Civil and Environmental Engineering Department, Virginia Tech, 418 Durham Hall, Blacksburg, VA 24061, USA.
Environ Monit Assess. 2013 Feb;185(2):1355-65. doi: 10.1007/s10661-012-2637-6. Epub 2012 May 4.
Assessing the health risk from lead (Pb) in potable water requires accurate quantification of the Pb concentration. Under worst-case scenarios of highly contaminated water samples, representative of public health concerns, up to 71-98 % of the total Pb was not quantified if water samples were not mixed thoroughly after standard preservation (i.e., addition of 0.15 % (v/v) HNO(3)). Thorough mixing after standard preservation improved recovery in all samples, but 35-81 % of the total Pb was still un-quantified in some samples. Transfer of samples from one bottle to another also created high errors (40-100 % of the total Pb was un-quantified in transferred samples). Although the United States Environmental Protection Agency's standard protocol avoids most of these errors, certain methods considered EPA-equivalent allow these errors for regulatory compliance sampling. Moreover, routine monitoring for assessment of human Pb exposure in the USA has no standardized protocols for water sample handling and pre-treatment. Overall, while there is no reason to believe that sample handling and pre-treatment dramatically skew regulatory compliance with the US Pb action level, slight variations from one approved protocol to another may cause Pb-in-water health risks to be significantly underestimated, especially for unusual situations of "worst case" individual exposure to highly contaminated water.
评估饮用水中铅 (Pb) 的健康风险需要准确量化 Pb 浓度。在最恶劣的情况下，即代表公共卫生问题的高度污染水样，如果水样在标准保存（即添加 0.15%（v/v）HNO(3)）后没有充分混合，那么多达 71-98%的总 Pb 将无法被量化。充分混合后，所有样品的回收率都得到了提高，但在某些样品中仍有 35-81%的总 Pb 未被量化。从一个瓶子转移到另一个瓶子也会产生很大的误差（转移样品中总 Pb 的 40-100%未被量化）。尽管美国环境保护署的标准协议避免了大多数这些误差，但某些被认为等同于 EPA 的方法允许在监管合规采样中出现这些误差。此外，美国用于评估人体 Pb 暴露的常规监测没有标准化的水样处理和预处理协议。总的来说，虽然没有理由认为水样处理和预处理会极大地影响美国 Pb 行动水平的监管合规性，但从一个批准的协议到另一个协议的细微变化可能会导致对水中 Pb 健康风险的严重低估，特别是对于个人接触高度污染水的“最坏情况”等特殊情况。
