PASSIVE MONITORING OF TRACE-METALS IN WATER BY IN-SITU SAMPLE PRECONCENTRATION VIA CHELATION ON A TEXTILE BASED SOLID SORBENT

A simple, inexpensive, passive monitor, based on a textile-bound polya cryloamidoxime chelating agent (polyacryloamidoxime cloth), was evalua ted for the analysis of selected trace heavy metals in water using bot h Energy Dispersive X-Ray Fluorescence (EDXRF) Spectroscopy and Wavele ngth Dispersive X-Ray Fluorescence (WDXRF) Spectroscopy as a means of analysis. Acid leaching of the sorbed metals followed by Graphite Furn ace Atomic Absorption (GFAA) Spectroscopy was also carried out. It was shown that, in controlled in vitro experiments using a flow chamber, the sorption profiles of Pb and Cu by the cloth used were similar to t hose of chelating resins and fibres containing the amidoxime group. Th e rate of uptake of metals by the cloth was found to be dependent on t he percent surface area converted to amidoxime groups, the concentrati on and type of metal being tested for, the time of exposure, the flow rate of solution and the temperature of solution. Distribution coeffic ients of 3.5 x 10(6) and 1.5 x 10(6) for Cu(II) and Pb(II) were observ ed and indicate a high degree of sample preconcentration. The average rates of uptake for Cu and Pb per gram of cloth were 600 and 200 mg pe r day respectively from dilute solution ([Cu]=5.9 mg l(-1), [Pb]=2.8 m g l(-1)). From replicate samples, a relative error of <10% was observe d for the sorption of Cu and Pb. Experimental results of field tests i nvolving the passive monitoring of river water and lake water under va rious conditions suggest that a number of ions can be identified and m onitored simultaneously. The deployment of the monitors by the general public and the use of a mailing program was tested and shown to be pr actical. These results indicate the feasibility of using polyacryloami doxime cloth as a passive monitor for trace metals in water.