Polyethylene and polypropylene microplastics reduce chemisorption of cadmium in paddy soil and increase its bioaccessibility and bioavailability.
J Hazard Mater
; 449: 130994, 2023 05 05.
Article
em En
| MEDLINE
| ID: mdl-36821898
ABSTRACT
Microplastics (MPs) usually coexist with heavy metals (HMs) in soil. MPs can influence HMs mobility and bioavailability, but the underlying mechanisms remain largely unexplored. Here, polyethylene and polypropylene MPs were selected to investigate their effects and mechanisms of sorption-desorption, bioaccessibility and bioavailability of cadmium (Cd) in paddy soil. Batch experiments indicated that MPs significantly reduced the Cd sorption in soil (p < 0.05). Accordingly, soil with the MPs had lower boundary diffusion constant of Cd (C1= 0.847â¼1.020) and the Freundlich sorption constant (KF = 0.444-0.616) than that without the MPs (C1 = 0.894â¼1.035, KF = 0.500-0.655). X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses suggested that the MPs reduced Cd chemisorption, by covering the soil active sites and thus blocking complexation of Cd with active oxygen sites and interrupting the formation of CdCO3 and Cd3P2 precipitates. Such effects of MPs enhanced about 1.2-1.5 times of Cd bioaccessibility and bioavailability in soil. Almost the same effects but different mechanisms of polyethylene and polypropylene MPs on Cd sorption in the soil indicated the complexity and pervasiveness of their effects. The findings provide new insights into impacts of MPs on the fate and risk of HMs in agricultural soil.
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Coleções:
01-internacional
Temas:
Geral
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Agentes_cancerigenos
Base de dados:
MEDLINE
Assunto principal:
Poluentes do Solo
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Metais Pesados
Idioma:
En
Revista:
J Hazard Mater
Assunto da revista:
SAUDE AMBIENTAL
Ano de publicação:
2023
Tipo de documento:
Article