discs of low-mass stars sweep up the enriched matter. In order to account for the observed abundances in the enriched population, the low-mass stars have to accrete of the order of their own mass, i.e. a 0.25 ${\mbox{$\mathrm{M}_{\odot}$}}$ star has to accrete about 0.25 ${\mbox{$\mathrm{M}_{\odot}$}}$ of enriched material in the most extreme case (as inferred from, e.g., the main sequence of NGC2808 [@piotto07]). The time scale of this scenario is limited by the lifetimes and sizes of protoplanetary discs. B13 assume that the protoplanetary discs can accrete material for up to 20 Myr. Current disc lifetimes are observed to be 5-15 Myr, but B13 argue that their lifetimes may have been considerably longer in GCs. The accretion rate averaged over 20 Myr therefore has to be about $10^{-8} {\mbox{$\mathrm{M}_{\odot}$}}/ yr$. In their scenario, they assume that the accretion rate is proportional to the size of the disc, $\pi R_{\rm disc}^2$, density of the ISM, $\rho_{\rm ISM}$, and the velocity, $v_{\rm ISM}$, of the disc with respect to the ISM, i.e. $\dot{M} \propto \rho_{\rm ISM} v_{\rm ISM} \pi R_{\rm disc}^2$. Furthermore, they assume an average and constant disc radius of 100 AU. In this work, we test several of these assumptions 