MMWR Morb Mortal Wkly Rep. 1994 Sep 16;43(36):661-9.
The risk for waterborne infectious diseases increases when filtration and other standard water-treatment measures fail. On December 6, 1993, water-treatment plant operators in the District of Columbia (DC) began to have difficulty maintaining optimal filter effectiveness. On December 7, filter performance worsened, and levels of turbidity (i.e., small suspended particles) exceeded those permitted by U.S. Environmental Protection Agency (EPA) standards. On December 8, DC residents were advised to boil water intended for drinking because of high municipal water turbidity that may have included microbial contaminants. Although adequate chlorination of the DC municipal water was maintained throughout the period of increased turbidity, the parasite Cryptosporidium parvum is highly resistant to chlorination. Because of the increased risk for infection with this organism and other enteric pathogens, the DC Commission of Public Health and CDC conducted four investigations to determine whether excess cases of diarrheal illness occurred because residents drank inadequately filtered water. This report describes the results of these investigations.
当过滤及其他标准水处理措施失效时，水源性传染病的风险会增加。1993年12月6日，哥伦比亚特区（DC）的水处理厂操作人员在维持最佳过滤效果方面开始遇到困难。12月7日，过滤性能恶化，浊度（即小悬浮颗粒）水平超过了美国环境保护局（EPA）标准允许的范围。12月8日，由于城市用水浊度高且可能含有微生物污染物，建议DC居民将饮用水煮沸。尽管在浊度增加期间DC城市用水一直保持了充足的氯化处理，但微小隐孢子虫对氯化处理具有高度抗性。由于感染这种生物体及其他肠道病原体的风险增加，DC公共卫生委员会和疾病预防控制中心开展了四项调查，以确定腹泻疾病的病例增多是否是因为居民饮用了过滤不充分的水。本报告介绍了这些调查的结果。
