Aarkrog A, Dahlgaard H, Nilsson K, Holm E
Health Phys. 1984 Jan;46(1):29-44. doi: 10.1097/00004032-198401000-00001.
Eleven years after the accidental loss of nuclear weapons in 1968, the fourth scientific expedition to Thule occurred. The estimated inventory of 1 TBq 239,240Pu in the marine sediments was unchanged when compared with the estimate based on the 1974 data. Plutonium from the accident had moved further away from the impact point and at some locations the vertical distribution indicated a downward displacement of Pu in the sediment column since 1974. Seawater and seaplants showed no evidence of the presence of Pu from sources other than fallout; but Pu in benthos varied nearly proportionally with the levels in sediments. From the measurements of 239,240Pu in the Macoma community since 1970, the transfer factor to this community was estimated at 0.01 Bq a per Bq released to the sediments. The inventory of 241Am was 0.1 TBq. The vertical distribution of Am in sediments did not differ from that of Pu, but in benthos 241Am/239,240Pu were two times higher than in sediments. Seaplants showed the same value of Am/Pu as seawater. There was no indication of any biomagnification of Pu or Am through the marine food chains at Thule.
1968年核武器意外丢失11年后，图勒第四次科学考察队展开了考察。与基于1974年数据的估计相比，海洋沉积物中钚-239、钚-240的估计存量为1太贝克勒尔，未发生变化。事故产生的钚已从撞击点扩散得更远，在一些地点，垂直分布表明自1974年以来钚在沉积柱中向下迁移。海水和海生植物未显示出来自沉降物以外其他来源的钚的迹象；但底栖生物中的钚与沉积物中的水平几乎成比例变化。根据自1970年以来对马科马群落中钚-239、钚-240的测量，该群落的转移系数估计为每释放到沉积物中1贝克勒尔每年0.01贝克勒尔。镅-241的存量为0.1太贝克勒尔。沉积物中镅的垂直分布与钚没有差异，但在底栖生物中，镅-241/钚-239、钚-240比沉积物中的高两倍。海生植物中的镅/钚值与海水中相同。在图勒，没有迹象表明钚或镅通过海洋食物链发生任何生物放大作用。
