Osmium and Platinum Decoupling in the Environment: Evidences in Intertidal Sediments (Tagus Estuary, SW Europe).
Catalytic converters in automobiles have significantly increased the input of platinum group elements (PGE) to the environment, and their coupled geochemical behavior has been proposed. To check this hypothesis, Pt and Os concentrations and (187)Os/(188)Os ratios were determined in sediment cores and interstitial waters from the Tagus Estuary (SW Europe) affected by different traffic pressure. Platinum concentration in surface sediments nearby the high traffic zone (up to 40 ng g(-1)) indicated severe contamination. Although lower than Pt, Os enrichment was also observed in surface sediments, with lower (187)Os/(188)Os ratios than in deeper layers. Dissolved Pt and Os in interstitial waters, 0.1-0.7 pg g(-1) and 0.03-0.10 pg g(-1), respectively, were higher than in typical uncontaminated waters. Results indicate two sources of Pt and Os into the Tagus Estuary salt marshes: a regional input associated with industrial activities, fossil fuel combustions, and regional traffic and a local source linked to nearby traffic density emissions. Estimations of Os and Pt released by catalytic converters support this two-source model. Differences in geochemical reactivity and range of dispersion from their sources lead to a decoupled behavior of Os and Pt, questioning the use of Os isotopes as proxies of PGE sources to the environment.
†Bioxeoquímica Mariña, Instituto de Investigacións Mariñas IIM-CSIC, Eduardo Cabello 6, 36208 Vigo, Pontevedra, Spain.|‡Radiogenic Isotope Geochemistry Laboratory, Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire 03755, United States.
Clara
C
Almécija
‡Radiogenic Isotope Geochemistry Laboratory, Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire 03755, United States.
Mukul
M
Sharma
†Bioxeoquímica Mariña, Instituto de Investigacións Mariñas IIM-CSIC, Eduardo Cabello 6, 36208 Vigo, Pontevedra, Spain.
Antonio
A
Cobelo-García
†Bioxeoquímica Mariña, Instituto de Investigacións Mariñas IIM-CSIC, Eduardo Cabello 6, 36208 Vigo, Pontevedra, Spain.
Juan
J
Santos-Echeandía
§IPMA-Portuguese Institute of Sea and Atmosphere, Av. Brasilia, 1449-006 Lisbon, Portugal.|∥CIIMAR, Marine and Environmental Research Center, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
Miguel
M
Caetano
D002384:Catalysis; D004784:Environmental Monitoring; D063366:Estuaries; D005060:Europe; D005843:Geography; D019015:Geologic Sediments / Q000737:chemistry*; D007554:Isotopes; D057230:Limit of Detection; D009992:Osmium / Q000032:analysis*; D010984:Platinum / Q000032:analysis*; D014872:Water Movements
D007554:Isotopes; D009992:Osmium; D010984:Platinum