Brown Kenneth G, Ross Gilbert L
Kbinc, Chapel hill, North Carolina 27516, USA.
Regul Toxicol Pharmacol. 2002 Oct;36(2):162-74. doi: 10.1006/rtph.2002.1573.
The purpose of this American Council on Science and Health report is to review issues and sources of uncertainty affecting assessment of potential health risks related to drinking water in the United States. Some background is included on how these issues arose, as is a review of the 1999 National Research Council report (with references to an updated version), to formulate a position based on the current science concerning how much of a risk of adverse health effects actually exists from arsenic in drinking water in the United States. ACSH concludes that there is clear evidence that chronic exposure to inorganic arsenic at concentrations of at least several hundred micrograms per liter may cause: (1) cancer of skin, bladder, lung (and possibly several other internal organs, including kidney, liver, and prostate), and (2) noncancer effects, including classic cutaneous manifestations that are distinctive and characteristic of chronic arsenic poisoning (diffuse or spotted hyperpigmentation and palmar-plantar hyperkeratoses). Noncancer effects may be multisystemic, with some evidence of peripheral vascular, cardiovascular, and cerebrovascular disease, diabetes, and adverse reproductive outcomes. Further study is needed to know if beneficial effects of arsenic in animal studies apply to humans. ACSH concludes that there is little, if any, evidence of a detrimental health effect in humans from inorganic arsenic in drinking water at the current maximum contaminant level (MCL) of 50 microg/L or below, either in the United States or elsewhere. As noted in the 1999 NRC report, "No human studies of sufficient statistical power or scope have examined whether consumption of arsenic in drinking water at the current MCL results in an increased incidence of cancer or noncancer effects" (NRC, 1999, p. 7). Based on our review, described in this article, ACSH finds that the limitations of the epidemiological data available and the state-of-the-science on the mode-of-action of arsenic toxicity, including can cer, are inadequate to support the conclusion that there are adverse health effects in the United States from arsenic in drinking water at or below the limit of 50 microg/L.
美国科学与健康委员会这份报告的目的是审视影响美国饮用水潜在健康风险评估的问题及不确定性来源。报告包含了这些问题是如何产生的一些背景信息，以及对1999年美国国家研究委员会报告（并参考了更新版本）的回顾，以便根据当前科学状况就美国饮用水中砷实际造成的健康不良影响风险程度确定立场。美国科学与健康委员会得出结论，有明确证据表明，长期接触浓度至少为每升数百微克的无机砷可能会导致：（1）皮肤癌、膀胱癌、肺癌（可能还包括其他几个内部器官，如肾脏、肝脏和前列腺），以及（2）非癌症影响，包括慢性砷中毒特有的典型皮肤表现（弥漫性或斑点状色素沉着过度以及掌跖角化过度）。非癌症影响可能涉及多个系统，有证据表明存在外周血管、心血管和脑血管疾病、糖尿病以及不良生殖结局。需要进一步研究以确定砷在动物研究中的有益作用是否适用于人类。美国科学与健康委员会得出结论，无论是在美国还是其他地方，几乎没有（如果有的话）证据表明目前50微克/升或更低的最大污染物水平（MCL）的饮用水中的无机砷会对人体健康产生有害影响。正如1999年美国国家研究委员会报告中所指出的，“没有足够统计效力或范围的人体研究考察过饮用目前最大污染物水平的含砷饮用水是否会导致癌症或非癌症影响的发病率增加”（美国国家研究委员会，1999年，第7页）。基于本文所述的审查，美国科学与健康委员会发现，现有流行病学数据的局限性以及砷毒性作用方式（包括致癌作用）的科学现状，不足以支持得出美国饮用水中50微克/升及以下水平的砷会对健康产生不良影响这一结论。
