NanoFASE Case Study: Biokinetics of Ag-NPs in isopods

Isopods are soil dwelling invertebrates that serve as important decomposers of organic matter. As they ingest soil, they are simultaneously exposed to potential soil contaminants, including metal nanoparticles (NPs). In this NanoFASE case study, we examined the biokinetics of silver (Ag) NPs, i.e. how much and how fast the animals take up, eliminate or accumulate this material. 

Study aim

 

The aim of the study is to provide uptake rate constants (k1) and elimination rate constants (k2) derived from the modelled biokinetic curve fitted to data on total body Ag concentration in isopods.
 

Overview

  1. Uptake phase - isopods are exposed to soil contaminated with Ag-NPs

  2. Elimination phase - isopods are transferred to clean soil

  • Samples are taken for measurements of Ag concentration in animal body (data points in the figure)

  • Parameters of interest are derived from the fitted curve

Environmental medium:
Soil (Lufa 2.2) 

NP type/size:

Pristine Ag-NP 50nm (Amepox)
Pristine Ag-NP 3-8 nm (Amepox)
Sulfidized Ag-NP (Ag2S) 20 nm
 

Species:
Porcellio scaber

Results

 
 

Ag-NPs are taken up via ingestion and eliminated via defecation. NPs are not internalized, but can dissolve in the hindgut and subsequently, released Ag+ ions are assimilated and accumulated in the digestive gland (hepatopancreas). In conclusion, only those Ag-NPs that can dissolve are of relevance for the isopods. Non-dissolving Ag particles (for example the sulfidized Ag-NPs) pass the gut and are excreted by the animal back to the soil.

 

Modelling parameter outputs

Compartment
 

 

 

Soil                                             Biota

Read more

Read also
 

Visit the NanoFASE Library  to read summaries of these reports:
NanoFASE Report D9.2 Loureiro et al.: Parameter sets on uptake and toxicokinetics of selected pristine NMs in aquatic and terrestrial organisms.
 

Tourinho, P.S., van Gestel, C.A., Morgan, A.J., Kille, P., Svendsen, C., Jurkschat, K., Mosselmans, J.F.W., Soares, A.M. and Loureiro, S., 2016. Toxicokinetics of Ag in the terrestrial isopod Porcellionides pruinosus exposed to Ag NPs and AgNO3 via soil and food. Ecotoxicology, 25(2), pp.267-278.

Ardestani, M.M., van Straalen, N.M. and van Gestel, C.A., 2014. Uptake and elimination kinetics of metals in soil invertebrates: a review. Environmental pollution, 193, pp.277-295.

Contact

 

Iva Talaber

 

 

 

 

Damjana Drobne

 

 

 

 

Anita Jemec