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Details van artikel 136 van 222 gevonden artikelen
| Titel: |
Modeling the Effect of Trace Metal Emissions on Boreal Forest Soils |
| Auteur: |
MacDonald, D. Taillon, K. Johnson, D. Hale, B. Hendershot, W. |
| Verschenen in: |
Human and ecological risk assessment |
| Paginering: | Jaargang 9 (2003) nr. 4 pagina's 723-747 |
| Jaar: |
2003-06-01 |
| Inhoud: |
In order to assess the fate and mobility of aerially deposited trace metals in forested ecosystems, transects were established with distance from two point source emitters in Rouyn PQ, and Sudbury ON, Canada. The sites closest to the smelters were exposed to heavy deposition in the past. Now that deposition has been reduced, these sites are returning to a new equilibrium. Using data from samples collected in the field, we developed equations that predict dissolved metal concentrations from total metal concentrations, soil pH, soil organic matter (SOM), and dissolved organic carbon (DOC) contents. We integrated these equations into a simple box model that calculates changes in the concentration of metals in the organic and upper mineral horizons and includes a loop for vegetative return of metals to the forest floor. The model provides a reasonable description of the changes in concentrations in the ecosystem compartments with time. Using this simple model, we identified the time to reach equilibrium and equilibrium concentrations at different soil pH values and at different metal loading rates. We used a chemical speciation model (WinHumicV) to calculate free metal ion concentrations in the soil solutions and then estimated the degree of inhibition in biological activity these levels would be expected to cause. Variations in the properties of the ecosystem, such as soil pH, significantly modify the nature of soil solution chemistry. Modeling results suggest that depending on the response of organism to changes in free metal ion activity, these differences could place a stress on an ecosystem equivalent to significant increases from present day aerial deposition rates. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 136 van 222 gevonden artikelen
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