GOALI: WERF, WRF: Collaborative Research: Quantifying the Contribution of DBPs to the Toxicity of Wastewaters Purified for Potable Reuse: Which Byproduct Classes Matter?

合作提案编号：1706154/1706575 PI姓名：William Mitch/Michael Plewa美国干旱地区人口的增加以及最近德克萨斯州和加州的干旱，使人们对净化城市污水作为当地安全的饮用水供应越来越感兴趣。 饮用水再利用项目的一个关键障碍是公用事业、监管机构和公众对净化废水中化学品对人类健康影响的不确定性。 PI将比较净化后用于饮用再利用的废水沃茨的总体毒性与传统饮用沃茨的毒性。国家研究理事会指出，水和净化废水消毒的副产物（消毒副产物或DBP）是人类健康风险的主要驱动因素;然而，DBP作为一个整体对毒性的贡献以及不同DBP类别的相对重要性尚未量化。 在本项目中，PI将量化不同DBP类别对消毒净化废水毒性的贡献，以确定哪些类别是毒性最重要的驱动因素。该项目的结果将提供关键数据，使监管机构能够评估饮用水再利用项目，并为监管监督确定化学污染物类别（特别是DBPs）的优先级。在该项目中，主要假设是，经过高级处理的城市废水沃茨比传统饮用沃茨显示出更低的总体毒性，事实上的再利用）或甚至原始的源沃茨。为了检验这一假设，PI将定量比较一系列具有代表性的传统饮用沃茨的毒性，这些饮用水使用原始或受废水影响的源沃茨与与饮用水再利用操作相关的沃茨。比较将采用定量体外生物测定法，目标是一系列相关终点（细胞毒性、遗传毒性和氧化应激）。为了量化不同DBP类别对消毒的可饮用再利用沃茨毒性的影响，PI将比较消毒的可饮用再利用沃茨的体外生物测定响应与加入了在这些沃茨中测量的所有DBP浓度的去离子水的体外生物测定响应，或特定DBP类的所有成员。DBP研究集中在个别化学类别（例如，亚硝胺），化学家和毒理学家经常分开工作。 通过将广泛的DBP类别的化学分析与定量毒理学相结合，以确定驱动毒性反应的类别，PI希望这项工作的结果可以改变DBP研究的方法。这项工作还将解决DBP研究的两个长期存在的问题。 首先，DBP混合物的毒性是相加的，还是协同作用或拮抗作用？将通过比较单个DBP类别与其混合物的生物测定响应来回答该问题。其次，DBP研究集中在低分子量物质上，通常仅占总有机卤素（TOX）的~30-40%。 高分子量的消毒副产物在多大程度上造成毒性？ 随着反渗透（RO）装置上游应用消毒剂，饮用水再利用列车是回答这个问题的理想选择。除了提供给研究生和本科生的研究机会外，一名高中科学教师和一名代表性不足的高中生将协助夏季研究，以期在下一年将这些材料纳入高中课程。

Collaborative Proposal Numbers: 1706154/1706575PI Names: William Mitch/Michael Plewa Increasing populations in arid regions of the US and recent droughts in Texas and California are increasing interest in purifying municipal wastewater as a local, secure supply for drinking water. A critical roadblock for potable reuse projects is lingering uncertainty among utilities, regulators, and the public regarding the human health impacts of chemicals in the purified wastewater. The PIs will compare the overall toxicity of wastewaters purified for potable reuse to the toxicity of conventional drinking waters. The National Research Council has indicated that byproducts of water and purified wastewater disinfection (disinfection byproducts or DBPs) are the predominant drivers of human health risks; however, the contribution to toxicity of DBPs as a whole and the relative importance of different DBP classes has not been quantified. In this project the PIs will quantify the contributions of different DBP classes to the toxicity of disinfected purified wastewaters to determine which classes are the most significant drivers of toxicity. Results from this project will provide critical data to enable regulators to evaluate potable reuse projects and to prioritize chemical contaminant classes (particularly DBPs) for regulatory oversight.In this project the main hypothesis is that advanced treated municipal wastewaters exhibit lower overall toxicity than conventional drinking waters employing wastewater-impacted (i.e., de facto reuse), or even pristine source waters. To test this hypothesis, the PIs will quantitatively compare the toxicity of a series of representative conventional drinking waters using either pristine or wastewater-impacted source waters with waters associated with potable reuse operations. The comparison will employ quantitative in vitro bioassays targeting a range of relevant endpoints (cytotoxicity, genotoxicity, and oxidative stress).To quantify the contributions of different DBP classes to the toxicity of disinfected potable reuse waters, the PIs will compare the in vitro bioassay responses of disinfected potable reuse waters to those of deionized water spiked with the concentrations of either all the DBPs measured in these waters, or all of the members of specific DBP classes. DBP research has focused on individual chemical classes (e.g., nitrosamines), with chemists and toxicologists often working separately. By integrating chemical analysis of a broad range of DBP classes with quantitative toxicology to identify the classes driving toxic responses, the PIs expect that results from this work could transform the approach to DBP research. This work will also address two long-standing questions for DBP research. First, is the toxicity associated with DBP mixtures additive or is there synergism or antagonism? This question will be answered by comparing the bioassay responses for individual DBP classes against their mixtures. Second, DBP research has focused on low molecular weight species, generally accounting for only ~30-40% of total organic halogen (TOX). To what extent do high molecular weight DBPs contribute to toxicity? With disinfectants applied upstream of reverse osmosis (RO) units, potable reuse trains are ideal for answering this question. In addition to the research opportunities afforded to graduate and undergraduate students, a high school science teacher and underrepresented high school student will assist in summer research, with an eye to incorporating this material into the high school curriculum over the following year.