Transient volume-averaged and spatial intraparticle contaminant concentration in a dissolved phase of spherical immobile aggregates is examined using the linear driving force (LDF) model a special case of a generalized concentration profile (GCP) approximation. Particular cases are solved when a mass Fur occurs between the surrounding bulk concentration and intraparticle concentration. Four different forms for the time-variant surrounding bulk concentration are considered: linear, exponential, sinusoidal (oscillatory) and step function. Both pointwise and volume-averaged intraparticle concentrations computed by the LDF model match the numerical and analytical (when available) solutions almost perfectly, when the surrounding bulk concentration is assumed to be changing linearly or exponentially. For the other two cases, however only volume-averaged concentrations across the immobile spherical particle and the temporal concentrations at the outer boundary of the particle computed from the LDF approximation match the numerical model results reasonably well.