Total-Hg, monomethylmercury (MMHg), and mercury isotopic composition was determined in sediment from a cold seep and background sites in the northern Gulf of Mexico (nGoM). Total-Hg averaged 50ng/g (n=28), ranged from 31 to 67ng/g, and decreased with depth (0–15cm). MMHg averaged 0.91ng/g (n=18), and ranged from 0.2 to 1.9ng/g. There was no significant difference for total-Hg or MMHg between cold seep and background sites. δ202Hg ranged from −0.5 to −0.8‰ and becomes more negative with depth (r=0.989). Mass independent fractionation (Δ199Hg) was small but consistently positive (0.04–0.12‰); there was no difference between cold seeps (Δ199Hg = +0.09±0.03; n=7, 1SD) and background sites (Δ199Hg=+0.07±0.02; n=5, 1SD). This suggests that releases of hydrocarbons at the cold seep do not significantly alter Hg levels, and that cold seeps are likely not major sources of MMHg to nGoM waters.

Ratios of sucrose-negative to sucrose-positive vibrios on TCBS agar (suc−/suc+) indicate the abundance of potential human pathogenic non-cholera vibrios in coastal mariculture environments of the Lingayen Gulf (Philippines. In guts of adult maricultured milkfish (Chanos chanos) of suc− vibrios reached extreme peak values ranging between 2 and 545millionperg wet weight. Suc− vibrios outnumbered suc+ vibrios in anoxic sediments, too, and were rarely predominant in coastal waters or in oxidized sediments. Suc−/suc+ ratios in sediments increased toward the mariculture areas with distance from the open sea at decreasing redox potentials. There is circumstantial evidence that suc− vibrios can be dispersed from mariculture areas to adjacent environments including coral reefs. An immediate human health risk by pathogenic Vibrio species is discounted, since milkfish guts contained mainly members of the Enterovibrio group. A representative isolate of these contained proteolytic and other virulence factors, but no genes encoding toxins characteristic of clinical Vibrio species.

We investigated the influence of salinity on sediment inorganic nitrogen dynamics in three Portuguese estuaries (Cávado, Ave and Douro). Anaerobic slurry experiments were run at different salinity treatments (0, 10, and 25) and net changes in concentration of nitrate, nitrite, ammonium, and nitrous oxide were monitored. Salinity-induced NH4+ sediment desorption was observed at all sites. No significant salinity driven changes in NO3- concentrations were observed, except for Ave estuarine sediments, where NO3- consumption increased 10 times as the salinity rose from 0 to 10. In the upper stretches of the three estuaries, N2O production increased sharply as salinity rose. Although no stimulation of N2O production was observed in higher salinity areas, the salinity-driven changes in N2O production are of major concern given the greenhouse characteristics of the gas. The global trend of decreasing freshwater discharge, and therefore increase in salinity, to estuarine systems could thereby exacerbate N2O production and global warming.

Nutrient bioindicators are increasingly being recognised as a diagnostic tool for nutrient enrichment of estuarine and marine ecosystems. Few studies, however, have focused on field translocation of bioindicator organisms to detect nutrient discharge from industrial waste. The brown macroalgae, Sargassum flavicans, was investigated as a potential bioindicator of nutrient-enriched industrial effluent originating from a nickel refinery in tropical north-eastern Australia. S. flavicans was translocated to a number of nutrient enriched creek and oceanic sites over two seasons and assessed for changes in stable isotope ratios of 15N and 13C within the plant tissue in comparison to reference sites. Nutrient uptake in macroalgae, translocated to the nutrient enriched sites adjacent to the refinery, increased 3–4-fold in δ15N, compared to reference sites. Using δ15N of translocated S. flavicans proved to be a successful method for monitoring time-integrated uptake of nitrogen, given the current lack of passive sampler technology for nutrient monitoring.

This study investigates green mussel filtration rates based on variation of the mussel size and density, and attempts to correlate these with the amount of Chaetoceros calcitrans consumed by kinetic modeling. The filtration rates were found to be more effective in small mussels and with greater volumes of seawater/mussel which represent low mussel densities in the mussel farms. Under field condition, the first order kinetic model is useful for evaluation of mussel filtration rate. However, the composite exponential kinetic model was determined to better describe filtration rates in a close system. Higher ratios of seawater volume L/g DW mussel tissue, resulted in an increasing filtration rate until a maximum plateau was reached at 10.37L/h/g DW tissue as determined by first order kinetics. Based on the filtration rate, carbon, nitrogen, and phosphorus uptake by green mussels were found to be 2128.72, 265.41, and 66.67mg/year/indv, respectively.

Atmospheric concentrations of elemental, organic and water–soluble organic carbon (EC, OC and WSOC) and polycyclic aromatic hydrocarbons (PAHs) have been studied in PM2.5 (particulate matter of aerodynamic diameter ≤2.5 μm) from a site (Barapani: 25.7 °N; 91.9 °E; 1 064 m amsl) in the foot–hills of NE–Himalaya (NE–H). Under favorable wind–regimes, during the wintertime (January–March), study region is influenced by the long–range transport of aerosols from the Indo–Gangetic Plain (IGP). For rest of the year, ambient atmosphere over the NE–H is relatively clean due to frequent precipitation events associated with the SW– and NE–monsoon. The concentration of PM2.5 over NE–H, during the wintertime, varied from 39–348 μg m–3, with average contribution of OC and EC as 36±8% (AVG±SD) and 6±3%, respectively. For the OC/EC ratio as high as 10–15 (relatively high compared to fossil–fuel source) associated with WSOC/OC ratio exceeding 0.5 in NE–H, it can be inferred that dominant source of carbonaceous aerosols is attributable to biomass burning emissions and/or contributions from secondary organic aerosols (SOA). The OC/PM2.5 ratio from NE–H is somewhat higher compared to upwind regions in the IGP (Range: 0.16–0.24). The abundance of ΣPAHs show large variability, ranging from 4–46 ng m–3, and the ratio of sum of 4– to 6–ring PAHs (Σ(4– to 6–) PAHs) to EC is 2.4 mg g–1; similar to that in the upwind IGP and is about a factor of two higher than that from the fossil–fuel combustion sources. The cross-plot of PAH isomers [FLA/(FLA+PYR) vs. ANTH/(ANTH+PHEN), BaA/(BaA+CHRY+TRIPH), BaP/(BaP+B[b,j,k]FLA) and IcdP/(IcdP+BghiP)] reaffirms the dominant impact of biomass burning emissions. These results have implications to large temporal variability in aerosol radiative forcing and environmental change over the NE–Himalaya.

Eggs from egrets (Egretta thula) were collected from Cartagena Bay and Totumo Marsh, two sites at the north of Colombia with different pollution background, and measured their morphometric parameters as well as total mercury (T-Hg) and calcium levels in eggshell. Statistically significant differences were observed for egg weight and size between the two sampling locations. T-Hg and calcium concentrations in eggshell were greater in eggs from Cartagena Bay, the industrial site, compared to Totumo Marsh, a non-industrial location. The opposite was observed for eggshell thickness (3.6% less in the bay). Pearson correlation analysis showed eggshell T-Hg negatively correlated with eggshell weight in eggs from the marsh (R=−0.795, P<0.006), but not from the bay (R=0.387, P=0.269), probably suggesting greater susceptibility to Hg in birds from the non-polluted site. In short, results suggest eggs from E. thula at Cartagena Bay have greater T-Hg concentrations and less eggshell thickness than those from Totumo Marsh.

Plastic debris is often ingested by marine predators and can cause health disorders and even death. We present the first assessment of plastic ingestion in Mediterranean seabirds. We quantified and measured plastics accumulated in the stomach of 171 birds from 9 species accidentally caught by longliners in the western Mediterranean from 2003 to 2010. Cory’s shearwaters (Calonectris diomedea) showed the highest occurrence (94%) and large numbers of small plastic particles per affected bird (on average N=15.3±24.4 plastics and mass=23.4±49.6mg), followed by Yelkouan shearwaters (Puffinus yelkouan, 70%, N=7.0±7.9, 42.1±100.0mg), Balearic shearwaters (Puffinus mauretanicus, 70%, N=3.6±2.9, 5.5±9.7mg) and the rest of species (below 33%, N=2.7, 113.6±128.4mg). Plastic characteristics did not differ between sexes and were not related to the physical condition of the birds. Our results point out the three endemic and threatened shearwater species as being particularly exposed to plastic accumulation.

Surface sediments from marine reserves of the Tuscan Archipelago National Park (Italy), including remote islands not directly affected by anthropogenic influences, were analyzed for two dominant perfluorinated compounds (PFCs), namely perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), using LC–ESI-MS/MS. The concentrations of PFOS were low, with medians ranging from 0.25 to 1.50ng/g dry wt, whereas PFOA was always below the detection limit of 0.1ng/g dry wt. The present paper can be considered a baseline study useful in future environmental monitoring programs.

Lead in atmospheric suspended particles was fractionized using simple acid extraction to assess differences in chemical properties of lead from roadside and residential areas. The Pb–LIII edge XANES measurement was also challenged to explore the possibilities of contamination from road dust into the air. Results suggest that 0.1 M–HCl extractable fractions of lead at the roadside area are significantly higher than those obtained at the residential area, especially for the coarse mode of the particulate samples. Moreover, the solubility characteristics of the roadside particulate lead have partially overlapped with those of the road dust samples. The XANES spectra for coarse mode of particulate lead also nearly correspond to that of the road dust collected around the roadside area. These results indicate effects by the re–suspension of road dust to the roadside air. However, it is difficult to clear the roadside contamination from specific lead material applied in this study. This might suggest that specific lead compounds do not exist exclusively in atmospheric particles but exist as mixtures or unknown complexes.