Evaluation of the STP model: comparison of modelled and experimental results for ten polycyclic aromatic hydrocarbons (PAHs)

Screening level risk assessment models are used by many countries to assess the treatability of organic chemicals during the sewage treatment process, especially those that are new to commerce. The performance of one such model, the sewage treatment plant model, is evaluated in the current study by comparing model predictions with actual measurement data collected at various stages of a typical full-scale activated sludge type sewage treatment plant. A suite of ten polycyclic aromatic hydrocarbons (PAHs) with widely varying physico–chemical properties were monitored for the comparison. Model predicted removal efficiencies were in very good agreement with those measured for all ten PAHs. Observed chemical concentrations and their trends at various stages of the sewage treatment process were also well simulated by the model. Results also suggest that a reasonable first approximation estimate of a range for the biodegradation half-life needed for the model may be obtained by dividing reported aqueous biodegradation half-life by scaling factors of 50 and 150.     

Synthesis of highly fluorescent and water soluble graphene quantum dots for detection of heavy metal ions in aqueous media

Environmental Science and Pollution Research - Fluorescent graphene quantum dots (GQDs) are nanomaterials which possess unique properties that show great potential in different applications. In...     

Recent advances based on the synergetic effect of adsorption for removal of dyes from waste water using photocatalytic process

The problem of textile dye pollution has been addressed by various methods,mainly physical,chemical,biological,and acoustical.These methods mainly separate and/or remove the dye present in water.Recently,advanced oxidation processes(AOP)have been focused for removal of dye from waste water due to their advantages such as ecofriendly,economic and capable to degrade many dyes or organic pollutant present in water.Photocatalysis is one of the advance oxidation processes,mainly carried out under irradiation of light and suitable photocatalytic materials.The photocatalytic activity of the photocatalytic materials mainly depends on the band gap,surface area,and generation of electron–hole pair for degradation dyes present in water.It has been observed that the surface area plays a major role in photocatalytic degradation of dyes,by providing higher surface area,which leads to the higher adsorption of dye molecule on the surface of photocatalyst and enhances the photocatalytic activity.This present review discusses the synergic effect of adsorption of dyes on the photocatalytic efficiency of various nanostructured high surface area photocatalysts.In addition,it also provides the properties of the water polluting dyes,their mechanism and various photocatalytic materials;and their morphology used for the dye degradation under irradiation of light along with the future prospects of highly adsorptive photocatalytic material and their application in photocatalytic removal of dye from waste water.     

Reactive solute transport in macroscopically homogeneous porous media: analytical solutions for the temporal moments

In this work, we investigate one-dimensional solute transport affected by rate-limited sorption, first-order mass transfer, and first-order transformation. Analytical expressions are obtained for the temporal moments of the solute in the solution phase. The effect of various rate coefficients on the temporal moments is examined. It was found that, in the presence of transformation reactions, the mean arrival time, and the spread and skewness of the breakthrough curves, are not monotonic functions of the rate coefficients. These solutions will be useful as a preliminary analysis tool for ascertaining the relative importance of various processes under given conditions. They may also be used to analyze the accuracy of various numerical techniques used for simulation of reactive transport.     

Analysis of Long-term Energy and Carbon Emission Scenarios for India

In the coming years India faces greatchallenges in energy and environment. Thepath of development chosen by India, uponwhich lies the future growth of energy andemission trajectories, would be greatlyinfluenced by technological developmentsboth within and outside the country,economic cooperation between countries, andglobal cooperation in limiting greenhousegas emissions. This paper discusses theintegrated modeling system used fordeveloping and analyzing the long-termtrajectories and presents results for thescenarios developed. In the context ofongoing market reforms two scenarios –accelerated and decelerated reforms – aredeveloped depicting fast and slow progressin energy sector reforms compared toexpectations in the baseline scenario.Accelerated market reforms would spurimprovements in technological efficiencies.Reforms would lower investment risks inIndia, thereby stimulating increased levelsof foreign direct investment. On the otherhand in decelerated reform scenarioeconomic growth is lower than that in thebase case, there is low access to capital,and technological improvements lag behindthose in the base case. In another scenariowe assume specific policy interventions forpenetration of renewable technologies overthe baseline scenario, for promotion andaccelerated deployment of renewable energytechnologies over and above the baselineassumptions. A scenario with carbon(c) constraints has also been developed and theresults discussed.     

Antioxidant role of ascorbic acid on oxidative stress induced by sub-acute exposure of lead and cypermethrin in erythrocytes of Wistar rats

This study aimed to evaluate the reparative potential of ascorbic acid (AA, 100 mg/kg, orally for 28 days) in sub-acute lead (Pb, 100 ppm in drinking water for 28 days) or cypermethrin (CPM, 50 mg/kg, orally in vehicle for 28 days) poisoning alone and as binary mixture on the basis of oxidative stress parameters in erythrocytes of Wistar rats. Both Pb and CPM produced significant increase in lipid peroxidation along with elevated glutathione-S-transferase and catalase activity individually but not as a binary mixture. Glutathione peroxidase activity was significantly increased but glutathione levels were significantly reduced irrespective of single or co-exposure while the activity of superoxide dismutase and erythrocytic protein content were not significantly affected. Co-exposure led to a comparatively lower level of oxidative stress than that induced by Pb or CPM alone indicating an antagonistic toxicodynamic profile in rat erythrocytes. Co-administration of AA along with Pb and/or CPM significantly restored the oxidative stress parameters to normal values. Overall results indicated that co-exposure induces a lower level of oxidative stress and AA ameliorates Pb- and/or CPM-induced oxidative damage in rat erythrocytes.     

Integrated approach of assessing sedimentary characteristics of onshore sand deposits on the Velankanni coast, Tamil Nadu, India: sheds light on extreme wave event signatures

The refraction of the 2004 Indian Ocean tsunami waves caused drastic devastation along East coast of India, mainly in the area of investigation. Here, we appraise and integrate the sedimentary characteristics and microfossil studies of the area. The gigantic tsunami waves caused the landward fining of sediments that were carried as suspended load. Tsunami sediments have distinctive characteristics, like fine-to-medium grained sand, moderately to poorly sorted sediments which indicating sudden winnowing followed by tranquil flood. Positively skewed grain size distribution indicating unidirectional transport, and mesokurtic to platykurtic character implying poorly sorted single source origin. The species of benthonic foraminifers and ostracods reside in marine environment indicating shallow water origin of sediments. The onshore deposits are vertically divided into three depositional units interpreted from Ground Penetrating Radar (GPR) signatures—Unit 1 is a relatively continuous parallel layer indicative of calm environment; Unit 2 has paleochannels and burial scarps, seen as oblique reflections that might be indicative of an intense erosional environment; Unit 3 is interpreted as 2004 tsunami layer, has three subunits. Each main units have been separated by Heavy Mineral Concentrated (HMC) layers, deposited by continuous wave action (~?20 cm) and by the tsunami (>?30 cm) activity, evidenced by low magnetic susceptibility values at the bottom compared to the top of the HMC layers. GPR has been effectively utilized in this paper as subsurface imaging tool for the interpretation and reconstruction of stratigraphy, and also helped to unearth the erosional and depositional environments.     

Opposable spines facilitate fine and gross object manipulation in fire ants

Ants inhabit diverse terrestrial biomes from the Sahara Desert to the Arctic tundra. One factor contributing to the ants’ successful colonization of diverse geographical regions is their ability to manipulate objects when excavating nests, capturing, transporting and rendering prey or grooming, feeding and transporting helpless brood. This paper is the first to report the form and function of opposable spines on the foretarsi of queens and workers used during fine motor and gross motor object manipulation in the fire ant, Solenopsis invicta. In conjunction with their mandibles, queens and workers used their foretarsi to grasp and rotate eggs, push or pull thread-like objects out of their way or push excavated soil pellets behind them for disposal by other workers. Opposable spines were found on the foretarsi of workers from seven of eight other ant species suggesting that they might be a common feature in the Formicidae.     

Heavy metal (Cu, Zn, Cd and Pb) contamination of vegetables in urban India: a case study in Varanasi

The contributions of heavy metals in selected vegetables through atmospheric deposition were quantified in an urban area of India. Deposition rate of Zn was recorded maximum followed by Cu, Cd and Pb. The concentrations of Zn and Cu were highest in Brassica oleracea, Cd in Abelmoschus esculentus and B. oleracea, while Pb was highest in Beta vulgaris. Heavy metal pollution index showed that B. oleracea was maximally contaminated with heavy metals followed by A. esculentus and then B. vulgaris. The results of washing showed that atmospheric deposition has contributed to the increased levels of heavy metals in vegetables. Both Cu and Cd posed health risk to local population via test vegetables consumption, whereas Pb posed the same only through B. oleracea. The study concludes that atmospheric depositions can elevate the levels of heavy metals in vegetables during marketing having potential health hazards to consumers.     

Correction to: Advancements in solar technologies for sustainable development of agricultural sector in India: a comprehensive review on challenges and opportunities

Environmental Science and Pollution Research -