Pinti Daniele L, Retailleau Sophie, Barnetche Diogo, Moreira Floriane, Moritz Anja M, Larocque Marie, Gélinas Yves, Lefebvre René, Hélie Jean-François, Valadez Arisai
GEOTOP and Département des sciences de la Terre et de l'atmosphère, Université du Québec à Montréal, CP 8888 Succ. Centre-ville, H3C 3P8, Montréal, QC, Canada.
GEOTOP and Département des sciences de la Terre et de l'atmosphère, Université du Québec à Montréal, CP 8888 Succ. Centre-ville, H3C 3P8, Montréal, QC, Canada.
J Environ Radioact. 2014 Oct;136:206-17. doi: 10.1016/j.jenvrad.2014.05.021. Epub 2014 Jun 26.
One hundred ninety-eight groundwater wells were sampled to measure the (222)Rn activity in the region between Montreal and Quebec City, eastern Canada. The aim of this study was to relate the spatial distribution of (222)Rn activity to the geology and the hydrogeology of the study area and to estimate the potential health risks associated with (222)Rn in the most populated area of the Province of Quebec. Most of the groundwater samples show low (222)Rn activities with a median value of 8.6 Bq/L. Ninety percent of samples show (222)Rn activity lower than 100 Bq/L, the exposure limit in groundwater recommended by the World Health Organization. A few higher (222)Rn activities (up to 310 Bq/L) have been measured in wells from the Appalachian Mountains and from the magmatic intrusion of Mont-Saint-Hilaire, known for its high level of indoor radon. The spatial distribution of (222)Rn activity seems to be related mainly to lithology differences between U-richer metasediments of the Appalachian Mountains and magmatic intrusions and the carbonaceous silty shales of the St. Lawrence Platform. Radon is slightly enriched in sodium-chlorine waters that evolved at contact with clay-rich formations. (226)Ra, the parent element of (222)Rn could be easily adsorbed on clays, creating a favorable environment for the production and release of (222)Rn into groundwater. The contribution of groundwater radon to indoor radon or by ingestion is minimal except for specific areas near Mont-Saint-Hilaire or in the Appalachian Mountains where this contribution could reach 45% of the total radioactive annual dose.
在加拿大东部蒙特利尔和魁北克市之间的区域，对198口地下水井进行了采样，以测量（222）Rn活度。本研究的目的是将（222）Rn活度的空间分布与研究区域的地质和水文地质联系起来，并估计魁北克省人口最密集地区与（222）Rn相关的潜在健康风险。大多数地下水样品显示出较低的（222）Rn活度，中值为8.6 Bq/L。90%的样品显示（222）Rn活度低于100 Bq/L，这是世界卫生组织推荐的地下水中的暴露限值。在阿巴拉契亚山脉以及以室内氡含量高而闻名的圣伊莱尔山岩浆侵入区的水井中，测量到了一些较高的（222）Rn活度（高达310 Bq/L）。（222）Rn活度的空间分布似乎主要与阿巴拉契亚山脉富含铀的变质沉积物、岩浆侵入体与圣劳伦斯地台的碳质粉砂质页岩之间的岩性差异有关。氡在与富含粘土的地层接触时演化出的氯化钠水中略有富集。（222）Rn的母体元素（226）Ra很容易吸附在粘土上，为（222）Rn在地下水中的产生和释放创造了有利环境。除了圣伊莱尔山附近或阿巴拉契亚山脉的特定区域外，地下水氡对室内氡或通过摄入的贡献极小，在这些特定区域，这种贡献可能达到年度总辐射剂量的45%。
