海洋学および海洋研究ジャーナル
オープンアクセス

概要

Accumulation of Natural Uranium Isotopes in Malaysian Harbour Sediment

Yusoff AH, Mohamed CAR

Sediment core samples were collected at eight stations in Peninsular Malaysia (PM) and East Malaysian (EM) harbour waters to estimate the sources of uranium deposits. The range of average activity of ²³⁴U was from 35.31 ± 4.39 Bq/kg to 67.34 ± 5.65 Bq/kg, while ²³⁸U was from 31.25 ± 4.50 Bq/kg to 81.27 ± 7.48 Bq/kg. The range of activities for ²³⁰Th and ²³²Th were also recorded during this study with values from 38.24 ± 3.62 Bq/kg to 150.83 ± 13.86 Bq/ kg and 28.08 ± 3.26 Bq/kg to 119.59 ± 14.58 Bq/kg, respectively. The accumulation rate of uranium in harbours were calculated using a simple box model as 0.66 x 10^-3 Bq/cm²/year to 6.14 × 10^-3 Bq/cm²/year and 3.98 × 10^-3 Bq/cm²/year to 17.82 × 10^-3 Bq/cm²/year for authigenic and lithogenic fractions of uranium, respectively. In Peninsular Malaysia, results indicated an 86% fraction of lithogenic uranium, while East Malaysian harbours only registered a 61% fraction of authigenic uranium. This result is because PM has a high input of base granitic rock and East Malaysia is affected by the western Pacific Ocean as well as shows by aluminum, zircon and organic carbon.