Uranium and Nickel Partitioning in a Contaminated Riparian Wetland
Uranium (U) and nickel (Ni) released 50 years ago have been immobilized in the Tims Branch wetlands located on the Savannah River Site in the United States. Sediments were collected from seven locations to identify the factors responsible for this attenuation. Ni and U contents in the solids were si...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-03-01
|
| Series: | Water |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4441/16/7/966 |
| _version_ | 1797211880037548032 |
|---|---|
| author | Peng Lin Maxim I. Boyanov Edward J. O’Loughlin Wei Xing Kenneth M. Kemner John Seaman Steven P. Simner Daniel I. Kaplan |
| author_facet | Peng Lin Maxim I. Boyanov Edward J. O’Loughlin Wei Xing Kenneth M. Kemner John Seaman Steven P. Simner Daniel I. Kaplan |
| author_sort | Peng Lin |
| collection | DOAJ |
| description | Uranium (U) and nickel (Ni) released 50 years ago have been immobilized in the Tims Branch wetlands located on the Savannah River Site in the United States. Sediments were collected from seven locations to identify the factors responsible for this attenuation. Ni and U contents in the solids were significantly correlated, suggesting that depositional as opposed to chemical processes contributed to their spatial distribution. Based on sequential extractions, 63 ± 16% of the U was partitioned into the organic fraction, whereas Ni was distributed between several sediment fractions. An inverse pH-organic matter (OM) correlation and positive correlations of OM with total U and organic-bound U/Ni suggest that increased OM preservation and binding to the mineral surfaces were likely responsible for Ni- and especially U-sediment retention (Tims Branch pH = 4.84 ± 0.68). EXAFS analysis indicated the predominance of U(VI) coordinated with clay minerals (~65%), together with ~35% coordinated to either OM (in areas with elevated OM levels) or iron oxides. The desorption-<i>K<sub>d</sub></i> coefficients of U (3972 ± 1370 L/kg) and Ni (30 ± 8 L/kg) indicate that dissolved Ni poses a greater long-term risk than dissolved U for migrating downstream. This study suggests that a delicate balance of geochemical properties controls whether wetlands behave as sinks or sources of contaminants. |
| first_indexed | 2024-04-24T10:33:31Z |
| format | Article |
| id | doaj.art-65b6b8f4e845421ba49607dfe90c92cc |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-04-24T10:33:31Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-65b6b8f4e845421ba49607dfe90c92cc2024-04-12T13:27:04ZengMDPI AGWater2073-44412024-03-0116796610.3390/w16070966Uranium and Nickel Partitioning in a Contaminated Riparian WetlandPeng Lin0Maxim I. Boyanov1Edward J. O’Loughlin2Wei Xing3Kenneth M. Kemner4John Seaman5Steven P. Simner6Daniel I. Kaplan7Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29803, USABiosciences Division, Argonne National Laboratory, Lemont, IL 60439, USABiosciences Division, Argonne National Laboratory, Lemont, IL 60439, USASavannah River Ecology Laboratory, University of Georgia, Aiken, SC 29803, USABiosciences Division, Argonne National Laboratory, Lemont, IL 60439, USASavannah River Ecology Laboratory, University of Georgia, Aiken, SC 29803, USASavannah River Mission Completion, Aiken, SC 29803, USASavannah River Ecology Laboratory, University of Georgia, Aiken, SC 29803, USAUranium (U) and nickel (Ni) released 50 years ago have been immobilized in the Tims Branch wetlands located on the Savannah River Site in the United States. Sediments were collected from seven locations to identify the factors responsible for this attenuation. Ni and U contents in the solids were significantly correlated, suggesting that depositional as opposed to chemical processes contributed to their spatial distribution. Based on sequential extractions, 63 ± 16% of the U was partitioned into the organic fraction, whereas Ni was distributed between several sediment fractions. An inverse pH-organic matter (OM) correlation and positive correlations of OM with total U and organic-bound U/Ni suggest that increased OM preservation and binding to the mineral surfaces were likely responsible for Ni- and especially U-sediment retention (Tims Branch pH = 4.84 ± 0.68). EXAFS analysis indicated the predominance of U(VI) coordinated with clay minerals (~65%), together with ~35% coordinated to either OM (in areas with elevated OM levels) or iron oxides. The desorption-<i>K<sub>d</sub></i> coefficients of U (3972 ± 1370 L/kg) and Ni (30 ± 8 L/kg) indicate that dissolved Ni poses a greater long-term risk than dissolved U for migrating downstream. This study suggests that a delicate balance of geochemical properties controls whether wetlands behave as sinks or sources of contaminants.https://www.mdpi.com/2073-4441/16/7/966radionuclidesmonitored natural attenuationorganic matterXANESEXAFSiron oxides |
| spellingShingle | Peng Lin Maxim I. Boyanov Edward J. O’Loughlin Wei Xing Kenneth M. Kemner John Seaman Steven P. Simner Daniel I. Kaplan Uranium and Nickel Partitioning in a Contaminated Riparian Wetland Water radionuclides monitored natural attenuation organic matter XANES EXAFS iron oxides |
| title | Uranium and Nickel Partitioning in a Contaminated Riparian Wetland |
| title_full | Uranium and Nickel Partitioning in a Contaminated Riparian Wetland |
| title_fullStr | Uranium and Nickel Partitioning in a Contaminated Riparian Wetland |
| title_full_unstemmed | Uranium and Nickel Partitioning in a Contaminated Riparian Wetland |
| title_short | Uranium and Nickel Partitioning in a Contaminated Riparian Wetland |
| title_sort | uranium and nickel partitioning in a contaminated riparian wetland |
| topic | radionuclides monitored natural attenuation organic matter XANES EXAFS iron oxides |
| url | https://www.mdpi.com/2073-4441/16/7/966 |
| work_keys_str_mv | AT penglin uraniumandnickelpartitioninginacontaminatedriparianwetland AT maximiboyanov uraniumandnickelpartitioninginacontaminatedriparianwetland AT edwardjoloughlin uraniumandnickelpartitioninginacontaminatedriparianwetland AT weixing uraniumandnickelpartitioninginacontaminatedriparianwetland AT kennethmkemner uraniumandnickelpartitioninginacontaminatedriparianwetland AT johnseaman uraniumandnickelpartitioninginacontaminatedriparianwetland AT stevenpsimner uraniumandnickelpartitioninginacontaminatedriparianwetland AT danielikaplan uraniumandnickelpartitioninginacontaminatedriparianwetland |