APPLICABILITY OF Pb-210 METHOD FOR AGES AND SEDIMETATION STUDY OF A RECENT FRESH WATER EX-MINING LAKE
Ahmad Saat1, Zaini Hamzah2, Zaharidah Abu Bakar2 , Zaharudin Ahmad3 and
Abdul Khalik Wood3
1Institute of Science,
2Faculty of Applied Sciences
Universiti Teknologi MARA, 40450 Shah Alam.
3Malaysian Nuclear Agency, Bangi, Selangor.
E-mail: ahmad183@salam.uitm.edu.my
ABSTRACT
Pb-210 method is an environmental dating method, taking advantage of the steady supply rate of Pb-210 radioisotope in a given locality, and its natural decay with a half-life of 22.26 years. The method has been successfully applied in many chronological and sedimentation studies in older natural water systems such as seas, rivers, estuaries, lakes, and marshes. The present study explores the applicability of this method on recent (less than 50 years) man-made fresh water lakes. The study was carried out in 2007 on one of the lake in the former tin mining lakes system in the vicinity of Universiti Teknologi MARA Training Centre, in Kampong Gajah, Perak. For sampling procedures of the five hectare lake, five representative cores were collected from the deepest water column in the middle zone. Representative sediment cores (depth down to 30 cm) collected were sliced at 2 cm length, mixed according to depth to form aggregate, dried and homogenized, and analysed for Pb-210 activity concentration by using alpha-spectrometry facilities at the Malaysian Nuclear Agency laboratory. The Pb-210 depth profiles of the cores enable the respective sediment age and sedimentation rate to be determined. The sedimentation rate was found to be 0.57 ± 0.10 cm.y-1. Age wise, the sediment were about 40 – 50 years old, and this is historically in agreement with the cease-operation year of the mining activities during the year 1960’s. Study on the concentration of a number of heavy metals in the sediment cores show higher concentration beginning the last few years, which coincides with the increment of anthropogenic activities such as human settlement, animal farming and agricultures around the lakes in recent years. The results show that to a certain extent the Pb-210 method is also applicable to recent sediments in water system.
Keywords: Pb-210 method, mining lake sediment, heavy metals.
Ahmad Saat1, Zaini Hamzah2, Zaharidah Abu Bakar2 , Zaharudin Ahmad3 and
Abdul Khalik Wood3
1Institute of Science,
2Faculty of Applied Sciences
Universiti Teknologi MARA, 40450 Shah Alam.
3Malaysian Nuclear Agency, Bangi, Selangor.
E-mail: ahmad183@salam.uitm.edu.my
ABSTRACT
Pb-210 method is an environmental dating method, taking advantage of the steady supply rate of Pb-210 radioisotope in a given locality, and its natural decay with a half-life of 22.26 years. The method has been successfully applied in many chronological and sedimentation studies in older natural water systems such as seas, rivers, estuaries, lakes, and marshes. The present study explores the applicability of this method on recent (less than 50 years) man-made fresh water lakes. The study was carried out in 2007 on one of the lake in the former tin mining lakes system in the vicinity of Universiti Teknologi MARA Training Centre, in Kampong Gajah, Perak. For sampling procedures of the five hectare lake, five representative cores were collected from the deepest water column in the middle zone. Representative sediment cores (depth down to 30 cm) collected were sliced at 2 cm length, mixed according to depth to form aggregate, dried and homogenized, and analysed for Pb-210 activity concentration by using alpha-spectrometry facilities at the Malaysian Nuclear Agency laboratory. The Pb-210 depth profiles of the cores enable the respective sediment age and sedimentation rate to be determined. The sedimentation rate was found to be 0.57 ± 0.10 cm.y-1. Age wise, the sediment were about 40 – 50 years old, and this is historically in agreement with the cease-operation year of the mining activities during the year 1960’s. Study on the concentration of a number of heavy metals in the sediment cores show higher concentration beginning the last few years, which coincides with the increment of anthropogenic activities such as human settlement, animal farming and agricultures around the lakes in recent years. The results show that to a certain extent the Pb-210 method is also applicable to recent sediments in water system.
Keywords: Pb-210 method, mining lake sediment, heavy metals.
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