Distribution and Sources of Aliphatic Hydrocarbons in Sediments from Sadong River, Sarawak, Malaysia

Abstract

Twenty-one surface sediment samples collected from Sadong River, Sarawak were analysed for aliphatic hydrocarbons. These hydrocarbons were recovered from sediment by Soxhlet extraction and then analysed using gas chromatography equipped with mass spectrometer (GC-MS). The sediments collected from Sadong River have high concentrations of total aliphatic hydrocarbons which ranged from 310.41 to 1296.43 g/g. Evaluation of various n-alkane indices such carbon preference index (CPI: 1.32 to 1.98) and average chain length (ACL: 26.26-27.19) showed that there was a predominance of petrogenic sources of n-alkanes in the river and biogenic origin n-alkanes from vascular plants. The petrogenic source of n-alkanes are predominantly heavy and degraded oil with fresh oil inputs. It is believed that the hydrocarbons originated from both natural and anthropogenic sources. The hydrocarbons were mostly transferred by lateral input than atmospheric movements.