Green synthesis of silver nanoparticles by microorganism using organic pollutant: its antimicrobial and catalytic application

A novel approach for the green synthesis of silver nanoparticles (AgNPs) from aqueous solution of AgNO₃ using culture supernatant of phenol degraded broth is reported in this work. The synthesis was observed within 10 h, and AgNPs showed characteristic surface plasmon resonance around 410 nm. Spherical nanoparticles of size less than 30 nm were observed in transmission electron microscopy. X-ray diffraction pattern corresponding to 111, 200, 220, and 311 revealed the crystalline nature of the as-formed nanoparticles. It was found that the colloidal solution of AgNP suspensions exhibited excellent stability over a wide range of ionic strength, pH, and temperature. The effect of pH and ionic strength indicated that stabilization is due to electrostatic repulsion arising from the negative charge of the conjugate proteins. The AgNPs showed highly potent antimicrobial activity against Gram-positive, Gram-negative, and fungal microorganisms. The as-prepared AgNPs showed excellent catalytic activity in reduction of 4-nitrophenol to 4-aminophenol by NaBH₄. By manufacturing magnetic alginate beads, the reusability of the AgNPs for the catalytic reaction has been demonstrated.     

Lead monitoring in air,soil and foliar deposits at Indore city with special reference to automobile pollution

Ambient lead levels in air, soil and dust deposits on selected plant species at ten distinctly located sampling stations of Indore city are presented. The maximum lead level in air was recorded at Palasia, where the traffic density was found to be the highest. Out of the plant species studied, the maximum lead was recorded on Dalbergia sissoo leaves. A possible relationship between leaf morphology and dust accumulation tendency is also discussed.     

Anti-barnacle biofouling coatings for the protection of marine vessels: synthesis and progress

Environmental Science and Pollution Research - Marine biofouling has gnawed both mobile and non-mobile marine structures since time immemorial, leading to the deterioration of designed operational...     

Organic waste streams as feedstock for the production of high volume-low value products

Environmental Science and Pollution Research - Valorisation of organic wastes to produce industrially relevant commodity products is a sustainable, cost-effective and viable alternative providing a...     

Agroindustry by-products as a carrier resource for plant-growth-promoting rhizobacterium, Bacillus subtilis

The traditional carriers viz., lignite and peat used in the biofertiliser industry are non-renewable, costly, non eco-friendly and have very limited reservoirs in India. Therefore, the present work in this paper was undertaken to check and evaluate whether the agroindustry by-products, viz., peanut shells, corn cobs, sawdust, paddy husk and pressmud, can be used as alternatives to the traditional carriers. Evaluation of the carriers was done by studying the survival of Bacillus subtilis at 28, 37 and 45?°C for a period of 3?months on a weekly basis by the viable plate count method. Physico-chemical characteristics of the agroindustry by-products showed that paddy husk has pH 6.66, 6.65?% (w/w) moisture content, 0.31 % (w/w) ash content, potassium 0.037?% (w/w) and other element content such as Co, Rb, Ag, Hg, Bi and Th is more as compared to that in lignite. The viable count of Bacillus subtilis was highest in paddy husk at 28 and 37?°C, which was 2.458?×?10⁵ and 2.470?×?10⁵ cfu/g, respectively. Thus, paddy husk is found to be an alternative carrier to lignite which is very cheap, renewable, eco-friendly, more easily available and is a very clean technology. Since it is the by-product of the agroindustry, its use as a carrier will give a value-added product and also protect the bacterial cells from desiccation.     

Evaluating pollution potential of leachate from landfill site, from the Pune metropolitan city and its impact on shallow basaltic aquifers

Leachate produced by municipal solid waste dumping site near the metropolitan city of Pune, India was examined for its pollution potential and impact on surrounding shallow basaltic aquifers. Twenty-eight physico-chemical parameters during post- and pre-monsoon seasons (Nov 2006 and May 2007) were determined to assess the seasonal variation in the leachate pollution index (LPI) as well as in the groundwater quality. The leachate demonstrated higher LPI value during pre-monsoon, comparable to those at other metropolises outside India. Potentially toxic leachates derived from the dumping site have largely influenced the adjoining basaltic aquifers through two different modes of transport. Despite high contents of heavy metals (Al, Cd, Cr, Cu, Co, Fe, Mn, Ni, Pb and Zn) in the leachate, the aquifers in the close proximity of landfill site are least polluted by metallic contaminants possibly due to redox controls. Various geoenvironmental features governing the dispersal of leachate contaminants in the basaltic aquifers under semi-arid climatic regime have been identified and discussed. Although a few remedial measures have been suggested to mitigate the impact of leachate percolation and dispersion, the present study demands for a proper solid waste management in metropolitan cities.     

Assessment of basin-scale hydrologic impacts of CO2 sequestration,Illinois basin

Idealized, basin-scale sharp-interface models of CO₂ injection were constructed for the Illinois basin. Porosity and permeability were decreased with depth within the Mount Simon Formation. Eau Claire confining unit porosity and permeability were kept fixed. We used 726 injection wells located near 42 power plants to deliver 80 million metric tons of CO₂/year. After 100 years of continuous injection, deviatoric fluid pressures varied between 5.6 and 18 MPa across central and southern part of the Illinois basin. Maximum deviatoric pressure reached about 50% of lithostatic levels to the south. The pressure disturbance (>0.03 MPa) propagated 10–25 km away from the injection wells resulting in significant well–well pressure interference. These findings are consistent with single-phase analytical solutions of injection. The radial footprint of the CO₂ plume at each well was only 0.5–2 km after 100 years of injection. Net lateral brine displacement was insignificant due to increasing radial distance from injection well and leakage across the Eau Claire confining unit. On geologic time scales CO₂ would migrate northward at a rate of about 6 m/1000 years. Because of paleo-seismic events in this region (M5.5–M7.5), care should be taken to avoid high pore pressures in the southern Illinois basin.     

Morphological and Biochemical Characteristics of Avian Faecal Droppings and Their Impact on Survival of Avian Influenza Virus

Environmental specimens such as faecal droppings are considered important for the detection of avian influenza viruses (AIV). In view of lower rates of AIV isolation from avian faecal droppings, characterization of droppings is imperative to elucidate contributing factors. However, there are no reports on morphological and biochemical characteristics of droppings. The objective of the present study was the characterization of droppings from different avian species and their impact on the AIV detection and isolation. A total of 373 droppings belonging to 61 avian species from 22 families of apparently healthy wild migratory, resident, domestic birds and poultry were studied during five winter migratory bird seasons between 2007 to 2012 and 2016–2017. The colour, morphology and size of the droppings varied from species-to-species. These data could be useful for the identification of avian species. Droppings from 67% of the avian species showed acidic pH (4.5–6.5); nine species showed neutral pH (7.0), and 11 species showed alkaline pH (7.5). The infectious titers of AIV in droppings with acidic pH were significantly lower (p < 0.05) than those of the droppings with neutral and alkaline pH. However, acidic pH did not hamper AIV detection by real-time RT-PCR. In order to avoid the impact of acidic pH, collecting fresh droppings into viral transport medium (pH 7.0–7.5) would help improve the rate of AIV isolation.     

Assessing site suitability potential for soil and water conservation structures by using modified micro-watershed prioritization method: geomorphometric and geomatic approach

Environment, Development and Sustainability - Efficiency of soil water conservation (SWC) structure depends on its precise locations as well as its success in reducing surface runoff, soil erosion...