Macondo-1 well oil-derived polycyclic aromatic hydrocarbons in mesozooplankton from the northern Gulf of Mexico

Copyright 2012 by the American Geophysical UnionMesozooplankton (>200 μm) collected in August and September of 2010 from the northern Gulf of Mexico show evidence of exposure to polycyclic aromatic hydrocarbons (PAHs). Multivariate statistical analysis revealed that distributions of PAHs extracted from mesozooplankton were related to the oil released from the ruptured British Petroleum Macondo-1 (M-1) well associated with the R/VDeepwater Horizon blowout. Mesozooplankton contained 0.03–97.9 ng g−1 of total PAHs and ratios of fluoranthene to fluoranthene + pyrene less than 0.44, indicating a liquid fossil fuel source. The distribution of PAHs isolated from mesozooplankton extracted in this study shows that the 2010 Deepwater Horizon spill may have contributed to contamination in the northern Gulf of Mexico ecosystem

Biogeochemical and physical controls on concentrations of polycyclic aromatic hydrocarbons in water and plankton of the Mediterranean and Black Seas

The Mediterranean and Black Seas are unique marine environments subject to important anthropogenic pressures due to atmospheric and riverine inputs of organic pollutants. They include regions of different physical and trophic characteristics, which allow the studying of the controls on pollutant occurrence and fate under different conditions in terms of particles, plankton biomass, interactions with the atmosphere, biodegradation, and their dependence on the pollutant physical chemical properties. Polycyclic Aromatic Hydrocarbons (PAHs) have been measured in samples of seawater (dissolved and particulate phases) and plankton during two east-west sampling cruises in June 2006 and May 2007. The concentrations of dissolved PAHs were higher in the south-western Black Sea and Eastern Mediterranean than in the Western Mediterranean, reflecting different pollutant loads, trophic conditions and cycling. Particle and plankton phase PAH concentrations were higher when lower concentrations of suspended particles and biomass occurred, with apparent differences due to the PAH physical chemical properties. The surface PAH particle phase concentrations decreased when the total suspended particles (TSP) increased for the higher molecular weight (MW) compounds, consistent with controls due to particle settling depletion of water column compounds and dilution. Conversely, PAH concentrations in plankton decreased at higher biomass only for the low MW PAHs, suggesting that biodegradative processes in the water column are a major driver of their occurrence in the photic zone. The results presented here are the most extensive data set available for the Mediterranean Sea and provide clear evidence of the important physical and biological controls on PAH occurrence and cycling in oceanic regions.This work was funded by the European Union and Spanish Ministry of Science and Innovation through the Thresholds projects. N. Berrojalbiz acknowledges a predoctoral fellowship from the Basque Government. C Duarte is acknowledged as PI of Thresholds project and for leading two legs of Thresholds cruises. A. Tovar and M. Alvarez are acknowledged for leading the other two Thresholds legs, respectively.Peer reviewe

Polycyclic aromatic hydrocarbons (PAHs) atmospheric concentrations and deposition over the open Mediterranean and Black Seas

The Mediterranean Sea is a region of special interest in terms of pollutants monitoring and research due to its nature of semi-enclosed environment surrounded by highly populated areas. Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants (POPs) which are ubiquitous in the environment, bioaccumulate and may cause a wide range of toxic effects in biota and humans1. Very limited information is available on ambient levels, occurrence and deposition of PAH in marine environments and in particular in the Mediterranean Sea far from the shore line (open seas). Existing data have been mainly acquired from coastal areas. The incorporation of PAH to marine open waters and possible toxic effects is driven by atmospheric deposition processes2. It is therefore important to understand what the current ambient levels in the Mediterranean Sea airshed are in order to have a realistic idea of the potential inputs to this marine environment. The overall objectives of this work were: (1) to obtain PAH ambient air concentrations and congener patterns along the open Mediterranean Sea and in the Black Sea; (2) To investigate the atmosphere occurrence of PAHs in the open Mediterranean Sea and their day/night cycling in open waters; (3) to estimate the atmospheric deposition of PAHs in the Mediterranean and Black Seas.JRC.DDG.H.5-Rural, water and ecosystem resource

Atmospheric occurrence, transport and deposition of polychlorinated biphenyls and hexachlorobenzene in the Mediterranean and Black seas

The Mediterranean and Black seas are unique marine environments subject to important anthropogenic pressures due to direct and indirect loads of atmospheric inputs of organochlorine compounds (OCls) from primary and secondary sources. Here we report the results obtained during two east-west sampling cruises in June 2006 and May 2007 from Barcelona to Istanbul and Alexandria, respectively, where gas-phase and aerosol-phase samples were collected. Both matrices were analyzed for 41 polychlorinated biphenyls (PCBs), including dioxin-like congeners, and hexachlorobenzene (HCB). The values reported in this study for gas-phase HCB and Sigma 41PCB limit of detection (LOD) to 418.3 pg m(-3) and from 81.99 to 931.6 pg m(-3) respectively) are in the same range of those reported in former studies, possibly suggesting a limited decline in their atmospheric concentrations during the last decade for the Mediterranean region due to land-based OCl sources. There is a clear influence of the direction of the air mass on the atmospheric concentrations of PCBs, with higher concentrations when the air mass was from southern Europe, and the lowest concentrations for air masses coming from the SW Mediterranean and Atlantic Ocean. PCBs and HCB are close to air-water equilibrium for most sampling periods, thus resulting in low atmospheric deposition fluxes at open sea. This is consistent with the oligotrophic character of the Mediterranean Sea with a small influence of the biological pump capturing atmospheric PCBs. Therefore, degradation of gas-phase PCBs by OH radicals is estimated to be the main loss process of atmospheric PCBs during their transport over the Mediterranean Sea. Conversely, atmospheric residence times of HCB are predicted to be very long due to a lack of atmospheric degradation and low depositional fluxes due to concentrations at air-water equilibrium

Atmospheric occurrence, transport and deposition of polychlorinated biphenyls and hexachlorobenzene in the Mediterranean and Black Seas

Abstract. The Mediterranean and Black Seas are unique marine environments subject to important anthropogenic pressures due to direct and indirect loads of atmospheric inputs of organochlorine compounds (OCl) from primary and secondary sources. Here we report the results obtained during two east-west sampling cruises in June 2006 and May 2007 from Barcelona to Istanbul and Alexandria, respectively, where gas phase and aerosol samples were collected. Both matrices were analyzed for 41 polychlorinated biphenyls (PCBs), including dioxin-like congeners, and hexachlorobencene (HCB). The values reported in this study for gas phase HCB and ∑41PCB (LOD to 418.3 pg m−3 and from 81.99 to 931.6 pg m−3 respectively) are in the same range of those reported in former studies, possibly suggesting a limited decline in their atmospheric concentrations during the last decade for the Mediterranean region due to land base OCl sources. There is a clear influence of the direction of the air-mass on the atmospheric concentrations of PCBs, with higher concentrations when the air mass was from southern Europe, and the lowest concentrations for air masses coming from the SW Mediterranean and Atlantic Ocean. PCBs and HCB are close to air–water equilibrium for most sampling periods, thus resulting in low atmospheric deposition fluxes at open sea. This is consistent with the oligotrophic character of the Mediterranean Sea with a small influence of the biological pump capturing atmospheric PCBs. Therefore, degradation of gas-phase PCBs by OH radicals is estimated to be the main loss process of atmospheric PCBs during their transport over the Mediterranean Sea. Conversely, atmospheric residence times of HCB are predicted to be very long due to a lack of atmospheric degradation and low depositional fluxes due to concentrations at air–water equilibrium.JRC.H.1-Water Resource

The “Degradative” and “Biological” Pumps Controls on the Atmospheric Deposition and Sequestration of Hexachlorocyclohexanes and Hexachlorobenzene in the North Atlantic and Arctic Oceans

The cycling of hexachlorobenzene (HCB) and hexachlorocyclohexanes (HCHs) has been studied in the North Atlantic and Arctic Ocean. Concentrations of HCHs and HCB were measured simultaneously in the atmosphere (gas and aerosol phases), seawater (dissolved and particulate phases), and phytoplankton. The atmospheric concentrations of HCHs decrease during transport over the Greenland Current with estimated e-folding times of 1.6 days, a trend not observed for HCB. This strong decrease in atmospheric concentrations of HCH is consistent with the estimated atmospheric depositional fluxes driven by the air–water disequilibrium. The removal of HCHs from the surface ocean by the degradative pump due to hydrolysis and microbial degradation and by the biological pump due to settling of particle-associated HCHs are estimated; the removal fluxes are within a factor of 2 of the atmospheric inputs for most sampling events, suggesting an important role of the degradative pump in the overall oceanic sink of HCHs. Conversely, the lack of degradation of HCB in surface waters and its relatively low hydrophobicity imply a lack of effective removal processes, consistent with the observed air and water concentrations close to equilibrium. This work is the first that estimates the relative importance of the biological and degradative pumps on the atmospheric deposition of the less persistent organic pollutants and points out the need for further research for quantifying the magnitude of degradative processes in the environment

Atmospheric Occurrence and Deposition of Polychlorinated Dibenzo- p -Dioxins and Dibenzofurans (PCDD/Fs) in the Open Mediterranean Sea

International audienceThe overall objective of this work is to provide the firstevaluation of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs) occurrence and deposition to Mediterraneanopen seawater. Σ2,3,7,8-PCDD/F air (gas+aerosol) concentrationsover the Mediterranean Sea ranged from 60 to1040fg m-3. The highest value (1555 fg m-3) was measured in areference sample taken in the SW Black Sea. No consistenttrend regarding the diel cycle of PCDD/Fswasobserved.PCDD/Fs transported to the open sea waters from continental areasand across the Atlantic as well as ship emissions may besignificant sources to the open Mediterranean. Seawaterconcentrations in the Mediterranean ranged from 42 to 64 fgL-1. The Σ2,3,7,8-PCDD/F dry deposition fluxes in theMarmara and Black Seas (210 kg year-1) are from 2 to 55times higher than dry fluxes in the Mediterranean Sea (4-156kg year-1). Analysis of estimated diffusive air-water fluxesand air/water fugacity ratios show that a net volatilization ofsome PCDD congeners is feasible. However, evidence of anet absorption flux for the rest of PCDD/F is found. When bothatmospheric deposition processes are considered togetherthe open Mediterranean Sea is a net sink of PCDD/F, due tothe importance of dry deposition fluxes of aerosol-boundPCDDFs