Removal of trivalent and pentavalent arsenic from water using chemically modified chitosan beads

A novel process for chemical modification of chitosan with iron oxide and potassium permanganate was developed and the beads of the modified material have been prepared for the removal of the two forms of the metalloid Arsenic - As(III) and As(V)from water in the concentration range 5-40 mg L-1. The maximum adsorption capacity (pH 7.0) is 43.28 and 32.26 mg g-1 for As(III) and As(V), respectively. The chemically modified chitosan beads are regenerated for successive treatment cycles through alkali treatment. The regenerated beads show negligible loss in their removal efficiency of As(III) and As(V). Overall, the study provides a novel process for fabrication of low-cost composite material of chitosan for enhanced removal of Arsenic. This report will facilitate the development and up-scaling of low-cost treatment technologies for adsorptive removal of Arsenic from water

Nutrient requirements of polar Chlorella-like species

Eukaryotic micro-algae, well adapted to extremely low and varying temperatures, varying light intensities, as well as low availability of essential macronutrients and other resources, represent ideal producers in low-temperature biotechnological processes. In order to identify the nutrient requirements of six biotechnologically perspective Arctic and Antarctic soil Chlorella-like strains at various temperature and light regimes, the algae were cultivated in a unit for cross gradients of temperature (-4 to 24°C) and irradiance (5 to 65 µmol m-2 s-1), and at different nutrient treatments in each temperature-irradiance combination. The nutrient treatments included two different carbon (bicarbonate and carbonate concentrations of 1 and 5 mM) and nitrogen (nitrate concentrations of 50 amd 100 µM and ammonium concentrations 100 and 500 µM) forms at two different concentrations for each. Temperature and irradiance growth requirements were similar in the majority of strains reflecting thus comparable conditions in the original microhabitat, regardless of its geographic position. All studied strains tolerated low temperatures (1 to 5°C), but were able to grow even at temperatures above 20°C, thus, they were considered to be psychrotolerant. All experimental strains were able to grow at very low irradiances. Nutrient manipulation either did not affect the growth limits and optimum, or narrowed the growth optima; the response was strain-specific. Ammonium and nitrate additions resulted in decreased growth rates in all tested strains, with the exception of one strain in which growth stimulation was observed. The decrease in growth rate was probably due to nutrient oversaturation in the inhibited strains. Carbonate addition stimulated growth of all strains. Bicarbonate also increased the growth rate in all strains with one exception, in which bicarbonate inhibited growth, indicating thus carbon limitation during cultivation and different carbon uptake mechanisms

Effect of application of some organic amendments on soil properties, extractable micronutrients and their chemical fractions in a sandy loam soil

In a 120-day incubation study, farmyard manure (FYM), mushroom compost (MC), poultry manure (PM), vermi-compost (VC), biogas slurry (BS) and biochar from Lantana sp.; a common weed (BC) each added at 15 t ha-1 significantly increased soil electrical conductivity and organic C content, however, only VC failed to increase soil organic C content significantly but increased soil pH when compared with the control sample. Among organic amendments, FYM, MC, VC and BS increased DTPA-extractable Zn and Mn in soil significantly when compared with the control sample, while BC was significantly effective in regard to increasing both DTPA-extractable Mn and hot water soluble B when compared with the control sample. Application of FYM and MC significantly increased DTPA-extractable Cu and Fe, respectively when compared with the control sample. Simple correlation and path coefficient analysis were performed to identify key chemical fractions of micronutrients in soil having the direct and indirect effects on availability of micronutrients in organically amended soils. Based on soil extractable concentrations of micronutrients in organically amended soils, FYM appeared to be the best source of Zn, Cu and Mn, while MC could serve as the best source of Fe. Biochar from Lantana sp. may serve as a good source of B

Fishing techniques and gears developed by tribal communities around Bargi Reservoir in Madhya Pradesh, India

1098-1101Traditional knowledge (TK) plays a very important role in the lives of millions of people around the world. There is an immense need for documentation of traditional knowledge especially in countries rich in biodiversity, such as India. Bargi is one of the major dams constructed on the river Narmada in Madhya Pradesh. Local communities have used various fishing methods since time immemorial. Construction of the dam changes the ecology and hydrology of the river. Tribal communities have adapted their fishing techniques to these changes and have also developed new techniques. Fishing technique described in this paper is practiced around Bargi Reservoir. Five types of crafts and different gears were encountered during the two years of seasonal survey

Fishing techniques and gears developed by tribal communities around Bargi Reservoir in Madhya Pradesh, India

Traditional knowledge (TK) plays very important role in the millions of people around the world. There is immense need of documentation of traditional knowledge especially in countries rich in biodiversity, such as India. Bargi is one of the major dam constructed on river Narmada in Madhya Pradesh. Local communities use various fishing methods since time memorable.  Dam changes ecology and hydrology of river. Tribal communities have adapted their fishing techniques to these changes and have also developed new techniques. Fishing technique described is this paper practiced around Bargi Reservoir. Six type  of  crafts  and different  gears  were encountered  during  the  two years of seasonal survey

Study on Sea Surface Temperature and Chlorophyll-a concentration along the south-west coast of India

Global climate change affects the oceanographic features and distribution of marine fishes as they are poikilothermic animals. Study of oceanographic variables in a localized region is more relevant in the context of ecological responses rather than global or continental variations. In this study, time series analysis of chlorophyll-a concentration (Chl-a) in sea water and sea surface temperature (SST) was performed separately for southern, middle and northern stratum along south-west coast of India using various statistical tools. The SST showed an increasing trend along the entire south-west coast of India after the year 1995. The northern and southern stratum of south-west coast were highly influenced by rising SST, whereas middle stratum in present scenario showed stable conditions in terms of Chl-a concentration. The study provides a baseline information about changing patterns of oceanographic features along the south-west coast of India giving a better understanding of changing global climatic conditions in coastal ecosystems

Application of a marine cyanobacterium <i>Phormidium fragile</i> for green synthesis of silver nanoparticles

110-113Green synthesis of silver nanoparticles using dry biomass of a marine cyanobacterium Phormidium fragile was investigated. The silver nanoparticles showed absorption maxima at 410 nm due to a shift in plasmon resonance during the process of bioreduction. The silver nanoparticles produced by the above process were of the monodisperse type with a size range of 5-6.5 nm. The zeta potential of synthesized nanoparticles was –15.96 mV, which shows a moderate stability of nanoparticles in the environment. Geometrically, the nanoparticles exhibited a phase centred cubic symmetry, evident from the intense peaks for (200) plane in the XRD-spectrum. Overall, this report provides evidence for the biopotentialities of cyanobacteria for nanotechnological applications

Column mode removal of copper through physically entrapped algal bioadsorbents

A polyurethane column with physically entrapped algal materials has been designed and tested for copper removal from aqueous medium. The performance of the column is assessed on the basis of the parameters viz. bio-removal efficiency, metal sequestered in the column and bio-sorption capacity. The findings show that the combination of calcium alginate and S. platensis exhibit highest bio-removal efficiency (38.42%) for Cu(II) in the concentration range 5-20 mg L-1. The maximum bio-sorption capacity (80.30 mg/g) is recorded for a mixture of calcium alginate and S. platensis after 60 min treatment time. FTIR analysis of algal adsorbents show that the adsorption efficiency depended on the availability of negatively charged groups such as carboxylic and hydroxyl groups. The study concluded that the algal compounds and dried biomass of S. platensis are effective bio-adsorbents for the removal of Cu(II) from water

Fishing techniques and gears developed by tribal communities around Bargi Reservoir in Madhya Pradesh, India

1098-1101Traditional knowledge (TK) plays a very important role in the lives of millions of people around the world. There is an immense need for documentation of traditional knowledge especially in countries rich in biodiversity, such as India. Bargi is one of the major dams constructed on the river Narmada in Madhya Pradesh. Local communities have used various fishing methods since time immemorial. Construction of the dam changes the ecology and hydrology of the river. Tribal communities have adapted their fishing techniques to these changes and have also developed new techniques. Fishing technique described in this paper is practiced around Bargi Reservoir. Five types of crafts and different gears were encountered during the two years of seasonal survey

Chlorella mirabilis as a potential species for biomass production in low temperature environment

Successful adaptation/acclimatization to low temperatures in micro-algae is usually connected with production of specific biotechnologically important compounds. In this study, we evaluated the growth characteristics in a micro-scale mass cultivation of the Antarctic soil green alga Chlorella mirabilis under different nitrogen and carbon sources followed by analyses of fatty acid contents. The micro-scale mass cultivation was performed in stable (in-door) and variable (out-door) conditions during winter and/or early spring in the Czech Republic. In the in-door cultivation, the treatments for nitrogen and carbon sources determination included pure Z medium (control, Z), Z medium + 5% glycerol (ZG), Z medium + 5% glycerol + 50 &#181;M KNO3 (ZGN), Z medium + 5% glycerol + 200&#181;M NH4Cl (ZGA), Z medium + 5% glycerol + 1 mM Na2CO3 (ZNC), Z medium + 5% glycerol + 1 mM Na2CO3 + 200&#181;M NH4Cl (ZGCA) and Z medium + 5% glycerol + 1 mM Na2CO3 + 50 &#181;M KNO3 (ZGCN) and were performed at 15&#176;C with an irradiance of 75 &#181;mol m-2 s-1. During the out-door experiments, the night-day temperature ranged from -6.6&#176;C to 17.5&#176;C (daily average 3.1&#177;5.3 &#176;C) and irradiance ranged from 0 to 2300 &#181;mol m-2 s-1 (daily average 1500&#177;1090 &#181;mol m-2 s-1). Only the Z, ZG, ZGN and ZGC treatments were used in the out-door cultivation. In the in-door mass cultivation, all nitrogen and carbon sources additions increased the growth rate with the exception of ZGA. When individual sources were considered, only the effect of 5% glycerol addition was significant. On the other hand, the growth rate decreased in the ZG and ZGN treatments in the out-door experiment, probably due to carbon limitation. Fatty acid composition showed increased production of linoleic acid in the glycerol treatments. The studied strain of C. mirabilis is proposed to be a promising source of linoleic acid in low temperature mass cultivation biotechnology. This strain is a perspective model organism for biotechnology in low-temperature conditions