Fluorometric detection of bisphenol A using β-cyclodextrin-functionalized ZnO QDs

Environmental Science and Pollution Research - The estrogenic property of bisphenol A (BPA) leads to potential adverse health and ecological effects. A simple, selective, and cost-effective sensor...     

Design and development of novel insect growth regulators: Synthesis,characterization and effect of benzoyl thymyl thioureas and ureas on total haemocyte count of Dysdercus koenigii

Insect-growth regulators (IGRs) have been receiving foremost attention as potential means of selective insect control. Benzoyl phenyl urea (BPU) is a well-known IGR having chitin synthesis inhibitor activity. Mimics of BPU have been synthesized by suitable derivatization of a naturally occurring monoterpenoid, thymol (2-isopropyl-5-methyl phenol) to form a = series of substituted benzoyl thymyl thioureas (BTTUs) [IVa-f] and benzoyl thymyl ureas (BTUs) [Va-f]. The synthesized compounds have been characterized by ¹H and ¹³C NMR, LC-MS and elemental analysis. These derivatives have been screened for their effect on total haemocyte count of Dysdercus koenigii. It has been observed that the introduction of substituted benzoyl thiourea and urea linkage into a thymol ring via an amino group results in higher activity than the parent compound thymol and a comparable pattern of results with the standard insect-growth regulators, Penfluron. Urea [Va-f] compounds exhibited greater effect on Total Haemocyte Count (THC) than thiourea [IVa-f]. Fluoro substitution enhanced the effect on THC more than chloro substituted compounds, while ortho-substitution resulted in a better effect than para-substitution. The results described in this paper are promising and provide new array of synthetic chemicals that may be utilized as insect growth regulators.     

Photocatalytic degradation of p-nitrophenol using biologically synthesized ZnO nanoparticles

Environmental Science and Pollution Research - The present work deals with the photocatalytic degradation of p-nitrophenol as it is a United States Environmental Protection Agency-listed priority...     

Design and development of novel insect growth regulators: synthesis, characterization and effect of benzoyl thymyl thioureas and ureas on total haemocyte count of Dysdercus koenigii

Insect-growth regulators (IGRs) have been receiving foremost attention as potential means of selective insect control. Benzoyl phenyl urea (BPU) is a well-known IGR having chitin synthesis inhibitor activity. Mimics of BPU have been synthesized by suitable derivatization of a naturally occurring monoterpenoid, thymol (2-isopropyl-5-methyl phenol) to form a = series of substituted benzoyl thymyl thioureas (BTTUs) [IVa-f] and benzoyl thymyl ureas (BTUs) [Va-f]. The synthesized compounds have been characterized by (1)H and (13)C NMR, LC-MS and elemental analysis. These derivatives have been screened for their effect on total haemocyte count of Dysdercus koenigii. It has been observed that the introduction of substituted benzoyl thiourea and urea linkage into a thymol ring via an amino group results in higher activity than the parent compound thymol and a comparable pattern of results with the standard insect-growth regulators, Penfluron. Urea [Va-f] compounds exhibited greater effect on Total Haemocyte Count (THC) than thiourea [IVa-f]. Fluoro substitution enhanced the effect on THC more than chloro substituted compounds, while ortho-substitution resulted in a better effect than para-substitution. The results described in this paper are promising and provide new array of synthetic chemicals that may be utilized as insect growth regulators.     

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.     

Solid-state fermentation: tool for bioremediation of adsorbed textile dyestuff on distillery industry waste-yeast biomass using isolated Bacillus cereus strain EBT1

Bioremediation of textile dyestuffs under solid-state fermentation (SSF) using industrial wastes as substrate pose an economically feasible, promising, and eco-friendly alternative. The purpose of this study was to adsorb Red M5B dye, a sample of dyes mixture and a real textile effluent on distillery industry waste-yeast biomass (DIW-YB) and its further bioremediation using Bacillus cereus EBT1 under SSF. Textile dyestuffs were allowed to adsorb on DIW-YB. DIW-YB adsorbed dyestuffs were decolorized under SSF by using B. cereus. Enzyme analysis was carried out to ensure decolorization of Red M5B. Metabolites after dye degradation were analyzed using UV–Vis spectroscopy, FTIR, HPLC, and GC-MS. DIW-YB showed adsorption of Red M5B, dyes mixture and a textile wastewater sample up to 87, 70, and 81 %, respectively. DIW-YB adsorbed Red M5B was decolorized up to 98 % by B. cereus in 36 h. Whereas B. cereus could effectively reduce American Dye Manufacture Institute value from DIW-YB adsorbed mixture of textile dyes and textile wastewater up to 70 and 100 %, respectively. Induction of extracellular enzymes such as laccase and azoreductase suggests their involvement in dye degradation. Repeated utilization of DIW-YB showed consistent adsorption and ADMI removal from textile wastewater up to seven cycles. HPLC and FTIR analysis confirms the biodegradation of Red M5B. GC-MS analysis revealed the formation of new metabolites. B. cereus has potential to bioremediate adsorbed textile dyestuffs on DIW-YB. B. cereus along with DIW-YB showed enhanced decolorization performance in tray bioreactor which suggests its potential for large-scale treatment procedures.     

Assessing combined toxic effects of tetracycline and P25 titanium dioxide nanoparticles using Allium cepa bioassay

• UVA pre-irradiation to TiO₂ NPs enhanced its toxicity toward plant A. cepa. • UVA TiO₂ NPs increased intracellular ROS, resulting in more cell damage. • Cell death enhanced cell permeability and increased uptake of NPs. • Being highly toxic (EC₅₀ = 0.097 µmol/L), TC did not increase ROS generation. • Even at a low dose, TC enhanced the toxic potential of TiO₂ NPs significantly. Usage of titanium dioxide nanoparticles (TiO₂ NPs) and tetracycline (TC) has increased significantly in the present era. This leads to their release and accumulation in the environment. Both the compounds, individually, can have adverse toxic effects on the plants. Their binary mixtures can increase this degree of damage. The present study aimed to evaluate the toxicity of both the contaminants in individual and binary mixtures in Allium cepa. Further, the toxicity of TiO₂ NPs upon UVA pre-irradiation was also measured. Results showed that UVA pre-irradiated NPs (UVA-TiO₂ NPs) had a significant decrease in cell viability than their non-irradiated counterparts (NI-TiO₂), denoting an increase in photocatalytic activity upon UVA pre-irradiation. Very low concentrations of TC (EC₁₀ = 0.016 µmol/L) mixed with TiO₂ NPs significantly increased the toxicity for both UVA-TiO₂ and NI-TiO₂ NPs. Intracellular ROS generation was significantly high for UVA-TiO₂ NPs. However, TC did not have any effects on ROS production. Both the compounds exhibited genotoxic potential in A. cepa. Different chromosomal abnormalities like anaphase bridges, telophase bridges, laggard chromosomes, binucleate cells, etc. were observed. The binary mixture of UVA-TiO₂ NPs and TC showed the highest chromosomal aberrations (64.0%±1.26%) than the mixture with NI-TiO₂ or the individual contaminants. This decreased significantly after recovery (46.8%±1.92%), denoting the self-repair processes. This study proved that UVA-TiO₂ NPs were more toxic and could be enhanced further when mixed with a sub-lethal concentration of TC. This work will help to assess the risk of both compounds in the environment.     

An insight into the influence of low dose irradiation pretreatment on the microbial decolouration and degradation of Reactive Red-120 dye

The influence of low dose irradiation pretreatment on the microbial decolouration and degradation of Reactive Red-120 (RR-120) dye was investigated in detail by using Pseudomonas sp. SUK1. About 27%, 56% and 66% decolouration of 150 ppm RR-120 dye solution was observed by applying 0, 0.5 and 1 kGy doses, respectively, in the first step followed by microbial treatment for 24 h under static condition. Similarly, about 70%, 88% and 90% TOC removal was observed by applying 0, 0.5 and 1 kGy doses, respectively, in the first step followed by the microbial treatment for 96 h under static condition. The radiation induced fragmented products of RR-120 at doses of 0.5 and 1 kGy were investigated by FTIR and electrospray ionization-MS analysis. The induction of the enzymes viz. laccase, tyrosinase, azoreductase and NADH-2,6-dichlorophenol indophenol reductase was studied in the decolourised solution obtained after irradiating 150 ppm RR-120 dye solution with 0 and 1 kGy doses followed by the microbial treatment for 96 h under static condition. The enzymatic degradation products were studied by FTIR, HPLC and GC–MS. The toxicity study of the treated dye solution on plants revealed the degradation of RR-120 into non-toxic products by combined radiation-microbial treatment. This study explores a reliable and promising way to use industrially viable dose (?1 kGy) and microbial strain viz. Pseudomonas sp. SUK1 for permissible safe disposal of dye solutions from textile industries.     

Municipal wastewater treatment using novel constructed soil filter system

The study gives a new approach for contaminant removal from municipal wastewater using constructed soil filter (CSF) and presents performance of two CSF units located in Mumbai, India. In this system, natural weathered rock is formulated which combines sedimentation, infiltration and biochemical processes to remove suspended solids and oxidisable organics and inorganics of the wastewater. Results show elevated dissolved oxygen (DO) levels, removal of COD (136-205 to 38-40 mg l(-1)) and BOD (80-125 to less than 12 mg l(-1)) suspended solids from 135-203 to 13-18 mg l(-1) and turbidity from 84-124 to 8-11 NTU, bacterial removal of 2.4-3.1 log order for Total coliform and Fecal coliform from site I which is almost 8 years old facility, and site II which is 3 years old. Estimated hydraulic retention time of 0.5-1.0 h, hydraulic loading of 0.036-0.047 m(3)m(-2)h(-1), no pretreatment, high DO levels in the effluent, no bio-sludge production, no mechanical aeration, low energy requirement (0.04 kW h m(-3)) and green aesthetic ambience are its unique features.     

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...