Abstract: The experimental crushed granite column breakthrough curves,using~(99)Tc as spike tracer and~3H as invariant tracer,are analyzed by different linear regression techniques. Dispersity of crushed granite and retardation factor of~(99)TcO_4~- on the crushed granite are determined simultaneously by one linear regression technique.Dispersity of crushed granite is also obtained with~3H as invariant tracer by the other linear regression technique. The dispersities found by spike source and invariant source methods are compared. The experimental results show that the dispersity found by spike source method is close to that found by invariant source method. It indicates that dispersity is only the characteristic of dispersion medium.