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。马里兰大学环境科学中心的Michael Gonsior博士及其同事与南卡罗来纳大学的Susan Richardson博士合作。他们研究了海水消毒过程中产生的化合物的形成。在美国和澳大利亚的主要海水淡化厂使用海水之前，消毒是必需的。在世界许多地方，海水淡化是将盐水转化为可饮用（饮用水）的一种重要方法。随着淡水供应越来越少，它正成为一种越来越重要的处理技术。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生环境中。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产生的以前未知的消毒副产物（DBPs）的形成提供了新的知识。在水环境中有机化合物的新的定量方法也被开发。本科生通过实习机会接触到这一研究，例如通过马里兰海洋基金REU项目和南加州大学。CBL游客中心的主持人展示了海水dbp，它们是如何形成的，以及它们对沿海海洋的影响。与切萨皮克生物实验室游客中心合作，研究小组为7-12年级的学生/教师举办了一个暑期讲习班。调查人员还与美国、澳大利亚和德国的同事合作，其中包括来自主要海水淡化厂的行业合作伙伴。预计未来全球将依靠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（DBPs）的形成以及不同淡水来源所呈现的复合因素，如高水平的溶解性有机物（DOM），已得到充分认识。然而，在海水的氯化过程中，形成了数百种溴化和碘化化合物，其中很少有特征，其中一些已经知道是剧毒的。研究人员利用新的分析技术来研究沿海环境中DBPs的产生、命运和毒性。超高分辨率质谱已被用于描述分子水平上的复杂有机基质，并成功地证明了船舶压载水氯化后形成的DBPS的复杂性，并表征了天然水域中的DOM。所有这些研究都表明，高度精确的质量测量结合软电离能够分配明确和精确的分子式。该团队将传统气相色谱法与质谱法相结合，以支持一组化合物的定量，表征了海水淡化过程中不同步骤的DBPs，并评估了生产的DBPs释放到环境中的命运。学生和教师将海水淡化厂的测量结果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、命运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.