Seasonal and body size-dependent variability in the bioaccumulation of PAHs and their alkyl homologues in pearl oysters in the central Arabian Gulf

Spatiotemporal concentration patterns for 19 parents and their alkyl homologues were measured in Pinctada radiata from 7 locations in the central Arabian Gulf around Qatar in the winter, spring and summer (2014–2015). The concentrations of PAHs ranged from 20 to 2240 (262 ± 38.0 ng·g−1 dw) with the highest occurrence in the Doha harbor (738.4 ± 197.3 ng·g−1 dw) and the lowest in the west coast of Qatar (48.3 ± 5.8 ng·g−1 dw). Residual PAHs in the oysters were about two times higher in winter than in spring and summer (P 55 % of the ΣPAHs. Statistically significant differences in PAHs profiles among oysters were due in part to differences in lipid contents and shell biometrics. Principal component analysis (PCA) and diagnostic ratios for sources identifications suggested that PAHs accumulations in oysters were due to petrogenic and fuel combustion.This work was made possible by NPRP grant 6-442-1-087 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made here are solely the responsibility of the authors.Scopu

Accumulation of semivolatile organic compounds in Antarctic vegetation: A case study of polybrominated diphenyl ethers

Antarctic plant communities are dominated by lichens and mosses which accumulate semivolatile organic compounds (SOCs) such as polybrominated diphenyl ethers (PBDEs) directly from the atmosphere. Differences in the levels of PBDEs observed in lichens and mosses collected at King George Island in the austral summers 2004-05 and 2005-06 are probably explained by environmental and/or plant parameters. Contamination of lichens showed a positive correlation with local precipitation, suggesting that wet deposition processes are a major mechanism controlling the uptake of most PBDE congeners. These findings are in agreement with physical-chemical data supporting that tetra- through hepta-BDEs in the Antarctic atmosphere are basically bound to aerosols. Conversely, accumulation of PBDEs in mosses appears to be controlled by other environmental factors and/or plant-specific characteristics. Model simulations demonstrated that an ocean-atmosphere coupling may have played a role in the long-range transport of less volatile SOCs such as PBDEs to Antarctica. According to simulations, the atmosphere is the most important transport medium for PBDEs while the surface ocean serves as a temporary storage compartment, boosting the deposition/volatilization ""hopping"" effect similarly to vegetation on continents. (C) 2011 Elsevier B.V. All rights reserved.CNPq[55.0348/02-6]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)College of Geosciences at Texas AM UniversityCollege of Geosciences at Texas AM UniversityCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), Ministry of Education, BrazilCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Chlorinated pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons in the fat tissue of seabirds from King George Island, Antarctica

Antarctic Brazilian Program (PROANTAR)Brazilian Antarctic Program (PROANTAR)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Pesquisa (CNPq)Secretaria da Comissao Interministerial para os Recursos do Mar (SECIRM)Secretaria da Comissao Interministerial para os Recursos do Mar (SECIRM

Mesocosm experiments to better understand hydrocarbon half-lives for oil and oil dispersant mixtures.

Concerns on the timing and processes associated with petroleum degradation were raised after the use of Corexit during the Deepwater Horizon oil spill. There is a lack of understanding of the removal of oil associated with flocculate materials to the sediment. Mesocosm studies employing coastal and open-ocean seawater from the Gulf of Mexico were undertaken to examine changes in oil concentration and composition with time. The water accommodated fractions (WAF) and chemically enhanced WAF (CEWAF) produced using Macondo surrogate oil and Corexit were followed over 3-4 days in controlled environmental conditions. Environmental half-lives of estimated oil equivalents (EOE), polycyclic aromatic hydrocarbons (PAH), n-alkanes (C10-C35), isoprenoids pristane and phytane, and total petroleum hydrocarbons (TPH) were determined. EOE and PAH concentrations decreased exponentially following first-order decay rate kinetics. WAF, CEWAF and DCEWAF (a 10X CEWAF dilution) treatments half-lives ranged from 0.9 to 3.2 days for EOE and 0.5 to 3.3 days for PAH, agreeing with estimates from previous mesocosm and field studies. The aliphatic half-lives for CEWAF and DECWAF treatments ranged from 0.8 to 2.0 days, but no half-life for WAF could be calculated as concentrations were below the detection limits. Biodegradation occurred in all treatments based on the temporal decrease of the nC17/pristane and nC18/phytane ratios. The heterogeneity observed in all treatments was likely due to the hydrophobicity of oil and weathering processes occurring at different rates and times. The presence of dispersant did not dramatically change the half-lives of oil. Comparing degradation of oil alone as well as with dispersant present is critical to determine the fate and transport of these materials in the ocean

Relationship Between Carbonaceous Materials and Polychlorinated Biphenyls (PCBs) In the Sediments of the Danshui River and Adjacent Coastal Areas, Taiwan

Persistent organic pollutants, POPs (e.g., polychlorinated biphenyls) can seriously and deleteriously affect environmental quality and human health. These organic pollutants are exhibiting high affinities to solid phases and thus, quickly end up in sediments. To better understand the role of carbonaceous materials in the transport and distributions of POPs in terrestrial and near-shore environments, concentrations of PCBs and carbonaceous materials (including total organic carbon, black carbon and total carbohydrates), were determined in surface sediments of the Danshui River and nearby coastal areas, Taiwan. Total concentrations of PCBs in the sediments ranged from non-detectable to 83.9 ng g(-1), dry weight, with the maximum value detected near the discharge point of the marine outfall from the Pali Sewage Treatment Plant. These results suggest that the sewage treatment plant has discharged PCBs in the past and the concentrations are still high due to their persistence; alternatively, PCBs are still being discharged in the estuarine and near-shore environment of the Danshui River. Organic carbon and black carbon concentrations correlated well with those of total PCBs in the sediments, suggesting that both organic carbon and black carbon significantly affect the distribution of trace organic pollutants through either post-depositional adsorption, or by co-transport of similar source materials. The field results demonstrate that black carbon and plays an important role in the general distribution of PCBs, while concentrations of some specific PCBs are affected by both black carbon and organic carbon concentrations. (c) 2006 Elsevier Ltd. All rights reserved

Long-term changes in contamination and macrobenthic communities adjacent to McMurdo Station, Antarctica

Improved waste management at McMurdo Station, Antarctica beginning in the 1980s has been followed by decreases in polycyclic aromatic hydrocarbon (PAH) and metal contamination in the adjacent marine sediments. However, determining the effect of the decreased contamination on marine ecological indicators (macrobenthic fauna) is confounded by concurrent changes in climate cycles and other physical forces. Between 2000 and 2013, there was a decrease in concentrations of some contaminants including mercury, copper, organochlorines, and PAHs in marine sediments adjacent to McMurdo Station. PAH concentrations in Winter Quarters Bay decreased an order of magnitude from 2000/2003 to 2012/2013 and were within an order of magnitude of reference area concentrations by 2013. Macrobenthic communities did not indicate any sign of recovery and have not become more similar to reference communities over this same period of time. Temporal changes in macrobenthic community composition during the study period had higher correlations with climatic and sea ice dynamics than with changes in contaminant concentrations. The Interdecadal Pacific Oscillation climatic index had the highest correlation with macrobenthic community composition. The Antarctic Oscillation climatic index, maximum ice extent and other natural environmental factors also appear to influence macrobenthic community composition. Despite large improvements in environmental management at McMurdo Station, continuing environmental vigilance is necessary before any noticeable improvement in ecological systems is likely to occur. The effects of climate must be considered when determining temporal changes in anthropogenic effects in Antarctica. Maintaining long-term monitoring of both contaminants and ecological indicators is important for determining the localized and global influences of humans on Antarctica, which will have implications for the whole planet