# 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.

## Algorithms

 Elimination curve when organism has been moved to clean medium (on day 50) (conceptual graph of exposure experiment) Elimination rate constantk2 (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.