Effects of rogar and endosulfan on the metabolism of fresh water sponge (Spongilla lacustris)

Spongilla lacustris were exposed to sub lethal concentrations of pesticides, rogar and endosulfan for one month period. Metabolites like carbohydrates, protein and enzymes like those that peroxidase and carbonic anhydrase were estimated in the experimental and control animals. The results show, depletion of carbohydrates while protein elevated as the days progressed. Similarly an enzyme activity found to be decreased in exposed Spongilla lacustris.     

Experimental investigation into different selectively coated receivers and silver-coated selective surface compound parabolic reflector using regression modelling for industrial heating

The paper explores the experimental results of the prototype compound parabolic trough made of mild steel and silver-coated selective surface. This prototype has been tested with top cover. The performance of the collector has been evaluated with two kinds of receivers coated with three types of black coatings. First receiver is of copper coated with black copper, second receiver is of mild steel coated with black copper and third receiver is of copper coated with black zinc. From actual field experiments, it has been observed that the efficiency of the system achieved with copper receiver coated with black copper is comparatively higher than the other two types of receivers. A simple regression analysis is used to correlate the thermal performance parameters of the system.     

Alumina-supported oxime for the degradation of sarin and diethylchlorophosphate

1-(4-Chlorophenyl))-N-hydroxymethanimine and cyclohexyl-N-hydroxymethanimine were synthesized and a well-established oxime, i.e., 2-[(hydroxyimino)methyl]-1-methylpyridinium chloride was purchased. Thereafter; all were loaded over Al₂O₃ using incipient wetness technique. The prepared systems were characterized using surface area analyzer, scanning electron microscope, energy dispersive X-ray spectrophotometer, Fourier transform infrared spectrophotometer and thermogravimetric analyzer. Kinetics of the degradation of sarin (GB) and simulant, i.e. diethylchlorophosphate (DEClP) was studied over synthesized oxime impregnated Al₂O₃ and results were compared with well reported oxime impregnated Al₂O₃. Kinetics of reaction was found to be following the pseudo first order reaction kinetics. The order of reactivity of the prepared systems was found to be cyclohexyl-N-hydroxymethanimine/Al₂O₃ > 1-(4-chlorophenyl)-N-hydroxymethanimine/Al₂O₃ > 2-[(hydroxyimino)methyl]-1-methylpyridinium chloride/Al₂O₃ > Al₂O₃. From the reaction kinetics it was observed that the reaction with DEClP was faster than with GB. Cyclohexyl-N-hydroxymethanimine/Al₂O₃ was found to be the most reactive system with half-life of 0.94 and 15 h for DEClP and GB respectively.     

Simulation of phytoremediation of a TNT-contaminated soil using the CTSPAC model

Knowledge of water movement in the plant-xylem system and contaminant bioavailability in the soil environment is crucial to evaluate the success of phytoremediation practices. This study investigated the removal of 2,4,6-trinitrotoluene (TNT) from a contaminated sandy soil by a single poplar (Populus fastigiata) tree through the examinations of temporal variations of xylem water potential, root water uptake, and soil TNT bioavailability. A mathematical model, CTSPAC (Coupled Transport of water, heat, and solutes in the Soil-Plant-Atmosphere Continuum), was modified for the purpose of this study. The model was calibrated using laboratory measurements before its application. Our simulations show that the xylem water potential was high in the roots and low in the leaves with a potential head difference of 3.55 cm H2O, which created a driving force for water flow and chemical transport upward from the roots through the stem to the leaves. The daily average root water uptake rate was 25 cm3 h(-1) when an equilibrium condition was reached after 24 h. Our simulations further reveal that no TNT was found in the stem and leaves and only about 1% of total TNT mass was observed in the roots due to the rapid biodegradation and transformation of TNT into its daughter products. About 13% of the soil TNT was removed by the poplar tree, resulting mainly from root uptake since TNT is a recalcitrant compound. In general, the soil TNT bioavailability decreased with time due to the depletion of soil solution TNT by the poplar tree. A constant bioavailability (i.e., 3.1 x 10(-6)) was obtained in 14 d in which the soil TNT concentration was about 10 mg L(-1). Our study suggests that CTSPAC is a useful model to simulate phytoremediation of TNT-contaminated sites.     

Isolation and screening of sulfur-oxidizing bacteria from coast of Bhavnagar,India, and formulation of consortium for bioremediation

Environmental Science and Pollution Research - Reduced sulfur compounds are a nuisance in coastal industries causing heavy economical as well as ecological loss. One such compound, hydrogen...     

Recent Cattail Expansion and Possible Relationships to Water Management: Changes in Upper Taylor Slough (Everglades National Park,Florida, USA)

Recent appearance of cattail (Typha domingensis) within a southern Everglades slough—Upper Taylor Slough (Everglades National Park)—suggests ecosystem eutrophication. We analyze water quality, nutrient enrichment, and water management operations as potential drivers of eutrophication in Upper Taylor Slough. Further, we attempt to determine why surface water phosphorus, a parameter used commonly to monitor ecosystem health in the Everglades, did not serve as an early warning for eutrophication, which has broader implication for other restoration efforts. We found that surface water total phosphorus concentrations generally were below a 0.01 mg L⁻¹ threshold determined to cause imbalances in flora and fauna, suggesting no ecosystem eutrophication. However, assessment of nutrient loads and loading rates suggest Upper Taylor Slough has experienced eutrophication and that continued total phosphorus loading through a point-source discharge was a major driver. These nutrient loads, combined with increases in hydroperiods, led to the expansion of cattail in Upper Taylor Slough. We recommend other metrics, such as nutrient loads, periphyton and arthropod community shifts, and sediment core analyses, for assessing ecosystem health. Monitoring surface water alone is not enough to indicate ecosystem stress.     

Utilization of banana agricultural waste: production of cellulases by soil fungi

Banana a major cash crop of Maharashtra is cultivated over 46900 hectares generating large amount of agro waste after the harvest. Attempts were made to utilize these agro wastes for production of cellulases. Of the 127 fungi isolated from the soil of banana field, 12 fungi were found to utilize cellulose as source of carbon. Trichoderma lignorum showed appreciable cellulolytic activity. It produced Cl, Cx and beta glucosidase in Carboxymethyl Cellulose Peptone medium as well as on agro waste based medium containing leaves, stem and rhizome powders. T. lignorum (0. 45 U/ml) produced maximum enzymes on leaf based medium.     

Gas chromatographic studies on the biodegradation of nitrobenzene and 2,4-dinitrophenol in the nitrobenzene plant wastewater

The biodegradation of nitrobenzene (NB) and 2,4-dinitrophenol (DNP) in NB plant wastewater has been studied using acclimated activated sludge in a batch bioreactor. The gas chromatographic (GC) monitoring shows simultaneous utilization of these two substrates, and both NB and DNP were ultimately biodegraded. The primary and ultimate biodegradation rates using GC and COD methods, respectively, are compared and reported.     

Sorption kinetics and equilibria of organic pesticides in carbonatic soils from South Florida

A batch reactor was used to determine sorption kinetic parameters (k2, F, and K*) and the equilibrium sorption coefficient (K). The two-site nonequilibrium (TSNE) batch sorption kinetics model was used to calculate the kinetic parameters. Two probe organic pesticides, atrazine [2-chloro-4-ethylamino-6-isopropylamino-s-triazine] and diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were studied using three carbonatic soils from South Florida (Chekika, Perrine, and Krome), one noncarbonatic soil from Iowa (Webster), and one organic soil (Lauderhill) from South Florida. Carbonatic soils contained more than 600 g kg(-1) CaCO3. Sorption is initially very fast up to 3 h and then slowly reaches equilibrium. All soil-chemical combinations reached sorption equilibrium after about 24 h and all sorption isotherms were linear. The sorption kinetics data were well described by the TSNE model for all soil-chemical combinations except for the marl soil data (Perrine-Atrazine), which were better described by the one-site nonequilibrium (OSNE) model. Diuron, with higher K, undergoes slower sorption kinetics than atrazine. The Lauderhill soil containing organic carbon (OC) of 450 g kg(-1) exhibited slowest sorption kinetics for both pesticides. An inverse relationship between k3 and K was observed for atrazine and diuron separately in Chekika, Webster, and Lauderhill soils but not in Perrine and Krome soils. The sorption kinetic parameters were used to distinguish the sorption behavior between atrazine and diuron and to identify differences between soils. Normalizing the sorption coefficient (K) to OC showed that atrazine and diuron had K oc values in carbonatic soils that were a third of reported literature values for noncarbonatic soils. Using existing literature K oc values in solute transport models will most likely underestimate the mobility of atrazine, diuron, and other neutral organic chemicals in carbonatic soils.