Doering Che, Akber Riaz, Heijnis Henk
International Laboratory for Air Quality and Health, School of Physical and Chemical Sciences, Queensland University of Technology, 2 George Street, Brisbane, Queensland 4000, Australia.
J Environ Radioact. 2006;87(2):135-47. doi: 10.1016/j.jenvrad.2005.11.005. Epub 2006 Jan 10.
Net accumulated areal activity densities and profiles of (210)Pb(ex), (7)Be and (137)Cs in the surface 10 cm of the soil are reported for eight sites in Southeast Queensland, Australia. Areal activity densities of (210)Pb(ex) and (7)Be varied from 1,080 to 4,100 Bqm(-2) and from 176 to 778 Bqm(-2), respectively. A significant (p < 0.001) portion of the variance (R(2) > 0.99) in their vertical distributions was explained by depth in the profile using an exponential function. Around 85% of accumulated (210)Pb(ex) was present in the surface 10 cm of the soil. Beryllium-7 was mainly confined to the grass and surface 2 cm of the soil. Average penetration half-depths of 3.6 +/- 0.2 and 0.3 +/- 0.1cm were determined for (210)Pb(ex) and (7)Be, respectively. Areal activity densities of global fallout (137)Cs varied from 10 to 361 Bqm(-2). Its signal was well mixed within the surface 10 cm. Comparison of the measured (137)Cs values to the estimated input value for the region ( approximately 490 Bqm(-2)) and profiling of a 1m deep soil core suggests a vertical migration of (137)Cs over the past decades. The paleo-radon activity flux determined from the (210)Pb(ex) areal activity density (5.1 +/- 0.9 mBqm(-2) s(-1)) was not statistically different to that measured using activated charcoal cups (5.5 +/- 0.4 mBqm(-2) s(-1)), tending to suggest that Southeast Queensland is neither a net source nor a net sink of (210)Pb-bearing aerosols.
报告了澳大利亚昆士兰东南部八个地点土壤表层10厘米深度处（210）Pb（ex）、（7）Be和（137）Cs的净累积面活度密度及分布情况。（210）Pb（ex）和（7）Be的面活度密度分别在1080至4100Bqm（-2）和176至778Bqm（-2）之间变化。它们垂直分布中很大一部分方差（R（2）>0.99）能用指数函数根据剖面深度来解释。累积的（210）Pb（ex）约85%存在于土壤表层10厘米处。铍-7主要集中在草和土壤表层2厘米处。（210）Pb（ex）和（7）Be的平均穿透半深度分别测定为3.6±0.2厘米和0.3±0.1厘米。全球沉降（137）Cs的面活度密度在10至361Bqm（-2）之间变化。其信号在表层10厘米内混合良好。将测得的（137）Cs值与该区域估计输入值（约490Bqm（-2））进行比较，以及对1米深土壤岩心的剖面分析表明，过去几十年里（137）Cs有垂直迁移。由（210）Pb（ex）面活度密度确定的古氡活度通量（5.1±0.9mBqm（-2）s（-1））与用活性炭杯测得的结果（5.5±0.4mBqm（-2）s（-1））在统计学上无差异，这倾向于表明昆士兰东南部既不是含（210）Pb气溶胶的净源也不是净汇。
