南水北调中线工程水中贾第虫和隐孢子虫污染调查及风险评估

项目名称： 南水北调中线工程水中贾第虫和隐孢子虫污染调查及风险评估

项目编号： No.20807013

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 环境科学、安全科学

项目作者： 肖淑敏

作者单位： 河南理工大学

项目金额： 18万元

中文摘要： 贾第虫和隐孢子虫（简称"两虫"）污染已经成为了国际上广为关注的热点环境问题之一。本项目建立了以膜溶解/密度梯度分离，免疫荧光染色分析为主要步骤的显微镜检测"两虫"的分析方法；对不同类型水体中"两虫"污染进行了抽样调查；建立了以PCR为基础的"两虫"种类及基因型识别方法，识别了部分区域贾第虫的污染来源；构建了基于疾病负担（DALY）的"两虫"感染健康风险评估体系，阐明了我国特定区域特定水体中"两虫"的健康风险。结果表明：（1）中线工程水源地丹江口水库及其主要支流受到"两虫"污染较为普遍，贾第虫检出率为86.7%（13/15），浓度为0～41个/10L，隐孢子虫检出率80.0%（12/15），浓度为0～25个/10L；（2）调水沿途区域及受水区城市污水处理厂污水或再生水中贾第虫含量较高，存在二次污染的隐患；（3）在常规处理条件下饮水中隐孢子虫的健康风险为6.46×^-6 DALYs，高出了WHO提出的每人每年10^-6 DALYs，而在臭氧消毒或微膜过滤条件下处于可接受的风险范围。上述研究为水处理行业针对"两虫"建立有效地水质管理机制提供了科学技术基础，对于保障水体安全具有重大意义。

中文关键词： 贾第虫；隐孢子虫；中线工程；污染；风险评估

英文摘要： Contaminations of Giardia cysts and Cryptosporidium oocysts are one of leading problems concerned by the environmental fields. In the present study, a method, including acetone dissolution, density gradient separation and immunofluorescence staining, was established for the detection of Giardia and Cryptosporidium in water. Occurrence of Cryptosporidium oocysts and Giardia cysts in different waters was investigated and the species/genotypes of Giardia were identified. Using Disability Adjusted Life Years (DALYs) as health metric, a comprehensive quantitative microbial risk assessment of Cryptosporidium infection was performed based on the results of oocysts concentration in source water. In addition, the risks of Giardia in sewage plant effluent from Jiaozuo and in reclaimed water from Tianjin were also assessed. The results showed that: (a) 86.7% and 80.0% of water samples from the Danjiangkou Reservoir and its tributary were Giardia and Cryptosporidium positive, respectively; (b) sewage plant effluent and reclaimed water would be sources of Giardia contamination since cysts concentration was high; (c) The cryptosporidiosis burden associated with drinking water treated with the conventional process was calculated to be 6.46×^-6 DALYs per person per year, which was higher than the reference risk level suggested by the WHO (10^-6). However, the risk for people who consume MF- or ozone-treated tap water would be considered acceptable. The above-mentioned studies provide scientific basis for the management of water quality, as well as for the control of these water-borne protozoan parasites.

英文关键词： Giardia; Cryptosporidium; the Middle Route Project of South-North Water Transfer; Contamination; Risk assessment