Sedimentation rate in the Sungai Linggi estuary using excess 210 Pb and 137 Cs
- PDF / 521,889 Bytes
- 6 Pages / 595.276 x 790.866 pts Page_size
- 98 Downloads / 234 Views
Sedimentation rate in the Sungai Linggi estuary using excess 210Pb and 137Cs Zal U’yun Wan Mahmood • Mei Wo Yii
Received: 28 March 2013 Ó Akade´miai Kiado´, Budapest, Hungary 2013
Abstract The purpose of this study was to estimate the sedimentation rate in the Sungai Linggi estuary using the constant initial concentration of unsupported or excess 210 Pb model and verified with 137Cs method. Five sediment cores were collected on 25 January 2011 using gravity corer with the inner tube of 50 cm length and 7.5 cm diameter. The total 210Pb activities in the sediment cores profile at all sampling stations were varied and upper than those obtained for supported 210Pb i.e. 226Ra, indicated disequilibrium among 210Pb and its grandparents in the 238 U decay series. Meanwhile, the lower 137Cs activities were observed at all sampling stations due to no significant sources of 137Cs releases were transferred into Malaysian marine. The estimation of sedimentation rate indicated the agreement of 210Pb and 137Cs method with a general presence of deep mixing in the Sungai Linggi estuary. Therefore, the apparent sedimentation rates calculated from 210Pb profiles generally reflect the true value with the range from 0.70 to 1.97 cmyr-1. High sedimentation rate was observed at some sampling stations which are located in river channel, estuary and closer to mainland. This suggested that land-use development, agriculture activities, channelization etc. introduced a large amount of sediment loaded into those areas. Keywords 210Pb 137Cs Sedimentation rate Sediment cores Sungai Linggi estuary
Z. U. Wan Mahmood (&) M. W. Yii Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor, Malaysia e-mail: [email protected]
Introduction As we know marine environments will represent an important value for human activities because sedimentation of sediment is a major problem affected the marine environment [1]. Therefore, the study of sediments in coastal areas has great importance to understanding the interaction between human activities and marine system. Furthermore, the estimation of sedimentation rate is importance to develop a continuum of insight into marine environmental processes [2]. One isotopic sedimentation tracer alone is not very useful, but two or more independent tracers can be very powerful and convincing. The understanding of recent sedimentary process in marine environments has been greatly in past decades through the application of short-live U-Th-series and bomb produced radioisotopes to sediment geochronology [3]. Cesium-137 (137Cs), used in conjunction with measurements of excess lead-210 (210Pbex), is recognized as a useful tool for the determination of sediment deposition history in lakes, wetlands, and estuaries [4]. Thus, concentrations of fallout 137 Cs and 210Pb are often used to estimate the rates of sedimentation in lakes, wetlands and estuaries on scales of several decades to 100 years [5, 6]. These chronological techniques are also used to estimate the average rate of sedimentation on scales o
Data Loading...
