Norwegian Radiation Protection Authority, PO Box 55, NO-1332 Østerås, Norway.
J Environ Radioact. 2013 Dec;126:99-103. doi: 10.1016/j.jenvrad.2013.07.010. Epub 2013 Aug 23.
In order to follow the turnover of (137)Cs in natural soils and estimate future trends in exposure of livestock, samples of natural surface soils were collected at 0-3 cm depth at 464 sites in 1995 and 463 sites in 2005 covering the country. In both cases the geographical pattern observed was similar to the original distribution from 1986, but the decline of (137)Cs activity in the surface soil was not the same everywhere. In 1995 the (137)Cs reduction since 1986 was found to be considerably greater in coastal areas than farther inland. The main reason for this appears to be the much greater deposition of marine cations such as Mg(2+) and Na(+) in the coastal areas, replacing Cs ions fixed on soil particle surfaces. This cation exchange appeared to be particularly strong near the southern coast where deposition of NH4(+) from transboundary air pollution is evident in addition to the marine cations. During 1995-2005 the (137)Cs decline in the surface soil was more uniform over the country than in the preceding 10-year period but still significantly higher in coastal areas than inland. Differences in precipitation chemistry may have influenced the uptake of (137)Cs in terrestrial food chains.
为了追踪天然土壤中 137Cs 的转移情况，并预测未来牲畜暴露的趋势，1995 年在全国 464 个地点和 2005 年在 463 个地点采集了 0-3 厘米深度的天然表层土壤样本。在这两种情况下，观察到的地理模式与 1986 年的原始分布相似，但表层土壤中 137Cs 活性的下降并非到处都一样。1995 年发现，自 1986 年以来，沿海地区的 137Cs 减少量明显大于内陆地区。这种情况的主要原因似乎是，海洋阳离子（如 Mg2+和 Na+）在沿海地区的沉积量要大得多，取代了固定在土壤颗粒表面的 Cs 离子。这种阳离子交换在南部沿海地区尤为强烈，除了海洋阳离子外，跨境空气污染导致的 NH4+也在那里沉积。1995 年至 2005 年期间，与前 10 年相比，全国表层土壤中 137Cs 的下降更为均匀，但沿海地区仍明显高于内陆地区。降水化学性质的差异可能影响了陆地食物链对 137Cs 的吸收。
