226Ra and 228Ra in Water Column of Peninsular Malaysia: Southern South China Sea

Abstract

The concentration activities of ²²⁶Ra and ²²⁸Ra were determined at ten stations around Pulau Redang, Malaysia, where high dissolved activity of ²²⁸Ra was found at the coastal stations. Meanwhile, activities of ²²⁶Ra and ²²⁸Ra isotopes in the suspended materials were slightly similar with ²²⁸Ra/²²⁶Ra ratio ranged from 0.88-1.86. High distribution coefficient (K_d) of radium isotopes found around Pulau Redang indicating that radium are strongly absorbed onto particulate phase. The K_d values of ²²⁶Ra and ²²⁸Ra were ranged from 0.78 × 10⁵ L g^-1 to 5.56 × 10⁵ L g^-1 and from 0.21 × 10⁵ L g^-1 to 1.86 × 10⁵ L g^-1, respectively. The impact caused by the amount of suspended particle material (< 10 mg L^-1) on the particle concentration was not found during this study.