Integrated Use of n-Alkanes and PAH to Evaluate the Anthropogenic Hydrocarbon Sources and the Toxicity Assessment of Surface Sediments from the Southwestern Coasts of the Caspian Sea

Document Type : Research Paper


1 PhD Student Department of Environmental Sciences, Faculty of Natural Resources and Marine Science, Tarbiat Modares University, Noor, Mazandaran, Iran

2 Assoc. Prof., Department of Environmental Sciences, Faculty of Natural Resources and Marine Science, Tarbiat Modares University, Noor, Mazandaran, Iran

3 Assist. Prof., Research Institute of Petroleum Industry, Tehran, Iran


Polycyclic aromatic hydrocarbon (PAH) compounds and normal alkanes form a large group of undegradable environmental contaminats. This study aims to determine the sources and distribution of oil pollution (PAH compounds and normal alkanes) in the sediments of the southwestern coastal areas of the Caspian Sea and to compare their levels with the relevant standards. For this purpose, 18 surface sediment samples were collected from depths of 10, 20, and 50 meters along two transects in the vertical direction located in the coastal areas of Sangachin and Hashtpar (Gilan Province). The samples were then examined using mass-spectrometric gas chromatography. The origins of n-alkanes were identified using CPI index (0.76-0.95), U/R (3.30‒6.57), and Pristane/Phytane (0.21‒0.42). The sources of PAHs were determined using the index ratios of LMW/HMW (1.93‒13.37), Phenanthrene/Anthracene (11.44‒ 16.7), Chrysene/Benzo (a) anthracene (4.69‒10/33), Fluoranthene/Pyrene (0.53‒0.69), and MP/P (0.05‒0.08). Results confirmed the dominant petrogenic source of the hydrocarbons found in the region. The total concentrations of 30 aliphatic hydrocarbons and PAHs in the sediments ranged from 823.8 to 3899.5 µg/g and from 626.95 to 3842.5362 ng/g, respectively. Comparison of the measured PAH concentrations with US sediment quality guidelines revealed that the levels of naphthalene, fluorine, Acenaphthylene, and Acenaphthene exceeded the ERLs at stations with depths of 50m in Sangachin and Hashtpar while comparisons with Canadian standards indicated that they were higher than PELs at all the stations sampled. A major point of great concern is the high concentration of naphthalene as the most toxic PAH compound, which naturally warrants due attention to adopt appropriate management programs.


Main Subjects

Abessi, A. & Saeedi, M., 2010, "The origin of oil hydrocarbons in southern coastal sediments of the Caspian Sea in vicinity of Golestan and Mazandran province", Journal of Environmental Studies, 36(55), 43-58.
Azimi-Yancheshmeh, R., Riyahi Bakhtiyari, A.R. & Mortazavi, S., 2010, "Distribution and source identification of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the southern shores of the Caspian Sea, Anzali City", MSc. Thesis, Tarbiat Modares University, Tehran. (In Persian)
Baumard, P., Budzinski, H., Michon, Q. & Garrigues, P., 1998, "Origin and bioavailability of PAH in the Mediterranean Sea from mussel and sediment records", Estuarine, Coastal and Shelf Science, 47, 77-90.
Bixiong, Y., Zhihuan, Z. & Ting, M., 2007, "Petroleum hydrocarbon in surficial sediment from rivers and canals in Tianjin, China", Chemosphere, 68, 140-149.
CCME., 1999, "Canadian sediment quality guidelines for the protection of aquatic life: Polycyclic aromatic hydrocarbons (PAHs)", In: Canadian environmental quality guidelines, Canadian Council of Ministers of the Environment: Winnipeg, pp. 1-16.
Chen, L. G., Ran, Y. & Xing, B. S., 2005, "Contents and sources of polycyclic aromatic hydrocarbons and organochlorine pesticides in vegetable soils of Guangzhou, China", Chemosphere, 60, 879-890.
Dongen, B.E.V., Rowland, H.A.L., Gault, A.G., Polya, D.A,, Bryant, C.& Pancost, R.D., 2008, "Hopane, sterane and n-alkane distributions in shallow sediments hosting high arsenic groundwaters in Cambodia", Applied Geochemistry. 23, 3047-3058.
Freydoni, R., Farhadi, Z., Riahi Bakhtiari, A. & Nasrollahzadeh, H., 2013, "Integrated use of n-alkanes and polycyclic aromatic hydrocarbons in the source identification petroleum hydrocarbons at 5, 15 and 30 m depths in Noshahr and Amir Abad Ports, Caspian Sea", Mazandaran University of Medical Sciences 23 (101), 62-7. (In Persian)
Gao, X. & Chen, S., 2008, "Petroleum pollution in surface sediments of Daya Bay, South China, revealed by chemical fingerprinting of aliphatic and alicyclic hydrocarbons", Estuarine, Coastal and Shelf Science, 80, 95-102.
Gao, X., Chen, S., Xie, X., Long, A. & Ma, F., 2007, "Non-aromatic hydrocarbons in surface sediments near the Pearl River estuary in the South China Sea", Environmental Pollution, 148, 40-47.
Hajizadeh, Z., Rahmani, A., Moghadam, M., Shadi, R. & Abesi, A., 2011, "Conentration and source identification of oil hydrocarbons in surface sediments from Anzali City", Mohitshenasi Journal, 60, 99-106. (In Persian)
Harris, K.A., Yunker, M.A., Dangerfield, N. & Ross, P.S., 2011, "Sediment-associated aliphatic and aromatic hydrocarbons in coastal British Columbia, Canada: Concentrations, composition, and associated risks to protected sea otters", Environmental Pollution, 159, 2665-2674.
Jeng, W. L. & Huh C. A., 2006, "A comparison of sedimentary aliphatic hydrocarbon distribution between the southern Okinawa Trough and a nearby river with high sediment discharge", Estuarine, Coastal and Shelf Science, 66, 217-224
Jeng, W., 2007, "Aliphatic hydrocarbon concentrations in short sediment cores from the southern Okinawa Trough: Implications for lipid deposition in a complex environment", Continental Shelf Research, 27, 2066-2078.
Johnson, L.L., Collier, T.K. & Stein, J.E., 2002, "An analysis in support of sediment quality thresholds for polycyclic aromatic hydrocarbons (PAHs) to protect estuarine fish", Aquatic Conservation, 12(5), 517-538.
Khoshravan, H., Ruhanizadeh, S. & Nezhadgholi, G., 2011, "Zoning of the Caspian Sea on the basis of sedimentary morphodynamic", Journal of Earth and Space Physics, 37(3), 1-15. (In Persian)
Lashte neshyi, M., Slami, A. & Piravi, M., 2006, "Investigation the potential of sediment transportation", International Journal of Engineering, 5(17), 39-45. (In Persian)
Long, E.R., Macdonald, D.D., Smith, S.L. & Calder, F.D., 1995, "Incidence of adverse biological affects with ranges of chemical concentrations in marine and estuarine sediments", Environmental Management, 19 (1), 81-97.
Maioli, O. L. G., Rodrigues, K. C., Knoppers B. A. & Azevedo, D. A., 2011, "Distribution and sources of aliphatic and polycyclic aromatic hydrocarbons in suspended particulate matter in water from two Brazilian estuarine systems", Continental Shelf Research, 31, 1116-1127.
Medeiros, P.M., Bı´cego, M.C., Renato Menezes Castelao, R.M., Rosso, C.D., Fillmann, G. & Zamboni, A. J., 2005, "Natural and anthropogenic hydrocarbon inputs to sediments of Patos Lagoon Estuary, Brazil", Environment International, 31, 77-87.
Nemati Varnosfaderany, M. & Riyahi Bakhtiari, A., 2014, "Vertical distribution and source identification of polycyclic aromatic hydrocarbons (PAHs) in southwest of the Caspian Sea", PhD. Thesis, Tarbiat Modares University, Tehran. (In Persian)
Nemirovskaya, I.A. & Brekhovskikh, V.F., 2008, "Origin of hydrocarbons in the particulate matter and bottom sediments of the northern shelf of the Caspian Sea", Oceanology, 48, (1), 43-53.
Nishigima, F.N., Weber, R.R. & Bicego, M.C., 2001, "Aliphatic and aromatic hydrocarbon in sediments of Santos and Cananeia SP, Brazil", Marine Pollution Bulletin, 42(11), 1064-1072.
Oliveira, C. & Madureira, L., 2011, "Assessment and sources of nonaromatic hydrocarbons in surface sediments of three harborsin Santa Catarina State, Brazil", Environmental Monitoring and Assessment, 173, 91-105.
Perra, G., Renzi, M., Guerranti, C. & Focardi, S.E., 2009, "Polycyclic aromatic hydrocarbons pollution in sediments: distribution and sources in a lagoon system (Orbetello, Central Italy)", Transitional Waters Bulletin, 3(1), 45-58.
Riyahi Bakhtiari, A., Zakaria, M. P., Ismail, M., Nordin, H., Lajis, M. & Bi, X., 2011, "Variation and origins of aliphatic hydrocarbons in sediment cores from Chini lake in Peninsular Malaysia", Environmental Forensics, 12(1), 1-12.
Riyahi Bakhtiari, A., Zakaria, M.P., Ismail Yaziz, M., Nordin, H, Lajis, M. & Bi, X., 2010, "Polycyclic aromatic hydrocarbons and n-alkanes in suspended particulate matter and sediments from the langat river, Peninsular Malaysia", Environment Asia, 2, 1-10.
Saha, M., Togo A., Mizukawa, K., Murakami, M., Takada, H., Zakaria, M.P., et al., 2009, "Sources of sedimentary PAHs in tropical Asian waters: Differentiation between pyrogenic and petrogenic sources by alkyl homolog abundance", Marine Pollution Bulletin, 58, 189-200.
Sicre, M.A., Marty, J.C., Saliot A., Aparicio, X., Grimalt, J. & Albaiges, J., 1987, "Aliphatic and aromatic hydrocarbons in different sized aerosols over the Mediterranean Sea", Occurrence and Origin Atmospheric Environment, 21, 2247-2259.
Silva, T.S., Lopes, S.R.P., Spörl, G., Knoppers, B.A. & Azevedo, D., 2012, "Evaluation of anthropogenic inputs of hydrocarbons in sediment cores from a tropical", Microchemical Journal, 109, 178-188.
Tolosa, I., Mora, S. & Sheikholeslami, M.R., 2004, "Aliphatic and aromatic hydrocarbons in coastal Caspian Sea sediments", Marine Pollution Bulletin, 48, 44-60.
Walker, S. E., Dickhut, R. M., Chisholm-Brause, C., Sylva, S. & Reddy C. M., 2005, "Molecular and isotopic identification of PAH sources in a highly industrialized urban estuary", Organic Geochemistry, 36, 619-632.
Yunker, M.B. & Macdonald, R.W., 2003, "Petroleum biomarker sources in suspended particulate matter and sediments from the Fraser River Basin and Strait of Georgia, Canada", Organic Geochemistry, 34, 1525-1541.
Zakaria, M.P. & Mahat, A.A., 2006, "Distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments in the Langat Estuary", Coastal Marine Science, 30(1), 387-395.
Zakaria, M.P., Horinouchi, A., Tsutsumi, S., Takada, H. & Ismail, A., 2000, "Oil pollution in the Straits of Malacca, Malaysia: Application of molecular markers for source identification", Environmental Science and Technology, 34, 1189-1196.