Bio-elimination

Bio-elimination of ENMs indicates the process whereby nanomaterials are excreted from an organism’s body. This elimination can occur in different forms, and depends entirely on:

  • the type of ENM
  • the internal concentrations of the ENMs in the organism
  • the physiology of the organism

It is assumed that external concentrations of ENMs do not affect the rate of elimination.

 

  Occurs in

Biota      

Fate descriptors

Algorithms
 

 

Elimination curve when organism has been moved to clean medium (on day 50) (conceptual graph of exposure experiment)

Elimination rate constant
k2 (day-1)

Elimination takes place together with uptake in contaminated media [equation 1]. Elimination also occurs in clean media, whereas no actual uptake takes place there [equation 2]. Elimination of a single form of the ENM is calculated below.

1. Elimination when exposed in contaminated medium

\(C_{org}= C_{env} \ast k_{1}\ast SF \ast t + C_{env} \ast \frac{k_{1}}{k_{2}+k_{g}}\ast (1-e^{-(k_{2}+k_{g})\ast t})(1 - SF)\)

2. Elimination when exposed in clean medium after tm days in contaminated medium

\(C_{org}= C_{env} \ast k_{1} \ast SF \ast t_{m} + C_{env} \ast \frac{k_{1}}{k_{2}+k_{g}}\ast (1-(e^{-(k_{2}+k_{g})\ast t}\ast e^{-(k_{2}+k_{g})\ast(t-t_{m})})\ast (1-SF)\)

Where: 

\(C_{org}\) - Concentrations in the organism (\(\mu g/g\))
\(C_{env}\) - Concentrations in the environmental compartment (\(\mu g/g\))
\(k_{1}\) - uptake rate constant (g*g-1* day-1)
\(k_{2}\) - elimination rate constant (day-1)

\(k_{g}\) - growth dilution constant (day-1)

\(SF\) - stored fraction (\(0\leq SF\leq 1\)) (unitless)

\(t\) - total time of experiment (day)

\(t_{m}\) - time of transfer from contaminated to clean soil (day)

 

Visit the Uptake, elimination and growth dilution page.

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

Baalousha et al. 2016. Environ Sci Nano 3, 323-345.
Cornelis, G. et al., 2014. Crit Rev Environ Sci Technol. 44: 2720–2764
Ardestani et al. 2014. Environ. Poll 193, 277-295.

Ardestani, M.M. et al. 2014. Uptake and elimination kinetics of metals in soil invertebrates: a review. Environ Poll 193, 277-295. DOI: 10.1016/j.envpol.2014.06.026

Baalousha, M. et al. 2016. Modeling nanomaterial fate and uptake in the environment: current knowledge and future trends. Environ Sci Nano 3, 323-345. DOI: 10.1039/c5en00207a

Cornelis, G. et al. 2014. Fate and Bioavailability of Engineered Nanoparticles in Soils: A Review. Crit Rev Environ Sci Technol 44, 2720–2764. DOI: 10.1080/10643389.2013.829767

van den Brink, N.W. et al. 2019. Tools and rules for modelling uptake and bioaccumulation of nanomaterials in invertebrate organisms. Environ Sci Nano 6, 1985-2001. DOI: 10.1039/C8EN01122B

Contact

 

  Nico van den Brink

  Wageningen University

  Email: Nico.vandenbrink@wur.nl

  Kees van Gestel

  Department of Ecological Science
  Faculty of Science, Vrije Universiteit

  Email: kees.van.gestel@vu.nl