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Arsenic hyperaccumulation efficiency depends on time and tissue in Pteris vittata
Get PDFThe metalloid arsenic is a toxic environmental pollutant. Arsenic pollution becomes serious due to mining, mineral, smelting and tannery industry. Leaching of naturally occurring arsenic into drinking water aquifers, has been reported in many countries including India and Bangladesh. Available engineering methods for remediation is costly and difficult. Many plant species reported to accumulate arsenic. Pteris vittata has been reported as arsenic hyperaccumulator. An Indian eco-type of P. vittata has been used to study the arsenic accumulation. The plants were grown in arsenic containing soil along with soil without arsenic (control). The ferns were separated into two portions, i.e., above ground (fronds), stage specific as well as tissues from different position of pinnae and below ground (roots and rhizomes). Futher, it was also harvested at different time interval. Dried fern samples (0.1 g) were digested with mixture of concentrated nitric acid and perchloric acid. Heavy metal measurement in foliar and root samples was performed with ICP-OES. Tissue specific arsenic accumulation indicates that juvenile leaf contains highest arsenic than mature leaf. Middle pinnae of mature leaf show high arsenic content compared to upper and lower pinnae. Among the underground parts of the plant, rhizome contains high arsenic than roots. Further, time dependent arsenic accumulation study indicates that active accumulation of arsenic starts from day 7 to day 30 in leaf tissue, while in roots, day 3 to 7 show sudden increase and no much drastic change in accumulation from day 7 onwards
Bench-scale Microbial assisted arsenic removal using Acidothiobacillus ferrooxidance mediated by iron oxidation
Get PDFOxidation of ferrous ions using Acidothiobacillus ferrooxidance has an important application in removal of arsenic(As) by chemo-biochemical process.Arsenite (As+3) was found to oxidised to arsenate (As+5) in presence of A. ferrooxidance and ferric (Fe+3) ions. The resulting arsenate can be removed by precipitation and filtration. The aim of present work was to establish the effect of basic parameters namely temperature, pH, initial cell density and Fe+2 concentration on microbial assisted arsenic removal using bio-oxidation of ferrous to ferric at bench scale
Cell cultures and molecular investigation on Polygonum tinctorium and Indigofera tinctoria plants to understand indican biosynthesis
Get PDFIndican biosynthesis in Indigofera tinctoria and Polygonum
tinctorium plants is of topical interest due to its academic and industrial relevance for indigo dye production. Dye yield depends on indican content in the plant biomass. Cell culture and molecular biological investigations were carried out to assess indican biosynthesis in these plants. Tissue culture protocols were optimized for explant identification, decontamination, in vitro culture medium & suitable growth regulators and culture conditions for P. tinctorium at Okayama University of Science, and I. tinctoria at CSIR-NEERI. Four different growth hormones i.e. BA, Kin, NAA, 2,4-D, at 0.01 –2 mg L-1
culture medium, in random combination, and two different explants i.e. leaf and internode of both plants were experimented. In both plants, callus proliferation was better from leaf tissue with growth index (GI) up to 10 on MS agar gelled medium fortified with BA+NAA in comparison to BA+2,4-D. Suspension cell cultures of I. tinctorium were induced in MS liquid medium with only 2,4-D through 3 stages with GI up to 30. In vitro raised cell biomass of I. tinctorium presented higher indican synthesis (p> 0.5) in comparison to that of P. tinctorium. Both of these plants synthesize indican, but the differential response under in vitro is interesting. Total transcriptomes of both plants were worked out and annotated. Comparative analysis of transcriptome profile indicated >80% genes are similar for the indican biosynthetic pathways. Complete alignment of both transcriptomes and validation for biosynthesis pathways specific genes is needed in both the plants to ascertain their differential expression
Dynamics of effluent treatment plant during commissioning of activated sludge process unit
No full textIndustrial effluent treatment plants (ETPs) are very important in protecting the environment and different life forms from harmful industrial waste. Hence, the efficiency of ETPs must be regularly monitored, particularly after major repair or replacement work. Present study evaluated the performance of an ETP over a period of 4 months, during which aeration tank (T1) of the activated sludge unit was replaced with a new one (T2). System had to be maintained operational during this transition, which warranted close monitoring of the system performance due to the daily load of hazardous industrial wastewater. Analysis showed that the raw wastewater was highly variable in composition and contained many hazardous organic and inorganic pollutants, such as heavy metals, bisphenol A and cyanoacetylurea. It showed significant toxicity against HepG2 cells in vitro. However, the ETP was found to successfully treat and detoxify the wastewater. Denaturing gradient gel electrophoresis (DGGE) analysis showed large temporal fluctuations in the ETP microbial community, which is consistent with the variable composition of wastewater. It indicated that functional stability of the ETP was not associated with stability of the microbial community, probably due to high microbial biodiversity and consequently high functional redundancy. In conclusion, the CETP showed consistent level of detoxification and microbial community dynamics after switching to T2, indicating successful development, acclimatization and commissioning of T
Technological Advances for Treating Municipal waste
No full textMunicipal solid waste management (MSWM) is a challenging task, which has grown immensely due to the changes in lifestyle throughout the world.In developed countries, appropriate norms and adequate administrative and financial resources clubbed with innovative technologies are some driving force, which is proving helpful in MSWM. However, an ever-changing waste composition and some techno-environmental issues still exist. On the other hand, in developing countries in the absence of these provisions, MSWM is becoming a key of socioeconomic development. Due to variations in waste composition, there is a need to adopt multiple means of waste disposal. It thus demands revisiting the available know-how and making the required corrections to suit the grossly ill-classified wastes. In this chapter, characteristic components of MSW and possibilities of their disposal through thermal and biological treatment technology are reviewed.The generation of renewable energy while treating waste, makes disposal an organized and attractive option
Shifts in Microbial Community and Its Correlation with Degradative Efficiency in a Wastewater Treatment Plant
No full textA wastewater treatment plant controls the level of pollution reaching the environment.
Yet, despite being the most common aerobic route for treatment of wastewater, the
activated sludge process is not utilized to its full potential. This is mainly due to the lack of
knowledge base correlating the microbial community in the activated sludge to its degradative
performance. In this study, the activated biomass at the treatment site was monitored for five
consecutive months. Even though operational parameters were kept constant, the microbial
community was observed to change after 3 months. This shift was seen to correlate with 25 %
loss of degradative efficiency. Target oxygenases were monitored at two time points, and
results indicated that the dominating pathway operating in the common effluent treatment plant
(CETP) is the degradation of chlorinated aromatics. This study demonstrates the change in
degradative efficiency in a CETP with the change in microbial community and analyzes the
parameters influencing the microbial community of activated sludge
Nanocrystalline cellulose for removal of tetracycline hydrochloride from water via biosorption: Equilibrium, kinetic and thermodynamic studies
No full texttCrystalline nanocellulose, synthesized from green seaweed, Ulva lactuca, was investigated for the sorptionof tetracycline hydrochloride (TC) from aqueous solutions. The effects of pH, contact time, concentra-tion of TC and desorption were studied in batch mode. The kinetics of TC biosorption was very fastand reached equilibrium in almost 2 h. The kinetic data was well described by double exponentialand the pseudo-second-order kinetic models. Film diffusion is the rate-limiting step for the biosorp-tion of TC on to crystalline nanocellulose. Both Redlich–Peterson (R–P) and Polanyi–Manes (P–M)isotherm models described the equilibrium data well. The values of maximum sorption capacities(6.48–7.73 mg/g for R–P and 6.57–7.96 mg/g for P–M models) increased with temperature. A ther-modynamic study (�H◦= 22.64 kJ/mol, �S◦= 9.85 kJ/(mol/K)) demonstrated that biosorption of TC isspontaneous, endothermic and an entropy-driven process. The reusability of sorbent was achieved byHNO3(5 w/w%) with desorption efficiency of 95.20% in 4 h. The overall results have significant implica-tions for the removal of TC from aqueous solution with crystalline nanocellulose
Effects of unregulated anthropogenic activities on mixing ratios of volatile organic air pollutants – A case study
No full textDuring the months of October to November, many important festivals are celebrated in India. Celebration of these festivals are marked by extensive use of fireworks or pyrotechnics, bonfire, incense burning, open air community cooking, and temporary eateries using crude fuel such as coal, wood, kerosene, cow dung, burning of raw/semiwood, and coconut shells. The present study deals with the influence of these unregulated anthropogenic activities on ambient mixing level of volatile organic compounds (VOCs), especially some carbonyl compounds. The study was undertaken in the metropolitan city of Kolkata, India, with very high population density, which is even higher during festival period. The average total carbonyl level at different sites in Kolkata varied from 134.8 to 516.5 μg m(-3) in pre-festival season, whereas in post-festival season the same varied from 252.2 to 589.3 μg m(-3). Formaldehyde to acetaldehyde ratio altered from 0.62 in pre-festival season to 1.78 in post-festival season. Diurnal variation also altered, indicating variation in source composition of carbonyls. The total ozone forming potential calculated for all 14 carbonyls in pre-festival season increased by 35% in post-festival season. The effect of anthropogenic activities typical to the event of Diwali night characterized by intense execution of pyrotechnics resulted in significantly high level of carbonyl VOCs. Principal component analysis study for the event of Diwali shows clear contribution of the event on certain carbonyl VOCs. The results indicate elevated primary emissions of these pollutants and also their effect on formation of secondary pollutants. The study emphasizes the need of generating awareness among the communities in society as well as need for regulations to minimize the emissions and related hazards to the extent possible.
Implications: Altered anthropogenic activities typical of festival season including extensive use of pyrotechnics affect ambient level of volatile organic compounds, especially some carbonyls. Such activities have considerable effect on interspecies ratio and diurnal variation. They also affect formation of secondary pollutants such as tropospheric ozone. Principal component analysis (PCA) study shows clear contribution of the pyrotechnics execution on certain carbonyl VOCs. The findings emphasize the need of generating awareness in society and need for regulations to minimize the emissions
Distribution of Gaseous Phase Polycyclic Aromatic Hydrocarbons (PAHs) in Rural Environment of India
Get PDFPolycyclic aromatic hydrocarbons are considered as atmospheric contaminants due to their carcinogenic and mutagenic
properties. In the present study, 8 selected gaseous phase PAHs were determined in ambient air representing rural
environment. The gaseous phase PAHs samples were investigated for quantification of selected PAHs in various seasons
and possible sources of gaseous phase PAHs in rural environment. The samples were collected using a cartridge
containing XAD-2 resin placed between layers of polyurethane foam (PUF) and analyzed by fluorescence technique. The
seasonal variation in selected gaseous phase individual PAHs varied between 28-496.9 ng m-3 during winter, summer and
post-monsoon season respectively. The concentration of gaseous phase PAHs was dominated by Phen, Anth and Flt. The
gaseous phase concentration of PAHs were 3.9 and 5.1 times higher in winter as compared to summer and post-monsoon
season respectively. The higher concentration winter may be due to higher emission from biomass burning, fuel used for
cooking such as coal and kerosene and other heating activities to protect from cold winter. The three ring gaseous phase
PAHs were predominant than four and five membered ring PAHs and contribution varied between74.9-93.9 % of selected
PAHs. The ratio analysis studies showed that traditional fuel used for cooking purposes mainly wood, kerosene, coal and
biomass burning are the major contributors in rural environmen
A mosquito attractant or lurent composition and the device thereof
No full textA device and method is describe for producing CO2, body odour and other attractants such as lights, heat, moisture, together as an mosquito-insects attractants near or within an electric field enclosure. The invention describes a use of developed low cost non-hazardous material in a specially design device which produces mosquito-insects attractants in more economical and convenient way, which lures the mosquitoes-insects towards the source i.e. device and gets eventually kill by electric field. The invention has low operating cost and effective way of controlling the mosquitoes-insects menace without any negative implications on user health or environment