International Atomic Energy Agency, Marine Environment Laboratories, 4, Quai Antoine Ier, MC-98000, Principality of Monaco, Monaco.
J Environ Radioact. 2011 Jun;102(6):543-50. doi: 10.1016/j.jenvrad.2011.02.008. Epub 2011 Mar 9.
In order to understand the bioaccumulation of (241)Am and (134)Cs in scallops living in sediments, the uptake and depuration kinetics of these two elements were investigated in the king scallop Pecten maximus exposed via seawater, food, or sediment under laboratory conditions. Generally, (241)Am accumulation was higher and its retention was stronger than (134)Cs. This was especially obvious when considering whole animals exposed through seawater with whole-body concentration factors (CF(7d)) of 62 vs. 1, absorption efficiencies (A(0l)) of 78 vs. 45 for seawater and biological half-lives (T(b½l)) of 892 d vs. 22 d for (241)Am and (134)Cs, respectively. In contrast, following a single feeding with radiolabelled phytoplankton, the assimilation efficiency (AE) and T(b½l) of (134)Cs were higher than those of (241)Am (AE: 28% vs. 20%; T(b½l): 14 d vs. 9 d). Among scallop tissues, the shells always contained the higher proportion of the total body burden of (241)Am whatever the exposure pathway. In contrast, the whole soft parts presented the major fraction of whole-body burden of (134)Cs, which was generally associated with muscular tissues. Our results showed that the two radionuclides have contrasting behaviors in scallops, in relation to their physico-chemical properties.
为了了解生活在沉积物中的扇贝体内（241）Am 和（134）Cs 的生物累积情况，在实验室条件下，通过海水、食物或沉积物，研究了这两种元素在海湾扇贝（Pecten maximus）体内的吸收和排泄动力学。一般来说，（241）Am 的积累量较高，滞留能力较强。这一点在考虑通过海水暴露的整个动物时尤为明显，其全身浓度系数（CF(7d)）分别为 62 和 1，海水的吸收效率（A(0l)）分别为 78 和 45，以及（241）Am 和（134）Cs 的生物半衰期（T(b½l)）分别为 892 d 和 22 d。相比之下，在单次投喂放射性标记的浮游植物后，（134）Cs 的同化效率（AE）和 T(b½l)高于（241）Am（AE：28%比 20%；T(b½l)：14 d 比 9 d）。在扇贝组织中，无论暴露途径如何，壳总是含有较高比例的（241）Am 总体内负荷。相比之下，整个软体组织则呈现（134）Cs 的大部分全身负荷，这通常与肌肉组织有关。我们的研究结果表明，两种放射性核素在扇贝体内的行为存在差异，这与它们的物理化学性质有关。
