Predicting the Fate and Transport of E. coli in Two Texas River Basins Using a Spatially Referenced Regression Model1

Abstract: The two main rivers of southeast Texas: Guadalupe and San Antonio have shown high temporal increase in bacteria concentration during the last decade. The SPAtially Referenced Regression On Watershed (SPARROW) attributes model, developed by the U.S. Geological Survey (USGS), has been applied to predict the fluxes and concentrations of contaminants in unmonitored streams and to identify the sources of these contaminants. This model identifies every reach as a basic network unit to distribute the sources, delivery, and attenuation factors. The model is data intensive and implements nonlinear regression to solve the parsimonious relations for describing various watershed processes. This study explored watershed and hydrological characteristics (land uses, precipitation, human and animal population, point sources, areal hydraulic load and drainage density, etc.) as the probable sources and delivery mechanisms of waterborne pathogens and their indicator (Escherichia coli [E. coli]) in the Guadalupe and San Antonio River basins. The effect of using various statistical indices for model selection on the final model’s ability to explain the various E. coli sources and transport processes was also analyzed.     

Exploration of the Effect of Chitosan and Crosslinking Agent Concentration on the Properties of Dual Responsive Chitosan-g-Poly (N-Isopropylacrylamide) Co-polymeric Particles

The objective of the present study was to synthesize and evaluate the effect of change in concentration of chitosan (CS) and N,N-methylenebisacrylamide (MBA)- a cross linking agent, on various properties such as lower critical solution temperature (LCST), zeta potential, particle size and poly dispersity index (PDI) of the synthesized co-polymer. Nine different formulations of chitosan-g-poly (N-isopropylacrylamide) (CS-g-PNIPAAm) co-polymer with varying CS and MBA concentrations were synthesized by a surfactant free dispersion copolymerization method. The synthesized co-polymer was further characterized and confirmed for its structure, morphology, particle size, zeta-potential, thermo and pH responsive properties, in-vitro cyto-compatability and stability studies using various analytical tools. The data confirms the successful synthesis of co-polymer. The increase in the concentrations of CS and MBA during the polymerization of co-polymer, resulted in proportional increase of LCST and zeta potential with decrease in particle size of co-polymeric nanoparticles. pH responsive studies showed that as the pH of the medium increases particle size and zeta potential decreases with increase in LCST of co-polymeric nanoparticles. From the results, it can be inferred that the synthesized co-polymeric nanoparticles exerted thermo and pH responsive properties with biocompatibility. By varying the CS and MBA concentrations in the co-polymer, desired LCST, particle size and zeta potential for co-polymeric nanoparticles can be obtained and thus the synthesized co-polymer may have great potential to be used as a drug carrier (nanoform) with both thermo and pH responsiveness.     

Utilization of fly ash in adsorption of heavy metals from wastewater

The aim of this study was to assess the toxicity reduction of wastewaster after treatment with fly ash. Fly ash is a waste material which is formed as a result of coal burning in power plants, but has the potential to adsorb heavy metal ions. The present study examined the adsorption capacity of fly ash to adsorb Pb²⁺, Cu²⁺, and Zn²⁺ from waste water under different conditions of contact time, pH, and temperature. Uptake of metal ions by fly ash generally rose with increasing pH. At lower temperatures the uptake of heavy metal adsorption were enhanced. Significant reduction in Pb²⁺ (79%), Cu²⁺ (53%), and Zn²⁺ (80%) content was found after treatment with fly ash of waste water treatment. Using the microtox test toxicity of the effluent was reduced by 75% due to removal of Pb²⁺ ion by the fly ash. Data indicated that fly ash generated by power plants may be used beneficially to remove metals from waste water.     

Ecofriendly approach of urban solid waste management: a case study of Jalgaon city, Maharashtra

In India, the traditional methods are used for urban solid waste management. These practices are associated with degradation of the urban environment Hence, an environmentally sound garbage management system is required for the urban waste management. The concept of waste minimization needs to be adopted in such systems. It is possible to implement certain corrective measures at collection, storage, transport and disposal of urban solid waste to minimize the adverse impacts on the environment The present investigations are emphasized on generation, characterzation and ecofriendly disposal of solid waste generated in Jalgaon city, Maharashtra. In the present study the waste generation at source was studied in the various income groups of the city. The per capita waste generation was studied by sampling the waste directly from the source of generation. The study reveals that the waste generation is large in the high-income group followed by middle and low-income group public. Further the physicochemical characterization of the waste was also studied. The data generated will help to develop environmentally sound and economically feasible solid waste management system for Ihe city.     

Synthesis,structural characterization and antimicrobial activity of nickel(II) tetrathiocyanato dicuperate(I) complexes with some acyl hydrazones

Heterobimetallic complexes of the type Ni[Cu(SCN)₂]₂ · L (where L = acetophenone benzoylhydrazone, acetophenone isonicotinoyl hydrazone, acetophenone salicyloylhydrazone (ash), acetophenone anthraniloylhydrazone, p-hydroxy acetophenone benzoylhydrazone, p-hydroxy acetophenone isonicotinoyl hydrazone p-hydroxy acetophenone salicyloylhydrazone (phash), p-hydroxy acetophenone anthraniloyl hydrazone), were synthesized and characterized. The complexes are polymeric, insoluble in common organic solvents and are nonelectrolytes. Magnetic moments and electronic spectral studies suggest a spin-free octahedral geometry for the complexes. IR spectra show the bidentate nature of all the ligands bonding through >C=O and >C=N–groups. The SCN group acts as a bridge between two metal centers. X-ray powder diffraction parameters for Ni[Cu(SCN)₂]₂ · ash and Ni[Cu(SCN)₂]₂ · phash correspond to orthorhombic and tetrahedral crystal lattices, respectively, for these complexes. The complexes show a significant antifungal activity against Rizoctonia, Stemphylium and Aspergillus sp. and antibacterial activity against Clostridium and Pseudomonas sp. The metal complexes are more active than the ligands.     

The Bhopal gas tragedy—A perspective

We, the then Mayor and Chief of Police of Bhopal, were the two people on whom the responsibility of handling the world's worst industrial disaster fell unceremoniously on the cold night of December 2–3, 1984 when 41 tons of MIC gas was released from the Union Carbide plant in Bhopal. With the company initially in denial mode about the release and then calling it a ‘tear-gas’ type and providing no information on antidote, and with the limited means of evacuation, handling of medical emergency affecting hundreds of thousand, identification and disposal of the thousands of dead, it was probably the most challenging task faced by a duo in peace time. The local people, the medical community, the railway staff, the NGOs, were all very helpful. We narrate the happening and the handling of the consequences and the spot decisions that had to be made with the hope that no such accident happens anywhere.     

Comparative Toxicological Evaluation of Untreated and Treated Tannery Effluent with Nostoc Muscorum L. (Algal Assay) and Microtox Bioassay

The relative sensitivity of tannery effluent before and after treatment was compared by employing Nostoc muscorum and microtox assay in laboratory. The effect on chlorophyll, protein and biomass content of Nostoc muscorum was studied with the luminescent property inhibition of Photobacterium phosphorium and compared with algal bioassay. The results of microtox assay after 5, 15 and 30 min of exposure were compared with data obtained from algal bioassay. It was observed that the luminescent property of Photobacterium phosphorium in microtox assay as well as the chlorophyll content of Nostoc muscorum in algal assay were the most sensitive parameters in toxicity evaluation of tannery effluent. The microtox assay produced notably comparable EC50 values with that of algal bioassay. The microtox assay of toxicity showed that EC50 (%) in 30 min was 3.19 and 63.49 for untreated and treated tannery effluent, respectively while in algal bioassay the EC50 for chlorophyll was in between 0-2.5% and 100%, respectively, in untreated and treated effluent. More than 60% reduction of toxicity was noted in treated tannery effluent in both test system.     

Photoelectrocatalytic systems for simultaneous energy recovery and wastewater treatment: a review

Environmental Chemistry Letters - The rising energy conflicts and environmental pollution are calling for the rapid development of advanced techniques such as photoelectrocatalysis to...