Prospecting for groundwater discharge in the canals of Bangkok via natural radon and thoron
Prospecting for groundwater discharge in the canals of Bangkok via natural radon and thoron
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DOI：
10.1016/j.jhydrol.2014.09.014
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发表时间：
2014-11
影响因子：
6.4
通讯作者：
S. Chanyotha;C. Kranrod;W. Burnett;D. Lane-Smith;Jesse Simko
中科院分区：
文献类型：
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作者：
S. Chanyotha;C. Kranrod;W. Burnett;D. Lane-Smith;Jesse Simko
我们进行了调查，在曼谷，泰国的几个运河使用连续测量天然存在的222 Rn（“氡”）和220 Rn（“钍射气”）。浅层地下水渗入这些运河是污染地表沃茨的重要途径。氡的半衰期（3.82天）比怀疑的运河冲洗时间短，在整个水道中广泛分布。因此，它可用于通过质量平衡方法估计排放，但无法精确说明排放发生的位置。另一方面，由于其快速衰变（半衰期为56秒），钍只会在非常接近进入点的地方发生。因此，如果有人在环境中探测到钍射气，附近一定有一个来源--一个很好的“勘探”工具。我们在2009年8月的一次调查中在Klong曼谷Noi发现了钍射钉。我们在2013年6月重复了同样的调查路线，发现了与运河沿着几座寺庙相邻的基本相同的高钍射气峰（指示排放点）模式。与寺庙的连接被认为是这些建筑建在相对较高的地面上并有桑迪基底的结果。
We conducted surveys of several canals in Bangkok, Thailand using continuous measurements of naturally occurring222Rn (“radon”) and220Rn (“thoron”). Shallow groundwater seeping into these canals is an important pathway for contamination of surface waters. Radon, with a half-life (3.82 days) shorter than the suspected flushing time of the canals, is widely distributed throughout the waterway. It can thus be used to estimate discharge via a mass balance approach but cannot specify precisely where the discharge is occurring. Thoron, on the other hand, with its rapid decay (56 s half-life) will only occur very close to points of entry. Thus, if one detects thoron in the environment, there must be a source nearby – a good ‘prospecting’ tool. We found thoron spikes in Klong Bangkok Noi during a survey in August 2009. We repeated the same survey route in June 2013 and found essentially the same pattern of high thoron peaks (indicating points of discharge) adjacent to several temples along the canal. The connection to temples is thought to be a consequence of these structures being built on relatively higher ground and having sandy substrates.