SIGNIFICANCE OF EXPOSURE ASSESSMENT TO ANALYSIS OF CANCER RISK FROM INORGANIC ARSENIC IN DRINKING-WATER IN TAIWAN
SIGNIFICANCE OF EXPOSURE ASSESSMENT TO ANALYSIS OF CANCER RISK FROM INORGANIC ARSENIC IN DRINKING-WATER IN TAIWAN
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DOI：
10.1111/j.1539-6924.1995.tb00340.x
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发表时间：
1995-08-01
期刊：
影响因子：
3.8
通讯作者：
CHEN, CJ
中科院分区：
文献类型：
--
作者：
BROWN, KG;CHEN, CJ
饮用水中的无机砷与内部部位（膀胱、肝脏、肺和其他器官）癌症死亡率增加有关的主要证据来源是在台湾西南部黑脚病流行地区进行的大型生态研究。肺癌、肝癌和膀胱癌的剂量-反应模式与砷暴露呈非线性剂量-反应关系。然而，这些数据似乎不适合更精确的剂量反应评估任务，特别是在美国一些供水中发现的低砷浓度下的风险推断。问题在于一个村庄内各威尔斯井之间的砷浓度不同，这主要是由于浅威尔斯井和深自流威尔斯井混合使用，而且60个村庄中有24个（40%）只进行了一次水井测试。根据文中所述的标准，目前的分析确定了14个村庄，这些村庄的接触似乎最有问题。然后改变了那些村庄中7个村庄的照射值，从用作默认值的中值井测试改为村庄井测试范围内的其他某个点，这将有助于平滑剂量-反应曲线的外观。其余7个村庄，其中6个只有一次水井测试，作为离群值被删除。由此产生的剂量反应模式显示，没有证据表明砷浓度低于0.1毫克/升的过度风险。当然，如前所述，这一结果取决于对数据的操纵。如果将7个被删除的村庄包括在内，则低剂量的风险估计值会高得多。在这七个村庄，癌症死亡率相对于其接触水平而言非常高，这表明其接触值可能过低，或者需要考虑其他病因因素。
The primary source of evidence that inorganic arsenic in drinking water is associated with increased mortality from cancer at internal sites (bladder, liver, lung, and other organs) is a large ecologic study conducted in regions of Southwest Taiwan endemic to Blackfoot disease. The dose-response patterns for lung, liver, and bladder cancers display a nonlinear dose-response relationship with arsenic exposure. The data do not appear suitable, however, for the more refined task of dose-response assessment, particularly for inference of risk at the low arsenic concentrations found in some U.S. water supplies. The problem lies in variable arsenic concentrations between the wells within a village, largely due to a mix of shallow wells and deep artesian wells, and in having only one well test for 24 (40%) of the 60 villages. The current analysis identifies 14 villages where the exposure appears most questionable, based on criteria described in the text. The exposure values were then changed for seven of the villages, from the median well test being used as a default to some other point in the village's range of well tests that would contribute to smoothing the appearance of a dose-response curve. The remaining seven villages, six of which had only one well test, were deleted as outliers. The resultant dose-response patterns showed no evidence of excess risk below arsenic concentrations of 0.1 mg/l. Of course, that outcome is dependent on manipulation of the data, as described. Inclusion of the seven deleted villages would make estimates of risk much higher at low doses. In those seven villages, the cancer mortality rates are significantly high for their exposure levels, suggesting that their exposure values may be too low or that other etiological factors need to be taken into account.