Determining organic copper speciation in stormwater and wastewater to improve treatment and regulation

重金属对地表水系统的污染是一个全球性的环境挑战。重金属通过人为活动释放到地表水系统，包括废水和雨水的产生和排放。重金属与溶解有机物（DOM）的相互作用是其在水生系统中的命运、运输和毒性的关键驱动因素。铜（Cu）在这方面尤其重要，因为它与DOM有很强的相互作用，并且对包括受威胁和濒危鲑鱼物种在内的多种水生生物具有毒性。目前对废水和雨水中Cu形态的理解主要基于分析方法和试验，这些分析方法和试验提供了物种体积浓度和与有机配体络合的信息。尽管这些研究表明，废水和雨水中超过99%的铜与有机配体结合，但这些配体的化学特性及其与人为水体中铜离子的相互作用的详细表征仍然难以捉摸。该项目的总体目标是：1)表征和识别与雨水和废水中铜相互作用的有机配体；2)评估和量化这些人为金属结合配体对铜化学形态的影响，以及使用基于吸附的水处理工艺去除铜的效果。这项研究的成功完成将通过产生新的基础知识和经过验证的模型来促进设计和实施更有效和更具成本效益的吸附剂和处理工艺，以在废水和雨水排放到接收地表水系统之前去除重金属，如铜，从而造福社会。通过教育和推广活动，包括培训和指导俄勒冈州立大学的一名研究生，将为社会带来额外的好处。重金属与溶解有机物（DOM）的络合作用在控制其从各种来源进入水生系统后的吸收、生物利用度和毒性方面起着关键作用。从组成上看，有证据表明，废水和雨水中的DOM与从地表水系统中分离出来的天然DOM在性质和金属结合性能上都有所不同。然而，关于雨水和废水中有机物的化学组成、分子特征和金属结合特性的详细知识仍然是难以捉摸的。本研究的目的是表征和鉴定雨水和废水中存在的金属结合配体，并评估金属-有机结合对Cu的化学形态的影响，以及使用活性炭和生物炭从这些人为废物流中去除Cu的效果。本研究的指导假设是，废水和雨水中的铜结合配体池是人为或微生物产生的，与地表水系统（包括湖泊和河流）中存在的DOM中的天然配体相比，它们具有不同的金属结合特性。本研究的具体目的是：(1)利用液相色谱（LC）、平行电感耦合等离子体质谱（ICP-MS）和超高分辨率电喷雾电离傅立叶变换质谱（ESI-FT-MS）等分析工具的组合，表征和鉴定废水和雨水中存在的铜结合配体池；(2)开发并验证新的Cu化学形态模型，该模型考虑了废水和雨水中的金属有机络合作用；(3)评价金属-有机络合作用对常用水处理吸附剂（如活性炭和生物炭）去除废水和雨水中Cu的影响。这项研究的成功完成有可能产生变革性的影响，通过产生新的基础知识和经过验证的模型来推进基于化学物种的法规的实施，以控制重金属（如Cu）排放到接收地表水系统，同时提供关键数据和建模工具，指导基于吸附的过程的设计和操作，以去除废水和雨水中的重金属。为了实现该项目的教育和推广目标，首席调查员（pi）计划利用他们与俄勒冈州一家大型水务公司的现有合作伙伴关系，交流并将他们的研究成果转化为该公司运营设施中重金属处理和去除的实践。此外，pi建议利用俄勒冈州立大学现有的项目（例如，国家科学基金会资助的路易斯·斯托克斯少数民族参与联盟项目），从代表性不足的群体中招募本科生参与该项目。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The pollution of surface water systems by heavy metals is a global environmental challenge. Heavy metals are released to surface water systems through anthropogenic activities including the generation and discharge of wastewater and stormwater. The interactions of heavy metals with dissolved organic matter (DOM) are key drivers of their fate, transport, and toxicity in aquatic systems. Copper (Cu) is of particular importance in this regard due to its strong interactions with DOM and toxicity to a broad range of aquatic organisms including threatened and endangered salmonid species. The current understanding of Cu speciation in wastewater and stormwater is largely based on analytical methods and assays that provide information on species bulk concentration and complexation to organic ligands. Although these studies have revealed that over 99% of Cu in wastewater and stormwater is bound to organic ligands, a detailed characterization of the chemical identity of these ligands and their interactions with Cu ions in anthropogenic waters has remained elusive. The overarching goals of this project are to 1) characterize and identify the organic ligands that interact with Cu in stormwater and wastewater and 2) evaluate and quantify the impact of these anthropogenic metal binding ligands on Cu chemical speciation and efficacy of removal using sorption-based water treatment processes. The successful completion of this research will benefit society through the generation of new fundamental knowledge and validated models to advance the design and implementation of more efficient and cost-effective sorbents and treatment processes to remove heavy metals such as Cu from wastewater and stormwater prior to their discharge into receiving surface water systems. Additional benefits to society will be achieved through educational and outreach activities including the training and mentoring of one graduate student at Oregon State University. The complexation of heavy metals with dissolved organic matter (DOM) plays a key role in controlling their uptake, bioavailability, and toxicity once they enter aquatic systems from various sources. Compositionally, there is evidence that the DOM in wastewater and stormwater differs from natural DOM isolated from surface water systems in both character and metal binding properties. However, a detailed knowledge of the chemical composition, molecular features, and metal binding properties of the organic matter present in stormwater and wastewater has remained elusive. The goal of this research is to characterize and identify metal-binding ligands present in stormwater and wastewater and evaluate the impact of metal-organic binding on the chemical speciation of Cu and the efficacy of Cu removal from these anthropogenic waste streams using activated carbon and biochar. The guiding hypothesis of the proposed research is that the pools of Cu-binding ligands in wastewater and stormwater are anthropogenic or microbial in origin and possess distinct metal-binding properties compared to the natural ligands present in DOM from surface water systems including lakes and rivers. The specific aims of the research are to: (1) Characterize and identify the pools of Cu-binding ligands present in wastewater and stormwater using a combination of analytical tools including liquid chromatography (LC) followed by parallel inductively coupled plasma mass spectrometry (ICP-MS) and ultra-high-resolution electrospray ionization Fourier transform mass spectrometry (ESI-FT-MS); (2) Develop and validate new Cu chemical speciation models that account for metal-organic complexation in wastewater and stormwater; and (3) Evaluate the impact of metal-organic complexation on Cu removal from wastewater and stormwater using common water treatment sorbents such as activated carbon and biochar. The successful completion of this research has the potential for transformative impact through the generation of new fundamental knowledge and validated models to advance the implementation of chemical speciation-based regulations for controlling the discharge of heavy metals such as Cu into receiving surface water systems while providing critical data and modeling tools to guide the design and operation of sorption-based processes for the removal of heavy metals from wastewater and stormwater. To implement the educational and outreach goals of this project, the Principal Investigators (PIs) plan to leverage their existing partnership with a large Oregon water utility to communicate and translate their research findings into the practice of heavy metals treatment and removal at the company’s operating facilities. In addition, the PIs propose to leverage existing programs at Oregon State University (e.g., NSF funded Louis Stokes Alliances for Minority Participation Program) to recruit undergraduate students from underrepresented groups to work on the project.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.