A set of springs were sampled along São Miguel Island (Azores, Portugal) to proceed to the characterization of the major-ion and radon (²²²Rn) content. According to the selection criteria a total of 42 discharges were sampled, both during winter and summer periods, along major geological units, namely 3 springs at Sete Cidades Volcano, 4 at Nordeste Volcano, 17 at Fogo Volcano, and 18 at Furnas Volcano. Spring water temperature ranges from 12.8 to 78.1 °C in winter (mean = 23.6 °C), and from 12.6 to 76.7 °C in summer (mean = 23.9 °C), and the dataset comprehends 26 (winter) to 21 (summer) cold springs, 3 to 8 ortothermal springs, as well as 13 thermal discharges. Mean electrical conductivity is equal to 552.9 μS/cm (winter) and 550 μS/cm (summer), suggesting a short residence time, and waters are acidic to slightly basic in character (pH_winter: 4.16–7.16; pH_summer: 4.05–7.35). Groundwater chemistry is manly controlled by silicate leaching, enhanced by the water temperature, seawater spraying and by the active volcanic environment. ²²²Rn content ranges between 0.99 and 551.64 Bq/L (mean = 47.8 Bq/L) in winter and between 1.42 and 559.67 Bq/L (mean = 49.4 Bq/L) in summer. All the springs with anomalously higher values are located in Fogo Volcano, while the lowest radon concentrations are observed at Furnas Volcano. Groundwater temperature exerts a control over the ²²²Rn concentration; thus, the lower content corresponds to the most mineralized thermal waters. Springs with the higher radon content show the radiogenic contribution from uranium-rich peralkaline syenite intrusive body. Furthermore, data reveal that besides this lithologic control some waters are influenced by ²²²Rn migration from a deeper source towards shallower aquifers, carried by a volatile flux of CO₂.

沿 São Miguel 岛（葡萄牙亚速尔群岛）对一组泉水进行采样，以进行主要离子和氡的表征（²²²Rn) 内容。根据选择标准，在冬季和夏季，沿主要地质单元共采集了 42 个排放点，即 Sete Cidades 火山的 3 个泉水、Nordeste 火山的 4 个、Fogo 火山的 17 个和 Furnas 火山的 18 个。春季水温范围为冬季 12.8 至 78.1 °C（平均值 = 23.6 °C），夏季为 12.6 至 76.7 °C（平均值 = 23.9 °C），数据集包含 26（冬季）至 21（夏季）冷泉，3至8个原热泉，以及13个热排放。平均电导率等于 552.9 μS/cm（冬季）和 550 μS/cm（夏季），表明停留时间很短，水呈酸性至微碱性（_冬季pH 值：4.16–7.16；_夏季pH 值）: 4.05–7.35)。地下水化学主要受硅酸盐浸出控制，受水温、海水喷洒和活跃火山环境的影响。²²² Rn 含量在冬季介于 0.99 至 551.64 Bq/L（平均值 = 47.8 Bq/L）之间，在夏季介于 1.42 至 559.67 Bq/L（平均值 = 49.4 Bq/L）之间。所有异常值较高的泉都位于福戈火山，而在弗纳斯火山观察到的氡浓度最低。地下水温度控制²²²Rn浓度；因此，较低的含量对应于矿化程度最高的温泉水。氡含量较高的泉水显示了富铀过碱性正长岩侵入体的辐射贡献。此外，数据显示，除了这种岩性控制之外，一些水域还受到²²² Rn 从较深源向较浅含水层迁移的影响，由 CO ₂的挥发性通量携带。