The application of microwave heating in sequential extractions of heavy metals in estuarine sediments

Abstract

Using a modification of the procedure elaborated by Tessier et al. (1979) the conditions under which microwave heat was applied to perform sequential extractions of metals in estuarine sediments were evaluated. Necessary times were determined for the complete metal extractions and substantial reductions in time were obtained in comparison with the traditional techniques, (from hours to minutes). The techniques were applied to two reference materials: MESS-1 and SEDIMENTO (a secondary standard prepared in our laboratory). The problems of methodology associated with the use of microwaves are discussed, as well as the results obtained regarding the variability of the data of each fraction and the percentages of recovery. The techniques were also applied to intertidal surface sediments of three northwestern Spanish estuaries. Percentages of recovery are discussed as well as the relationship of the results to the physical/chemical variables of the medium.