Mass balance modeling to elucidate historical and continuing sources of dioxin into an urban estuary

Polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins) are typically found in sediment, water and tissue as in the case of the Houston Ship Channel and Upper Galveston Bay (HSC–UGB) in Texas studied in this research. While hydrodynamic and fate and transport models are important to understand dioxin distribution in the various media, it is difficult to assimilate modeling results into a decision framework without appropriate tools that can aid in the interpretation of the simulated data. This paper presents the development of a mass-balance modeling tool linked to RMA2 and WASP models of the HSC–UGB system for 2002–2005. The mass-balance tool was used to aggregate modeling results spatially and temporally and estimate the relative contribution of sediments to dioxin loading into the Channel in comparison to runoff, deposition, and permitted effluent discharges. The total sediment associated-dioxin load into the system calculated using the mass balance model was 2.34 × 10⁷ ng d⁻¹ (almost 86% of the toxic equivalent load), and the re-deposited load to the sediment from the water column was 1.48 × 10⁷ ng-TEQ d⁻¹, such that 8.6 × 10⁶ ng-TEQ d⁻¹ or approximately 69% of the average daily dioxin flux is transported between model segments as sediment. The external loads to the system contribute approximately 3.83 × 10⁶ ng-TEQ d⁻¹, a value that is an order of magnitude smaller when compared to the contribution from sediment. These findings point to the need for sediment remediation strategies that take into account the spatial locations within the system that serve as sediment sources to dioxin in the water column.     

Safety evaluation of flubendiamide and its metabolites on cabbage and persistence in soil in different agroclimatic zones of India

Supervised field trials following good agricultural practices were conducted at the research farms of four agricultural universities located at four different agroclimatic zones of India to evaluate the persistence and dissipation of flubendiamide and its metabolite, des-iodo flubendiamide, on cabbage. Two spray applications of flubendiamide 480 SC of standard and double dose at the rate of 24 and 48 g a.i. ha^?1 were given to the crop at a 15-day interval, and the residues of flubendiamide 2 h after spray were found in the range of 0.107–0.33 and 0.20–0.49 mg kg^?1 at respective doses. Residue of des-iodo flubendiamide was not detected in any cabbage sample during study period. No residues were found in the soil samples collected from all treated fields after 15 days of application. On the basis of data generated under All India Network Project on Pesticide Residues, a preharvest interval (PHI) of 10 days has been recommended, and the flubendiamide 480 SC has been registered for its use on cabbage by Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of flubendiamide on cabbage has been fixed by the Ministry of Health and Family Welfare, Government of India, under Food Safety Standard Authority of India as 0.05 μg/g after its risk assessment.     

Unique phenotypes in the sperm of the earthworm Eudrilus eugeniae for assessing radiation hazards

The earthworm, Eudrilus eugeniae is a segmented worm. It has two pairs of testes whose cells are highly proliferative. It was found that the earthworm, which is irradiated with X-ray, shows the following phenotypic changes in its sperm: fragmented acrosome in the head, break in the tail, and the appearance of zigzag sperm tail. Sperm morphology can be used as a tool to study radiation hazards in local areas. These three phenotypes were not observed in the sperm of worms exposed to different concentration of toxic chemicals such as sodium arsenate, lead acetate, and mercuric chloride. In contrast, exposure of worms to ethidium bromide caused fragmented acrosome in the head of their sperm cells.     

Evaluation of developmental toxicity and apoptotic induction of the aqueous extract of Millettia pachycarpa using zebrafish as model organism

Extensive and indiscriminate use of synthetic compounds and natural compounds obtained from plant sources have resulted in serious threats to the aquatic ecosystem and human health. Aqueous extract of the root of the plant, Milletia pachycarpa Benth, is currently used for killing fish in the state of Manipur, India. Moreover, this plant is also used as traditional medicine in this region. Although it is widely used in traditional medicine, there is limited information available regarding the adverse effects and mechanism underlying its toxicity. This study examined the effects of exposure to aqueous extract of M. pachycarpa (AEMP) on early embryonic development of zebrafish embryos and mechanisms underlying toxicity. Zebrafish embryos treated with different concentrations of the AEMP produced embryonic lethality and developmental defects. The 96-hr-LC₅₀ of AEMP was found to be 4.276 µg/mL. Further, multiple developmental abnormalities such as pericardial edema, yolk sac edema, spinal curvature, swim bladder deflation, decreased heart rate, and delayed hatching were also observed in a dose-dependent manner. Zebrafish embryo showing moderate-to-severe developmental defects following AEMP exposure cannot swim properly. Further, this study examined oxidative stress and apoptosis in embryos exposed to AEMP. Enhanced production of ROS and apoptosis was found in brain, trunk, and tail of zebrafish embryos treated with AEMP. Data suggest that oxidative stress and apoptosis are associated with AEMP-induced embryonic lethality and developmental toxicity in zebrafish embryos.     

A study of Malaiyur village ecosystem of Madurai district, Tamil Nadu (India)

The interaction between man and environment in Malaiyur, a hilly village of Madurai District (Tamil Nadu) was studied during the year 1998. The village is sustained on agriculture labour and hence occupies the lowest hierarchy with traditional occupation and the people may be categorised as 'ecosystem people'. The study suggests that the people has to be changed as 'Biosphere people' to protect the environmental degradation due to human activities.     

Algal biofuel production and mitigation potential in India

Energy and energy services are the backbone of growth and development in India and is increasingly dependent upon the use of fossil based fuels that lead to greenhouse gases (GHG) emissions and related concerns. Algal biofuels are being evolved as carbon (C)-neutral alternative biofuels. Algae are photosynthetic microorganisms that convert sunlight, water and carbon dioxide (CO₂) to various sugars and lipids Tri-Acyl-Glycols (TAG) and show promise as an alternative, renewable and green fuel source for India. Compared to land based oilseed crops algae have potentially higher yields (5?C12 g/m²/d) and can use locations and water resources not suited for agriculture. Within India, there is little additional land area for algal cultivation and therefore needs to be carried out in places that are already used for agriculture, e.g. flooded paddy lands (20 Mha) with village level technologies and on saline wastelands (3 Mha). Cultivating algae under such conditions requires novel multi-tier, multi-cyclic approaches of sharing land area without causing threats to food and water security as well as demand for additional fertilizer resources by adopting multi-tier cropping (algae-paddy) in decentralized open pond systems. A large part of the algal biofuel production is possible in flooded paddy crop land before the crop reaches dense canopies, in wastewaters (40 billion litres per day), in salt affected lands and in nutrient/diversity impoverished shallow coastline fishery. Mitigation will be achieved through avoidance of GHG, C-capture options and substitution of fossil fuels. Estimates made in this paper suggest that nearly half of the current transportation petro-fuels could be produced at such locations without disruption of food security, water security or overall sustainability. This shift can also provide significant mitigation avenues. The major adaptation needs are related to socio-technical acceptance for reuse of various wastelands, wastewaters and waste-derived energy and by-products through policy and attitude change efforts.     

Facile synthesis of graphitic carbon-nitride supported antimony-doped tin oxide nanocomposite and its application for the adsorption of volatile organic compounds

Antimony-doped tin oxide(ATO) nanoparticles with an average size of ～ 6 nm were prepared by co-precipitation and subsequent heat treatment. Graphitic carbon nitride(g-CN)/ATO hybrid nanocomposite was designed by the combination of thermally synthesized g-CN and ATO nanoparticles by ultrasonication. The materials were characterized using N2 adsorption/desorption(BET), X-ray diffraction(XRD), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), transmission electron microscopy(TEM) and Fourier transform infrared spectroscopy(FTIR). A mixture of five volatile organic compounds(VOCs, chloroform, benzene, toluene, xylene and styrene) was used to compare the adsorption capacity of the samples. The adsorption capacity of ATO nanoparticles was improved by the addition of g-CN. Experimental data showed that, among the five VOCs,chloroform was the least adsorbed, regardless of the samples. The g-CN/ATO showed nearly three times greater adsorption capacity for the VOC mixture than pure ATO. The unchanged efficiency of VOC adsorption during cyclic use demonstrated the completely reversible adsorption and desorption behavior of the nanocomposite at room conditions. This economically and environmentally friendly material can be a practical solution for outdoor and indoor VOC removal.     

Physicochemical characteristics of paper industry effluents��a case study of South India Paper Mill (SIPM)

Pulp and paper mills generate varieties of pollutants depending upon type of the pulping process being used. This paper presents the characteristics of wastewater from South India Paper Mill, Karnataka, India which is using recycled waste paper as a raw material. The raw wastewater consists of 80?C90 mg L^???1 suspended solid and 1,010?C1,015 mg L^???1 dissolved solid. However, pH varied from 5.5?C6.8. The biochemical oxygen demand and chemical oxygen demand ranged from 200?C210 and 1,120?C1,160 mg L^???1, respectively. Aerobic treatment of raw effluent attribute to significant reduction in suspended solid (range between 25 to 30 mg L^???1) and total dissolved solid (range between 360 to 390 mg L^???1). However, pH, temperature, and electrical conductivity were found superior after treatment. Copper, cadmium, iron, lead, nickel, and zinc were found in less quantity in raw effluent and were almost completely removed after treatment. The dendrogram of the effluent quality parameters clearly indicate that South India Paper Mill does not meet Minimal National Standard set by central Pollution Control Board to discharge in agricultural field.     

Biocatalytic polymeric membranes to decrease biofilm fouling and remove organic contaminants in wastewater: a review

The presence of recalcitrant contaminants in wastewater is major challenge to decrease pollution and associated health issues. As a consequence, membrane technologies have recently attracted industrial attention, yet a major setback of membrane employment is membrane fouling which leads to frequent discarding of membrane modules. More than 45% of all membrane fouling cases are caused by biofilms that are resistant to antimicrobial agents. Here we review polymeric membranes with antifouling properties, with focus on surface properties, fabrication, characterization, biocatalysis using enzymes and application towards the removal of dyes, phenol, pesticides and fertilizers. Nano-engineered fabrication of polymeric membranes allow to decrease fouling by 80–90%. Immobilized oxidoreductases in polymeric membranes allow 65–98% removal contaminants in wastewater.

     

Assessment of coastal dune characteristics using georadar imaging and sedimentological analysis: Odisha and Visakhapatnam, India

The East coast of India is subject to continuous changes by high energy events. We sought to assess the depositional conditions along the coast from the geophysical and sedimentological character of the dune sands of the Gopalpur and Paradeep coast of Odisha, and the Sagarnagar coast of North Visakhapatnam. Quartz layers of the heavy mineral-rich zone collected at a depth of ~2 m from the landward foot of the dunes in the Visakhapatnam and Odisha coast, gave the OSL age estimates as 1,050?±?50 and 260?±?10 years respectively, revealing that the age of the dunes in Visakhapatnam are older than those on the Odisha coast. Episodic high energy events have affected the coast. Evidence from ground penetrating radar data consists of three stratigraphic units. The upper unit consists of vague reflections, parallel to the ground in continuous manner, most probably formed by wind action. On the other hand, the middle layer shows high amplitude reflections of heavy mineral-rich massive layers, possibly the result of tsunami activity. The lower massive layer parallel to the ground surface shows a low reflection pattern. The GPR studies showed that the thickness of the heavy mineral layers is greater on the landward foot of the dune as compared to that on the seaward side. According to the grain size analysis, the dune is composed of both wind generated and tsunamigenic sediments. The scanning electron microscope studies revealed that the heavy minerals present in the dunes are mainly sillimanite, ilmenite, garnet, pyroxene, rutile, sphene, biotite, hornblende, zircon, monazite and magnetite. The study demonstrates the origin of sand dunes in different ages along the East Coast of India by the effect of various natural phenomena.