Passive sampling by deploying organic polymers for 20–30 days in soils or sediments has been used for the assessment of bioavailability and mobility of hydrophobic organic contaminants. An important step in their interpretation is the estimation of the degree of equilibration, typically through the release of performance reference compounds (PRCs). This paper develops an improved modeling tool for predicting the behaviors of PRCs and contaminant compounds in devices in cylindrical geometry, such as polydimethylsiloxane (PDMS) fibers or dialysis samplers of cylindrical cross-section. The model is solved by both a numerically inverted Laplace domain solution and an asymptotic analytical solution. The solutions are verified with the numerically simulated results. A comparison of the developed model to existing models for the calibration of uptake/release rates and the estimation of soil or sediment transport properties is performed. The result suggests that the cylindrical model provides a more accurate prediction for the transient behavior of PRC and target compounds as well as a better estimate of transport properties in the media.