermions initially form a non-thermal distribution, signified by a brief spike in the differential reflectivity whose sign is controlled by the relative energy of the pump and probe photons. In ZrSiS, electron-electron scattering rapidly thermalizes the electrons, and the spike is not observed. Subsequently, hot carriers in both materials cool within a few picoseconds. This cooling, as seen in the two materials’ differential reflectivity, differs in sign, shape, and timescale. Nonetheless, we find that it may be described in a simple model of thermal electrons, without free parameters. The electronic cooling in ZrSiS is particularly fast, which may make the material useful for optoelectronic applications

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

A multivariate statistical approach for monitoring of heavy metals in sediments: a case study from Wailpalli Watershed, Nalgonda District, Andhra Pradesh

Abstract: The aim of the present study, focuses on investigation of heavy metal distribution in sediments of the Wailpalli watershed located in Nalgonda district of Andhra Pradesh, India, and to study different causes of enrichment by applying multivariate statistics on the studied elements, including correlation and factor analyses, and to identify possible sources of sediment bound heavy metals. Sediment samples were collected along the streams from a depth of 0-10 cm and were analyzed for Ba, Co, Cr, Cu, Ni, Pb, Rb, Sr, V, Zn and Zr by using Philips PW 2440 X-ray fluorescence spectrometer (XRF). The concentration ranges were Ba 128.5 to 929.4 mg/kg, Co 0.4 to 36.2 mg/kg, Cr 15.8 to 107.8 mg/kg, Cu 1.6 to 43.1 mg/kg, Ni 0.2 to 69.8 mg/kg, Pb 2.3 to 14.1 mg/kg, Rb 8.0 to 446.2 mg/kg, Sr 73.0 to 360.6 mg/kg, V 7.9 to 240.8 mg/kg, Zn 24.5 to 130.1 mg/kg, and Zr 108.4 to 2668 mg/kg. Distribution maps metal concentrations in sediments were plotted by Golden Software's SURFER program. Using multivariate statistical analysis (correlation coefficients, factor analysis), the interrelationships among elements, and Enrichment Factor (EF) was calculated to differentiate the origin of metals between anthropogenic and geogenic sources. The results of median EF indicate no significant enrichment of the metals (Co, Cu, Ni, Pb, Rb, V and Zn) except for high Pb and Ni possibly indicating some point source input to the stream sediments. However, systematic and continuous monitoring of the study area for heavy metals is necessary as most of the area in Wailpalli watershed is under active irrigation and these elements may enter the food chain, and could be hazardous to human health

Boninites in the ~3.3 Ga Holenarsipur Greenstone Belt, Western Dharwar Craton, India

In this contribution, we present detailed field, petrography, mineral chemistry, and geochemistry of newly identified high-Si high-Mg metavolcanic rocks from the southern part of the ~3.3 Ga Holenarsipur greenstone belt in the western Dharwar craton, India. The rocks occur as conformable bands that were interleaved with the mafic-ultramafic units. The entire volcanic package exhibits uniform foliation pattern, and metamorphosed under greenschist to low grade amphibolite facies conditions. The rocks are extremely fine grained and exhibit relict primary igneous textures. They are composed of orthopyroxene and clinopyroxene phenocrysts with serpentine, talc, and amphibole (altered clinopyroxene). Cr-spinel, rutile, ilmenite, and apatite occur as disseminated minute grains in the groundmass. The mineralogical composition and the geochemical signatures comprising of high SiO2 (~53 wt. %), Mg# (~83), low TiO2 (~0.18 wt. %), and higher than chondritic Al2O3/TiO2 ratio (~26), reversely fractionated heavy rare earth elements (REE) (GdN/YbN ~ 0.8), resulting in concave-up patterns, and positive Zr anomaly, typically resembled with the Phanerozoic boninites. Depletion in the high field strength elements Nb, and Ti relative to Th and the REE in a primitive mantle normalized trace element variation diagram, cannot account for contamination by pre-existing Mesoarchean continental crust present in the study area. The trace element attributes instead suggest an intraoceanic subduction-related tectonic setting for the genesis of these rocks. Accordingly, the Holenarsipur high-Si high-Mg metavolcanic rocks have been identified as boninites. It importantly indicates that the geodynamic process involved in the generation of Archean boninites, was perhaps not significantly different from the widely recognized two-stage melt generation process that produced the Phanerozoic boninites, and hence provides compelling evidence for the onset of Phanerozoic type plate tectonic processes by at least ~3.3 Ga, in the Earth’s evolutionary history

Paleo–Mesoarchean sedimentary record in the Dharwar Craton, India: Implications for Archean ocean oxygenation

The early Archean oceans were marked by significant redox changes which have subsequently shaped the Earth’s biosphere. Archean chemical sediments of banded Iron and Manganese formations provide important geochemical proxies for these historical shifts in the redox conditions and to trace the ancient sedimentation patterns and protoliths. In this study, we investigate the proto-ore of the Archean Mn-formations of the Sandur, Chitradurga and Shimoga greenstone belts of Dharwar Craton of southern Peninsular India, which is geochemically characterised as quartz arenites, Mn-arenites, Fe-arenites, Mn-argillites and Fe-argillites. The geochemical systematics suggest their deposition in shallow to deeper shelf in the Archean proto-ocean. The detrital zircon U-Pb systematics of Mn arenites and argillites indicate their maximum depositional age of 3230 ± 52 Ma representing the oldest onset of sedimentation during the Paleo–Mesoarchean timeframe in the Chitradurga Group of Dharwar Supergroup. The detrital influx proxies suggest variations in sedimentation rates associated with the Archean transgressive–regressive cycles and fluctuating hydrodynamic conditions, together reflecting an increasing trend in the contributions of recycled sediment from Sandur to Chitradurga and Shimoga greenstone belts. The available detrital zircon ages of the Mn arenites and argillites from these greenstone belts indicate a ∼ 600 Ma prolonged period of Mn deposition for which high-T hydrothermal fluids from Archean mid-oceanic ridges supplied the manganese. The trace element compositions of the concordant detrital zircons suggest 3.3–3.1 Ga Dharwar basement TTG/granitoid source which is corroborated by the zircon crystallization temperatures of 690–820 °C. The source-normalised α-dose rates of the detrital zircons signify greater degrees of sediment transport and multi-cycle nature which correspond to the earliest episode of crustal growth in the Indian sub-continent associated with the Mesoarchean Ur supercontinent. The clastic-chemogenic sedimentation attained through concomitant detrital sediment–seawater-metalliferous hydrothermal fluid mixing at an epicontinental passive margin resulted in the deposition of Mn-arenites and argillites closer to the higher Eh shore, while the Fe-rich sediments formed at a relatively deeper shelf characterised by comparatively lower Eh and more alkaline conditions. The comprehensive geochemical and geochronological data of the Archean Mn arenite-argillite sequences reveal the significance of regional episodes of ocean oxygenation at the shallow shelves of Archean oceans prior to great oxygenation event (GOE) that was mediated by the prolific growth of ancient microbiota which transformed the Earth to a more habitable planet