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.

Waples 0630847该项目将评估一种新的创新技术，以测量基于90SR/90Y不平衡的饮用水分配系统中的水时代。 90SR是核武器测试中普遍存在的污染物，而90y是其衰减的女儿产物。由于这些放射性同位素的衰减相对速率，因此发展了世俗平衡，使得在初始（不平衡）条件下仅存在90SR，这两个同位素最终达到了相等的活性。该技术通过确定两个同位素的活性之比来衡量自不平衡以来的时间。在使用絮凝和过滤去除悬浮物的水上处理厂中，达到90SR/90Y的不平衡，因为90y具有颗粒反应性并且有效地从水中取出，而90SR则无反应性并通过治疗系统。密尔沃基市供水系统的初步数据表明，该技术将起作用。与复杂的密尔沃基系统相比，PI将使用较小的分布系统使用较小的分配系统测试技术（就水居时间而言）。将进行实验室研究，以解决有关拟议程序可靠性的不确定性，即同位素吸附对分配系统中有机和无机膜对管壁的影响。对饮用水分配系统中水的停留时间的了解对于了解细菌生长和衰减的机会以及饮用水离开治疗厂的化学质量的变化以及在公众消费之前的变化很重要。