In this work, we investigate the interstitial injection into the silicon lattice due to high-dose, low energy arsenic implantation. The diffusion of the implanted arsenic as well as of boron, existing in buried δ-layers below the silicon surface, is monitored while successive amounts of the arsenic profile are removed by low temperature wet silicon etching. From the analysis of the diffusion profiles of both dopants, consistent values for the interstitial supersaturation ratio can be obtained. Moreover, the experimental results indicate that the contribution of the implantation damage to the TED of boron, and thus the interstitial injection, is not the main one. On the contrary, interstitial generation due to arsenic clustering seems to be more important for the present conditions.