Device for field determination of heavy metals in natural waters

The objective of this project was the development and testing of a simple, portable, self-contained device suitable for in situ analysis of natural waters for certain trace metals. The trace metals which were of primary interest were copper, lead, cadmium, nickel, chromium and zinc. Two models of the analyzer were built during the course of this experiment. The first model utilized a rotating platinum electrode in sulfosalicylic acid electrolyte. This was abandoned due to the inconsistent quality of high sensitivity results in the field and the interference of the sulfosalicylic acid medium with analysis of lead and iron ions. The second model used a dropping mercury electrode in the same electrolytic medium. The medium was discarded due to the interference with lead and iron, but the DME was retained with tri-sodium citrate as the medium since this allows analysis of lead, cadmium, zinc and iron. Details of the construction and field operation of the kit are explained in full. Field sampling techniques are also discussed. The operation of the device is relatively simple and the cost of construction of the initial model was less than $400. The design of the instrument allows the possibility of future development and adaptations. At present, however, the determination of metals is limited to only four ions. The use of mercury makes careful disposal of waste materials necessary. The results have not been compared with the results from known different tests with known reliability.U.S. Department of the InteriorU.S. Geological SurveyOpe