SGER: Y-90/Sr-90 disequilibria: A new method for determining water age in a drinking water distribution system

SGER：Y-90/Sr-90 不平衡：确定饮用水分配系统中水龄的新方法

• 批准号: 0630847
• 负责人: James Waples
• 金额: $ 5万
• 依托单位: University of Wisconsin-Milwaukee
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2007-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0630847&HistoricalAwards=false
• 关键词: SGER; 90; Sr; disequilibria; new

Waples 0630847 This project will evaluate a new and innovative technique to measure water age in drinking-water distribution systems based on 90Sr/90Y disequilibrium. 90Sr is a ubiquitous contaminant from nuclear weapons testing, and 90Y is the daughter product of its decay. Because of the relative rates of decay of these radioisotopes, secular equilibrium is developed such that following initial (disequilibrium) conditions where only 90Sr is present, the two isotopes eventually reach equal activities. The technique measures the time since disequilibrium was established by determining the ratio of activities of the two isotopes. In water-treatment plants that use flocculation and filtration to remove suspended matter, 90Sr/90Y disequilibrium is achieved because 90Y is particle-reactive and is effectively removed from water, whereas 90Sr is unreactive and passes through the treatment system. Preliminary data from the water distribution system for the City of Milwaukee suggests that the technique will work. The PI will test the technique using smaller distribution systems that will provide results easier to analyze (in terms of water residence times) than the complicated Milwaukee system. Laboratory studies will be done to address an uncertainty concerning the reliability of the proposed procedure, i.e., the influence of isotope sorption onto organic and inorganic films on pipe walls in distribution systems. Knowledge of water residence times in drinking water distribution systems is important in understanding opportunities for bacterial growth and decay and changes in the chemical quality of drinking water after it leaves a treatment plant and before it is consumed by the public.

瓦普勒斯 0630847 该项目将评估一种新的创新技术，根据90 Sr/90 Y不平衡测量饮用水分配系统的水龄。90 Sr是核武器试验中普遍存在的污染物，90 Y是其衰变的子产物。由于这些放射性同位素的相对衰变率，长期平衡发展为使得在仅存在90 Sr的初始（不平衡）条件下，两种同位素最终达到相等的活性。该技术通过测定两种同位素的活性比来测量自建立不平衡以来的时间。在使用絮凝和过滤来去除悬浮物的水处理厂中，90 Sr/90 Y不平衡是实现的，因为90 Y是颗粒反应性的，可以有效地从水中去除，而90 Sr是非反应性的，可以通过处理系统。来自密尔沃基市配水系统的初步数据表明，这项技术将发挥作用。PI将使用较小的分配系统测试该技术，该系统将提供比复杂的密尔沃基系统更容易分析的结果（就水停留时间而言）。将进行实验室研究，以解决有关拟定程序可靠性的不确定性，即，在分配系统中，同位素吸附到管壁上的有机和无机膜上的影响。了解饮用水分配系统中的水停留时间对于了解细菌生长和腐烂的机会以及饮用水离开处理厂后和公众消费之前的化学质量变化非常重要。