Linear alkylbenzenes (LABs) as sewage pollution indicators in the aquatic ecosystem of Peninsular Malaysia

Linear alkylbenzenes (LABs) as sewerage indicators were investigated in the sediments of the West and South Peninsular Malaysia. Surface sediment samples were analyzed using gas chromatography-mass spectrometry. Results showed that LAB concentration in the samples of Port Dickson and the Kim Kim River varied from 111.6 to 255.8 and from 88.2 to 119.0 ng{middle dot}g-1 dry weight, respectively. The ratios of internal isomer, in which the benzene ring was close to the center of the linear alkyl chain, to external isomer, in which the benzene ring was near the end of the linear alkyl chain (I/E ratios), of LABs in Port Dickson coast sediments ranged from 2.6 to 4.1. By contrast, the ratios for sediment from the Kim Kim River varied from 1.7 to 1.9. I/E, long-chained LABs over short-chained LABs (L/S), and C13/C12 ratios indicated that the aquatic environment received primary and secondary sewage effluents. These findings emphasized the necessity of continued water treatment system development in Malaysia.