Browsing by Author "Noor Azhar, Mohamed Shazili"

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    Accumulation of Trace Metals in Anadara granosa and Anadara inaequivalvis from Pattani Bay and the Setiu Wetlands
    (Bull Environ Contam Toxicol, 2016-01-02) Siriporn, Pradit; Noor Azhar, Mohamed Shazili; Prawit, Towatana; Wuttipong, Saengmanee
    This study was undertaken to assess the levels of trace metals (As, Cd, Cu, Pb, and Zn) in two common species of cockles (Anadara granosa and Anadara inaequivalvis) from two coastal areas in Thailand (Pattani Bay) and Malaysia (the Setiu Wetlands). A total of 350 cockles were collected in February and September 2014. Trace metals were determined by Inductively Coupled Plasma Mass Spectrometry. We observed that cockles in both areas had a higher accumulation of metals in September. Notably, the biota-sediment accumulation (BSAF) of Cd was highest in both areas. A strong positive correlation of Cd with the length of the cockles at Pattani Bay (r2 = 0.597) and the Setiu Wetlands (r2 = 0.675) was noted. It was suggested that As could be a limiting element (BSAF\1) of cockles obtained from Pattani Bay. In comparison with the permissible limits set by the Thailand Ministry of Public Health and the Malaysia Food Regulations, mean values of As, Cd, Cu, Pb, and Zn were within acceptable limits, but the maximum values of Cd and Pb exceeded the limits for both areas. Regular monitoring of trace metals in cockles from both areas is suggested for more definitive contamination determination.
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    The geochemistry of rare earth elemenst in Brunei Bay, Borneo
    (Penerbit UMT, 2016) Adiana, Ghazali; Noor Azhar, Mohamed Shazili; Joseph, Bidai
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    Heavy metal toxicity to rainbow trout, Salmo Gairdneri Richardson, during early development
    (Fakulti Sains dan Teknologi, 1983) Noor Azhar, Mohamed Shazili
    The toxicity of cadmium, copper and zinc to rainbow trout, Salmo gairdneri Richardson, during early development was investigated. In addition the synthesis of cadmium-binding protein by the perfused rainbow trout liver was studied. It was concluded that; 1) Cadmium is extremely toxic to rainbow trout during early development. A continuous cadmium exposure during embryonic development resulted in almost complete mortality of eggs at 1.0 mgCdl *. Some sublethal effects were also observed in hatched alevins. 2) Embryonic sensitivity was not uniform throughout egg development. The fertilisation process was particularly sensitive to cadmium viexe, exposure. Reductions in the fertilisation of eggs was obtained as a result of exposure to 1.0 mgCdl * and higher. The results also indicated that the period of axiation was sensitive to cadmium exposure as shown by a high mortality rate of eggs in continuous exposure tests. 3) Embryonic sensitivity to cadmium and zinc differed from sensitivity to copper indicating possible differences in toxic actions between these metals. 4) The toxicity of mixtures of cadmium, copper and zinc indicated that the toxicity of these metals to trout eggs and fry could be assessed by the additive toxic unit method to give the total toxicity of the mixture. However sublethal effects and metal uptake studies showed possible departures from additive joint action. 5) Post exposure mortalities may result from brief exposure of fish to cadmium even after restoration to clean water. These results highlight the inadequacy of a standard toxicity test in predicting the consequences of brief exposure to a pollutant.
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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 flushed 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 fine sand. The apparent changes in metals distribution and metals fractionation during January 2014 corresponded to the effects of monsoons. Port activities, aquaculture, fisheries, palm oil and paper mill industries are the potential sources of metals in the Brunei Bay ecosystem