Creeks outfall affects not only PCB distribution in this coastal environment, due to their discharge of such compounds but also due to their input of carbon from different source. In the present study, PCB contamination from land based sources related to a landfill area has been found in an intertidal marine ecosystem of the south-eastern region of Buenos Aires Province, Argentina. These contaminants would reach the intertidal zone through creeks, which are so far poorly studied sources. Thus, although the studied creeks have small flow and despite the relatively high capacity of dispersion of the marine environment, PCB reached concentration of concern in the nearby coast. Finally, PCB accumulation in mussels B. rodriguezii was enhanced by the organic matter input from creeks, which highlights the importance to consider this factor when studying PCB distribution in organisms of coastal systems.