the concentration and origin of total petroleum hydrocarbons (tphs) in coastal sediments of the kharg island in the persian gulf

introductionpersian gulf is a water body at the margin of indian ocean which makes way to oman sea and indian oceanthrough the strait of hormuz with the minimum width of 56 km. specific condition of the persian gulf such ashigh evaporation, high salinity, aqueous species diversity, fisheries value and especially oil sources of the area,which have extra importance in the world, have made it a sensitive and strategic area. marine environment of thepersian gulf suffers severely from oil pollution. oil extraction and transportation together with the effluentdischrges from the coastal cities and oil refinneries are among the major sources of oil pollution in the gulf.kharg island is a coral anticline in the persian gulf located within 28 km of the southern coasts of iran. thisisland has a length of approximately 8 km and a width of approximately 4 to 5 km. the coastal environment ofthe kharg island is rich with corals. the corals are the host to many types of local fishes of the persian gulf.kharg island contains the most important and also the biggest crude oil export terminal of iran. more than 90%of iranin oil exportation is conducted through the island. in addition, many other oil related activities includingstoring and filtering of the crude oil are performing in the island. hosting extensive oil related activites duringthe past 50 years has subjected the marine and coastal environment of kharg island to huge amount of oildischarges from different sources icluding oil tanker accidents, leakages at the oil term inals, discharge of oilyeffluents from crude oil stores and oil refineres. however, surprisingly, there are only a few studies conductedon the oil pollution around the island. in this paper, the oil pollution and its origin in the near shore coastalsediments of the kharg island are examined and discussed. this is conducted by using the analysis of theconcentration of hydrocarbones in the sediment samples collected early 2012 from 11 points around the island.materials and methodsnear shore sediment samples were collected at 11 points around the island. the stations were selected in a waythat they cover the whole parts of the island's coastline. the samples were also more concentrated near the oilterminals. all of the samples were taken near the coastline at knee deep water points in low tide condition. about200 to 300 grams of wet sediments were taken from the top 5 centimeter of surface sediment and was pouredinto boron silicate vial which was washed by washer material, hot water, acetone solution and distilled water andhad a lid of polyethylene. the collected samples were packed and protected for transferring to laboratory usingthe usepa-sw-846 standard method.the standard method of american association of environmental protection (usepa-sw-846#3540c)named soxhlet has been used for preparation of the samples and extraction of petroleum hydrocarbons fromthem. the samples were passed through a 63 micron sieve (