Anubha Kaushik

Heavy metal contamination of river Yamuna, Haryana, India: Assessment by Metal Enrichment Factor of the Sediments.

Concentration of Heavy Metals (Cd, Cr, Fe, Ni) in water, plants and sediments of river Yamuna flowing in Haryana through Delhi are reported here selecting 14 stations covering the upstream and downstream sites of major industrial complexes of the State. Some important characteristics of river water and sediments (pH, EC, Cl(-), SO(3)(2-), and PO(4)(3-) in water and sediments, COD of water and organic matter content of sediments) were also analysed and inter-relationships of all these parameters with heavy metal concentration in different compartments were examined. The sediments of the river show significant enrichment with Cd and Ni indicating inputs from industrial sources. Concentrations of Cr are moderate and show high enrichment values only at a few sites. Enrichment factor for Fe is found to be <1, showing insignificant effect of anthropogenic flux. Concentrations of these metals in river water are generally high exceeding the standard maximum permissible limits prescribed for drinking water, particularly in the downstream sites. The aquatic plants show maximum accumulation of Fe. The other heavy metals Cd, Cr and Ni, though less in concentration, show some accumulation in the plants growing in contaminated sites. Interrelationships of metal concentration with important characteristics of water and sediment have been analysed. Analysis of heavy metals in water, sediments and littoral flora in the stretch of river Yamuna is first study of itself and interrelationship of metal concentration and other important characteristics make the study significant and interesting in analysing the pollution load at different points of the river body.

Suitability assessment of groundwater for drinking, irrigation and industrial use in some North Indian villages

The study comprised suitability assessment of groundwater for drinking, irrigation, and industrial use. A total of 34 groundwater samples were collected from Rewari town and its perimeter from the land chiefly used for agriculture. Physico-chemical characterization of the samples revealed that groundwater from most of the sources was not fit for drinking owing to a high concentration of calcium, magnesium, hardness and fluoride. Suitability for irrigation, too, was low since most of the sources had high value of sodium adsorption ratio (SAR), residual sodium carbonate (RSC), soluble sodium percentage (SSP) and magnesium hazard which can render salinity and alkali hazard to soils on long term use in irrigation. No source of water was found to be suitable for industrial application since it had high concentration of calcium carbonate which can precipitate very easily. It was observed that sodium, sulphate, and chloride were the chief ions present in water and based on the abundance of ions and their correlation type, most of the groundwater samples are of sodium sulphate and/or sodium chloride type. The high concentration of the chemical constituents is attributed to the lithologic composition of the area. It was observed that the water of deep meteoric percolation type was of sodium sulphate type and the shallow of sodium chloride type.

Sequestration of chromium by exopolysaccharides of Nostoc and Gloeocapsa from dilute aqueous solutions

This article reports the chromium removal potential of exopolysaccharides (EPS) of two indigenously isolated cyanobacterial strains, Gloeocapsa calcarea and Nostoc punctiforme. The biosorption was studied by varying pH from 2 to 6 and initial chromium concentration from 5 to 20mg/L to find out the optimized conditions for maximum chromium removal by EPS. Two equilibrium models, Langmuir and Freundlich, were used to explain these results. The Freundlich model was found to be better applicable to the experimental data as compared to Langmuir as inferred from high value of coefficient of determination whereas the optimal conditions were found to be same for the two (pH 2 and initial chromium concentration 20 mg/L). EPS production by the two strains was also studied which was found to be higher for Gloeocapsa. On the basis of experimental results and model parameters, it can be inferred that the EPS extracted from Nostoc has comparatively high biosorption capacity and can be utilized for the removal of chromium from dilute aqueous solution. Adsorption of chromium on EPS was further confirmed by surface morphology observed in scanning electron micrographs.

Assessment of heavy metal tolerance in native plant species from soils contaminated with electroplating effluent

Heavy metals concentrations of (Cr, Zn, Fe, Cu and Ni) were determined in plants and soils contaminated with electroplating industrial effluent. The ranges of total soil Cr, Zn, Fe, Cu and Ni concentrations were found to be 1443-3240, 1376-3112, 683-2228, 263-374 and 234-335 mg kg⁻¹, respectively. Metal accumulation, along with hyperaccumulative characteristics of the screened plants was investigated. Present study highlighted that metal accumulation in different plants varied with species, tissues and metals. Only one plant (Amaranthus viridis) accumulated Fe concentrations over 1000 mg kg⁻¹. On the basis of TF, eight plant species for Zn and Fe, three plant species for Cu and two plant species for Ni, could be used in phytoextraction technology. Although BAF of all plant species was lesser than one, these species exhibited high metal adaptability and could be considered as potential hyperaccumulators. Phytoremediation potential of these plants can be used to remediate metal contaminated soils, though further investigation is still needed.

Hydrogen production and metal-dye bioremoval by a Nostoc linckia strain isolated from textile mill oxidation pond

Biohydrogen production by Nostoc linckia HA-46, isolated from a textile-industry oxidation-pond was studied by varying light/dark period, pH, temperature and ratio of carbon-dioxide and argon in the gas-mixture. Hydrogen production rates were maximum under 18 h of light and 6 h of darkness, pH 8.0, 31°C, a CO(2):Ar ratio 2:10. Hydrogen production of the strain acclimatized to 20 mg/L of chromium/cobalt and 100 mg/L of Reactive red 198/crystal violet dye studied in N-supplemented/deficient medium was 6-10% higher in the presence of 1.5 g/L of NaNO(3). Rates of hydrogen production in the presence of dyes/metals by the strain (93-105 μmol/h/mg Chlorophyll) were significantly higher than in medium without metals/dyes serving as control (91.3 μmol/h/mg Chlorophyll). About 58-60% of the two metals and 35-73% of dyes were removed by cyanobacterium. Optimal conditions of temperature, pH and metals/dyes concentration for achieving high hydrogen production and wastewater treatment were found practically applicable as similar conditions are found in the effluent of regional textile-mills.

Bioassays for toxicological risk assessment of landfill leachate: A review

Landfilling is the most common solid waste management practice. However, there exist a potential environmental risk to the surface and ground waters due to the possible leaching of contaminants from the landfill leachates. Current municipal solid waste landfill regulatory approaches consider physicochemical characterization of the leachate and do not assess their potential toxicity. However, assessment of toxic effects of the leachates using rapid, sensitive and cost-effective biological assays is more useful in assessing the risks as they measure the overall toxicity of the chemicals in the leachate. Nevertheless, more research is needed to develop an appropriate matrix of bioassays based on their sensitivity to various toxicants in order to evaluate leachate toxicity. There is a need for a multispecies approach using organisms representing different trophic levels so as to understand the potential impacts of leachate on different trophic organisms. The article reviews different bioassays available for assessing the hazard posed by landfill leachates. From the review it appears that there is a need for a multispecies approach to evaluate leachate toxicity.

Power generation in microbial fuel cell fed with post methanation distillery effluent as a function of pH microenvironment

The effect of anolyte and catholyte pH on power generation in an MFC using post methanation distillery effluent (PMDE) was studied in batch mode. Higher anodic pH (7-9) and low cathodic pH (2) were more favorable and at the optimal cathode:anode pH ratio of 2:8, power density attained was 0.457 W/m(3). An initial feed solution pH up to 10 was tolerated by the MFC. However, internal resistance increased 1.5 times and power density decreased by 60% at pH 10 as compared to that at pH 7, the normal anolyte pH. Internal resistance of the MFC was minimum (266 ohms) at cathodic pH 2, thus favoring better power generation. Under low cathodic and high anodic pH ratio of the MFC, a low internal resistance favored both high current density and power density.

Integrating photobiological hydrogen production with dye–metal bioremoval from simulated textile wastewater

The study reports production of hydrogen in photobioreactors with free (PBR(Fr)) and immobilized (PBR(Imm)) Nostoc biomass at enhanced and sustained rates. Before running the photobioreactors, effects of different immobilization matrices and cyanobacterial dose on hydrogen production were studied in batch mode. As hydrogen production in the PBRs declined spent biomass from the photobioreactors were collected and utilized further for column biosorption of highly toxic dyes (Reactive Red 198+Crystal Violet) and metals (hexavalent chromium and bivalent cobalt) from simulated textile wastewater. Breakthrough time, adsorption capacity and exhaustion time of the biosorption column were studied. The photobioreactors with free and immobilized cyanobacterium produced hydrogen at average rates of 101 and 151 μmol/h/mg Chl a, respectively over 15 days, while the adsorption capacity of the spent biomass was up to 1.4 and 0.23 mg/g for metals and 15 and 1.75 mg/g for the dyes, respectively in continuous column mode.

Thermal convection over East Antarctica: Potential microorganism dispersal

The Indian Antarctic station, Maitri is in the Schirmacher oasis of east Antarctica. The oasisis covered with snow/ice; except for the local summer season when it gets deglaciated and exposes the small hilly region. During summer, minute microorganisms are observed near water bodies of this rocky terrain. In the year 1996a monostatic acoustic sounder probed planetary boundary layer dynamics over this region. From the data it is observed that the thermal convection (both free and forced) persist for 5.63% of the time in the whole year. The occurrence of free convection predominates in the local summer season around midday, while sporadic cases of forced convection have been recorded during the autumn and winter seasons. The onset of convection is mainly at 0600 hrs to 1200 hrs, while the cessation period is limited within 1400 hrs to 1900 hrs. The cessation of convection is basically governed by the katabatic wind flow around the Schirmacher region and it indicates that the interior of Antarctica or the polar cap ice becomes cooler much faster than the rocky region of Schirmacher oasis.Examples taken from the literatures on atmospheric structure and their effects on dispersal of microorganisms and their distribution by the wind are discussed. The study of monostatic acoustic sounder for thermal convections/plumes may form input for the study of dispersal, survival, metabolicactivities and dispersion model of microorganisms. The application of convection/plume to aerobiology can also lead to improvements in forecasting, monitoring and understanding the various mechanisms of organism dispersal.

Changing patterns of organochlorine pesticide residues in raw bovine milk from Haryana, India

Bovine milk samples were collected and analyzed during 1992 and 1998 from rural areas of 14 different districts of Haryana state for the presence of HCH and DDT residues. The study revealed that the mean residues of ΣHCH in raw bovine milk have declined by 67.5% while mean levels of ΣDDT have decreased by 92.8% during six years gap. The obtained results reveal that during 1992 p,p′-DDT was the main component followed by p,p′-DDD, α-HCH and β-HCH while in 1998, p,p′-DDE and β-HCH followed by p,p′-DDT were relatively more as compared to other isomers and metabolites of these pesticides.