Persistent Organic Pollutants in Mediterranean Seawater and Processes Affecting their Accumulation in Plankton

The Mediterranean and Black Seas are unique marine environments subject to important anthropogenic pressures due to riverine and atmospheric inputs of organic pollutants. 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 water and plankton samples were collected simultaneously. Both matrices were analized for hexaclorochyclohexanes (HCHs), hexachlorobencene (HCB) and 41 polychlorinated biphenyl (PCB) congeneres. The comparison of the measured HCB and HCHs concentrations with previously reported dissolved phase concentrations suggests a temporal decline in their concentrations since the 1990s. On the contrary, PCB seawater concentrations did not exhibited such a decline, but show a significant spatial variability in dissolved concentrations with lower levels in the open Western and South Eastern Mediterranean, and higher concentrations in the Black, Marmara, Aegean sea and Sicilian Strait. PCB and OCPs (organochlorine pesticides) concentrations in plankton were higher when lower concentrations of biomass occurred, but the intensity of this trend depended on the compound hydrophobicity (KOW). For the more persistent PCBs and HCB, the described differential dependence of POP concentrations in plankton versus biomass can be explained by interactions between air-water exchange, particle settling and/or bioaccumulation processes, whereas degradation processes ocurring in the photic zone drive the trends showed by the more labile HCHs. The results presented here are the most extensive data set available for the Mediterranean Sea and provide clear evidence of the important physical and biogeochemical controls on POP occurrence in the marine environment

BERROJALBIZ Naiara;  DACHS Jordi;  OJEDA María José;  VALLE María Carmen;  DEL VENTO Sabino;  CASTRO-JIMENEZ Javier;  MARIANI Giulio;  WOLLGAST Jan;  HANKE Georg; 

2011-05-30

AMER CHEMICAL SOC

JRC62942

0013-936X,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC62942,   

10.1021/es103742w,