A new method for accurately measuring in situ conservative tracer and colloid concentrations in packed columns was developed. The method consists of fabricating clear sintered glass-bead-packed columns, taking digital photographs of the column under an ultraviolet light source, and determining concentrations by measurement of the fluorescence intensity of the tracer or colloids in the photographs. The sintering process prevents changes in the geometry of the porous medium making it particularly useful for contaminant transport experiments in packed columns in the presence of seismic or acoustic wave vibrations. Because fluorescence is measured, the method of quantification is limited to fluorescent tracers and fluorescent colloidal suspensions. The method is shown to be within 3% of the accuracy of traditional effluent sampling and analysis procedures and allows for quick and accurate in situ measurement of dissolved or suspended tracer concentrations at multiple times. However, the method is not useful for decaying chemical species unless the decay rate constant is known in advance, because the intensity curves at all times must be scaled to the known injected mass to yield concentrations. (C) 2010 Elsevier Ltd. All rights reserved.