Evaluation of Hydrocarbons Pollution, Biodegradation and Weathering Extent in Surface Sediments of the Caspian Sea along Gholestan and Mazandran Provinces

Abessi, Ozeair; Saeedi, Mohsen

Evaluation of Hydrocarbons Pollution, Biodegradation and Weathering Extent in Surface Sediments of the Caspian Sea along Gholestan and Mazandran Provinces

Document Type : Original Articles

Authors

Ozeair Abessi ¹
Mohsen Saeedi ²

¹ PhD. Student Hydraulics and Environment, Faculty of Civil Engineering, Iran University of Science and Technology, Tehran, Iran

² Department of Hydraulics and Environment, Faculty of Civil Engineering, Iran University of Science and Technology, Tehran, Iran

Abstract

Due to the location of a domestic, industrial and agricultural zone near the Caspian Sea, this water body has long been under pressure and environmental threat. As a result of development of oil production activities in Caspian region, such as oil exploration and extraction in the central and eastern part, a large volume of oil related pollutants is released annually into this important water body. Considering the fact that hydrocarbons may cause adverse impacts on the aquatic and marginal life, the monitoring of sediment as hydrocarbons in the sea has long been considered. In this paper, oil contamination of surface sediments in large areas of the Mazandran and Golestan coasts (southeastern Caspian) are investigated in detail. In this study, using different concentrations of hydrocarbon components and developing related ratios and indices, the biodegradation and weathering extent of oil residues in the bottom sediments of the southern and southeastern Caspian Sea were appraised. The general concentration of the total petroleum hydrocarbon (TPH), normal Alkanes (n-Alkanes) and polycyclic aromatic hydrocarbons (PAHs) in the study area shows the relatively clean condition of sediments in the western part of the sea and moderate contamination in the central and eastern parts. Indices developed also corroborate the presence of degraded oil residue, high relative biodegradation and a degree of weathering of hydrocarbons in the surface sediment of the area, which suggest a chronic input of oil-related hydrocarbons in the neighbourhood of the study region.

Keywords