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Background and purpose: Polycyclic aromatic compounds (PAHs) are considered as priority organic compounds pollutants worldwide due to their high toxicity. Presence of oil wells has made petroleum hydrocarbon as one of the sources of pollution in the Caspian Sea. These are the pollutants of soil and water which are very dangerous and lethal for the aquatic ecosystem. The purpose of this study was to determine the 16PAHs (as oil pollution) in the sediments and two commercial fish in the Caspian Sea. Materials and methods: In this study, 32 sediment samples were collected from 8 stations at eight transects at 10 meter depth during four seasons. Also, 34 samples of Liza saliens (n=17) and Rutilus frisii kutum (n=17) were taken from the south of Caspian Sea. The samples were extracted using Soxhlet execrator with organic solvents and then analyzed using GC-FID (Shimadzu-14 A) instruments. Results: Concentration of 16PAHs in sediment in most stations was lower than critical level (NOAA standard). Applying different PAHs ratios, it was found that PAHs originated predominantly from the pyrogenic source either from the combustion of grass, wood and coal (majority of the samples) or from petroleum combustion (harbor area). The mean concentration of PAHs in Liza. s and R. frisii kutum were observed 2460 ± 60 and 2710 ± 56 µg/kg dw, respectively and 990 ± 33 µg/kg dw for sediment. In general, concentrations of PAHs in edible tissue of two species were higher than their corresponding sediment concentrations reflecting their great bioavailability (242-3880 µg/kg dw). The highest concentrations were observed in some ports of the southern Caspian Sea (Anzali, Nowshahr, and Amirabad), probably due to intensive shipping activities. Conclusion: The distribution pattern of PAHs was similar for fish and sediments, particularly for sediments characterized by high contamination level, and they were dominated by the high molecular weight PAHs (4-6-rings) which have high ecological risks.

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Background and purpose: Petroleum hydrocarbons might have a natural origin, but human activity is the main source of these pollutants in the environment. This study was done to determine the origin of n-alkanes and PAHs in surface sediments of the southeastern coast of the Caspian Sea. Materials and methods: A total of 12 sediment samples from six stations in Noshahr and Amir Abad ports were collected from 5, 15 and 30 meters depths. The samples were analyzed using gas chromatography. Results: In order to determine the origin of the n-alkanes we used CPI index (0.40-1.20), and biomarkers such as U/R (1.20-5.40), LMW / HMW (1.90-24.00), Pristane and Phytane (0.13-0.65). Also, to identify the source of PAHs the ratios of LMW / HMW (1.31-3.31), Phenanthrene / Anthracene (10.35- 12.88), Fluoranthene/Fl (0-0/43) + Pyrene, Benzo (a) anthracene / Chrysene (0.18-0/39), Fluoranthene / Pyrene (0.002-0.77) and An / An + Phe (0.01-0.09) were used. The results showed that n-alkanes and PAHs in the region both had petrogenic origins. This could be due to the reason that the studied regions are commercial ports with high rate of shipping activities. Conclusion: According to this study oil extraction in the country of Azerbaijan was the main source of oil pollution in the region which polluted the water by anticyclonic flow.

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Background and purpose: Heavy metals are non-degradable pollutants that could accumulate in marine animals including fish. The aim of this study was to determine the levels of six heavy metals (Zn, Cu, Ni, Pb, Cd and Hg) in edible tissue of Caspian carp (Cyprinus Carpio). We also studied the bioaccumulation factor (BFA) and target hazard quotients (THQ) of this fish in the southern Iranian Caspian Sea coast. Materials and methods: Twenty eight samples of fish were collected from seine and trawl during winter and spring 2010. Heavy metals were prepared (using Freeze dryer) by digestion and extraction process and then analyzed using atomic absorption equipped with flame, graphite and cold vapor system. Results: Results showed that Zinc (185±57) and Cu (3.68±0.30) µg/g.dw were seen more amongst the contaminants in the edible tissue of the Caspian carp. Concentration of Hg was 0.50±0.17 µg/g.dw and levels of Cd and Pb were below the limit of detection. BAF of metals were Zn> Cu> Hg. Conclusion: Ni, Cd and Pb in the Caspian carp muscle were lower that standard levels, but concentration of Hg was higher than the standard levels recommended by WHO, and ERL and ERM limits.

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Background and purpose: Hydrocarbons such as Polycyclic Aromatic Hydrocarbons (PAHs) are considered as priority organic compounds pollutants of the Caspian Sea due to their high toxicity nature. Increasing the concentration of hydrocarbons in the environment has adverse effect on aquatic life and human health. This study was conducted to determine the 16 Polycyclic Aromatic Hydrocarbons (16PAHs) concentrations in the edible tissue of Cyprinus Carpio in the Caspian Sea.. Material and Methods: A total of 28 samples of fish were collected during winter and spring. All samples were prepared by Soxhlet and extracting processes and then determined using High Performance Liquid Chromatography (HPLC) instrument. Results: Results showed that pattern of 16PAH compounds were obtained in 82% of samples (23 samples out of 28) for 3, 4 and 5 rings. The mean concentration and standard error (±SE) of edible tissue of Cyprinus Carpio mussels were observed 2.21 (±0.42) μg/g.dw. Conclusion: We observed Pyrene (75%), Fluorathene (61%), Benzo (a) pyrene (43%) and Chrycene (36%) in edible tissue of Cyprinus Carpio. Hence, consumption of this fish could endanger human health.