Groundwater salinization in Graciosa and Pico islands (Azores archipelago, Portugal): processes and impacts
Study region: Graciosa and Pico islands, Azores, Portugal Study focus: Seawater intrusion is a main driver of groundwater salinization in the Azores archipelago. In order to characterize the associated geochemical processes through major-ion and determination of stable (δ18O; δ2H; δ11B) and radiogen...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2017-08-01
|
| Series: | Journal of Hydrology: Regional Studies |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214581816300970 |
| _version_ | 1828749762218688512 |
|---|---|
| author | J.V. Cruz C. Andrade |
| author_facet | J.V. Cruz C. Andrade |
| author_sort | J.V. Cruz |
| collection | DOAJ |
| description | Study region: Graciosa and Pico islands, Azores, Portugal
Study focus: Seawater intrusion is a main driver of groundwater salinization in the Azores archipelago. In order to characterize the associated geochemical processes through major-ion and determination of stable (δ18O; δ2H; δ11B) and radiogenic isotopic ratios (δ87Sr) a total of 46 wells were sampled in Graciosa and Pico, as well as 51 wells from other islands.
New hydrological insights for the region: The overall groundwater chemistry is mainly controlled by Cl and Na, which account respectively for 10.4%–46.9% and 16%–39.7% of the relative major-ion content. Mean electrical conductivity (EC) in Graciosa is in the range 308 − 3462 μS/cm, while hand-dug wells in Pico are highly mineralized (1758–9732 μS/cm). Drilled wells in Pico are in the range of 186 μS/cm to 5625 μS/cm. Besides mixture with seawater, groundwater chemistry is also influenced by dissolution of silicate minerals which also contributes to water composition. Moreover, 18O and 2H stable isotope data show that a few samples depict an evaporative effect, resulting in heavier isotopic compositions besides mixing with a marine source. About 70% of the wells in Graciosa and Pico exceed the 200 mg Cl/L and the EC Portuguese reference values, severely constraining water supply. The impact on water quality is also shown by exceedances of the groundwater threshold values derived for the Azores River Basin District (89%). |
| first_indexed | 2024-12-10T20:27:50Z |
| format | Article |
| id | doaj.art-8cf6fa48e41f4ffe97b06f9fbe4a7030 |
| institution | Directory Open Access Journal |
| issn | 2214-5818 |
| language | English |
| last_indexed | 2024-12-10T20:27:50Z |
| publishDate | 2017-08-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Hydrology: Regional Studies |
| spelling | doaj.art-8cf6fa48e41f4ffe97b06f9fbe4a70302022-12-22T01:34:48ZengElsevierJournal of Hydrology: Regional Studies2214-58182017-08-0112C698710.1016/j.ejrh.2017.04.003Groundwater salinization in Graciosa and Pico islands (Azores archipelago, Portugal): processes and impactsJ.V. CruzC. AndradeStudy region: Graciosa and Pico islands, Azores, Portugal Study focus: Seawater intrusion is a main driver of groundwater salinization in the Azores archipelago. In order to characterize the associated geochemical processes through major-ion and determination of stable (δ18O; δ2H; δ11B) and radiogenic isotopic ratios (δ87Sr) a total of 46 wells were sampled in Graciosa and Pico, as well as 51 wells from other islands. New hydrological insights for the region: The overall groundwater chemistry is mainly controlled by Cl and Na, which account respectively for 10.4%–46.9% and 16%–39.7% of the relative major-ion content. Mean electrical conductivity (EC) in Graciosa is in the range 308 − 3462 μS/cm, while hand-dug wells in Pico are highly mineralized (1758–9732 μS/cm). Drilled wells in Pico are in the range of 186 μS/cm to 5625 μS/cm. Besides mixture with seawater, groundwater chemistry is also influenced by dissolution of silicate minerals which also contributes to water composition. Moreover, 18O and 2H stable isotope data show that a few samples depict an evaporative effect, resulting in heavier isotopic compositions besides mixing with a marine source. About 70% of the wells in Graciosa and Pico exceed the 200 mg Cl/L and the EC Portuguese reference values, severely constraining water supply. The impact on water quality is also shown by exceedances of the groundwater threshold values derived for the Azores River Basin District (89%).http://www.sciencedirect.com/science/article/pii/S2214581816300970Groundwater salinizationHydrogeochemistryWater qualityVolcanic islandsAzores |
| spellingShingle | J.V. Cruz C. Andrade Groundwater salinization in Graciosa and Pico islands (Azores archipelago, Portugal): processes and impacts Journal of Hydrology: Regional Studies Groundwater salinization Hydrogeochemistry Water quality Volcanic islands Azores |
| title | Groundwater salinization in Graciosa and Pico islands (Azores archipelago, Portugal): processes and impacts |
| title_full | Groundwater salinization in Graciosa and Pico islands (Azores archipelago, Portugal): processes and impacts |
| title_fullStr | Groundwater salinization in Graciosa and Pico islands (Azores archipelago, Portugal): processes and impacts |
| title_full_unstemmed | Groundwater salinization in Graciosa and Pico islands (Azores archipelago, Portugal): processes and impacts |
| title_short | Groundwater salinization in Graciosa and Pico islands (Azores archipelago, Portugal): processes and impacts |
| title_sort | groundwater salinization in graciosa and pico islands azores archipelago portugal processes and impacts |
| topic | Groundwater salinization Hydrogeochemistry Water quality Volcanic islands Azores |
| url | http://www.sciencedirect.com/science/article/pii/S2214581816300970 |
| work_keys_str_mv | AT jvcruz groundwatersalinizationingraciosaandpicoislandsazoresarchipelagoportugalprocessesandimpacts AT candrade groundwatersalinizationingraciosaandpicoislandsazoresarchipelagoportugalprocessesandimpacts |