大亚湾近岸沉积物对人工放射性核素的吸附

用大亚湾近岸沉积物进行人工放射性核素的吸附研究。测得各放射性核素的吸附分配系数分别为：＾８５Ｓｒ，１６０；＾１３４Ｃｓ，３３０；＾６０Ｃｏ，６４００；＾１４１Ｃｅ，９５００；＾５９Ｆｅ，９４００；＾５４Ｍｎ，１５０００。并测得核素吸附分配系数随悬浮物浓度和示踪剂活度变化的规律。当悬浮物浓度增加时，＾８５Ｓｒ，＾５９Ｆｅ的Ｋｄ值显著降低，＾１４１Ｃｅ，＾５４Ｍｎ，＾６０Ｃｏ的Ｋｄ值稍有降低，而＾１３

ADSORPTION OF RADIONUCLIDES BY THE PARTICULATE MATTER FROM THE SURFACE SEDIMENT OF DAYA BAY

Adsorption of six radiotracers, 85Sr, 134Cs, 141Ce, 59Fe, 60Co and 54Mn by the parti-culate matter from the surface sediment of Daya Bay was studied in laboratory experi-ments from the magnitude and change of adsorption distribution coefficients (Kd)of these radiotracers as functions of equilibration time, suspended particle concentra-tion and radiotracer activity, this work has given an important insight into the pos-sible behaviors of these radionuclides and their radioisotopes in the seawater/suspe-nded particle system of Daya Bay.In this study, the adsorption distribution coefficients of these tracers were dete-rrnined as follows: 85Sr, 160; 134Cs, 330; 60Co,6400; 141Ce, 9500; 59Fe, 9 400 and 54Mn,1500. Kd for most employed radiotracers increased with equilibration time and rea-ched constant value within one day (except60Co). For 60Co, its Kd reached constant in about three days. As a function of suspended particle concentration (Cp), Kd for 85Sr and 59Fe obviously decreased with increasing Cp, and Kd for 141Ce, 54Mn and 60Co decreased slightly while Kd for 134Cs was nearly constant with increasing Cp. As a function of tracer activity, Kd for 141Ce and 59Fe increased with increasing tracer activity, but Kd for 54Mn, 60Co, 85Sr and 134Cs decreased slightly with increasing tra-cer activity.