NanoFASE Case Study: Stable Isotope Tracing of Silver Nanoparticles in Wheat

Silver nanoparticles (Ag NPs) can enter natural ecosystems by direct application or by release from products, or when Ag NPs from wastewater streams are captured in sewage sludge and applied on agricultural land as biosolid fertilisers. Ag NPs have been reported to be taken up by plants through the root and therefore it is important to understand the patterns of accumulation and translocation of Ag NPs in plants, particularly at environmentally relevant exposure concentrations. In this study, isotopically labelled 109Ag NPs were used to expose plants to Ag concentrations to assess accumulation in the crop plant wheat, Triticum aestivum.

Study aim


The aim of this study was to quantify uptake of Ag NPs and Ag+ from isotopically labelled 109Ag by wheat plants at environmentally relevant concentrations using a stable isotope approach. 

Experimental approach


  1. Stable Ag isotope nanoparticles are synthesised (109Ag NP)
  2. Soil is spiked with 109Ag NPs
  3. Winter wheat is grown to maturity in the spiked soil and samples are collected from the four treatment conditions at eight different biological plant growth stages
  4. Digestion and column chemistry
  5. Isotopic analysis with MC-ICPMS (multiple collector - inductively coupled plasma mass spectrometry) - measures both 109/107Ag ratio and 109Ag concentrations

Compartment involved:  


NP type/size:

Citrate coated Ag NPs - 20nm
Wheat (Triticum aestivum)
Bioaccumulation assay
Extractable Ag assay




  •  No adverse effects for winter wheat exposed to Ag NPs  & Ag+ at environmentally relevant concentrations were found.
  •  The concentrations of Ag derived from NPs were highest in the roots and lowest in the grains.

  • Ag uptake by wheat was higher for nanoparticles than for dissolved Ag+ which is likely related to the greater soluble Ag in the pore water of the nanoparticle exposure.




  • Bioaccumulation factor – BAF
  • Transfer function – TF
  • Pore water and soil concentrations
  • Fresh and dry biomass in time



   Agricultural soil                         Wheat         


Read more

Read also


Visit the NanoFASE Library to read summaries of these reports:

NanoFASE Report D7.2 Soil property – NM fate relationships

NanoFASE Report D9.2 Parameter sets on uptake and toxicokinetics of selected pristine NMs in aquatic and terrestrial organisms (summary of internal report) 

OECD Test No. 208: Terrestrial Plant Test: Seedling Emergence and Seedling Growth Test

Laycock, A, Stolpe, B, Römer, I, Dybowska, A, Valsami-Jones, E, Lead, J.R., Rehkämper, M (2014) Synthesis and characterization of isotopically labeled silver nanoparticles for tracing studies ES Nano 1:3 271-283



Amaia Green Etxabe

Centre for Ecology and Hydrology (CEH)
Wallingford, UK



Denny Tarnovska

Imperial College London, UK

Centre for Ecology and Hydrology (CEH)