Wastewaters convey important amounts of trace metals and organic contaminants into the environment. Still, the monitoring of dissolved micro-pollutants in wastewaters remains a major issue of environmental chemistry because of their high temporal variability and of the complexity of the organic matrix. Hence, measuring labile contaminants in wastewaters constitutes an interesting application of the various passive samplers that appeared in the mid 90's. The Diffusion Gradient in Thin Films (DGT) technique was proposed as a robust way to quantitatively measure free and labile metal species in aquatic environments. Because the technique provides in situ preconcentration of metals, it allows avoiding most contamination problems. Moreover, because the measurement is performed in the acidic eluate of the binding resin, DGT considerably reduces the analytical difficulties linked to complex chemical matrices. Similarly, Semi-Permeable Membrane Devices (SPMD) have been developed in order to sample truly dissolved hydrophobic organic contaminants in water. As DGTs, SPMDs concentrate the contaminants and simplify detection limit and analytical interferences problems. In addition, DGTs and SPMDs are believed to sample bioavailable contaminants, and could eventually give an insight on the potential toxicity of the effluents. In this study, the use of DGTs and SPMDs in wastewaters was investigated. Passive samplers were deployed directly into wastewater at different stages of the treatment for 6 days. In SPMDs, the systematic use of Performance Reference Compounds allowed to calculate proper sampling rates for individual SPMD that would have otherwise be underestimated. Accumulated metals and Polycyclic Aromatic Hydrocarbons were related to a time-weighted average labile concentration in wastewater. This experimental procedure allows estimating labile concentrations coherent with total dissolved concentrations.