Semi–volatile polycyclic aromatic hydrocarbons (PAHs) and their oxygenated analogues (OPAHs) are associated with adverse health effects. They are normally sampled by active sampling but recently a number of passive samplers that rely on calibrated sampling rates (Rs), have successfully captured the full suite of PAHs associated with both the gas–and particulate phases. However, there have been few studies on the mechanisms controlling particle deposition during passive sampling. To address this issue, a diesel exhaust aerosol with a number mode of ~120 nm containing PAHs and OPAHs that are partitioned approximately equally between the gas and particle phases was used to study the performance of a passive sampler design of axial badge type. The sampler was tested with two different collection substrates and the diffusion distance was varied to determine its effects on sample collection. The results obtained were compared to data gathered by active sampling of the gas and particle phases. In addition, Rs values were calculated for selected PAHs and OPAHs. The material collected by the passive samplers was analyzed using a highly sensitive protocol involving thermal desorption followed by GC–MS. The passive sampler yielded highly reproducible Rs values and its PAH uptake was shown to be enhanced by using a collection substrate modified with a gas–adsorbing coating (Tenax®) which was exclusively addressed being uptake from the gaseous phase. However, the uptake of the less volatile OPAHs was not affected by the use of a coated substrate. Experimental data and theoretical calculations showed that particle diffusion may have substantially less impact on particulate matter collection than other deposition mechanisms. The high sensitivity and small size of the sampler suggest that after testing in other environments it may have diverse applications in sampling campaigns and as a promising candidate for a personal sampler.

In this study, we are interested in spatial and temporal variations of the biological and physiological responses of mussels collected from contrasting marine sites regarding their levels of pollution. We measured both the conditions indices and the enzymatic biomarker expression: acetylcholinesterase (AChE), catalase (CAT) and glutathione S-transferase (GST) activity. The enzymatic biomarkers were chosen because they respond to environmental stress. Results show a significant interactions between biomarker variations and conditions indices in the industrial harbor site throughout the seasons. But no significant changes in the reference site. Furthermore, we classified the sites along the seasons according to their potential ecotoxicity, calculated based on the sum of the normalised values of the biomarkers. The results show a very high biomarker index in the impacted site with irregular changes between seasons. This biomarker index is therefore a valuable tool that could be used to classify the toxic potential of coastal sites.

This study describes the geochemical distribution of lead (Pb) and identifies the critical factors that significantly control Pb distribution and speciation in coastal and estuarine sediments around India by using published data from the literature. Crustal sources influence the abundance of Pb in coastal sediment from the south-east and central-west coast of India. Parts of north-east, north-west, and south-west coast of India were polluted by Pb. Distribution of Pb in sediments, from the north-east and north-west coasts of India, were controlled by Fe–Mn oxyhydroxide mineral phases of the sediments. However, organic carbon (OC) seemed to be a dominant factor in controlling the distribution of Pb in sediments from the central-east and south-west coasts of India. The outcome of this study may help in decision-making to predict the levels of Pb from natural and anthropogenic sources and to control Pb pollution in coastal and estuarine sediments around India.

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.

The indigenous oil-degrading bacterial consortia MARA and MARB were enriched from the deep-sea sediments of South Mid-Atlantic Ridge (MAR) with crude oil as sole carbon and energy sources. Biodiversity and community analyses showed that members of α-Proteobacteria were the key players in consortium MARA, whereas those of γ-Proteobacteria were the key players in consortium MARB, which were studied by MiSeq sequencing method. Gravimetric method estimated the oil degradation rates of MARA and MARB to be 63.4% and 85.8%, respectively, after 20d. Eleven cultivable oil degraders with different morphologies were isolated. These strains were identified as Alcanivorax, Bacillus, Dietzia, Erythrobacter, Marinobacter, Nitratireductor, and Oceanicola based on 16S rRNA gene sequences. Three strains belonging to Dietzia exhibited the highest oil degradation capability. Results indicated that the intrinsic biodegradation capacity of oil contaminants by indigenous microbial communities exists in South MAR sediments.

Mercury (Hg) has a complex biogeochemical cycle in aquatic environments. Its most toxic form, methylmercury (MeHg), is produced by microorganisms. This study investigated how the sea anemone Bunodosoma caissarum affects Hg distribution, methylation and volatilization in laboratory model systems. 203Hg was added to microcosms and its distribution in seawater, specimens and air was periodically measured by gamma spectrometry. MeHg was measured by liquid scintillation. After the uptake period, specimens had a bioconcentration factor of 70 and in microcosms with and without B. caissarum, respectively 0.05% and 0.32% of the initial spike was found as MeHg. After depuration, MeHg in specimens ranged from 0.2% to 2.4% of total Hg. Microcosms with B. caissarum had higher Hg volatilization (58%) than controls (17%), possibly due to Hg2+ reduction mediated by microorganisms associated with its tissues and mucus secretions. Marine organisms and their associated microbiota may play a role in Hg and MeHg cycling.

Seasonal mean oxygen depletion in offshore and coastal North Sea bottom waters was shown to range between 0.9 and 1.8mg/L, corresponding to 95–83% saturation, between July and October over a 30-year assessment period (1980–2010). The magnitude of oxygen depletion was controlled by thermal stratification, modulated by water depth and nitrogen availability. Analyses were based on about 19,000 combined data sets. Eutrophication problem areas were identified mainly in coastal waters by oxygen minima, the lower 10th percentile of oxygen concentrations, and deviations of oxygen depletion from correlated stratification values. Connections between oxygen consumption and nitrogen sources and conversion, including denitrification, were indicated by correlations. Mean oxygen consumption reflected a minimum seasonal turnover of 3.1gN/m2 in the south-eastern North Sea, including denitrification of 1gN/m2. Oxygen depletion was underestimated in shallow coastal waters due to repeated erosion of stratification as indicated by local high variability.

The Plateau Rosa Alpine station (Italy) has collected atmospheric concentrations of carbon dioxide since 1989. If the complete set of hourly data is observed, two distinct and exceptional very high concentration events are evident for February 2004. Similar and almost contemporary peaks were registered at the European high–altitude stations of Zugspitze–Schneefernerhaus and Sonnblick in the Alps, and at Mt. Cimone in the Northern Apennines. A regional meteorological model (the Weather Research and Forecast) was applied over a medium–high resolution grid to study the evolution of the meteorological fields and to identify the trajectories of the polluted air masses during the CO2 observed peaks. The results show that, during both episodes, atmospheric circulation conveyed highly polluted air from the European plains to the Alpine stations. This conclusion has been also confirmed through concentration measurements of the atmospheric trace gases in the same area.

In order to examine the influence of discharge from different rivers from peninsular India and urban sewage on intensity and dissemination of heterotrophic, indicator and pathogenic bacteria, a study was carried out during peak discharge period along coastal Bay of Bengal. The coastal Bay received freshwater inputs from the river Ganges while Godavari and Krishna contributed to the south. Contrasting difference in salinity, temperature, nutrients and organic matter was observed between north and south east coast of India. The highest heterotrophic, indicator and pathogenic bacterial abundance was observed in the central coastal Bay that received urban sewage from the major city. Intensity and dissemination of heterotrophic, indicator and pathogenic bacteria displayed linear relation with magnitude of discharge. The coliform load was observed up to 100km from the coast suggesting that marine waters were polluted during the monsoon season and its impact on the ecosystem needs further studies.