منشأ یابی و ارزیابی خطر هیدروکربن های چند حلقه ای آروماتیک (PAHs) در رسوبات ساحلی دریای خزر، استان گیلان

         Background and purpose: The Caspian Sea is the largest lake in the world. Due to having a long            coastal line, population areas, agricultural and industrial activity its have always been exposed to variety of pollutants. Due to variaty effects of pollutant on aquatic life and human, periodic investigation of pollutant in water bodis is wery important.         Materials and methods: In this study, oil pollution and heavy metal (nickel and vanadium) contamination of sediment and gamaros samples from Guilan province coasts were investigated. For hydrocarbon analyze, the samples were extracted with a Soxhlet extractor and analyzed with (GC-MS). In order to heavy metals analyzes, samples were digested with HNO3 /HCL (1:3) and analysed with ICP-OES spectrometers.          Results: Total mean concentration of PAHs in sediment and Living tissue was 19.8 ng/g and 35.4 ng/g respectively. Also total mean concentration of TPH in sediment and Living tissue was 11.4 µg/g and 38.4 µg/g respectively. mean concentration of nickel and vanadium in sediment was 16.45 µg/g and 45 µg/g respectively also mean concentration of nickel and vanadium in soft tissue was 2.16 µg/g and 2.06 µg/g respectively.          Conclusion: Ratio values of PAH compounds were calculated to evaluate the possible source of PAH contamination. This ratios suggesting that this reagain have a petrogenic and pyrogenic input of PAHs. Sediment quality guidelines were conducted to assess the toxicity of PAH compounds. The levels of total PAHs at all of stations were below the effects range low. Also, concentrations of nickel and vanadium were below the standards.