Occurrence and trophic transfer of aliphatic hydrocarbons in fish species from Yellow River Estuary and Laizhou Bay, China

Abstract Petroleum pollution in aquatic environment has caused great concerns around the world, which produce harmful impacts on aquatic organisms and human health. Aliphatic hydrocarbons in the environment are mainly derived from petroleum and its products. However, limited information is available regarding their occurrence and trophic transfer behavior in aquatic biota. Here, eight fish species collected from Yellow River Estuary and Laizhou Bay were analyzed to investigate the residual level, homolog profiles and trophic magnification of aliphatic hydrocarbons. Carbon and nitrogen stable isotope ratios (δ13C and δ15N) of studied fish species ranged from −22.1 to −14.5‰ and 8.56 to 15.7‰, respectively, indicating different carbon sources and trophic positions. The lowest and highest levels of n-alkanes were found in Cyprinus carpio (376 μg/kg wet weight, ww) and Silurus asotus (8179 ± 7955 μg/kg ww), respectively. The different distribution patterns of n-alkane homologs were observed among different species, which could be attributed to their particular habitat, feeding preference and elimination activity. Analysis of biomarker indices indicated the presence of petroleum hydrocarbons in muscle tissues of studied fish species. And natural n-alkanes were probably more easily eliminated than anthropogenic n-alkanes in fish muscle tissues. Moreover, trophic magnification factor (TMF) values ranged from 0.656 to 1.15, indicating limited trophic transfer of aliphatic hydrocarbons. The octanol/water partition coefficient (KOW) probably was an important factor to affect the bioaccumulation of n-alkanes in organism-sediment system and the biomagnification along the trophic levels.