The nature and extent of bomb tritium remaining in deep vadose zones: A synthesis and prognosis

Tritium present in deep vadose zones is a useful tracer for estimating groundwater recharge, but its full utility is constrained by not knowing where and for how long the tritium tracing method remains applicable. We obtained 44 tritium profiles from 17 globally distributed sites with vadose zone thicknesses of 13−624 m and used transport models to estimate the number of years that tritium may still be useful. Results show that the method may still be usable for 26 of 44 soil profiles surveyed, mainly in China, Australia, USA, South Africa, and Senegal, with a remaining useful period of between 6 and 83 years. We also developed a statistical model that uses outputs from a hydrological model to predict the applicability of the tritium tracing method. Global implementation of the statistical model showed that the method remains usable at 20% of Earth’s land mass (excluding Antarctica and Greenland) over the next few decades., The dataset – soil water tritium profiles (n = 40) – was compiled from the peer-reviewed literature (see Text S2 in manuscript). This was supplemented with 4 profiles from study sites in Changwu, Shaanxi Province, China. The dataset was compiled by co-authors Yanan Huang ([e-mail]) and Zhi Li ([e-mail]) of Northwest A&F University., , The dataset -- soil water tritium profiles (n = 40) -- was compiled from the peer-reviewed literature (see Text S2 in manuscript). This was supplemented with 4 profiles from study sites in Changwu, Shaanxi Province, China. The dataset was compiled by co-authors Yanan Huang () and Zhi Li () of Northwest A&F University. For any questions regarding the dataset, please send an email to Yanan Huang () and Zhi Li (). --- Filename: tritium_profile_all_data.csv * SiteID - refers to the assigned site identifier as also referenced to in tritium_sourcepapers.csv * depth (m) - depth of sampling in meters * 3H - tritium concentration in T.U. or tritium units * sampling year - year of sampling Filename: tritium_sourcepapers.csv * No - numeric identifier assigned to each unique soil tritium profile * Country - country where the sample was collected * SiteID - refers to the assigned site identifier as also referenced to in tritium_profile_all_data.csv * Source paper - Author-...深包气带（deep vadose zone）中存在的氚（Tritium）是估算地下水补给的有效示踪剂，但由于尚不明确氚示踪法的适用区域与有效时长，其全部应用潜力尚未充分发挥。我们从全球分布的17个研究点位获取了44条氚剖面数据，这些点位的包气带厚度介于13~624米之间，并采用运移模型（transport models）估算了氚示踪法仍可发挥作用的剩余年限。研究结果显示，本次调研的44条土壤氚剖面中，有26条仍可使用该示踪方法，这些点位主要分布在中国、澳大利亚、美国、南非与塞内加尔，其剩余有效使用年限为6~83年。此外，我们还构建了一种统计模型，该模型依托水文模型（hydrological model）的输出结果来预测氚示踪法的适用性。该统计模型的全球应用结果表明，未来数十年内，全球陆地面积的20%（不含南极洲与格陵兰岛）仍可使用该示踪方法。 本数据集包含40条土壤水氚剖面（soil water tritium profiles，n=40），均整理自同行评议文献（详见手稿中的补充材料S2），另有4条剖面补充自中国陕西省长武县的研究点位。本数据集由西北农林科技大学的共同作者黄亚楠（[e-mail]）与李志（[e-mail]）整理汇编。 本数据集包含40条土壤水氚剖面（soil water tritium profiles，n=40），均整理自同行评议文献（详见手稿中的补充材料S2），另有4条剖面补充自中国陕西省长武县的研究点位。本数据集由西北农林科技大学的共同作者黄亚楠（无邮箱）与李志（无邮箱）整理汇编。若您对本数据集有任何疑问，请致信黄亚楠（无邮箱）与李志（无邮箱）。 --- 文件名：tritium_profile_all_data.csv * SiteID：指分配的点位标识符，与tritium_sourcepapers.csv中引用的标识符一致 * depth (m)：采样深度，单位为米 * 3H：氚浓度，单位为氚单位（T.U.） * sampling year：采样年份 文件名：tritium_sourcepapers.csv * No：为每条独立土壤氚剖面分配的数字标识符 * Country：样品采集所在国家 * SiteID：指分配的点位标识符，与tritium_profile_all_data.csv中引用的标识符一致 * Source paper：作者-……（原文未完整展示）