Correlation of natural radionuclides (Ra-226, Ra-228 and K-40) in catchment soil and river sediment from Middle Langat River Basin

Abstract

Natural radionuclides Ra-226, Ra-228 and K-40 along three (3) stations in Middle Langat River Basin were collected over a 9-year period at 3 months interval. Variations of activity concentration in the catchment soil and river sediment samples were analysed using HPGe detector to identify temporal and spatial trend. Activity concentrations show indication of long-Term fluctuation especially for K-40, but will require long data for further validations. Increased activity concentrations in the down-river direction suggests a couple catchment loss and river sediment relative gain based on analysis of the ratios between element pair. Correlation of Ra-226 and Ra-228 is very strong, but their correlation with K-40 varies considerably possibly due to the high potassium solubility.