Dissolution of ag nanoparticles in agricultural soils and effects on soil exoenzyme activities

Nuno C. Cruz, Márcia Farto, Clarisse Mourinha, Daniela Tavares, Armando C. Duarte, Tito Trindade, Eduarda Pereira, Paul F.A.M. Römkens, Paula Alvarenga, Sónia M. Rodrigues*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

To assess environmental risks related to the mobility and toxicity of AgNPs, the chemical availability of AgNPs and polyvinylpyrrolidone-coated AgNPs (PVP-AgNPs) in three agricultural soils was quantified in a pot experiment. Porewater collection and soil extractions with 0.01 M CaCl2, 0.4 M Glycine (pH 1.5) and 0.05 M NH4-EDTA were performed. The effect on soil exoenzyme activities was also assessed. Porewater concentration was low (<0.4% and <0.04% of dosed Ag, for AgNPs and PVP-AgNPs, respectively) and only detected in acidic soils (pH 4.4 and 4.9). The PVP-coating reduced the downward mobility of AgNPs in soil and possibly also their dissolution rate (and subsequent release of dissolved Ag+ ions into porewater). The effect of variation in organic matter on soil enzymatic activity was larger than that of AgNPs, as no significant additional inhibitory effect from Ag could be observed. Only at low pH and in the presence of complexing ligands that form very stable Ag complexes (0.4 M Glycine extraction at pH 1.5) up to 58% of the Ag added to soil was released (independently of PVP coating). An extraction with glycine is proposed as a useful indicator of potentially available Ag in soils.

Original languageEnglish
Article number22
JournalEnvironments - MDPI
Volume8
Issue number3
DOIs
Publication statusPublished - 19 Mar 2021

Keywords

  • Exoenzyme activities
  • Fungicides
  • Polymer coating
  • Silver nanoparticles
  • Soil extraction tests

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