CHARACTERIZATION OF COMPOST WITH RESPECT TO ITS CONTENT OF HEAVY-METALS .1. SAMPLE DIGESTION AND ICP-AES ANALYSIS

This paper forms part of a study aimed at the development of a procedure for the determination of heavy metals in compost. An unambiguous analytical procedure must be available to enable supervision of the observance of the legal regulations on maximum tolerable content of heavy metals. The present study deals with the element determination stage, including the digestion of a test portion and the element determination in the test solution. Aqua regia digestion was examined using conventional as well as microwave heating. It is shown that the performance of both procedures is similar with respect to accuracy and precision. Microwave heating was preferred because that procedure is less time-consuming. Simultaneous determination of the elements Cr, Cu, Ni, Pb and Zn by ICP-AES was feasible. However, due to the occurrence of severe spectral interferences, Cd had to be determined separately. © 1990, Taylor & Francis Group, LLC. All rights reserved.