A semiquantitative colorimetric analytical method using dithizone to detect traces of heavy metals in natural water is described. Although reagents of exceptional purity are required, only simple equipment is needed and the test can be made in a few minutes in the field. A combined mixed color and mono color technique makes the test suitable for a wide range of concentrations. The test is very sensitive; as little as 0.01 part per million of either copper, lead, zinc or any combination of the three metals can be detected readily.The dithizone test permits rapid field identification of drainage elements which contain significant concentrations of heavy metals. An example is given showing how the test can be used to trace the heavy metal content of a drainage system back to its source. It is possible that, under favorable conditions, the field test may facilitate prospecting by detecting metals discharged by the weathering of hidden ore bodies. However, until the method receives further investigation, it would be premature to predict its value.
