Aliphatic hydrocarbons and triterpane biomarkers in mangrove oyster (Crassostrea belcheri) from the west coast of Peninsular Malaysia

The Straits of Malacca is one of the world's busiest shipping routes where frequent oil spills occur. Rapid development in the west coast of Peninsular Malaysia is the other major source of petroleum pollution in this narrow waterway. In order to identify occurrence and origin of hydrocarbons in the Straits, mangrove oysters (Crassostrea belcheri) were collected from five sampling locations and analysed for n-alkanes and biomarkers. Soxhlet apparatus and two step column chromatography were used for extraction, purification and fractionation of the oysters. Petroleum origin n-alkanes were detected in majority of the sampling locations which is indicative of anthropogenic activities in this region. Using source and maturity diagnostic ratios for hopanes revealed used crankcase oil as the main source of petroleum hydrocarbons in oysters from all sampling locations except for the Pulau Merambong where signature of South East Asia crude oil (SEACO) was detected. •The concentrations of n-alkanes ranged from 56,661 to 262,515ng·g−1dw in oysters.•The concentrations of hopanes ranged from 1289 to 11,530ng·g−1dw in oysters.•Petroleum origin n-alkanes were predominant in most sampling locations.•Used crankcase oil and SEACO were the main sources of petroleum hydrocarbons.