Title: Biomagnification Profile of Polycyclic Aromatic Hydrocarbons (pahs) in Mangrove Ecosystem Elucidated by C and N Isotopes Ratios as Guides to Trophic Web Structure

Polycyclic aromatic hydrocarbons (PAHs) are natural, ubiquitous substances in marine environments; they consist of two or more benzene rings fused in various arrangements. A range of biological effects has been demonstrated for these compounds, including acute toxicity, carcinogenicity, mutagenicity, teratogenicity and endocrine disrupting activity (Takeuchi et al., 2009). There are two types of anthropogenic sources of PAHs: petrogenic and pyrogenic. Petrogenic sources include crude oil and petroleum products such as kerosene, gasoline, diesel fuel, lubricating oil, and asphalt. Pyrogenic sources form by the incomplete combustion of organic matter (e.g., coal, petroleum, and wood) in industrial operations and power plants that use fossil fuels, smelting, garbage incinerators, and vehicle engines powered by gasoline or diesel fuel, and forest fires (Saha et al., 2009). Being persistent in the sediment, PAHs can continually affect bottomdwelling organisms and high trophic level animals via food webs. It has been clarified that while relatively high concentrations are often detected in macroinvertebrates, and macroinvertebrates have been widely used as bioindictors to monitor spatial and temporal trends of PAH concentrations the concentration in animals at high trophic levels is relatively low and the primary concern is the potential of some PAHs’ metabolites to cause damage to DNA, RNA, and cellular proteins.