Calculation should be here. This web page uses the first boundary condition though a pulse input can be simulated by using a short injection time T . The calculation solves for concentration at whatever time and distance is desired by the user. The calculation includes advection, dispersion, and retardation. If there were no dispersion, all of the contaminant would travel at the mean chemical velocity.
Retardation causes the mean chemical velocity to be slower than the groundwater velocity.
For Figure 1, T was selected large enough to simulate an infinite duration injection. TCE concentration profile at 1000 days for an injection of duration 1,000,000 days Figure 2. TCE concentration profile at 1000 days for an injection of duration 100 days. Large scale tests have higher a than small lab column tests. Represents chemical partitioning between groundwater and soil.