Showing papers by "Punarbasu Chaudhuri published in 2017"
TL;DR: Assessing the resistance pattern of wastewater bacteria against multiple HMs and plant growth promotion activity associated with indole-3-acetic acid found great promise as inoculants to promote plant growth in the presence of toxic HMs, as well as plant inoculant systems useful for phytoremediation of polluted soils.
Abstract: Water and soil pollution by toxic heavy metals (HMs) is increasing globally because of increase in population, industrialization and urbanization. It is a burning problem for the public, scientists, academicians and politicians how to tackle the toxic contaminants which jeopardize the environment. One possible solution for pollution abatement is a bioremediation-effective and innovative technology that uses biological systems for treatment of contaminants. Many bacteria synthesize indole-3-acetic acid (IAA) which is a product of L-tryptophan metabolism and belongs to the auxin class of plant growth-promoting hormone. The present study aimed at assessing the resistance pattern of wastewater bacteria against multiple HMs and plant growth promotion activity associated with IAA. A Gram-negative bacterial strain Pseudomonas aeruginosa KUJM was isolated from Kalyani Sewage Treatment Plant. This strain showed the potential to tolerate multiple contaminations such as As(III) (50 mM), As(V) (800 mM), Cd (8 mM), Co (18 mM), Cu (7 mM), Cr (2.5 mM), Ni (3 mM) and Zn (14 mM). The capability of IAA production at different tryptophan concentration (1, 2, 5 and 10 mg mL-1) was determined, and seed germination-enhancing potential was also estimated on lentil (Lens culinaris). Such type of HM-resistant, IAA-producing and seed germination-enhancing P. aeruginosa KUJM offer great promise as inoculants to promote plant growth in the presence of toxic HMs, as well as plant inoculant systems useful for phytoremediation of polluted soils. Hence, P. aeruginosa KUJM finds significant applications in HM-contaminated poor agricultural field as well as in bioremediation of HM-contaminated wastewater system.
32 citations
TL;DR: The study of micro-spatial variation of elemental distribution in estuarine sediment and bioaccumulation of those elements in different mangrove species of the Indian Sundarbans can act as a useful tool for determining health ofEstuarine ecosystem.
Abstract: This work describes the micro-spatial variation of elemental distribution in estuarine sediment and bioaccumulation of those elements in different mangrove species of the Indian Sundarbans. The potential ecological risk due to such elemental load on this mangrove-dominated habitat is also discussed. The concentrations of elements in mangrove leaves and sediments were determined using energy-dispersive X-ray fluorescence spectroscopy. Sediment quality and potential ecological risks were assessed from the calculated indices. Our data reflects higher concentration of elements, e.g., Al, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, and Pb, in the sediment, as compared to that reported by earlier workers. Biological concentration factors for K, Ca, Mn, Fe, Cu, and Zn in different mangroves indicated gradual elemental bioaccumulation in leaf tissues (0.002-1.442). Significant variation was observed for elements, e.g., Ni, Mn, and Ca, in the sediments of all the sites, whereas in the plants, significant variation was found for P, S, Cl, K, Ca, Mn, Fe, Cu, and Zn. This was mostly due to the differences in uptake and accumulation potential of the plants. Various sediment quality indices suggested the surface sediments to be moderately contaminated and suffering from progressive deterioration. Cu, Cr, Zn, Mn, and Ni showed higher enrichment factors (0.658-1.469), contamination factors (1.02-2.7), and geo-accumulation index (0.043-0.846) values. The potential ecological risk index values considering Cu, Cr, Pb, and Zn were found to be within "low ecological risk" category (20.04-24.01). However, Cr and Ni in the Sundarban mangroves exceeded the effect range low and probable effect level limits. Strong correlation of Zn with Fe and K was observed, reflecting their similar transportation and accumulation process in both sediment and plant systems. The plant-sediment elemental correlation was found to be highly non-linear, suggesting role of some physiological and edaphic factors in the accumulation process. Overall, the study of micro-spatial distribution of elements can act as a useful tool for determining health of estuarine ecosystem.
31 citations
TL;DR: In this article, the first attempt to generate baseline data on the level of Naturally Occurring Radioactive Materials, (NORMs) 238U, 232Th and anthropogenic radionuclide, 137Cs in surface soil of Indian Sundarban.
Abstract: This is the first attempt to generate baseline data on the level of Naturally Occurring Radioactive Materials, (NORMs) 238U, 232Th and anthropogenic radionuclide, 137Cs in surface soil of Indian Sundarban. The activities of 238U and 232Th vary from 39.9 ± 2.4 to 57.9 ± 2.5 Bq kg−1 and 47.3 ± 2.4 to 64.8 ± 3.1 Bq kg−1 with mean of 48.7 ± 2.8 Bq kg−1 and 58.3 ± 3.3 Bq kg−1 respectively. The corresponding median values are 46.7 and 59.9 Bq kg−1. The close proximity of mean and median values indicates normal distribution of 238U and 232Th. In most of the samples, anthropogenic 137Cs activity has been found below detection limit (BDL).
15 citations
07 Apr 2017
TL;DR: Fungi-mediated biosynthesized nanomaterials can be a good alternative for this purpose, being environment friendly for both the synthesis and sequestration part as discussed by the authors. But most of the nanoparticles utilized in sequestration methods have been synthesized chemically, triggering risk to human and ecological health.
Abstract: The science of nanotechnology, dealing with particles ranging from 1 to 100 nm, is composed of multidisciplinary approaches involving physics, chemistry, biology, material science, and medicine. Growing research in this field has stressed on different synthesis procedures for nanomaterials and their application potential. Green synthesis of nanoparticles mostly consists of bioreduction processes using plants or microbes. Fungi can act as a good bioreductant to synthesize metal nanoparticles both intracellularly and extracellularly, mostly due to the proteins, organic acids, enzyme hydrogenase, and nitrate-dependent reductase released by them. Some common fungi successfully employed for the biosynthesis of nanoparticles are Aspergillus sp., Cladosporium sp., Fusarium sp., Trichothecium sp., Penicillium sp., and Trichoderma sp. mostly from the phyla Ascomycetes, Basidiomycetes, and Phycomycetes. Exclusive properties of nanoparticles offer us a wide range of applications in fields of medicine to environmental science, including environmental remediation, hazardous waste management, and metal sequestration. Nanomaterials with a high surface-to-volume ratio have been explored to detect and treat pollutants in various environmental matrixes like wastewater, soil, and sediment. Several batch and column experiments incorporating nanomaterials (nanoscale zerovalent iron, iron complexes, nanopolymers, etc.) have been successfully carried out for the sequestration of Ag, As, Cd, Co, Cr, Cu, H2S, Hg, Ni, Pb, Zn, chlorinated pollutants, etc., by means of adsorption, oxidation–reduction, surface complexation, and other mechanisms. However, most of the nanomaterials utilized in sequestration methods have been synthesized chemically, triggering risk to human and ecological health. Fungi-mediated biosynthesized nanomaterials can be a good alternative for this purpose, being environment friendly for both the synthesis and sequestration part.
13 citations
TL;DR: In this paper, an effort has been made to optimize the counting time for low-level measurement of naturally occurring radioactive material (NORM) by considering the standard deviation between the activity values of different photopeaks and counting error.
Abstract: An effort has been made to optimize the counting time for low-level measurement of naturally occurring radioactive material (NORM) by considering the standard deviation between the activity values of different photopeaks and counting error. It is observed that at lower counting time, relative standard deviation (RSD) varies randomly, but attains a gradual trend with increasing time and also comes closure to the counting error. Therefore minimum counting time for low-level NORM measurement of 238U and 232Th would be the time required to stabilize the RSD values.
10 citations
TL;DR: In this article, it has been shown that in the case of ultra-low level NORM measurement, one can comfortably by pass efficiency calibration by using comparator method i.e., comparing the peak area counts of different photopeaks of standard and samples provided they are counted in same geometry and comparable composition.
Abstract: A well-calibrated and highly shielded HPGe detector with considerable relative efficiency is an efficient tool for measurement of naturally occurring radioactive material (NORM) present at ultra low-level in the environmental samples. Efficiency calibration is standard protocol required for quantitative estimation of the activity of any radioactive sample. In the present work it has been shown that in the case of ultra-low level NORM measurement, one can comfortably by pass efficiency calibration by using comparator method i.e., comparing the peak area counts of different photopeaks of standard and samples provided they are counted in same geometry and comparable composition.
7 citations