Adsorption of thorium from aqueous solutions by perlite

The use of expanded perlite for the adsorption of thorium from aqueous solution by batch technique is presented. The effects of particle size, pH of the solution, initial thorium concentration, shaking time, V/m ratio and temperature were determined. It was found that the adsorption capacity increases by the increase in the pH of the suspensions. The rate of thorium adsorption on expanded perlite was observed to be fast in the first hour of the reaction time. Adsorption isotherms were expressed by Langmuir and Freundlich adsorption models and the adsorption experiments conducted at 30 ± 1 °C showed that the adsorption isotherms correlated well with the Langmuir model. From the adsorption data, thermodynamic parameters such as ΔG^o, ΔH^o and ΔS^o were calculated as a function of temperature.     

Erosion Modeling in Hard Rock Terrain Using Morphometry: A Case Study from Tamilnadu,India

Remote sensing and geographical information system (GIS) can help identify erosion‐prone areas in need of soil conservation efforts     

Complaint reports for violations of health and safety legislation in the area of Thessaloniki (Greece)

Prosecution is one of the frequently employed instruments for the enforcement of health and safety legislation. In Greece, the penal procedure for such issues usually starts on initiative of a labour inspector who sends a complaint report to the public prosecutor. Should the complaint report be the result of a serious accident, there is an increased probability for the judgement of the court to remain unknown to the labour inspector, as well as the predicted penalty in the first instance court to be reduced. However, the appointment of a counsel by the victim of the accident could reverse such an effect, thus reducing the probability of the court’s judgement remaining unknown and raising the predicted penalty.     

The impact of enhanced ammonium sulphate inputs exceeding critical load on calluna vulgaris /peat soil microcosms

Ammonium sulphate at six concentrations in simulated precipitation has been applied weekly over two years to Calluna vulgaris growing in peat soil. The nitrogen deposition treatments were chosen to embrace and exceed critical load. The growth and composition of the Calluna and the changes over time in the chemistry of the peat soil and its soil solution were monitored. In spite of significant increases in foliar nitrogen concentration in new shoots, especially in the first year, growth did not increase significantly in response to nitrogen treatment. Several factors could be contributing to the lack of significant growth response. (1) Increasing ammonium input significantly acidified the soil solution, which could adversely effect growth directly. (2) Foliar calcium concentration was reduced significantly in both years by the ammonium sulphate treatments, and more calcium was undoubtedly lost from the rooting zone at higher nitrogen inputs. (3) Foliar phosphate declined significantly between the first and second year, so lack of growth response might also reflect a phosphorus limitation. There was a distinctly visible darkening of the leaves in response to increasing ammonium applications, especially for the first year's growth, and the chlorophyll a and b concentrations in leaves from new growth at the three highest nitrogen treatments were significantly (at P <0.05) higher than those for the control. The pigment concentrations fell markedly by the end of the second season, and treatment effects were much less consistent. It is suggested that pigment analysis therefore probably has little diagnostic value for assessing damage from pollutant nitrogen effects.     

Thermodynamics of interaction of lindane on silty loam and silty clay loam Indian soils

Abstract

Interaction of lindane with silty loam and silty clay loam soils was studied in batch tests at 23, 30 and 37° C. Sorption experiments were carried out at four concentrations and for varying time of contact upto 72 hours. This was followed by desorption studies. No desorption was observed. The sorption data was analysed using sorption equations and evaluating the thermodynamic parameters. The sorption was found to be predominantly entropic in nature and a combined effect of adsorption and chemisorption. The effect of organic matter and other chemical and mineralogical constituents of soils has also been discussed. The sorption with single application of lindane with the two soil types indicates that the insecticide is less likely to reach groundwater.     

Molecular composition of recycled organic wastes,as determined by solid-state 13C NMR and elemental analyses

Using solid state ¹³C NMR data and elemental composition in a molecular mixing model, we estimated the molecular components of the organic matter in 16 recycled organic (RO) wastes representative of the major materials generated in the Sydney basin area. Close correspondence was found between the measured NMR signal intensities and those predicted by the model for all RO wastes except for poultry manure char. Molecular nature of the organic matter differed widely between the RO wastes. As a proportion of organic C, carbohydrate C ranged from 0.07 to 0.63, protein C from <0.01 to 0.66, lignin C from <0.01 to 0.31, aliphatic C from 0.09 to 0.73, carbonyl C from 0.02 to 0.23, and char C from 0 to 0.45. This method is considered preferable to techniques involving imprecise extraction methods for RO wastes. Molecular composition data has great potential as a predictor of RO waste soil carbon and nutrient outcomes.     

Novel synthesis of multicomponent porous nano-hybrid composite,theoretical investigation using DFT and dye adsorption applications: disposing of waste with waste

Environmental Science and Pollution Research - Extensive studies have shown that doping can enhance the properties of graphene, but the application to real industrial wastewater treatment and...     

Are either sod and catalase or the polyamines involved in the paraquat resistance of Conyza canadensis ?

Abstract

Paraquat/atrazine coresistant (PqAR) and paraquat resistant (PqR) horseweed (Conyza canadensis /L./ Cronq.) plants showed ‐ in the first hour after 0.5 mM paraquat spraying ‐ a decreased catalase activity followed by a slight increase. However, the enzyme activity remained always below the initial value. Sensitive plants showed a significant increase of catalase activity in the first 4 hour after spraying. The transient character of paraquat inhibition, the recovery of photosyn‐thetic activity of the PqAR Conyza plants (characterized by variable fluorescence) after spraying remained unaffected by the Superoxide dismutase (SOD) inhibitor, diethyldithiocarbamate. This indicates that SOD is not involved in the resistance mechanism. Untreated resistant biotypes showed about 2.5 times higher total polyamine and putrescine level than the sensitive one. 100 μM of exogenously added putrescine was observed as having a protecting effect against paraquat in floated leaves of the sensitive biotype only. The resistant leaves were unaffected probably on account of their higher endogenous polyamine level. It is concluded that polyamines may play a role in the paraquat resistance of Conyza canadensis.     

Inexact fuzzy-stochastic constraint-softened programming – A case study for waste management

In this study, an inexact fuzzy-stochastic constraint-softened programming method is developed for municipal solid waste (MSW) management under uncertainty. The developed method can deal with multiple uncertainties presented in terms of fuzzy sets, interval values and random variables. Moreover, a number of violation levels for the system constraints are allowed. This is realized through introduction of violation variables to soften system constraints, such that the model’s decision space can be expanded under demanding conditions. This can help generate a range of decision alternatives under various conditions, allowing in-depth analyses of tradeoffs among economic objective, satisfaction degree, and constraint-violation risk. The developed method is applied to a case study of planning a MSW management system. The uncertain and dynamic information can be incorporated within a multi-layer scenario tree; revised decisions are permitted in each time period based on the realized values of uncertain events. Solutions associated with different satisfaction degree levels have been generated, corresponding to different constraint-violation risks. They are useful for supporting decisions of waste flow allocation and system-capacity expansion within a multistage context.     

Fire Regime Changes in La Michilía Biosphere Reserve, Durango, Mexico

Abstract: The ability of reserves to maintain natural ecosystem processes such as fire disturbance regimes is central to long-term conservation. Fire-scarred tree samples were used to reconstruct fire regimes at five study sites totaling approximately 230 ha in pine (   Pinus spp.) and oak ( Quercus spp.) forests of La Michilía Biosphere Reserve on the dry east slope of the Sierra Madre Occidental, Durango, Mexico. Study sites covered a 20-km environmental gradient of elevation, topography, and human land uses. Plant communities ranged from oak-pine to mixed conifer forests. Fires were frequent at all sites prior to 1930, when large-scale grazing of domestic livestock was initiated. Widespread fires have been excluded from four of the five sites since 1945, with an essentially uninterrupted regime of frequent fires continuing only in the reserve core. Xeric sites had many, smaller fires, whereas mesic sites had fewer but larger fires. On a reserve-wide scale, a fire burned on at least one site nearly every year, usually in the dry spring or early summer season, but fire years were rarely synchronous among the sites. Fire occurrence was weakly related to the Southern Oscillation climate pattern; major reserve-wide fire years almost never coincided with wet Southern Oscillation extremes but only occasionally matched dry extremes. Maintenance of the long-term frequent-fire regime in the reserve core is one indicator that the biosphere reserve model has been successful in conserving natural processes, but the protected area is small ( 7000 ha). Because of the key role of frequent-fire regimes in regulating ecosystem structure and function, restoration of the ecological role of fire disturbance is a desirable conservation strategy.