Abstract: An improved method and apparatus for simultaneously monitoring the fluid flux, and the dissolved contaminants fluxes, in a flow field is provided comprising the use of a permeable unit containing an insoluble sorbent matrix that retains dissolved contaminants. The matrix may also contain tracers that can be displaced by the fluid flow. The method of monitoring comprises placing permeable units in contact with the contaminated flow field, thereby allowing contaminants to flow through the permeable unit and be sorbed on the insoluble sorbent matrix. Sufficient time is allowed for the contaminant concentrations in the flow field to reach equilibrium. The permeable unit is then removed from contact with the flow field and analyzed to determine cumulative contaminant fluxes and cumulative fluid fluxes.