Investigation of Aliphatic and Polycyclic Aromatic Hydrocarbons in Surface Sediments of Brunei Bay, East Malaysia

Abstract

The surface distributions of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were investigated from coastal sediments of Brunei Bay, southern South China Sea. The concentrations of total n-alkane (TNA) and 16 USEPA priority PAHs ranged from 0.67 to 9.88 μg/g and 4.72 to 102 ng/g, respectively. Principal component analysis (PCA) clustered the hydrocarbons in surface sediments according to their relationship and geographical locations, anticipated to the inputs and activities in proximity. Biomarker diagnostic ratios revealed that biogenic n-alkane inputs in the coastal sediments are exported from the fluviomarine and mangrove swamp environment, while the PAHs inputs are derived from mixed petrogenic and petroleum combustion residues. Overall, the level of PAHs in the study area is between low to moderate, based on the comparison with other areas worldwide.

Organic Geochemical Characteristics of Ngrayong Formation Polaman Sediment Rock, Northeast Java Basin-Indonesia

“…All samples exhibited a wide range of alkanes, with the highest and the lowest abundance being n-C 27 and n-C 16 , respectively. This result concludes that the organic matter source originated from bacteria, algae, and vascular plants, as found in sediments in Teluk Bunai, eastern Malaysia [20]. In terms of isoprenoid, pristane was observed in PLM 2, and phytane was found in PLM 2 as well as PLM 3.…”

“…The main role of vascular plants as the source of organic matter for PLM samples is confirmed by the AlkTerr value, as found in the Brunei Bay sediments, East Malaysia [20]. The AlkTerr value of PLM 1 samples was 0.39, and PLM 2 was 0.34 (or > 0.3), confirming the main role of vascular plants as the origin of organic matter and indicating the dominance of terrestrial higher plants.…”

“…The LHCPI also provided information on the maturity of Polaman sediments. It was confirmed that the major organic compound source was vascular plants, as affirmed by all samples possessing LHCPI lower than one, mentioned on Teluk Brunei sediment, Malaysia [20]. Another parameter was the wax index as an affirmation of the organic source.…”

“…If the Pr/Ph ratio is more than > 1, it indicates an oxic depositional environment, while a ratio less than < 1 indicates an anoxic depositional environment. A Pr/Ph ratio higher than 1 as an indicator of oxic deposition was reported in the Brunei Bay sediments in Malaysia [20]. Table 2 shows the presence of pristane in PLM 2 and PLM 3, while phytane was only identified in PLM 2 [10,[33][34].…”

“…The medium chain confirmed the contribution of bacteria, algae, and machropyte, including the submerged and floating ones. In addition, the vascular plant as the source of organic matter was affirmed by the long-chain alkane [14][15][16][17][18][19][20].…”