Browsing by Author "NOOR AZHAR MOHAMED SHAZILI"

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    ExPERIMENTAL AND FIELD STUDY ON ACCUMULATION OF HEAVY METALS IN SEAGRASSES (Halodule pinifolia and Halophila minor) IN SETIU WETLAND, TERENGGANU
    (Journal of Sustainability Science and Management, 2008) SYARIFAH NOORMAISARAH TUAN BESAR; NOOR AZHAR MOHAMED SHAZILI; SITI AISHAH ABDULLAH
    The aims of this study were: (i) to determine the content of copper and cadmium into seagrass Halodule pinifolia and Halophila minor from the Setiu Wetland and Setiu River estuary, Terengganu and (ii) to study the bioaccumulation response of the seagrass towards the metals. The contents of the two metals in leaves and root-rhizomes of the seagrasses collected from the feld study samples were determined. in laboratory experiments, the two seagrass were exposed to sediments spiked with four different concentrations of copper (56.44 µg/g, 112.87 µg/g, 225.74 µg/g and 451.49 µg/g) or cadmium (36.00 µg/g, 72.00 µg/g, 144.00 µg/g and 288.00 µg/g). The exposure period was for 8 weeks during which plants were sampled weekly and the metal concentrations in leaves and root-rhizomes determined. The content of heavy metals was measured by aaS. Pearson Correlation were used to determine the relationship between the accumulation of heavy metals in root-rhizomes and leaves. in the exposure experiments, Cu and Cd were bioaccumulated, with tissue concentration generally increased with duration of exposure and increase in sediment metal concentrations. Metal concentrations in root-rhizomes were higher than in leaves for both species. in Halodule pinifolia, the mean copper in root-rhizomes and leaves were 120.86 ± 6.79 µg/g and 96.99 ± 8.58 µg/g respectively while the mean cadmium concentration in root-rhizomes was 38.40 ± 4.71 µg/g and in leaves was 36.08 ± 3.21 µg/g. In Halophila minor, the mean copper concentration in root-rhizomes and leaves were 49.53 ± 7.67 µg/g and 35.40 ± 6.52 µg/g respectively. The mean cadmium concentration in rootrhizomes was 30.34 ± 3.15 µg/g and in leaves was 29.71 ± 2.64 µg/g. Generally, the metals in rootrhizomes showed strong correlation with the metals in leaves. Halodule pinifolia and Halophila minor exposed to high concentrations of copper were dead in week 4 and 5 respectively, while exposure to high concentrations of cadmium resulted in death of plants in week 4. oxygen produced by both seagrass species also began showed negative values in week 4. For the feld study, the highest concentrations of Cd and Cu in Halodule pinifolia and Halophila minor were found for the month of October 2004 and month of November respectively.
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    INHIBITIVE CHEMICAL CUE OF Pseudomonas pseudoalcaligene ON BIODEGRADATION OFANTHRACENE IN SEAWATER MEDIUM
    (Journal of Sustainability Science and Management, 2009) HII YII SIANG; LAW AH THEEM; CHUAH LAI FATT; NOOR AZHAR MOHAMED SHAZILI; MOHAMED KAMILABDUL RASHID; YONG JAW CHUEN
    This study aims to reveal the self-inhibitive mechanism of an oil degrading bacteria, Pseudomonas pseudoalcaligene biodegradation of anthracene in seawater. Biodegradation of anthracene by the oil-degrading bacteria was analogue to the Monod equation and exhibited a typical bacterial growth pattern. Biodegradation of anthracene was retarded when the bacteria approached its stationary growth phase. The results indicated that the level of dissolved organic carbon and hydrogen ion in the seawater mediwn increased due to anthracene biodegradation. The organic compounds were believed to be secondary metabolites produced by the oil-degrading bacteria. These metabolites seem to inhibit activities of the oil degrading bacteria. The inhibitive effect was confirmed when the newly inoculated oil degrading bacteria failed to grow in the residue mediwn replenished with nutrients and new carbon source and incubated under optimal condition. It is interesting to note that, this replenished mediwn supported the growth of other non-oil degrading bacteria, Erythrobacter citreus. Presence of E. citreus in the mediwn utilized the inhibitive metabolites and thus reswned activities of the oil degrading bacteria for anthracene. Mixing the oil-degrading bacteria (P. pseudoalcaligenes) and non-oil degrading bacteria (E. citreus) improved biodegradation ofanthracene in the seawater. The bacterial mixture improved anthracene degradation by 36% compared to the oil degrading bacteria alone.
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    THE SPATIAL DISTRIBUTION OF Al, Fe, Cu, Cd AND Pb IN THE SURFACE SEDIMENT OF BRUNEI BAY, BORNEO DURING THE SOUTHWEST AND NORTHEAST MONSOONS
    (The International Seminar on the Straits of Malacca and the South China Sea 2016, 2016) ADIANA GHAZALI; NOOR AZHAR MOHAMED SHAZILI; JOSEPH BIDAI; HASRIZAL SHAARI
    A geochemical assessment of Al, Fe, Cu, Cd and Pb was carried out for the surface sediment of Brunei Bay. Samples were collected during July 2013 and January 2014 representing the Southwest and Northeast Monsoon respectively. Fe, Pb, Al and Cu were high in July 2013 samples whereas Cd had a similar range of concentration during both sampling periods. Cd showed no particular spatial distribution pattern whereas Fe and Pb were highly distributed at the transect stations compared to the coastal stations due to the river flshed out. In contrast, Al and Cu were uniformly distributed between all stations. The Al, Fe and Pb in Brunei Bay sediment were dominantly bound to the mineral fraction which is also an indicator of natural sources whereas Cu was more dominant in the ion exchangeable fraction which is the most bioavailable fraction. The risk assessment code (RAC) indicated that Al has no risk (RAC<1%) whereas Fe and Pb showed a low risk (RAC<10%) to the benthic organisms. However, Cu presented a very high risk (RAC>50%) in both sampling periods. Even though the RAC showed some risk of these metals on the ecosystem, the geoaccumulation index indicated no serious pollution by these metals. Additionally, the surface sediment of Brunei Bay was dominated by silt and very fie sand. The apparent changes in metals distribution and metals fractionation during January 2014 corresponded to the effects of monsoons. Port activities, aquaculture, fiheries, palm oil and paper mill industries are the potential sources of metals in the Brunei Bay ecosystem.