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

The Mediterranean Sea and Black Sea 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 ecological characteristics, which allow the studying of the drivers for pollutants occurrence and fate under different conditions. 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 Black Sea and Eastern Mediterranean than in the Western Mediterranean, reflecting different source strength and trophic status. Particle and plankton phases PAHs concentrations were higher when lower concentrations of suspended particles and biomass occurred, but with differences depending on the PAH physical chemical properties. For the surface PAH particle phase concentrations, the dependence on TSP was significative for the higher MW compounds, consistent with controls due to interactions between atmospheric deposition and particle settling. Conversely, PAH in plankton decreased at higher biomass only for the low MW PAHs, suggesting that degradative processes in the water column are a major driver of their occurrence in the photic zone. The results provided here is the most extensive data set available for the Mediterranean Sea and provide clear evidence of the important trophic controls on PAH occurrence in the marine 34 rine environment, which for open sea water exert a higher influence than distance to sources.

BERROJALBIZ Naiara;  DACHS Jordi;  OJEDA Maria Jose;  VALLE Maria Carmen;  CASTRO JIMENEZ Javier;  WOLLGAST Jan;  GHIANI Michela;  HANKE Georg;  ZALDIVAR COMENGES Jose'; 

2011-11-30

AMER GEOPHYSICAL UNION

JRC53565

0886-6236,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC53565,   

10.1029/2010GB003775,