Application of U-234/U-238 activity ratios to investigations of subterranean groundwater discharge in the Cadiz coastal area (SW Spain)

作者：Rodrigo J F; Casas Ruiz M^*; Vidal J; Barbero L; Baskaran M; Ketterer M E

来源：Journal of Environmental Radioactivity, 2014, 130: 68-71.

DOI：10.1016/j.jenvrad.2014.01.004

• ICP-MS
• U-234/U-238 activity ratios
• Coastal aquifers
• Submarine groundwater discharge (SGD)

The activity ratios of U-234/U-238 were used to investigate processes of subterranean groundwater discharge into coastal marine waters in a study location at Bay of Cadiz (southwest Spain). Marine waters in the bay and surrounding open ocean exhibited U concentrations of 3.4 +/- 0.1 mu g/L and activity ratios of 1.15 +/- 0.01, in agreement with the expected composition of seawater (U-234/U-238 activity ratio = 1.148 +/- 0.002). Three water samples obtained from the discharge zone of the Guadalete River exhibited activity ratios of 1.17-1.22 along with slightly lower U concentrations compared to seawater, which is likely due to mixing between seawater and a groundwater end-member. One possible source of groundwater was characterized by sampling and analyzing a well water sample collected in the neighboring village of El Puerto de Santa Maria; this water sample exhibited an activity ratio of 1.34 +/- 0.03 and a U concentration of 1.22 mu g/L. Water from the Guadelete River estuarine zone can be explained to result from a two-component mixture of seawater and groundwater from the El Puerto de Santa Maria well; however, if there are several groundwater reservoirs with different U activity ratios that discharge to the coastal water, then, it may be difficult and more studies are being conducted to address this issue.

• 出版日期2014-4