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Aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were studied in two sediment cores of southern South China Sea off Johor coastal area. The concentrations of the total identified resolved aliphatic hydrocarbons (TiRAHs) in the coastal station (STC104) ranged from 0.35 to 2.07 µg/g while the offshore station (STC100) varied from 0.05 to 14.7 µg/g. The concentrations of total PAHs were varied from not detected to 33.9 ng/g. The nalkanes distribution in STC104 were predominant in short chain carbons from marine productivity, petroleum mixture and minor higher plant input, while STC100 exhibited a bimodal distribution with mixed input of marine and terrestrial origin. PAHs isomer ratios cross-plot have showed mixed input of pyrogenic and petrogenic inputs while perylene was dominated in STC100 followed by fossil fuels and pyrogenic source. Presence of perylene in both cores suggesting the contribution of biogenic sources. Principal component analysis was used to cluster the relationship of the hydrocarbons at both sediment cores.

This work reported the n-alkanes contents in a 10 m peat core collected at Timbarap, Sarawak. Different biomarker proxies were used to understand the predominance of sources present in the tropical peatland of Borneo. The total concentrations of n-alkanes in selected depths of Timbarap peat core ranged between 0.01 and 12.60 μg/g with an average of 1.58 μg/g. The presence of strong odd-to-even predominance from higher molecular weight n-alkanes homologues with high values of carbon preference index (CPI) provide clear evidences of the terrestrial plant wax assemblages. Increment of low-molecular-weight n-alkanes provide an indicator of biogenic-aquatic organic materials. The ratios of isoprenoids (pristane and phytane) have shown that the peat core was under anaerobic and reducingdepositional conditions, which could result the predominance source that alternated between aquatic-biogenic and terrestrial-derived materials.

Fine particulate matter (aerodynamic diameter ≤2.5 µm) (PM2.5) has become a major concern because it can adsorb chemicals e.g. polycyclic aromatic hydrocarbons (PAHs) onto its surface. Although PAHs are priority pollutants that can cause adverse health effect, there is still limited information concerning indoor exposures to PAHs in Malaysia. This study aimed to characterise the distribution of PAHs bounded to PM2.5 in primary school environments. Indoor and outdoor PM2.5 were collected between May and July 2017 using low volume samplers (LVS) at three public primary schools in the Federal Territory of Kuala Lumpur. PAHs were extracted by ultrasonic extraction with Dichloromethane:n-Hexane (1:1, v/v) as the extraction solvent and analysed using gas chromatography coupled with mass spectrometer (GC-MS). Based on the results, the average total concentration of PAHs (∑PAHs) ranged from 3.8 to 10.1 ng m-3 and 1.6 to 8.0 ng m-3 for outdoors and indoors, respectively. PAHs in PM2.5 samples indicated the potential contribution of combustion at high temperature and indoor sources, and the infiltration of outdoor PAHs were the important sources for outdoor and indoor, respectively. In addition, the diagnostic ratio analysis showed that vehicular emissions were the most predominant sources of PAHs in school environments.

The surface distribution of lipid biomarkers, elemental and isotopic compositions ( δ 13 C and δ 15 N, C/N) were investigated from coastal sediments of Brunei Bay, in order to understand the sources and biogeochemical processes of the organic matter. Fatty acid biomarkers from terrestrial higher plants (e.g., long-chain fatty acids > 20), phytoplankton (e.g., 20:5n-3 and 22:6n-3) and microbial activity (e.g., iso-, anteiso fatty acids, 10Me-16:0) were identified. The ratios of carbon and nitrogen isotopes ( δ 13 C, δ 15 N) and C/N had values ranging from –30.62 to –27.43‰, 1.70 to 3.57‰, and 4.07 to 15.62 respectively, suggesting the prevailed inputs of terrestrially-derived organic matter sources with typical characterization of mangrove estuaries. Principal component analysis separated lipids of autochthonous aquatic production as the major source, followed by allochthonous terrestrial derived input. The presence of bacterial derived lipids and short chain lipids with low and C/N ratios suggest the preferential utilization and decomposition of organic matter by microbial activity. An enrichment of the δ 15 N ratios could be due to marine cage culture activities and surface runoff from cultivated areas via fluvial transport.

A baseline study to assess the distributions of aliphatic and polycyclic aromatic hydrocarbons in abiotic environment consisting of soil, sediment and atmospheric particulate samples was carried in Terengganu National Park. Aliphatic hydrocarbons were found in all three media studied whilst polycyclic aromatic hydrocarbon (PAH) compounds were detected, only in the atmospheric particulate samples, at trace levels. The 24 hr-PM10 and Total Suspended Particulate (TSP) concentrations is still below the recommended Malaysian Air Quality Guidelines for the respective parameter. Analyses of the results suggest that terrestrial plant waxes is the main source of aliphatic hydrocarbons in the study area whereas sources for PAHs in the particulate samples are most likely derived from combustion sources. The detection of PAHs in the aerosol samples also suggest possible anthropogenic input of particulate matter to the study area; however the levels are still well below the values reported for other locations in Malaysia.

This study aimed to determine the distribution and potential health risks of polycyclic aromatic hydrocarbons (PAHs) in PM

This study aims to determine the composition of BTEX (benzene, toluene, ethylbenzene and xylene) and assess the risk to health at different sites in Malaysia. Continuous monitoring of BTEX in Kuala Lumpur City Centre, Kuala Terengganu, Kota Kinabalu and Fraser Hill were conducted using Online Gas Chromatograph. For comparison, BTEX at selected hotspot locations were determined by active sampling method using sorbent tubes and Thermal Desorption Gas Chromatography Mass Spectrometry. The hazard quotient (HQ) for non-carcinogenic and the life-time cancer risk (LTCR) of BTEX were calculated using the United States Environmental Protection Agency (USEPA) health risk assessment (HRA) methods. The results showed that the highest total BTEX concentrations using continuous monitoring were recorded in the Kuala Lumpur City Centre (49.56 ± 23.71 μg/m3). Toluene was the most dominant among the BTEX compounds. The average concentrations of benzene ranged from 0.69 ± 0.45 μg/m3 to 6.20 ± 3.51 μg/m3. Measurements using active sampling showed that BTEX concentrations dominated at the roadside (193.11 ± 114.57 μg/m3) in comparison to petrol station (73.08 ± 30.41 μg/m3), petrochemical industry (32.10 ± 13.13 μg/m3) and airport (25.30 ± 6.17 μg/m3). Strong correlations among BTEX compounds (p 0.7) at Kuala Lumpur City Centre showed that BTEX compounds originated from similar sources. The values of HQ at all stations were

Hydrocarbon compounds viz. aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), sterols, long chain fatty acids, alkanones and alkanals in surface sediment of Setiu Wetland were analysed and characterized using GCMS. The concentration of total identified resolved n-alkanes (TIRNA) in sediment ranged from 2.99–11.6 μ g g− 1 dry weight. The distribution of the aliphatic fraction showed the presence of n-alkanes ranging from C12 to C36 with high predominance for long chain homologues (C25-C31) and a carbon maximum at C29 and C31 with CPI > 3; these observations provide evidence for the presence of biogenic terrigenous input corresponding to epicuticular plant waxes into the lagoon sediments. Positive and strong correlation between n-alkanes associated with terrigenous input (ALK TER) and TIRNA suggest terrestrial input is the main sources of TIRNA in this study area. The absence of unresolved complex mixture (UCM) in the chromatogram and the absence of hopanes, steranes and PAHs compounds are indicative of uncontaminated sediment by petrogenic and pyrogenic hydrocarbons. The concentration of total identified sterols (TIS) ranged from 1.41 μ g g− 1 dry weight to 3.11 μ g g− 1 dry weight with cholesterol, β -Sitosterol and stigmasterol were generally the most dominant and abundant components detected at almost all stations. A positive and strong correlation was observed between B-Sitosterol and TIS and the distribution of long chain n-alkan-2-ones in the range of C21 to C27 with odd to even predominance and n-alkanals (C20 to C28), n-alkanols (C22–C30) and n-alkanoic acids (C22–C30) with even to odd predominance provide further evidence for biogenic sources of hydrocarbons with terrestrial plant input as the predominant source. It was noted that a minor contribution associated with marine phytoplankton (algae) as well as bacteria were also observed in some of the sediment samples superimposing with the terrigenous plant wax input. In general results from this study clearly showed the lagoon sediment of Setiu Wetland is still in uncontaminated condition where terrestrial plants input are the dominant contributor of organic compounds in the sediments with a minor input from marine organisms.