2000年，加利福尼亚州根据环境健康危害评估办公室（OEHHA）对六价铬（Cr-6）的健康评估，提出了饮用水中总铬含量为2.5 ug/L的公共健康目标。OEHHA表示，对Cr-6的兴趣水平为0.2 ug/L。2.5 ug/L的总铬公共卫生目标基于总铬的7%作为Cr-6出现的假设。因此，迫切需要对总铬和Cr-6进行准确、低水平的分析，以评估Cr-6的出现，并确定以Cr-6形式存在的总铬的百分比。如果7%的分数不能反映大多数饮用水，那么能够在亚微克/升水平下直接准确测量Cr-6至关重要。在本文中，作者基于对加利福尼亚州2000多个样本的测试，提供了与准确分析低水平总铬和Cr-6相关的数据。 研究表明，对于加利福尼亚州的饮用水，通常90%以上的铬以六价铬的形式存在，并且铬的形态在较长时间内是稳定的，无需在24小时内分析样品。包括6个参考文献、图表。

In 2000, the State of California proposed a public health goal of 2.5 ug/L in drinking water for total chromium, based on health assessments for hexavalent chromium (Cr-6) from the Office of Environmental Health Hazard Assessment (OEHHA). The OEHHA indicated that the level of interest for Cr-6 was 0.2 ug/L. The 2.5 ug/L total chromium public health goal was based on the presumption that 7% of the total chromium occurred as Cr-6. Thus there is a strong need for an accurate, low-level analysis of both total chromium and Cr-6 to assess the occurrence of Cr-6 and to determine the percentage of total chromium existing as Cr-6. If the 7% fraction is not reflective of most drinking waters, it is critical to be able to accurately measure Cr-6 directly at sub ug/L levels. In this paper the authors present data pertinent to accurate analysis of both total chromium and Cr-6 at low levels based on the testing of over 2,000 samples from across the State of California. It is demonstrated that, for California drinking waters, typically more than 90% of the chromium is present as hexavalent chromium and that the chromium speciation is stable over an extended period of time, eliminating the need to analyze samples within 24 hours. Includes 6 references, figures.