"In recent years, a relatively new technique, compound specific isotope analysis (CSIA) has begun to be applied in a novel way to apportion sources of contaminants in the environment and answer to a variety of biogeochemical questions. The originality of this proposal will be to explore, develop and exploit the potential use of Compound Specific Isotope Analysis (CSIA) to persistent hydrocarbons (PAHs) and persistent organic pollutant (POPs) compound groups in marine environments in order to unambiguously allocate and distinguish their contaminant sources, track their contamination pathways (“environmental forensics”), identify and quantify transformation reactions, chemical or biological remediation processes as well as degradation mechanisms. Research will include both field and laboratory experiments studies. It will be a novel and exciting part of this project the determination of the isotopic signature of chlorine and bromine in addition to the more frequently used carbon and hydrogen isotopic characterization. Potential of combined stable isotopic systems will be also investigated. New extraction, enrichment and clean up methods will be developed or improved, and consequently protocol procedures established, to overcome the poor sensitivity of this technique for the analysis of organic compounds at trace levels and constrain specific compounds' isotopic composition. Modifications of the original isotopic composition through biodegradation and/or metabolic processes will be monitored in chamber experiments. The observation of different C, H, Cl, Br isotopic signatures in marine compartments could be very useful for modelling the dynamic of POPs which is a big challenge for 21st century. A better understanding of pollutant inputs, pathways, processing and bioavailability in marine environment will facilitate remediation efforts in contaminated areas and environmental management decisions."