Bio-palladium nanoparticles (bio-Pd NPs) are receiving extensive interests as one of the latest innovative catalysts to remove a wide variety of common environmental contaminants, such as chlorinated organic solvents. This study aims to develop a biogenic nano Pd-based remediation method for reducing chlorinated hydrocarbons from marine environments. Bio-Pd NPs were synthesized using Shewanella oneidensis and the catalytic feasibility of novel catalysts was evaluated by monitoring the dechlorination of TCE and Aroclor 1254 PCBs. Complete dehalogenation of TCE was achieved using bin-formed Pd-catalysts in marine conditions including: synthetic marine water, marine water slurries and marine water. Moreover, extensive dechlorination of Aroclor 1254 PCBs to mainly monochlorobiphenyls was detected excluding sediment slurries from the Venice Lagoon. Additionally, the reactivity of immobilized NPs was evaluated in marine water and sediment slurries. Our study presents a new possibility in nano-based remediation strategies toward chlorinated pollutant in marine water and sediments. (C) 2014 Elsevier B.V. All rights reserved.