2013年北太平洋公海渔场柔鱼体内典型放射性核素分析及风险评估

为了解福岛核泄漏放射性核素对北太平洋公海渔场的后续性污染影响情况,于2013年8—11月在北太平洋公海渔场(40°—44° N、145°—160° E)采集柔鱼样品,利用超低本底HPGe γ 谱仪分析5种放射性核素.结果表明: ¹³⁴Cs和^110mAg未检测出高于本底值的比活度,而²¹⁰Pb、¹³⁷Cs和⁴⁰K均有检出.其中²¹⁰Pb在柔鱼体的比活度范围为0.99～7.60 Bq·kg^-1,¹³⁷Cs的比活度范围为最低检测限～0.37 Bq·kg^-1,⁴⁰K的比活度范围为46.00～107.00 Bq·kg^-1.²¹⁰Pb核素含量在柔鱼250～300 mm胴长组分布最高;在200～250和>400 mm胴长组中最低.¹³⁷Cs含量在柔鱼200～250 mm胴长组中最高;在250～300和350～400 mm胴长组较低.⁴⁰K核素含量在柔鱼250～300 mm胴长组中最高,在150～200 mm胴长组最低,总体分布比较均匀.3种核素在柔鱼的不同组织中含量不同,但均在内脏中含量最高.通过风险评估发现,北太平洋公海渔场所有检测的海洋生物的放射性核素含量值与基准值的熵值均未超过1,说明目前核辐射对该海域渔业资源的影响暂无大风险.研究可为福岛核事故对海洋环境生态影响及公众健康危害评估提供理论依据.

Analysis of the typical radionuclides for neon flying squid of the high seas fisheries in North Pacific Ocean and risk assessment in 2013.

To understand the pollution effect of radionuclides emitted from Fukushima nuclear accident on marine organisms, we collected flying squid samples in the North Pacific Ocean (40°-44°N, 145°-160° E) from August to November in 2013. Radionuclides’ concentrations at different localities were analyzed by the ultra-low background high purity germanium (HPGe) γ spectrometer. The result showed that nuclide specific activities of ¹³⁴Cs and ^110mAg were not higher than the background values, while those of ²¹⁰Pb, ¹³⁷ Cs and ⁴⁰ K were detected in all samples. Specific activity ranges of ²¹⁰Pb, ¹³⁷ Cs and ⁴⁰ K for neon flying squid were 0.99-7.60 Bq · ^-1, the mininum detection limit to 0.37 Bq · ^-1and 46.00-107.00 Bq · ^-1, respectively. The 250-300 mm mantle length group of neon flying squid had the highest nuclide concentration of ²¹⁰Pb, and the minimum concentration of ²¹⁰Pb was found in the 200-250 mm and >400 mm groups. The 200-250 mm mantle length group had the highest nuclide concentration of ¹³⁷Cs, and the 250-300 mm and 350-400 mm groups had the minimum. The 250-300 mm mantle length group had the highest nuclide concentration of ⁴⁰K, and the 150-200 mm group had the minimum, and the overall distribution was much more uniform. Nuclide concentration distributions were different in different organs of neon flying squid, but all highest values were detected in innards. Risk assessment showed that the entropy values of all tested marine life value and basic value of radionuclide content in the fishing grounds of North Pacific high seas were not higher than 1, indicating there was no high risk of the radiation on fishery resources temporarily in North Pacific Ocean. The study provided the theory basis for assessment of the marine ecological environment and public health hazard resulted from Fukushima nuclear accident.