Biodegradation of C.I. Acid Red 1 by indigenous bacteria <Emphasis Type="Italic">Stenotrophomonas</Emphasis> sp. BHUSSp X2 isolated from dye contaminated soil

A significant proportion of xenobiotic recalcitrant azo dyes are being released in environment during carpet dyeing. The bacterial strain Stenotrophomonas sp. BHUSSp X2 was isolated from dye contaminated soil of carpet industry, Bhadohi, India. The isolated bacterial strain was identified morphologically, biochemically, and on the basis of 16S rRNA gene sequence. The isolate decolorized 97 % of C.I. Acid Red 1 (Acid RED G) at the concentration of 200 mg/l within 6 h under optimum static conditions (temperature ?35 °C, pH 8, and initial cell concentration 7?×?10⁷ cell/ml). Drastic reduction in dye degradation rate was observed beyond initial dye concentration from 500 mg/l (90 %), and it reaches to 25 % at 1000 mg/l under same set of conditions. The analysis related to decolorization and degradation was done using UV-Vis spectrophotometer, HPLC, and FTIR, whereas the GC-MS technique was utilized for the identification of degradation products. Phytotoxicity analysis revealed that degradation products are less toxic as compared to the original dye.     

Metal concentrations in water, sediment, and fish from sewage-fed aquaculture ponds of Kolkata, India

The concentrations of lead, cadmium, chromium, copper, and zinc were investigated in the sewage-fed pond water, sediment, and the various organs of Labeo rohita, Catla catla, Cirrhinus mrigala, Oreochromis mossambicus, and Cyprinus carpio cultured in sewage-fed ponds, Kolkata, India. Among the metals, cadmium, lead, and zinc were detected in water and, except lead, were below the water quality guideline levels for the protection of freshwater aquatic life proposed by CEQG (Canadian Environmental Quality Guidelines) and AENV (Alberta Environment). Therefore, lead could pose danger to aquatic organisms. All the five metals were detected in the sediment and, except cadmium and lead, were below the sediment quality guideline levels for aquatic life proposed by EPA (Environmental Protection Agency). Therefore, these two metals could be toxic to aquatic organisms. Significant (P > 0.05) differences were observed among the five fish species for all these metals accumulation. Also, significant (P > 0.05) differences were noticed among these metals accumulation in fish organs. Cadmium showed the least bioaccumulation, while zinc showed the highest bioaccumulation in all the fish species. Though the metal concentration in the different fish tissues was variable, the highest concentration was found in kidney and the lowest in the muscle. Concentrations of these metals in the muscle tissue of all the fish species were well below the consumption safety tolerance in fish set by WHO/FAO, and thus, so far as these metals are concerned, these sewage-fed cultured fishes are safe and suitable for human consumption.     

Experimental investigation of turning AISI 1045 steel using cryogenic carbon dioxide as the cutting fluid

The intensive temperatures in high speed machining not only limit the tool life but also impair the machined surface by inducing tensile residual stresses, microcracks and thermal damage. This problem can be handled largely by reducing the cutting temperature. When the conventional coolant is applied to the cutting zone, it fails to remove the extent of the heat effectively. Hence, a cryogenic coolant is highly recommended for this purpose. In this paper, an attempt has been made to use cryogenic carbon dioxide (CO₂) as the cutting fluid. Experimental investigations are carried out by turning AISI 1045 steel in which the efficiency of cryogenic CO₂ is compared to that of dry and wet machining with respect to cutting temperature, cutting forces, chip disposal and surface roughness. The experimental results show that the application of cryogenic CO₂ as the cutting fluid is an efficient coolant for the turning operation as it reduced the cutting temperature by 5%–22% when compared with conventional machining.It is also observed that the surface finish is improved to an appreciable amount in the finished work piece on the application of cryogenic CO₂. The surface finish is improved by 5%–25% in the cryogenic condition compared with wet machining.     

Study of the Relationship of Distant SO2 Emissions to Dallas-Fort Worth Winter Haze

ABSTRACT

A study was conducted to estimate the changes in wintertime visual air quality in Dallas-Fort Worth (DFW) that might occur due to proposed reductions in SO₂ emissions at two steam electric generating plants in eastern Texas, each over 100 km from the city. To provide information for designing subsequent investigations, the haze was characterized broadly during the first year of the study. Meteorological data acquired then demonstrated that, during haze episodes, emissions from only one of the two plants were likely to be transported directly to DFW. Therefore, the second year of the study was centered on just one of the power plants. Air quality was then characterized within the urban area and at rural locations that would be upwind and downwind of the plant during transport to DFW. An instrumented aircraft measured plume dispersion and the air surrounding the plume on selected days. A mathematical model was used to predict the change that would occur in airborne particulate matter concentrations in DFW if SO₂ emissions were reduced to reflect the proposed limitations. The contribution of particles in the atmosphere to light extinction was estimated, and simulated photographs were produced to illustrate the visibility changes. The study concluded that the proposed emission reductions would, at most, subtly change perceived wintertime visibility.     

Modeling of Potential Power Plant Plume Impacts on Dallas-Fort Worth Visibility

ABSTRACT

During wintertime, haze episodes occur in the Dallas-Ft. Worth (DFW) urban area. Such episodes are characterized by substantial light scattering by particles and relatively low absorption, leading to so-called “white haze.” The objective of this work was to assess whether reductions in the emissions of SO₂ from specific coal-fired power plants located over 100 km from DFW could lead to a discernible change in the DFW white haze. To that end, the transport, dispersion, deposition, and chemistry of the plume of a major power plant were simulated using a reactive plume model (ROME). The realism of the plume model simulations was tested by comparing model calculations of plume concentrations with aircraft data of SF₆ tracer concentrations and ozone concentrations. A second-order closure dispersion algorithm was shown to perform better than a first-order closure algorithm and the empirical Pasquill-Gifford-Turner algorithm. For plume impact assessment, three actual scenarios were simulated, two with clear-sky conditions and one with the presence of fog prior to the haze. The largest amount of sulfate formation was obtained for the fog episode. Therefore, a hypothetical scenario was constructed using the meteorological conditions of the fog episode with input data values adjusted to be more conducive to sulfate formation. The results of the simulations suggest that reductions in the power plant emissions lead to less than proportional reductions in sulfate concentrations in DFW for the fog scenario. Calculations of the associated effects on light scattering using Mie theory suggest that reduction in total (plume + ambient) light extinction of less than 13% would be obtained with a 44% reduction in emissions of SO₂ from the modeled power plant.     

Enhanced visual detection of pesticides using gold nanoparticles

The presence of parts per billion (ppb) levels of chlorpyrifos (O,O-Diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) and malathion (S-1,2-bis(ethoxycarbonyl) ethyl O,O-dimethyl phosphorodithioate), two common pesticides found in the surface waters of developing countries, have been visually detected using gold nanoparticles. Visual detection of the presence of pesticide is possible when the color change occurring by the adsorption of pesticides on gold nanoparticles is enhanced by sodium sulfate. The method presented here is simple and there is no need of sample preparation or preconcentration. The response occurs within seconds and the color change is very clear. The detection is possible if chlorpyrifos and malathion are present up to a concentration of 20 and 100 ppb, respectively. The method shows great potential for on-site pesticide monitoring. The method is also applicable as a qualitative technique for the performance evaluation of various household water filters, which claim pesticide removal.     

Channel Characteristics and Planform Dynamics in the Indian Terai, Sharda River

The Sharda River creates and maintains the ecologically diverse remnant patches of rare Terai ecosystem in northern India. This study used repeat satellite imagery and geographic information system analysis to assess the planform dynamics along a 60 km length of the Sharda River between 1977 and 2001 to understand the altered dynamics and its plausible causes in this data-poor region. Analyses revealed that the Sharda River has undergone significant change corresponding to enhanced instability in terms of increased number of neck cut-offs and consistent occurrence of avulsions in subsequent shorter assessment periods. An increased channel area (8 %), decreased sinuosity (15 %), increased braiding intensity, and abrupt migrations were also documented. The river has migrated toward the east with its west bankline being more unstable. The maximum shifts were 2.85 km in 13 years (1977–1990), 2.33 km in next 9 years (1990–1999), and a substantial shift of 2.39 km in just 2 years (1999–2001). The altered dynamics is making the future of critical wildlife habitats in Kishanpur Wildlife Sanctuary and North Kheri Forest Division precarious and causing significant economic damage. Extensive deforestation and expansion of agriculture since the 1950s in the catchment area are presumed to have severely impacted the equilibrium of the river, which urgently needs a management plan including wildlife habitat conservation, control, and risk reduction. The present study provides a strong foundation for understanding channel changes in the Sharda River and the finding can serve as a valuable information base for effective management planning and ecological restoration.     

Mutagenicity evaluation of industrial sludge from common effluent treatment plant

Sludge from common effluent treatment plant (CETP) receiving effluents from textile industries at Mandia Road, Pali, was analyzed to assess the level of mutagenicity. Mutagenicity assay using Salmonella typhimurium tester strains TA 98 and TA 100 gave positive results, thus suggesting presence of genotoxic contaminants in the samples investigated. Further, mutagenic activity of chemical sludge was found to be lesser than that of biological sludge. This result is very surprising and unexpected as it is indicating that some mutagenic compounds are either being formed or certain promutagenic compounds are being converted into stable mutagenic metabolites during the biological treatment of the wastewater effluents. There have been no previous reports giving similar or contrary results. Most of the previous studies have reported effects of single combined sludge.     

The OEIS complex: two case reports that illustrate the spectrum of abnormalities and a review of the literature

We present two cases of OEIS (omphalocele, exstrophy, imperforate anus, spinal defects) complex -MIM 258040 and a review of the literature. Case 1 was a 14-year-old girl who presented at 30 weeks' gestation. An ultrasound examination showed an omphalocele and spina bifida; the bladder was not visualised. She went into spontaneous labour two weeks later and the baby died shortly after birth. A full post-mortem examination was refused, but the mother did agree to an external examination, skin biopsy for fibroblast culture, X rays and MR imaging. The MR imaging showed a pelvic kidney, a large omphalocele containing the other kidney, liver, bowel and a fluid filled structure thought to represent an exstrophy of the bladder (EB). Case 2 was a 30-year-old woman who had an ultrasound examination at 20 weeks' gestation; this showed an omphalocele, but the bladder was not visualised. The pregnancy was subsequently terminated and a post-mortem examination showed a low set umbilical cord associated with a small omphalocele; there was an imperforate anus; a blind ending rectum terminated in the omphalocele. We conclude that these two cases illustrate the variability of the OEIS complex. Copyright © 2006 John Wiley & Sons, Ltd.     

Influence of home characteristics on airborne and dustborne endotoxin and β-D-glucan

The aim of this study was to assess the associations between airborne and dustborne microbial contaminants (endotoxin and β-D-glucan) and estimate the effects of home characteristics on exposure levels of these microbial contaminants. Endotoxin and β-D-glucan concentrations in airborne inhalable particles, airborne PM1 (<1 μm) and vacuumed dust from 184 residential homes were determined using specific Limulus amebocyte assays. Home characteristics were recorded by visual inspection and questionnaires. Linear regression and correlation analyses were performed. Inhalable endotoxin correlated with dust endotoxin (r = 0.34, p < 0.001) and PM1 endotoxin (r = 0.33, p < 0.001). Inhalable β-D-glucan correlated with dust β-D-glucan (r = 0.18, p < 0.01), but not with PM1 β-D-glucan. Significant correlation was also found between PM1 and dust concentrations for endotoxin (r = 0.26, p < 0.001), but not for β-D-glucan. Multivariate regression analyses showed only one significant association between airborne contaminants and environmental characteristics: inhalable β-D-glucan was positively associated with relative humidity with an effect size (change in the dependent variable corresponding to a unit increase in the independent variable) of 2.32 and p < 0.05. In contrast, several associations were found between dust concentrations and environmental characteristics. Dust endotoxin was positively associated with temperature (2.87, p < 0.01) and number of inhabitants (2.76, p < 0.01), whereas dust β-D-glucan was inversely associated with the presence of dogs (-2.24, p < 0.05) and carpet (-3.05, p < 0.01) in the home. In conclusion, dustborne contaminants were more strongly affected by home characteristics than airborne contaminants. Furthermore, even though statistically significant, the correlations between airborne and dustborne contaminants were weak. This indicates that airborne concentrations cannot be reliably predicted based on dustborne concentrations.