NIWR (National Institute for Water Research) Interlaboratory Comparison Study No. 80/C: Determination of Trace Metals in Sewage Sludge. Evaluation of Results

摘要

This study forms part of the NIWR's series of interlaboratory comparison studies involving Southern African laboratories engaged in water and wastewater analysis, and is concerned with the analysis by 20 laboratories of two samples of dried sewage sludge for aluminium, cadmium, chromium, copper, iron, lead, manganese, nickel and zinc. The results obtained are evaluated and discussed, along with some of the advantages and disadvantages of various sample pretreatment techniques. The mean values of the results obtained using the U.S. EPA's recommended sample pretreatment procedure were found to be in good agreement with those obtained using a wide variety of other sample pretreatment techniques, with the exception of those for aluminium. More drastic pretreatment, in the form of fusion or a more vigorous digestion procedure, is advisable for complete extraction of this metal. Most of the laboratories employed flame atomic absorption spectrophotometry for the analyses. The use of suitable interference suppressants and, in certain cases, background correction, was recommended with this method. (Atomindex citation 14:736039)