A trichloroethene (TCE) plume has been identified in an unconfined sand aquifer in Perth, Western Australia. This is the first known major occurrence of groundwater contamination by chlorinated aliphatic compounds in Perth. A small-scale (ca. 13m), natural-gradient tracer test, utilizing deuterated TCE (TCEdl) and potassium bromide, was undertaken within the TCE plume to determine hydrodynamic and sorptive properties of TCE in the aquifer. No sorption of TCEdl was observed, which is in contrast to a retardation coefficient estimate of 1.8, calculated from equations based on the organic carbon fraction of the aquifer sand. A low dispersivity of the aquifer material was calculated, indicating that dispersion was negligible with respect to the advective flow. Variable advective flow at distinct levels in the aquifer profile is shown to produce tailing of the depth-averaged breakthrough curves. The C-D bond of the deuterated TCE was stable, indicating the usefulness of deuterated TCE as a tracer within the contaminated zone.