Silver nanoparticles entering soils via the wastewater-sludge-soil pathway pose low risk to plants but elevated CI concentrations increase Ag bioavailability
Date
2016
Authors
Wang, P.
Menzies, N.W.
Dennis, P.G.
Guo, J.
Forstner, C.
Sekine, R.
Lombi, E.
Kappen, P.
Bertsch, P.M.
Kopittke, P.M.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Environmental Science and Technology, 2016; 50(15):8274-8281
Statement of Responsibility
Conference Name
Abstract
The widespread use of silver nanoparticles (Ag-NPs) results in their movement into wastewater treatment facilities and subsequently to agricultural soils via application of contaminated sludge. On-route, the chemical properties of Ag may change, and further alterations are possible upon entry to soil. In the present study, we examined the long-term stability and (bio)availability of Ag along the "wastewater sludge soil" pathway. Synchrotron based X-ray absorption spectroscopy (XAS) revealed that ca. 99% of Ag added to the sludge reactors as either Ag-NPs or AgNO3 was retained in sludge, with _>:79% of this being transformed to Ag2S, with the majority (>= 87%) remaining in this form even after introduction to soils at various pH values and Cl concentrations for up to 400 days. Diffusive gradients in thin films (DGT), chemical extraction, and plant uptake experiments indicated that the potential (bio)availability of Ag in soil was low but increased markedly in soils with elevated Cl, likely due to the formation of soluble AgClx complexes in the soil solution. Although high Cl concentrations increased the bioavailability of Ag markedly, plant growth was not reduced in any treatment. Our results indicate that Ag-NPs entering soils through the wastewater-sludge soil pathway pose low risk to plants due to their conversion to Ag2S in the wastewater treatment process, although bioavailability may increase in saline soils or when irrigated with high-Cl water.
School/Discipline
Dissertation Note
Provenance
Description
Data source: Supporting information, http://pubs.acs.org/doi/abs/10.1021/acs.est.6b01180
Link to a related website: https://research-repository.griffith.edu.au/bitstream/10072/382404/1/SekinePUB488.pdf, Open Access via Unpaywall
Access Status
Rights
Copyright 2016 American Chemical Society