Collaborative Research: Fundamental Understanding of the Environmental Fate of Disinfection By-Products Arising from Desalination Plants

该奖项由化学部门的环境化学科学项目和化学、生物工程、环境和运输系统部门的环境工程项目共同支持。马里兰州大学环境科学中心的Michael Gonsior博士和他的同事与南卡罗来纳大学的Susan Richardson博士合作。他们研究在海水消毒过程中产生的化合物的形成，这是美国和澳大利亚的主要海水淡化厂使用水之前所需的。在世界许多地区，海水淡化是将咸水变成可饮用(饮用水)水的重要方法。随着淡水供应变得越来越稀缺，它正成为一项日益重要的处理技术。然而，目前在消毒处理过程中产生的潜在有害有机化合物在废水流中排放到水环境中。这些有机化合物对水生生物的影响在很大程度上是未知的。这项研究为海水淡化过程中以前未知的消毒副产物(DBPs)的形成提供了新的知识。还开发了水环境中有机化合物的新的定量方法。本科生通过实习接触到这项研究，例如通过马里兰海洋赠款REU计划和在南加州大学。CBL游客中心的主持人展示了关于海水DBP的情况，它们是如何形成的，以及它们可能对沿海海洋产生什么影响。该研究小组与切萨皮克生物实验室访客中心合作，为7-12年级的学生/教师举办了一次夏季研讨会。调查人员还与美国、澳大利亚和德国的同事合作，包括来自主要海水淡化厂的行业合作伙伴。全球预计未来将依赖海水淡化和水再利用来提供合适的饮用水。在海水淡化过程中，需要对水进行氯化处理，以限制膜的生物污染并杀死潜在的有害细菌。饮用水氯化过程中消毒副产物(DBP)的形成以及不同来源的淡水呈现的复合因素，如高水平的溶解有机物(DOM)，得到了很好的认识。然而，在海水的氯化过程中，会形成数百种溴化和碘化化合物，其中很少有被表征的化合物，其中一些已经被认为是剧毒的。研究人员利用新的分析技术来调查沿海环境中DBPs的产生、去向和毒性。超高分辨质谱学已被用来在分子水平上描述复杂的有机基质，并成功地证明了船舶压载水氯化后形成的DBPs的复杂性以及对天然水域中DOM的表征。所有这些研究都表明，结合软电离的高精度质量测量能够给出明确和准确的分子式。该团队结合传统的气相色谱和质谱学方法来支持化合物子集的量化，从而表征了海水淡化过程中不同步骤的DBPs，并评估了释放到环境中的DBPs的命运。学生和教师将海水淡化工厂的测量与受控的实验室研究相结合，以更好地了解在预氯化过程中在海水中形成的已知和新发现的DBP的产生、去向和毒性的机制和因素，并在排放到沿海生态系统的废水中积累。

This award is supported jointly by the Chemistry Division's Environmental Chemical Sciences Program and the Environmental Engineering Program in the Division of Chemical, Bioengineering, Environmental, and Transport Systems. Dr. Michael Gonsior and colleagues at the University of Maryland Center for Environmental Science collaborate with Dr. Susan Richardson at the University of South Carolina. They study the formation of chemical compounds that arise during disinfection of seawater, which is required before water can be used in major desalination plants in the U.S. and Australia. Desalination is an important method for turning salt water into drinkable (potable) water in many parts of the world. It is becoming an increasingly important treatment technology as freshwater supplies are becoming scarcer. However, currently potentially harmful organic compounds produced during disinfection treatments are discharged into the aquatic environment in the waste water stream. The consequences of these organic compounds to aquatic organisms are largely unknown. This study provides new knowledge regarding the formation of previously unknown disinfection by-products (DBPs) produced during desalination. New quantification methods for organic compounds in aqueous environments are also developed. Undergraduate students are exposed to this research through internships, such as through the Maryland Sea Grant REU program and at USC. The CBL Visitor Center host displays about seawater DBPs, how they are formed and what impact they may have on the coastal ocean. In partnership with the Chesapeake Biological Laboratory Visitor Center, the research team hosts a summer workshop for 7-12th grade school students/teachers. The investigators also collaborate with colleagues in the U.S, Australia, and Germany, including industry partners from major desalination plants.Future reliance on desalination and water reuse to provide suitable drinking water is expected globally. During the desalination process, chlorination of water is required to limit biofouling of membranes and to kill potentially harmful bacteria. The formation of Disinfection Byproducts (DBPs) during drinking water chlorination and the compounding factors presented by different sources of fresh water, such as high levels of dissolved organic matter (DOM), is well recognized. However, during the chlorination of seawater, hundreds of brominated and iodinated compounds are formed, few of which have been characterized, and some of which are already known to be highly toxic. The researchers utilize new analytical techniques to investigate the production, fate and toxicity of DBPs in the coastal environment. Ultrahigh resolution mass spectrometry has been utilized to describe complex organic matrices at the molecular level, and has successfully demonstrated the complexity of DBPS formed after chlorination of ship ballast water as well as characterizing DOM in natural waters. All of these studies have shown that highly precise mass measurements combined with soft ionization are capable of assigning unambiguous and exact molecular formulas. In combination with traditional gas chromatography interfaced with mass spectrometry methods to support quantification of a subset of compounds, the team characterizes DBPs at different steps of the desalination process and evaluates the fate of produced DBPs released into the environment. The students and faculty combine desalination plant measurements with controlled laboratory studies to better understand the mechanisms and factors contributing to the production, fate and the toxicity of known and newly discovered DBPs formed in seawater during pre-chlorination and accumulated in waste waters discharged into coastal ecosystems.