Determination of Origin and Concentration of n-Alkanes Residues in Eggs of four Tern Species on Shidvar Island, the Persian Gulf

The prevention of pollution of marine ecosystems is very important for the sustainable use of resources. Given the persistence of pollutants in the aquatic food chain, the likelihood of damage to all living organisms is high, including humans who are at the top of the food chain. n-alkanes were used as an indicator of the origin and changes in organic substances. The present study was aimed at determining the origin and concentration of these compounds in the eggs of four sea-bird species (White-cheeked Sterna repressa, Bridled Sterna anaethetus, Greated Crested and Lesser Created T. bengalensis Terns) on Shidvar Island in July 2013. n-alkanes were mostly determined in the range of n-C14 - n- C35, and their total obtained concentrations in the sampled eggs of White-cheeked, Bridled, Greated Crested and Lesser Created Terns were also in the range of 41.39-86.32, 22.88-53.19, 21.82- 54.94 and 59.47-95.46 (μg.mg-1 lipid), respectively. However, the concentrations of these compounds in eggs of the White-cheeked and Lesser Created Terns were higher than the Greater Crested and Bridled Terns. Diagnostic ratios of CPI, Pr/Ph, n-C17/Pr, n- C18/Pr and U/R, in addition, n-alkanes in all the samples were mostly recognized as originating from petrogenic compounds and, so, the most important causes involved are presumably contamination from oil refineries which have been established on Lavan Island closed to Shidvar Island. The presence of oil pollutants cause by oil spills in the Persian Gulf, shipping, the discharge of ballast water from ships to this area is also an important source.