Presentation on theme: "Natural thorium isotopes levels in marine sediments of Coal-Fired Power Plant at Kapar, Selangor, Malaysia Che Abd Rahim Mohamed, Zaharuddin Ahmad 1 &"— Presentation transcript:
Natural thorium isotopes levels in marine sediments of Coal-Fired Power Plant at Kapar, Selangor, Malaysia Che Abd Rahim Mohamed, Zaharuddin Ahmad 1 & Azlina Shafie Marine Ecosystem Research Centre (EKOMAR), Faculty of Science & Technology, Universiti Kebangsaan Malaysia Bangi, Selangor, Malaysia Bangi, Selangor, Malaysia *corresponding 1 Malaysia Nuclear Agency, Bangi, Selangor, Malaysia
Introduction Coal is a fossil fuel. It is a combustible, sedimentary, organic rock, which is composed mainly of carbon, hydrogen and oxygen. It is formed from vegetation, which has been consolidated between other rock strata and altered by the combined effects of pressure and heat over millions of years to form coal seams. Coal is a fossil fuel. It is a combustible, sedimentary, organic rock, which is composed mainly of carbon, hydrogen and oxygen. It is formed from vegetation, which has been consolidated between other rock strata and altered by the combined effects of pressure and heat over millions of years to form coal seams.
Types of coal
Combustion of coal, like any other fossil fuel, occurs due to an exothermic reaction between the components of the fuel source, and the components air surrounding it. Coal is made primarily of carbon, but also contains sulfur, oxygen and hydrogen. The reaction between coal and the air surrounding it produces oxides of carbon, usually carbon dioxide (CO2 - a major greenhouse gas) in a complete combustion, along with oxides of sulfur, mainly sulfur dioxide (SO2), and various oxides of nitrogen (NOx). Because of the hydrogen and nitrogen components of air, hydrides and nitrides, of carbon and sulfur, are also produced during the combustion of coal in air. These could include hydrogen cyanide (HCN), sulfur nitrate (SNO3) and many other toxic substances.
Waste from coal activities Coal and coal waste products including fly ash, bottom ash, and boiler slag, contain many heavy metals, including arsenic, lead, mercury, nickel, sulphur, vanadium, beryllium, cadmium, barium, chromium, copper, molybdenum, zinc, selenium and radium, which are dangerous if released into the environment. Coal also contains low levels of uranium, thorium, and other naturally- occurring radioactive isotopes whose release into the environment may lead to radioactive contamination. While these substances are trace impurities, enough coal is burned that significant amounts of these substances are released, resulting in more radioactive waste than nuclear power plants. Mercury emissions from coal burning are concentrated as they work their way up the food chain and converted into methylmercury, a toxic compound that may affect people who frequently consume freshwater fish affected by mercury pollution from nearby coal-fired power plants. Ocean fish account for almost all of most people's exposure to methylmercury; the sources of ocean fish methylmercury ???
Settling pond was cover with ash from the factory
Treatment pond (pH < 6.0)
Pipeline transport effluents from the factory into the treatment pond.
Hot water discharge from the factory into marine environment
Chemical Analyses Cation and anion resin column
Results & Discussion Percentage of sediment grain size in core at St. 2, St. 3 and St. 7
Vertical distribution of thorium and others parameter
Surface mixing coefficient D (cm 2 /yr) MethodNoteAreaReference Th ex Kapar coastal 3.5- ≥ ≥ Pb ex Margin ~ water column depth; m Central basin~ water column depth; m. Nutrient-rich, affected by human activities Gulf of Thailand Srisuksawad et al. (’97) >80-> Pb ex Cherrystone (12-15 m depth) Wolf Trap (11-12 m depth) Chesapeake Bay, North America Dellapenna et al. (1998) Th ex Water column depth; m Anthropogenic contaminant from wastewater treatment facilities, stromwater runoff, atmospheric fallout & marine-related activities Santa Monica Bay coastal, California Alexander & Venherm (2003) Th ex Water column depth; 910 m Most intense level of human activities in the borderland area Santa Monica Basin Chih-An Huh et al. (1987) Mixing coefficient rate published at various location
Thorium isotopes at study location In the ranged of others location
Variable 232 Th 230 Th 228 Th AlFeMnTCpH 232 Th Th 0.733**1 228 Th 0.866**0.838**1 Al0.543*0.427**0.482**1 Fe0.497**0.463**0.351*0.814**1 Mn0.493**0.349*0.434** TC-0.374* ** pH0.551**0.518**0.615** ** *Correlation is significant at the 0.05 level (2-tailed) ** Correlation is significant at the 0.01 level (2-tailed) Pearson correlations coefficient (r) of thorium and others variables obtained during this study
232 Th 230 Th 228 Th 230 Th/ 232 Th 228 Th/ 232 Th FasaCatatanKawasanRujukan (dpm/g) (dpm/g) M HCl Coal (washed) Bottom ash Taken from power plant, Kapar This study Gamma spectrometry Coal Fly ash Bottom ash Yatagan Thermal Power Plant, M u ğla, Turkey Baba (2002) (2.42) (4.36) Gamma spectrometry Coal Fly ash M u ğla, Turkey Ayçik & Ercan (1997) INAACoalPakistanNigerianUSA Waheed et al. (2001) Gamma spectrometry Coal Fly ash Bottom ash 3 Lodz power stations, Poland Bem et al. (2002) Thorium isotopes measured in coals, bottom ash and fly ash at various country - Level still in the world ranged
Remarks The level of natural thorium isotopes at Coal-Fired Power Plant were still in the world ranged. Thanks
Acknowledgments Universiti Kebangsaan Malaysia Universiti Kebangsaan Malaysia Malaysia Nuclear Agency Malaysia Nuclear Agency JSPS JSPS Graduate students of Faculty Science & Technology, Universiti Kebangsaan Malaysia Graduate students of Faculty Science & Technology, Universiti Kebangsaan Malaysia