Partial pressure and diffusion question

[FrankRizzo]

I've got a closed system that consists of a glass container (non gas permeable) filled with pure CO2 at atmospheric pressure, with an airlock that will let CO2 escape if the pressure inside the system becomes higher (barometric pressure changes, etc.), but will not let air back into the system without a non-trivial pressure difference. The airlock is a piece of thick-walled vinyl tubing (negligible O2 permeability), immersed in a depth of tap water. Gas can bubble out, but a significant amount of water would have to be pushed up the tubing to let air into the system.

The way I figure it, because the system is devoid of oxygen (and nitrogen, etc...only concerned about O2), oxygen molecules are constantly bombarding the closed system at ~3psi (1atm X 21% O2 concentration in air).

Is there any real danger that the water in the airlock is actively absorbing oxygen, and transporting it to the rarefied chamber of pure CO2 on the other side?

 

[DixitDominus]

Some Oxygen is always diluted in water, something around 6 ppm. Oxygen molecules are able to exit the water at the other side of the tubing and they will tend to do so since there are no Oxygen molecules to enter the water at that side, this way they can enter the Carbon Dioxide environment.

However, considering the size of the water surface inside the tubing, the rate of Oxygen contamination of the Carbon Dioxide environment will be very low.