Your question is very (too) broad. Give details on which contaminant(s)and what column(s) to allow people to give meaningful suggestions.

C.A. (Kees) Kan Bacteria like E. coli can be used as a contaminant transport through vertical pvc pipe (column) which is filled with soil.

I can imagine that a microorganism is attached so firmly (in a biofilm) to the pvc, that it is not rinsed out, but instead multiplies and in that way spreads out through the column over time.