Mahyar Sakari

Gas chromatography-mass spectrometry analysis of various organic extracts of Merremia borneensis from Sabah

OBJECTIVE To analyse the chemical composition of different extracts of Merremia borneensis (M. borneensis) by gas chromatography-mass spectrometry (GC-MS). METHODS The dried leaves powder was extracted with methanol at room temperature by using Soxhlet extractor. Methanol crude extracts of M. borneensis were extrastel with hexane, chloroform, ethyl acetate and butanol. RESULTS Qualitative analyses of various organic crude extracts showed that majority of these are flavonoids, terpeniods, alkaloids and glycosides. Most of the identified compounds by GC-MS are biologically important. Further the M. borneensis leaf possesses certain characteristics that can be ascribed to cultivation on a domestic plantation. CONCLUSIONS The suitable extracts for respective compounds can be chosen on the basis of above GC-MS analysis. All the major compounds from different extracts are biologically active molecules. Thus the identification of a good number of compounds from various extracts M. borneensis might have some ecological significance.

Urban vs. Marine Based Oil Pollution in the Strait of Johor, Malaysia: A Century Record

Polycyclic aromatic hydrocarbons (PAHs) constitute a class of organic pollutants in the environment that come from combustion of organic matter and petroleum products and from natural sources. Reconstruction of PAH history from two sedimentary cores of the Strait of Johor in peninsular Malaysia showed predominance of urban over marine-based sources of oil pollution. Laboratory analysis of the cores found oil pollution from city-sourced material since 1910 and 1940 in the near-shore and offshore samples, respectively. Using hopane as molecular biomarker of petroleum pollution, this study found a predominance of Southeast Asian-originated oil and its derivatives. This study concludes that crankcase oil, asphalt, street dust and urban sediments considerably contribute to oil pollution of the study area.

Polycyclic Aromatic Hydrocarbons and Hopane in Malacca Coastal Water: 130 Years of Evidence for Their Land-Based Sources

Massive development over the past century has led to environmental oil-related pollution around the Malaysian city of Malacca. To characterize the concentration, sources, and origins of polycyclic aromatic hydrocarbons in Malacca’s coastal water in the Strait of Malacca, sediment cores from near shore and offshore were collected and analyzed. The highest concentration of total polycyclic aromatic hydrocarbons (PAHs) in the Near Shore station core was 4447 ng/g dry weight (dw) (1963–1969), and the lowest was 177 ng/g dw (1949–1955). The lowest concentration of PAHs in the Near Shore sample was 452 ng/g dw (1991 to 1997). In general, the Offshore core showed lower concentrations of total PAHs than did the Near Shore core, ranging from 1.71 (1914–1920) to 714.37 ng/g dw (1963–1969). Diagnostic tools such as specific compound, isomer ratio, and hopane characteristics indicate pollution by petroleum and combustion of oils from Southeast Asia and the Middle East in the study area since the1940s.

Three Centuries of Polycyclic Aromatic Hydrocarbons and Teriterpane Records In Tebrau Strait, Malaysia; Recent Pollution Concern in a Pristine Marine Environment

In the last century, application of fossil fuel as the primary source of energy caused environmental pollution in many countries including Malaysia. Polycyclic Aromatic Hydrocarbons (PAHs) are an important class of petroleum contamination. Two sediment cores were collected from the Tebrau Strait at the southern part of Peninsular Malaysia near the border line to Singapore, where entering into the South China Sea. The samples were sliced in certain intervals, extracted with Dichloromethane in Soxhlet apparatus, cleaned and fractionated in 2-steps column chromatography, and analyzed in Gas Chromatography – Mass Spectrometry. The results showed that PAHs input were started soon after World War II and exponentially increased from 1980 onward by 310 ng/g d. w., in comparison it was negligible and probably nature derived during 18th and 19th century. The application of compound-specific ratios and pentacyclic teriterpanes suggested the vicinity of sources that atmospherically transported to the sampling locations. They were originated from combusted oil of Southeast Asian and the Middle East, polluting urban sediment and street dusts prior to final deposition. Biomass burning appeared historically as a predominant minor background pollution of both cores. Remarkably, crankcase oil was not traced in this study while it was reported as a predominant source in Malaysia. This study suggested ocean-going ships and Singapore International Airport as the main sources of petroleum pollution in recent decades since there was insignificant rural development surrounding the studied area.

Seasonal Variation of Aliphatic Hydrocarbons in Atmospheric Environment of Kota Kinabalu, Sabah

Suspended particulate matters of atmospheric samples were collected and analyzed for aliphatic hydrocarbons from Kota Kinabalu, Sabah, on 2011. Samples were extracted using Soxhlet apparatus, run in two-step column chromatography and the final fraction was spiked into gas chromatography-mass spectrometry. An authentic n-alkane standard (10 mg/l) ranging from C10 to C40 was used as external standard for quantification and qualification of target compounds in the samples. The result showed that the dry season had the highest concentration of atmospheric n-alkane of around 151 ng/m3/d comparing to a minimum of 89 ng/m3/d in the wet season. The results indicate that the amount of high molecular weight n-alkane increases during dry season while wet season had the peak range of lower molecular weight. The carbon preference index value indicates an important contribution from petroleum and diesel materials in the study area. Presence of unresolved complex mixture in most of the samples reveals vehicular exhaust output involvement. Natural hydrocarbons as the minor contributor in the samples were observed during dry season due to the availability of plant material and dust in the atmosphere. It seems that frequent tropical rain clears the atmosphere from dust, burned particulate matters and plant residues during wet season while less rain in dry season provides availability of particulate matters in the atmosphere.

Health risk assessment of heavy metals via consumption of bivalves species in Kota Kinabalu, Sabah, Malaysia

Bivalve organisms are more vulnerable to a variety of aquatic pollution. It has high adaptability to various levels of contaminations. It can accumulate pollutants such as heavy metal in its tissues and cause major concern on potential risk of heavy metal especially to the consumers. The objectives of this study were to determine heavy metal (Cu, Zn, Pb and Cd) concentrations in five most consumed and popular bivalve species among Kota Kinabalu community and to compare with the Food Regulation Malaysia (1985) and Food and Agriculture Organization. Five most consumed bivalves species are Meretrix meretrix (Kepah), Anadara granosa (Kerang), Tridacna squamosa (Kima), Polymesoda erosa (Lokan) and Crassostrea gigas (Tiram). Health risk associated with these heavy metals in the five bivalves species were estimated based on target quotients (THQs). The results indicated that the metal concentrations in the bivalves ranged from 3.21 to 36.22 mg/kg for Cu, 28.62–1771.12 mg/kg for Zn, 0.20–3.43 mg/kg for Pb and 0.44–7.27 mg/kg for Cd. These concentrations were significantly correlated with species and the size of bivalves. Some of the heavy metal concentrations exceeded the permissible level by Food Regulation Malaysia (1985) and Food and Agriculture Organization. However, based on the THQs value for adults, only metal concentrations in Crassostrea gigas (Tiram) exceeded, which indicates potential health risks associated with the consumption of this species.