核素137Cs在北太平洋典型生物体内的分布与富集

摘要

To understand the harm of Japan’s Fukushima nuclear leak to the high seas fisheries Marine life in North Pacific and its effect status, typical biological samples were approached in high sea fishing ground for two consecutive years from 2011—2012. It was found that all samples contained radionuclide137Cs by a gamma ray spectrometer. And cross-check analysis was carried out among different species, organs and tissues. The result indicated that. In 2011, the density of137Cs distribution in sharks was the highest with 1.16 Bq∙kg-1 and Japanese flying squidwas the lowest with 0.05 Bq∙kg-1. In 2011, the highest densities of137Cs, with value of 0.73 Bq∙kg-1, appeared in group with mantle length of 250~300 mm for neon flying squid. In 2012, the highest value of 0.034 Bq∙kg-1 appeared in group with mantle length of 200~250 mm for neon flying squid. In terms of concentration density distribution of137Cs in different tissues, it reached highest values in viscera, while obviously low in other parts, including head, trunk and fin for neon flying squid. Through the analysis of trophic level in two years, the distributions of137Cs presented an opposite pyramid structure. All levels measured species does not exceed standard which were food limit concentration and the levels of radioactive nuclide in Chinese general level. Radiation effects was preliminary understood which came from the nuclear leak in the North Pacific high seas fishing grounds, and basic information for further research of marine radioactivity was provided.%为了解日本福岛核泄漏对北太平洋公海渔场海洋生物的危害程度及影响状况，2011—2012年连续两年在北太平公海渔场采集典型生物样品，采用γ谱仪进行检测，发现所采样品均含有放射性核素137Cs。同时运用分类和分组织器官等处理方法，进行对照分析。结果显示，（1）2011年，137Cs在鲨鱼（Mustelus griseus）体内的分布最高，高达1.16 Bq∙kg-1，最低是日本海的太平洋褶柔鱼（Todarodes pacificus），仅为0.05 Bq∙kg-1。2012年整体上所有海洋生物体内的137Cs质量活度降低了1个数量级，137Cs最高质量活度出现在鲯鳅（Coryphaena hippurus）体内，达0.04 Bq∙kg-1，最低也是日本海的太平洋褶柔鱼，仅为0.001 Bq∙kg-1。（2）2011年中不同胴长组巴特柔鱼（Ommastrephes bartramii）的137Cs质量活度最高的是250~300 mm，达到了0.73 Bq∙kg-1。2012年中137Cs质量活度最高的胴长组是200~250 mm，达0.034 Bq∙kg-1。（3）从两年巴特柔鱼的不同组织部位的质量活度分布情况来看，内脏聚集的核素137Cs质量活度最高，其他3个部位（头部、躯干和鳍部）明显偏低。（4）通过两年的营养级分析，137Cs核素质量活度初步呈倒金字塔分布。所测得的生物体中的核素质量活度水平均未超过中国食品放射性核素质量活度的限制水平与通用水平。初步了解了核泄漏对北太平洋公海主要渔场核辐射的影响，以期为海洋放射性深入研究提供基础资料。