Water-Rock Interaction and the Hydrogeochemistry of Chromium in Groundwater from Multilevels Monitoring Wells in Urania, SP, Brazil
Anomalous natural concentrations of chromium, sometimes exceeding the potability limit (0.05 mg.L-1), have been detectedin the groundwater of Adamantina Aquifer in the municipality of Urânia, and in a wide region of the western part ofthe State of São Paulo. In order to identify the possible geochem...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Universidade de São Paulo
2009-06-01
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| Series: | Geologia USP. Série Científica |
| Subjects: | |
| Online Access: | http://ppegeo-local.igc.usp.br/pdf/guspsc/v9n2/v9n2a03.pdf |
| _version_ | 1818482739413778432 |
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| author | Reginaldo Antonio Bertolo Leonardo Nobuo Oshima Marcolan Christine Laure Marie Bourotte |
| author_facet | Reginaldo Antonio Bertolo Leonardo Nobuo Oshima Marcolan Christine Laure Marie Bourotte |
| author_sort | Reginaldo Antonio Bertolo |
| collection | DOAJ |
| description | Anomalous natural concentrations of chromium, sometimes exceeding the potability limit (0.05 mg.L-1), have been detectedin the groundwater of Adamantina Aquifer in the municipality of Urânia, and in a wide region of the western part ofthe State of São Paulo. In order to identify the possible geochemical reactions that may explain the occurrence of chromiumin groundwater, chemical and mineralogical analyses were conducted in rock samples collected from deep boreholes drilledin the city of Urânia. Multilevel monitoring wells were installed in the boreholes, and stratifi ed groundwater samples werecollected for chemical analyses. The analyses of the borehole samples indicated the occurrence of a geochemical anomaly ofchromium (average concentrations of 221 ppm) and pointed to chrome-diopside containing from 1,000 to 6,000 ppm Cr as themain reactive mineral that contributes to this anomaly. Groundwater chemical analyses indicated the occurrence of a hydrochemicalstratifi cation of the aquifer: waters from the base of the aquifer are alkaline (pH higher than 10) whereas in the shallowzone of the aquifer, pH is neutral to mildly acid. Chromium has been identifi ed in its hexavalent form, and prevails in theaquifer, reaching the maximum concentration of 0.13 mg.L-1. The geochemical reactions that explain the release of chromiumfrom the solid phase to the water probably involve the dissolution of Cr3+ minerals such as diopside, followed by a redox reactionthat oxidizes Cr3+ to Cr6+ and reduces manganese oxide minerals. Additionally, adsorption reactions may take place, anddesorption and mobilization of Cr6+ may be favored in some portions of the deep aquifer where pH is anomalously alkaline. |
| first_indexed | 2024-12-10T11:51:07Z |
| format | Article |
| id | doaj.art-dcfe3fb3e04545c5890ced9ecfa21f4f |
| institution | Directory Open Access Journal |
| issn | 1519-874X |
| language | English |
| last_indexed | 2024-12-10T11:51:07Z |
| publishDate | 2009-06-01 |
| publisher | Universidade de São Paulo |
| record_format | Article |
| series | Geologia USP. Série Científica |
| spelling | doaj.art-dcfe3fb3e04545c5890ced9ecfa21f4f2022-12-22T01:49:56ZengUniversidade de São PauloGeologia USP. Série Científica1519-874X2009-06-01924762Water-Rock Interaction and the Hydrogeochemistry of Chromium in Groundwater from Multilevels Monitoring Wells in Urania, SP, BrazilReginaldo Antonio BertoloLeonardo Nobuo Oshima MarcolanChristine Laure Marie BourotteAnomalous natural concentrations of chromium, sometimes exceeding the potability limit (0.05 mg.L-1), have been detectedin the groundwater of Adamantina Aquifer in the municipality of Urânia, and in a wide region of the western part ofthe State of São Paulo. In order to identify the possible geochemical reactions that may explain the occurrence of chromiumin groundwater, chemical and mineralogical analyses were conducted in rock samples collected from deep boreholes drilledin the city of Urânia. Multilevel monitoring wells were installed in the boreholes, and stratifi ed groundwater samples werecollected for chemical analyses. The analyses of the borehole samples indicated the occurrence of a geochemical anomaly ofchromium (average concentrations of 221 ppm) and pointed to chrome-diopside containing from 1,000 to 6,000 ppm Cr as themain reactive mineral that contributes to this anomaly. Groundwater chemical analyses indicated the occurrence of a hydrochemicalstratifi cation of the aquifer: waters from the base of the aquifer are alkaline (pH higher than 10) whereas in the shallowzone of the aquifer, pH is neutral to mildly acid. Chromium has been identifi ed in its hexavalent form, and prevails in theaquifer, reaching the maximum concentration of 0.13 mg.L-1. The geochemical reactions that explain the release of chromiumfrom the solid phase to the water probably involve the dissolution of Cr3+ minerals such as diopside, followed by a redox reactionthat oxidizes Cr3+ to Cr6+ and reduces manganese oxide minerals. Additionally, adsorption reactions may take place, anddesorption and mobilization of Cr6+ may be favored in some portions of the deep aquifer where pH is anomalously alkaline.http://ppegeo-local.igc.usp.br/pdf/guspsc/v9n2/v9n2a03.pdfChromiumHydrogeochemistryGroundwaterAquifer |
| spellingShingle | Reginaldo Antonio Bertolo Leonardo Nobuo Oshima Marcolan Christine Laure Marie Bourotte Water-Rock Interaction and the Hydrogeochemistry of Chromium in Groundwater from Multilevels Monitoring Wells in Urania, SP, Brazil Geologia USP. Série Científica Chromium Hydrogeochemistry Groundwater Aquifer |
| title | Water-Rock Interaction and the Hydrogeochemistry of Chromium in Groundwater from Multilevels Monitoring Wells in Urania, SP, Brazil |
| title_full | Water-Rock Interaction and the Hydrogeochemistry of Chromium in Groundwater from Multilevels Monitoring Wells in Urania, SP, Brazil |
| title_fullStr | Water-Rock Interaction and the Hydrogeochemistry of Chromium in Groundwater from Multilevels Monitoring Wells in Urania, SP, Brazil |
| title_full_unstemmed | Water-Rock Interaction and the Hydrogeochemistry of Chromium in Groundwater from Multilevels Monitoring Wells in Urania, SP, Brazil |
| title_short | Water-Rock Interaction and the Hydrogeochemistry of Chromium in Groundwater from Multilevels Monitoring Wells in Urania, SP, Brazil |
| title_sort | water rock interaction and the hydrogeochemistry of chromium in groundwater from multilevels monitoring wells in urania sp brazil |
| topic | Chromium Hydrogeochemistry Groundwater Aquifer |
| url | http://ppegeo-local.igc.usp.br/pdf/guspsc/v9n2/v9n2a03.pdf |
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