Characterization of major pollution events (dust, haze, and two festival events) at Agra, India

Total suspended particulate (TSP) samples were collected during dust, haze, and two festival events (Holi and Diwali) from February 2009 to June 2010. Pollutant gases (NO₂, SO₂, and O₃) along with the meteorological parameters were also measured during the four pollution events at Agra. The concentration of pollutant gases decreases during dust events (DEs), but the levels of the gases increase during other pollution events indicating the impact of anthropogenic emissions. The mass concentrations were about two times higher during pollution events than normal days (NDs). High TSP concentrations during Holi and Diwali events may be attributed to anthropogenic activities while increased combustion sources in addition to stagnant meteorological conditions contributed to high TSP mass during haze events. On the other hand, long-range transport of atmospheric particles plays a major role during DEs. In the dust samples, Ca²⁺, Cl^?, NO₃ ^?, and SO₄ ^2? were the most abundant ions and Ca²⁺ alone accounted for 22 % of the total ionic mass, while during haze event, the concentrations of secondary aerosols species, viz., NO₃ ^?, SO₄ ^2?, and NH₄ ⁺, were 3.6, 3.3, and 5.1 times higher than the normal days. During Diwali, SO₄ ^2? concentration (17.8 μg?m^?3) was highest followed by NO₃ ^?, K⁺, and Cl^? while the Holi samples were strongly enriched with Cl^? and K⁺ which together made up 32.7 % of the total water-soluble ions. The ion balances indicate that the haze samples were acidic. On the other hand, Holi, Diwali, and DE samples were enriched with cations. The carbonaceous aerosol shows strong variation with the highest concentration during Holi followed by haze, Diwali, DEs, and NDs. However, the secondary organic carbon concentration follows the order haze > DEs > Diwali > Holi > NDs. The scanning electron microscope/EDX results indicate that KCl and carbon-rich particles were more dominant during Holi and haze events while DE samples were enriched with particles of crustal origin.     

Bacterial colonization and endocytosis on the gill of a new limpet species from a hydrothermal vent

Calcification rates in different fragments along branches of the hermatypic coral Stylophora pistillata were tested in the laboratory using a new technique, the optic glassfiber method. By this method, the tested colony remains constantly in dark conditions while a narrow beam of light, transferred through the optic fiber, illuminates a small distinct point of coral tissue (on a branch tip or base). The selected illuminated portion of the branch serves as the experimental fragment, while all the other parts of the same colony serve as the dark controls. The results indicate that significantly more calcium is incorporated in the tip fragments than in the bases, both in light and in dark conditions (4.1 to 13.2 times more). Illumination of the tips or the bases did not stimulate or enhance the calcification rates of these fragments. Thus, in all colonies tested, the calcification rates of the illuminated fragments were not significantly different from the average rates of other similar, non-illuminated fragments of the same colony. It is suggested that light does not directly enhance calcification in hermatypic corals, but rather, that light enhances O₂ production, which consequently stimulates coral metabolism. Our preliminary results indicate that calcification rates recorded in aerated dark experiments are significantly higher than calcification rates of non-aerated dark controls.     

Non-edible vegetable oil–based feedstocks capable of bio-lubricant production for automotive sector applications—a review

Environmental Science and Pollution Research - Fossil fuel resource is on the draining stage which leads to an increment in the cost of the petroleum products. Nowadays, research is focused on the...     

Towards an integrated framework for air quality monitoring and exposure estimation—a review

For the health and safety of the public, it is essential to measure spatiotemporal distribution of air pollution in a region and thus monitor air quality in a fine-grain manner. While most of the sensing-based commercial applications available until today have been using fixed environmental sensors, the use of personal devices such as smartphones, smartwatches, and other wearable devices has not been explored in depth. These kinds of devices have an advantage of being with the user continuously, thus providing an ability to generate accurate and well-distributed spatiotemporal air pollution data. In this paper, we review the studies (especially in the last decade) done by various researchers using different kinds of environmental sensors highlighting related techniques and issues. We also present important studies of measuring impact and emission of air pollution on human beings and also discuss models using which air pollution inhalation can be associated to humans by quantifying personal exposure with the use of human activity detection. The overarching aim of this review is to provide novel and key ideas that have the potential to drive pervasive and individual centric and yet accurate pollution monitoring techniques which can scale up to the future needs.     

Bacterial symbiosis in Northeast Pacific Vestimentifera: a TEM study

A number of new vestimentiferan species occur at northeast Pacific hydrothermal vent sites. The trophosome and bacterial symbionts of three species, collected from the Juan de Fuca and Explorer Ridges between 1984 and 1986, were studied by transmission electron microscopy (TEM). As in Riftia pachyptila, trophosome tissue is organised into lobules each having an axial blood vessel, and intracellular bacterial symbionts are contained in membrane vacuoles. The bacteria have many cytoplasmic inclusions including tubular membrane systems, glycogen-like particles and poly--hydroxybutyrate (PHB) or sulfur bodies. Glycogen production may be quantitatively important to both the symbionts and the host. Glycogen-like granules appear to first accumulate in the bacterial cells and then be released into the bacteriocyte cytoplasm as bacteria are degraded. Although various stages of bacterial growth and degradation are observed, data are insufficient to verify any across-lobule progression of these processes. Morphological comparison of the symbionts reveals that similar symbionts are found in different vestimentiferan species and that one to two bacterial types exist within single individuals. Two possible models of trophosome function and nutrient exchange are discussed.Deceased     

Arsenic toxicity in crop plants: physiological effects and tolerance mechanisms

Heavy metals are toxic substances released into the environment, contributing to a variety of toxic effects on living organisms in food chain by accumulation and biomagnifications. Certain pollutants such as arsenic (As) remain in the environment for an extensive period. They eventually accumulate to levels that could harm physiochemical properties of soils and lead to loss of soil fertility and crop yield. Arsenic, when not detoxified, may trigger a sequence of reactions leading to growth inhibition, disruption of photosynthetic and respiratory systems, and stimulation of secondary metabolism. Plants respond to As toxicity by a variety of mechanisms including hyperaccumulation, antioxidant defense system, and phytochelation. Arbuscular mycorrhizae symbiosis occurs in almost all habitats and climates, including disturbed soils. There is growing evidence that arbuscular mycorrhizae fungi may alleviate metal/metalloid toxicity to host plant. Here, we review (1) arsenic speciation in the environment and how As is taken up by the roots and metabolised within plants, and (2) the role of arbuscular mycorrhizae in alleviating arsenic toxicity in crop plants.     

Hydrogen fuel and fuel cell technology for cleaner future: a review

Environmental Science and Pollution Research - One of the main problems facing our planetary bodies is unexpected and sudden climate change due to continuously increasing global energy demand,...     

Chemical characteristics and source apportionment of PM<Subscript>2.5</Subscript> using PCA/APCS,UNMIX, and PMF at an urban site of Delhi,India

The present study investigated the comprehensive chemical composition [organic carbon (OC), elemental carbon (EC), water-soluble inorganic ionic components (WSICs), and major & trace elements] of particulate matter (PM_2.5) and scrutinized their emission sources for urban region of Delhi. The 135 PM_2.5 samples were collected from January 2013 to December 2014 and analyzed for chemical constituents for source apportionment study. The average concentration of PM_2.5 was recorded as 121.9 ± 93.2 μg m^?3 (range 25.1–429.8 μg m^?3), whereas the total concentration of trace elements (Na, Ca, Mg, Al, S, Cl, K, Cr, Si, Ti, As, Br, Pb, Fe, Zn, and Mn) was accounted for ～17% of PM_2.5. Strong seasonal variation was observed in PM_2.5 mass concentration and its chemical composition with maxima during winter and minima during monsoon seasons. The chemical composition of the PM_2.5 was reconstructed using IMPROVE equation, which was observed to be in good agreement with the gravimetric mass. Source apportionment of PM_2.5 was carried out using the following three different receptor models: principal component analysis with absolute principal component scores (PCA/APCS), which identified five major sources; UNMIX which identified four major sources; and positive matrix factorization (PMF), which explored seven major sources. The applied models were able to identify the major sources contributing to the PM_2.5 and re-confirmed that secondary aerosols (SAs), soil/road dust (SD), vehicular emissions (VEs), biomass burning (BB), fossil fuel combustion (FFC), and industrial emission (IE) were dominant contributors to PM_2.5 in Delhi. The influences of local and regional sources were also explored using 5-day backward air mass trajectory analysis, cluster analysis, and potential source contribution function (PSCF). Cluster and PSCF results indicated that local as well as long-transported PM_2.5 from the north-west India and Pakistan were mostly pertinent.