Metallic components of traffic-induced urban aerosol, their spatial variation, and source apportionment

This study proposes a practical method to estimate elemental composition and distribution in order to attribute source and quantify impacts of aerosol particles at an urban region in Kolkata, India. Twelve-hour total particulates were collected in winter (2005–2006) and analyzed by energy-dispersive X-ray fluorescence technique to determine multi-elemental composition, especially trace metals. The aerosols consist of various elements including K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, and Pb which exhibit significant concentration at various sites (p?<?0.05). The concentration of different metallic elements were found in the order of Zn ?> ?Pb ?> ?Ni ?> ?Cu ?> ?Cr ?>? Co. Statistical multivariate analysis and correlation matrix analyses were performed for factor identification and consequent source apportionment. Contour profiles demonstrate spatial variation of elemental compositions indicating possible source contribution along with meteorological influences. Spatial differences were clearly most significant for Zn, Ni, Pb, and Cu reflecting the importance of anthropogenic inputs, primarily from automobile sources.     

Continuous and filter-based measurements of PM2.5 nitrate and sulfate at the Fresno Supersite

PM(2.5) nitrate [Formula: see text] and sulfate ([Formula: see text]) were measured continuously with R&P8400N and R&P8400S instruments, respectively, and compared with filter-based measurements at the Fresno Supersite from October, 2000 through December, 2005. [Formula: see text] concentrations were higher in winter than summer with a long-term decreasing trend. Correlations between 24-h average continuous and filter-based [Formula: see text] were greater than 0.96 in 4 out of 5 years. Continuous [Formula: see text] was generally lower than filter-based [Formula: see text] although the difference decreased over time, from -52% in 2001 to +13% in 2005. These differences were similar in winter (-23%) and summer (-19%) while the corresponding differences between ambient and instrument temperature were -12 and 0.7 degrees C, respectively. Neither seasonal nor long-term trends in [Formula: see text] can be explained by variations in ambient temperature, the difference between ambient and instrument temperature, or changes in aerosol chemical composition. There were no seasonal or long-term trends in [Formula: see text] concentrations, partially due to low concentrations observed in Fresno. Long-term variability in the performance of R&P8400 [Formula: see text] and [Formula: see text] instruments suggest that collocation with filter measurements is needed for long-term measurements.     

Antimicrobial activity of tissue and associated bacteria from benthic sea anemone Stichodactyla haddoni against microbial pathogens

Associated bacteria from Stichodactyla haddoni are found maximum in tentacle tissues than the body tissue. There are eight associated bacterial species viz., Alcaligenes sp, Corynebacterium sp, Aeromonas sp, Sporosarcina sp, Renibacterium sp, Camobacterium sp1, Camobacterium sp2 and Salinococcus sp were recorded. The culture extracts from the associated bacterial species showed sensitivity against human bacterial and fungalpathogens. However, the hexane tissue extract of sea anemone showed maximum sensitivity (24 mm dia.) against the fish bacterial pathogen Aeromonas hydrophila than the other chosen pathogens. Comparatively the tissue extracts showed promising antimicrobial sensitivity than the cell free extracts of associated bacteria, and hence, the tissue samples from the sea anemone Stichodactyla haddoni is recommended for further exploration of novel antimicrobial drugs than the associated bacteria.     

Growth of Avicennia marina and Ceriops decandra seedlings inoculated with halophilic azotobacters

Inoculation of azotobacter has significant positive effects on the growth characteristics and pigments in mangrove seedlings of Avicennia marina and Ceriops decandra. The bacterial inoculation significantly increased the root dry biomass at the maximum of 75.8% at 30 gl(-1) salinity in Ceriops decandra. But in Avicennia marina, the shoot dry biomass was increased significantly at the maximum of 56.12% at 30 gl(-1) salinity in general, the Azotobacter beijerinkii improved the growth characteristics better in both species of mangroves preferably at higher salinity levels in A. marina and at a range of salinity in C. decandra. The results recommend this forraising vigorous seedlings under nursery conditions.     

The Development of a Model to Examine Source-Receptor Relationships for Visibility on the Colorado Plateau

This paper describes the development and application of the Visibility and Haze in the Western Atmosphere (VISHWA) model to understand the source-receptor relationships that govern chemical species relevant to visibility degradation in the western United States. The model was developed as part of a project referred to as Visibility Assessment for Regional Emission Distributions (VARED), the objective of which is to estimate the contributions of various geographical regions, compounds, and emission

sources to light scattering and absorption by particles on the Colorado Plateau.

The VISHWA model is a modified version of a comprehensive Eulerian model, known as the Acid Deposition and Oxidant Model.1 The modifications were designed to obtain the computational efficiency required to simulate a one-year period at about 1/25th of real time, and at the same time incorporate mechanistic features relevant to realistic modeling of the fate and transport of visibility degrading species. The modifications included use of a condensed chemical mechanism; incorporation of reactions to simulate the formation of secondary organic particles; and use of a semi-Lagrangian advection scheme to preserve concentration peaks during advection.

The model was evaluated with 1992 air quality data from Project MOHAVE (Measurements of Haze and Visual Effects) intensive experiments. An important conclusion of this evaluation is that aqueous-phase oxidation of SO2 to sulfate in nonprecipitating clouds makes a significant contribution to observed sulfate levels during winter as well as summer. Model estimates of ambient sulfate

for the winter intensive were within a factor of 2 of the observations for 75% of the values. The corresponding statistic for the summer intensive was 90%. Model estimates of carbon were within a factor of 2 of the limited set of observations.     

Simulation of Sulfate and Nitrate Chemistry in Power Plant Plumes

ABSTRACT

The rate of formation of secondary particulate matter (PM) in power plant plumes varies as the plume material mixes with the background air. Consequently, the rate of oxidation of sulfur dioxide (SO₂) and nitrogen dioxide (NO₂) to sulfate and nitric acid, respectively, can be very different in plumes and in the background air (i.e., air outside the plume). In addition, the formation of sulfate and nitric acid in a power plant plume is a strong function of the chemical composition of the background air and the prevailing meteorological conditions.

We describe the use of a reactive plume model, the Reactive and Optics Model of Emissions, to simulate sulfate and nitrate formation in a power plant plume for a variety of background conditions. We show that SO₂ and NO₂ oxidation rates are maximum in the background air for volatile organic compound (VOC)-limited airsheds but are maximum at some downwind distance in the plume when the background air is nitrogen oxide (NO_x)-limited. Our analysis also shows that it is essential to obtain measurements of background concentrations of ozone, aldehydes, peroxyacetyl nitrate, and other VOCs to properly describe plume chemistry.     

Copper and cadmium removal from synthetic industrial wastewater using chitosan and nylon 6

Purpose

Chitosan with nylon 6 membranes was evaluated as adsorbents to remove copper and cadmium ions from synthetic industrial wastewater.

Methods

Chitosan and nylon 6 with glutaraldehyde blend ratio with (1:1+Glu, 1:2+Glu, and 2:1+Glu) have been prepared and these were used as membranes to remove copper and cadmium ions from synthetic industrial wastewater. Characterization of the synthesized membrane has been done with FTIR, XRD, TGA/DTA, DSC, and SEM. Chemical parameters for quantities of adsorption of heavy metal contamination have been done and the kinetics of adsorption has also been carried out.

Results

The optimal pH for the removal of Cd(II) and Cu(II) using chitosan with nylon 6. Maximum removal of the metals was observed at pH 5 for both the metals. The effect of adsorbent dose also has a pronounced effect on the percentage of removal of the metals. Maximum removal of both the metals was observed at 5 g/100 ml of the adsorbent.

Conclusion

Copper and cadmium recovery is parallel at all time. The percentage of removal of copper increased with increase in the pH from 3 to 5. In the case of cadmium containing wastewater, the maximum removal of metal occurred at pH 5. The uptake amount of Cu²⁺ ions on chitosan increased rapidly with increasing contact time from 0 to 360 min and then reaches equilibrium after 360 min; the equilibrium constant for copper and cadmium ions is more or less the same for the adsorption reaction.     

Oxidative potential (OP) and mineralogy of iron ore particulate matter at the Gol-E-Gohar Mining and Industrial Facility (Iran)

Concentrations of total suspended particulate matter, particulate matter with aerodynamic diameter <2.5 μm (PM_2.5), particulate matter <10 μm (PM₁₀), and fallout dust were measured at the Iranian Gol-E-Gohar Mining and Industrial Facility. Samples were characterized in terms of mineralogy, morphology, and oxidative potential. Results show that indoor samples exceeded the 24-h PM_2.5 and PM₁₀ mass concentration limits (35 and 150 µg m^?3, respectively) set by the US National Ambient Air Quality Standards. Calcite, magnetite, tremolite, pyrite, talc, and clay minerals such as kaolinite, vermiculite, and illite are the major phases of the iron ore PM. Accessory minerals are quartz, dolomite, hematite, actinolite, biotite, albite, nimite, laumontite, diopside, and muscovite. The scanning electron microscope structure of fibrous-elongated minerals revealed individual fibers in the range of 1.5 nm to 71.65 µm in length and 0.2 nm to 3.7 µm in diameter. The presence of minerals related to respiratory diseases, such as talc, crystalline silica, and needle-shaped minerals like amphibole asbestos (tremolite and actinolite), strongly suggests the need for detailed health-based studies in the region. The particulate samples show low to medium oxidative potential per unit of mass, in relation to an urban road side control, being more reactive with ascorbate than with glutathione or urate. However, the PM oxidative potential per volume of air is exceptionally high, confirming that the workers are exposed to a considerable oxidative environment. PM released by iron ore mining and processing activities should be considered a potential health risk to the mine workers and nearby employees, and strategies to combat the issue are suggested.     

Potential of Anopheles philippinensis-nivipes complex mosquitoes as malaria vector in north-east India

Anopheles philippinensis-nivipes complex mosquitoes, captured in outdoor human landing catches and light traps in human dwellings from four different sites in Assam state and adjoining areas, were examined (n=1670) for the presence of circumsporozoite antigen (CSA) through enzyme linked immunosorbent assays (ELISA), using species specific capture monoclonal antibodies, of Plasmodium falciparum and two Plasmodium vivax polymorphs (Pv 210 and VK 247). In ELISA, 28 pools were found positive for CSA that accounted for minimum sporozoite rate of 1.7% (95% CI 1.11-2.41). Twenty five percent (7/28) of the positive pools were reactive for P. falciparum and between the two polymorphs of P. vivax, VK 247 was predominant with 77% (20/26) of all P. vivax positive pools. Results were suggestive of most likely involvement of Anopheles philippinensis-nivipes complex mosquitoes in malaria transmission in north-east India.