Biomagnification vs. diffusive uptake of PAHs in marine zooplankton: an experimental study.

ANDRES ARIAS; ANISSA SOUISSI; SOPHIE NET; OLIVIER GLIPPA; DAVID DUMOULIN; BAGHDAD OUDANNE; PAMELA QUINTAS; JORGE MARCOVECCHIO; SAMI SOUISSI

Mar del Plata

Congreso; III Reunión Argentina de Geoquímica de la Superficie (III RAGSU); 2014

Facultad de Cs.Exactas y Naturales - UNMdP

Polycyclic aromatic hydrocarbons (PAHs) are a widely distributed group of organic pollutants originating from petrogenic, pyrogenic and natural sources, which have the potential to enter to the marine trophic web, bioaccumulate and biomagnificate. Whether biomagnification between the trophic levels ?phytoplankton? and ?zooplankton? actually occurs in the field is still an open question, but a question that needs to be answered in order to make reliable predictions about persistent organic compounds fate in aquatic ecosystems. Then, the aim of the present study was to perform carefully controlled experiments to investigate the importance of the exposure route (water or contaminated food) for the bioaccumulation of some PAHs in the marine copepod Pseudiaptomus marinus. Two main hypotheses were tested: 1. Biomagnification is higher in feeding animals due to the uptake of PAHs via contaminated food in addition to diffusive uptake via body surfaces. 2. Biomagnification increases with hydrophobicity of the exposed compound. Experimental procedure were set in duplicate and each copepod condition was fed during the treatment in order to parallel realistic marine conditions. During the exposure, continuous sub-sampling of water medium and animals was performed. Each sample was extracted and GC/MS analyzed for selected PAHs. Results showed that the marine copepod is capable of accumulate PAHs by the two ways of exposure, either present in the medium (diffusive uptake) or in the food (algae) and that both mechanisms were increased with the Log Kow of the corresponding PAH. Therefore, PAH?s bioaccumulation cannot be solely modelled as a passive partitioning between the organisms and the surrounding water.