Removal of aqueous nickel (II) using laterite as a low-cost adsorbent.

The present paper describes the laboratory study of laterite as a low-cost adsorbent for removal of aqueous nickel (II). At pH 7 and a temperature of 30 degrees C, a sorbent dose of 15 mg/L resulted in approximately 90% removal of nickel (II) from its initial concentration of 10 mg/L. A maximum removal of 98% of the adsorbate was observed with an adsorbent particle size of 210 micro with the above conditions. Batch kinetics results were described by fitting in a Langmuir isotherm. Helffrich's half-time equation (Helffrich, 1962) has been applied to evaluate the adsorption process. It appears that film diffusion would be the rate-limiting step. The effect of pH on the sorption process was carried out to a value of 8.0. The removal rate of nickel was found to be the function of pH of the reaction mixture. The rate of nickel uptake by laterite with the decrease in pH value has been explained on the basis of aqueous-complex formation and the subsequent acid-base dissociation at the solid-solution interface.     

Nickel toxicity in partially hepatectomized rats: I. accumulation of radioactive nickel in various organs and subcellular fractions of liver

The distribution of radioactive nickel (50 μmol/kg/200μ Ci S.C.) was studied in various organs as well as in the hepatic subcellular fractions of sham operated and partially hepatectomized rats at 16 hr after injection. ⁶³Ni was maximally accumulated in kidney followed by lung, liver, heart and spleen. The incorporation of ⁶³Ni was lowered in partially hepatectomized rats compared to sham operated ones. Subcellular binding of ⁶³Ni showed significantly high affinity of nickel to cytosol followed by nuclear, mitochondria and microsomes in both the groups.     

Mobility in pastoral systems: Dynamic flux or downward trend?

Several interdependent strategies have allowed pastoralists to survive for centuries in patchy and unpredictable low-productivity environments while sustaining their resource base: mobility, diversity, flexibility, reciprocity and reserves. Recent decades have witnessed curtailed mobility due to agricultural expansion into rangelands, the establishment and enforcement of political and administrative boundaries, the usurpation of local institutional control and disruption of local practices, increased labour costs, and the development of stationary goods and services. Pastoralists have responded by becoming sedentary, diversifying or intensifying their production strategies, leaving the herding sector, or adapting and transforming their practices and institutions. While these trends may be significant, an historical precedence of ebbs and surges in mobility indicates they may not be new or unidirectional. Emerging political trends and technologies may provide an opportunity for pastoral populations to maintain or increase their mobility in the future, but will the customary pastoral institutions that support sustainable practices still be viable, or will new, viable institutions emerge? These institutions are often subtle, contextual, and norm-based; 'invisible' and easily dismantled or replaced by more authoritarian regimes. There is relatively little understanding of how they work or how to support them. Without them, the trend may be towards open access or privatization.     

Thermal, Mechanical and Rheological Behavior of Poly(lactic acid)/Talc Composites

In the present study, influence of talc on thermal, mechanical and rheological behavior of PLA is investigated and the structure?Cproperty correlation for the PLA/talc composites is established. Poly(lactic acid)/talc composites are prepared by melt mixing of PLA with talc in twin screw extruder followed by blown film processing. Various characterizations techniques are used to evaluate thermal, morphological, mechanical and rheological behavior of PLA/talc composites and its blown film. DSC analysis showed that degree of crystallinity of PLA/talc composites was higher than that of neat PLA because of nucleating ability of talc. Spherulite morphology of PLA/talc composites showed that talc has increased nucleation density of spherulite having smaller radius than that of neat PLA. Talc is effective in enhancing tensile modulus and storage modulus of PLA due to reinforcing ability of talc particles.     

Sorption kinetics and leachability of heavy metal from the contaminated soil amended with immobilizing agent (humus soil and hydroxyapatite)

Release of heavy metals onto the soil as a result of agricultural and industrial activities may pose a serious threat to the environment. This study investigated the kinetics of sorption of heavy metals on the non-humus soil amended with (1:3) humus soil and 1% hydroxyapatite used for in situ immobilization and leachability of heavy metals from these soils. For this, a batch equilibrium experiment was performed to evaluate metal sorption in the presence of 0.05 M KNO(3) background electrolyte solutions. The Langmuir isotherms applied for sorption studies showed that the amount of metal sorbed on the amended soil decreased in the order of Pb(2+)>Zn(2+)>Cd(2+). The data suggested the possibility of immobilization of Pb due to sorption process and immobilization of Zn and Cd by other processes like co-precipitation and ion exchange. The sorption kinetics data showed the pseudo-second-order reaction kinetics rather than pseudo-first-order kinetics. Leachability study was performed at various pHs (ranging from 3 to 10). Leachability rate was slowest for the Pb(2+) followed by Zn(2+) and Cd(2+). Out of the metal adsorbed on the soil only 6.1-21.6% of Pb, 7.3-39% of Zn and 9.3-44.3% of Cd leached out from the amended soil.     

Limnochemistry and nutrient dynamics in Upper Lake, Bhopal, India

In limnetic ecosystem, water quality depends upon physical, chemical, and biological factors. Effects of temperature, light scattering, and absorption by suspended and dissolved matter, transport, and mixing of nutrients within the lake are the significant factors as far as water quality is concerned. Nutrient loading into the lake and internal cycling of nutrients is always a matter of concern and critical to number of processes. During the winter season, heat and momentum transfer at the lake surface and the temperature-density relation of water destabilize the water column and drive vertical mixing and transport processes. The deepening of the surface layer produces nutrient transfer from the hypolimnion into the euphotic zone of epilimnion. It may also resuspend sediments that would have settled under stratified conditions, or redistribute particles that may still be in suspension. Thus, there exists a complex connection between the hydrodynamics and water quality issues. Present study is an effort to understand how seasonal changes in the limnetic ecosystem regulate the limnochemistry and movement of nutrient. The study revealed that significant variations of nutrients and organic load were observed between epilimnion and hypolimnion during summer season, and the lake was found in hyper-eutrophic condition throughout the study period.     

Induction of cytochrome P-450 and phosphatidylcholine synthesis by endosulfan in liver of rats: effect of quality of dietary proteins

Administration of endosulfan significantly increased microsomal protein, cytochrome P-450 content and the activity of aminopyrine N-demethylase. Effect of endosulfan and actinomycin D either alone or together on microsomal protein, cytochrome P-450, NADPH cytochrome c reductase, aniline hydroxylase, aminopyrine N-demethylase, phosphatidylcholine content, incorporation of 3H-choline and 14C-methionine were studied in rats given amino acid deficient and supplemented diets. Administration of endosulfan significantly increased the above parameters in both the dietary groups, whereas administration of actinomycin D did not have any effect in rats fed supplemented diets, however, significant decrease in the PC and the incorporation of choline and methionine into PC of rats fed deficient diet were observed. A positive correlation in the effect of endosulfan on hepatic mixed function oxidase activity and hepatic phosphatidylcholine is observed.     

Removal of chromium and reduction of toxicity to Microtox system from tannery effluent by the use of calcium alginate beads containing humic acid

Removal of chromium (Cr) from tannery effluents by recovery of metal also reduces the ecotoxicological impact. To develop such a process, columns packed with calcium alginate (CA) beads with or without humic acid (HA) have been used as an adsorbent and tannery effluent was passed through it. Concentration of Cr in beads and in different fractions collected after adsorption was measured. Change in total organic carbon content during the process was also noticed. The fractions were also tested for toxicity towards Microtox assay. EC(50) values were determined with the help of Microtox analyser 500. Data showed that the CA beads along with HA could be effectively utilised in removal of 54% Cr and also in reducing the toxicity (EC(50) (%) in 5 min=>100 in fractions collected after 72 h).     

Conservation and development in Amazonian extractive reserves: the case of Alto Juruá

Extractive reserves constitute an innovative approach to match conservation and development objectives, which were originally envisaged as part of a land struggle by forest dwellers in Brazil. In spite of the idea's popularity and the attempts to apply the concept to different tropical regions, there has been little analysis of the combined conservation and development performance of extractive reserve programs. We present a detailed analysis of deforestation and demographic and socioeconomic changes in Alto Juruá, the first extractive reserve created in Brazil in 1990. Forest cover has remained fairly stable. Population has declined slightly, with some internal displacements. The cash economy base has shifted from the original rubber production to a diversified portfolio of agriculture and livestock, and there has been a dramatic rise in nonagrarian income. We conclude that the Reserve represents a very dynamic setting with positive conservation and development outcomes during its first decade.     

Distribution of heavy metals in sediment and water of river Gomti

Gomti river receives industrial as well as domestic wastes from various drains of Lucknow city. In the process the water and sediment of the river Gomti get contaminated with heavy metals and other pollutants. In the present study, impacts of domestic/industrial wastes on the water and sediment chemistry of river Gomti with special reference to heavy metals have been investigated in different seasons (summer, winter and rainy). For this, seven sampling sites: Gaughat, Mohan Meakin, Martyrs Memorial, Hanuman Setu, Nishatganj bridge, Pipraghat and Malhaur, in the river Gomti in Lucknow region were identified and samples of water and sediments were collected in all the three seasons. In the collected water and sediment samples, six metals (Cd, Cr, Cu, Ni, Pb, and Zn) were analyzed on ICP-AES (Inductively coupled plasma emission spectroscopy) Labtam Plasmalab 8440. High concentrations of all the metals were noticed in water and sediment in rainy season compared to summer and winter. Because in rainy season runoff from open contaminated sites, agricultural field and industries, directly comes into the river without any treatment. In both the cases, the concentration of zinc was maximum (0.091 g/ml in water and 182.13 g/g in sediment) and the concentration of cadmium (0.001 g/ml in water and 17.26 g/g in sediment) was minimum. Higher concentration of metal in water and sediment during rainy season could be due to the industrial/agricultural/domestic runoff coming into the river.