AWWA JAW36110

In light of the fact that the maximum contaminant level (MCL) for arsenic is likely to be lowered significantly, the purpose of this study was to assess the capabilities of laboratories for arsenic analysis by atomic absorption spectrometry at concentrations near those being considered for the revised MCL. The evaluation involved 22 laboratories and used four representative drinking water matrixes to determine a practical quantitation level (PQL) for arsenic, which could be used by the US Environmental Agency in setting the new MCL. Samples were spiked with arsenic at concentrations ranging from 1 to 10 ug/L. On an interlaboratory basis, analytical precision and bias changed markedly at concentration <4 ug/L, setting a lower limit to the PQL of 4 ug/L. Reliable quantitation levels were also determined. Includes 10 references, tables, figures.