中国边缘海沉积物中239+240Pu的来源与存量模型

对海水和沉积物中^239+240Pu活度、²⁴⁰Pu/²³⁹Pu比值和^239+240Pu存量的分析,可以为海洋环境中水团输运、黑潮海水入侵、颗粒物通量、颗粒清除过程、污染物堆积、沉积年代等问题的研究提供有效途径。针对中国边缘海沉积物中^239+240Pu活度分布、²⁴⁰Pu/²³⁹Pu比值特征和^239+240Pu存量进行比较讨论,发现虽然全球大气沉降和太平洋核试验场的输入是中国边缘海沉积物中^239+240Pu的2个主要来源,但是中国边缘海海洋环境中不同区域Pu的来源的比例有差异。同时,文中系统探讨了利用Pu端元法研究中国边缘海海洋沉积物中^239+240Pu存量的质量平衡模型,这对认识海洋中沉积物的源与汇以及海洋放射性环境状况具有一定意义。

The Source and Inventory Model of 239+240Pu in the Sediment Cores of the Marginal Sea of China

Plutonium (Pu) is valuable a tracer for the study of marine biogeochemical processes, and an important element for evaluating the state of the marine environment. In seawater and marine sediments, it provided an effective tool for the studies of water transport in the marine environment, seawater intrusion, particle inventories, particle removal processes, the accumulation of pollutants, sediment age and other issues. In this article, the distribution of ^239+240Pu activities, ²⁴⁰Pu/²³⁹Pu atom ratios and ^239+240Pu inventories in marine sediments from China's marginal seas were analyzed. It was found that different regions of the marine environment show differences in the origins of the Pu, with global fallout and PPG (Pacific Proving Grounds) inputs being the two major sources of Pu. The ²⁴⁰Pu/²³⁹Pu atom ratios in the surface sediments from China’s marginal seas ranged from 0.158 to 0.297, and the activity range was 0.048 to 1.160 Bq/kg.The ocean is a continuous whole, and there was no simple linear relationship between ^239+240Pu and ²⁴⁰Pu/²³⁹Pu in marine surface sediments.Using a simplified Pu two-end members model to calculate the ratio of PPG contribution ^239+240Pu in China's marginal sea sediments range was from 0 to 68%. The data of Pu were discussed to have significance for understanding the sources and sinks of Pu in the ocean and marine environment.