黄河下游及河口区表层沉积物中U,Ra,Th,^(40)K和^(137)Cs的测定

DETERMINATION OF RADIOISOTOPES IN SURFACE SEDIMENT FROM LOWER REACH AND ESTUARY OF HUANGHE RIVER

本文从地球化学和环境保护的角度,用8180—4Kγ谱仪直接测定方法确定了天然放射性元素U,Ra,Th,^(40)K,及人工核素^(137)Cs的含量,讨论了它们的分布特点及其影响因素,指出了河口区与下游段元素变化的差异及其制约条件。

Determination by 8180-4K multichannel Ge(Li) γ spectrometer of five important radioi-sotopes (U, Ra, Th, 40K and 137Cs) in surface sediments from lower reaches and estuary of Huanghe River and investigation of their contents and distribution show that the contents of U, Ra, Th are higher in lower reach than-in estuary of Huanghe River, that of 137Cs and 40K are higher in estuary than in lower reach. This distribution pattern may be related to their chemical properties and hydrological environmental condition, for example, K is affected by seawater and 137Cs by suspends. The Th/U ratio is little higher in estuary than in lower reach of Huanghe River, but U/Ra ratio is less in estuary than in lower reach. It demonstrates that U is more active than Th and Ra.