Temporal Changes in Cadmium Speciation in Brazilian Soils Evaluated Using Cd LIII-Edge XANES and Chemical Fractionation.
J Environ Qual
; 46(6): 1206-1214, 2017 Nov.
Article
em En
| MEDLINE
| ID: mdl-29293850
Chemical speciation of soil cadmium (Cd) dictates its mobility and potential toxicity in the environment. Our objective was to compare temporal changes in speciation of Cd(II) reacted with samples from six Brazilian soils having varying Cd(II) sorption capacities. Cadmium L-edge X-ray absorption near edge structure (XANES) analysis showed there were short-term changes in speciation after reaction with 4.45 mmol Cd kg for 0.5 and 6 h. Chemical fractionation evaluated changes in Cd extractability after reaction with 89 µmol Cd kg for up to 4 mo. The XANES spectral fits suggested that Cd(II) bound with organic matter was a dominant species in all samples, along with Cd(II) bound with iron and aluminum oxides or montmorillonite. In several samples, CdCl apparently precipitated from aqueous Cd(II) during drying. The XANES spectral fits typically showed <25% change in speciation between 0.5 and 6 h of reaction, and chemical fractionation showed significant ( < 0.05) temporal changes in Cd extractability over time in two samples. Our results suggest that Cd(II) discharged into these soils, such as that occurring as a release into the environment, would bind with soil organic matter and oxide minerals or remain dissolved, with little change in speciation in the months following release.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Poluentes do Solo
/
Cádmio
País/Região como assunto:
America do sul
/
Brasil
Idioma:
En
Revista:
J Environ Qual
Ano de publicação:
2017
Tipo de documento:
Article
País de publicação:
Estados Unidos