鉴于砷的最大污染水平（MCL）可能会显著降低，本研究的目的是评估实验室通过原子吸收光谱法进行砷分析的能力，其浓度接近修订后的MCL。评估涉及22个实验室，并使用四个具有代表性的饮用水矩阵来确定砷的实际定量水平（PQL），美国环境署可将其用于设定新的MCL。样品中加入浓度为1至10 ug/L的砷。在实验室间基础上，分析精度和偏差在浓度为lt4 ug/L时发生显著变化，将PQL设置为4 ug/L的下限。还确定了可靠的定量水平。 包括10个参考文献、表格和图。

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.