The health of a substantial portion of urban populations is potentially being impacted by exposure to traffic–related atmospheric pollutants. To better understand the rapid physical and chemical transformation of these pollutants, the number size distributions of non–volatile traffic–related particles were investigated at different distances from a major highway. Particle volatility measurements were performed upwind and downwind of the highway using a fast mobility particle sizing spectrometer with a thermodenuder on a mobile laboratory. The number concentration of non–denuded ultrafine particles decreased exponentially with distance from the highway, whereas a more gradual gradient was observed for non–volatile particles. The non–volatile number concentration at 27 m was higher than that at 280 m by a factor of approximately 3, and the concentration at 280 m was still higher than that upwind of the highway. The proportion of non–volatile particles increased away from the highway, representing 36% of the total particle number at 27 m, 62% at 280 m, and 81% at the upwind site. A slight decrease in the geometric mean diameter of the non–volatile particle size distributions from approximately 35 nm to 30 nm was found between 27 m and 280 m, in contrast to the growth of non–denuded particles with increasing distance from the highway. Single particle analysis results show that the contribution of elemental carbon (EC)–rich particle types at 27 m was higher than the contribution at 280 m by a factor of approximately 2. The findings suggest that people living or spending time near major roadways could be exposed to elevated number concentrations of nucleation–mode volatile particles (<30 nm), Aitken–mode non–volatile particles (30-100 nm), and EC–rich fine–mode particles (>100 nm). The impact of the highway emissions on air quality was observable up to 300 m.

Small amounts (0.15wt%) of platinum and palladium were incorporated in porous, high surface area, ultra–stable H–USY–Zeolite by ion exchange method, and their catalytic activity was studied for carbon monoxide (CO) oxidation reaction, under various conditions of industrial importance. The catalyst was characterized by p–XRD, chemical analysis, SEM, TEM, evaluated for catalytic activity using a steady state, fixed bed catalytic reactor. The catalysts show high CO oxidation activity and it was possible to convert 0.044 mmols of CO per gram of catalyst at 120 °C, at a space velocity of 60 000 h−1 and with 100 ppm CO concentration in feed gas. The high catalytic activity of this noble metal catalyst also appears to be a factor of porous structure of zeolite facilitating mass transfer; high surface area as well as highly dispersed catalyst sites of palladium and platinum on zeolite structure. Introduction of acidic sites in zeolites probably makes them more resistant towards SO2, while their surface area and pore characteristics make this catalyst efficient even under high space velocity conditions, thus suggesting the potential of larger pore size zeolites over conventional porous materials for industrial applications.

The study first illustrates a comprehensive account of large-scale changes in water quality characteristics and plankton community structure due to occurrence of Annual Gangasagar Festival (AGF) at Sagar Island, western part of Indian Sundarban megadelta for 3-year duration (2012–2014; n=36). About 1 million pilgrims across India converge to take their holy bath at the confluence of Hooghly estuary and Bay of Bengal during January each year. This mass scale bathing results negative impact on water quality due to high turbidity (14.02±2.34 NTU) coupled with low chlorophyll a (1.02±0.21mgm−3) and dissolved oxygen (3.94±1.1mgl−1). A marked decrease in abundance (from 4140 to 2997cellsl−1) and diversity (H′=2.72–1.33) of phytoplankton and microzooplankton tintinnids (from 450 to 328 ind l−1; H′=4.31–2.21) was recorded. The festival acts as multiple stressors modifying natural functions of the delta. Sound and sustainable management strategies are to be adopted to maintain the protection-usage equilibrium.

In this study, 54 sediment samples were collected from the Pearl River Estuary (PRE) in Southern China to study the spatial distribution and patterns of PFASs in this region. PFAS concentrations in the sediment samples ranged from nd (below detection limit) to 2.41ngg−1dw (dry weight) with an average value of 0.79ngg−1dw. PFAS concentrations were higher at the nearshore sampling sites than in the others. Perfluorobutanesulfonate (PFBS) and perfluorohexanesulfonate (PFHxS) were the two dominant compounds among the target PFASs, which may be due to their production and use as PFOS substitutes in the Pearl River Delta (PRD) areas. Significant linear relationships were found between total PFAS concentrations and total organic carbon (TOC) (R=0.30, p<0.05). The preliminary environmental risk assessment indicated that PFOS and PFOA in the regional sediments posed no significant ecological risk to the benthic organisms at present levels.

Freshwater cyanobacteria produce highly toxic substances such as microcystins (MCs), and water containing MCs is often discharged to downstream and coastal areas. We conducted field monitoring in Isahaya Bay to clarify the short-term dynamics of MCs discharged from a reservoir following a cyanobacteria bloom in the warm season. MCs were detected in the seawater of the bay (max. 0.10μgL−1), and were deposited on the sea floor, with the MC content of the surface sediment increasing by approximately five times (0.11±0.077–0.53±0.15μgkgww−1, mean±SD) at the four stations near the reservoir drainage gate before and after the discharge. The MCs was then transported from the mouth of the bay by tidal currents during the period of the study. Therefore, the MCs were moved away from the closed water area where the cyanobacteria blooms, and spread throughout the coastal area.

A method based on sample preparation by accelerated solvent extraction and analysis by liquid chromatography–tandem mass spectrometry was validated and used for determination of seven typical lipophilic marine toxins (LMTs) in marine sediment samples collected from three typical coastal bays in China. Satisfactory specificity, reproducibility (RSDs≤14.76%), stability (RSDs≤17.37%), recovery (78.0%–109.0%), and detection limit (3.440pg/g–61.85pg/g) of the developed method were achieved. The results obtained from the analysis of samples from Hangzhou Bay revealed okadaic acid as the predominant LMT with concentrations ranging from 186.0 to 280.7pg/g. Pecenotoxin-2 was quantified in sediment samples from Laizhou Bay at the concentrations from 256.4 to 944.9pg/g. These results suggested that the proposed method was reliable for determining the typical LMTs in marine sediments and that the sediments obtained from Hangzhou Bay, Laizhou Bay and Jiaozhou Bay were all contaminated by certain amounts of LMTs.

We analyzed n-alkane contents and their stable carbon isotope composition, as well as the carbon and nitrogen isotope composition (δ13C, δ15N) of sediment organic matter and different tissues of Posidonia oceanica seagrass sampled in Alexandroupolis Gulf (A.G.), north-eastern Greece, during 2007–2011. n-Alkane contents in P. oceanica and in sediments showed similar temporal trends, but relative to bulk organic carbon content, n-alkanes were much more enriched in sediments compared to seagrass tissue. Individual n-alkanes in sediments had similar values than seagrass roots and rhizomes and were more depleted in 13C compared to seagrass leaves and sheaths, with δ13C values ranging from −35‰ to −28‰ and from −25‰ to −20‰, respectively. n-Alkane indexes such as the Carbon Preference Index, carbon number maximum, and n-alkane proxy 1 (C23+C25/C23+C25+C29+C31) indicate strong inputs of terrestrial organic matter, while the presence of unresolved complex mixtures suggests potential oil pollution in some sampled areas.

The aim of this study was to analyze the density, diversity, biomass and assemblage composition of the phytoplankton in relation to environmental conditions (physical, chemical, hydrological and meteorological variables), measured under the different scenarios caused by the ENSO phenomenon in the period between 2005 and 2012, in six sampling sites in the tidal freshwater zone of the Río de la Plata estuary, covering almost 100km of coastline. The results revealed changes in the structure of the phytoplankton, such as a significant reduction of diversity, and decreases in biomass and phytoplankton density, particularly during El Niño phases. Cyanobacteria were more abundant in the neutral periods, Chlorophyceae dominated La Niña phase while Bacyllariophyceae dominated El Niño. However, no complete replacement of species between cycles was observed. The results obtained were highly variable due to the inherent natural variability of the Río de la Plata, emphasized by the anthropogenic impact in this area.

The polycyclic aromatic hydrocarbons (PAHs) in PM2.5 contribute significantly to health risk. The objectives of this study were to assess the occurrence and variation in the concentrations and sources of PM2.5-bound PAHs sampled from the atmosphere of a typical southeastern Chinese city (Guangzhou) from June 2012 to May 2013, with the potential risks being investigated. The annual average concentration of PM2.5 was 64.88μgm−3. The annual average concentration of PAHs in PM2.5 was 33.89ngm−3. Benzo(a)pyrene (BaP) was found to be the predominant PAH in all PM2.5 samples throughout the year, constituting approximately 8.78% of the total PAH content. The significant meteorological parameters for most of the PAHs were sunshine time, air pressure, and humidity, together representing 10.7–52.4% of the variance in atmospheric PAH concentrations. Motor-vehicle exhaust and coal combustion were probably the main sources of PAHs in PM2.5 in Guangzhou. The average inhalation cancer risk (ICR) for a lifetime of 70years was 5.98×10−4 (ranging from 8.39×10−5 to 1.95×10−3).