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。重金属通过人类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)的相互作用是决定其在水生系统中的去向、迁移和毒性的关键驱动因素。铜(铜)在这方面特别重要，因为它与DOM有很强的相互作用，而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铜形态的了解主要是基于分析方法和分析，这些方法和分析提供了关于有机配体的物种体积浓度和络合作用的信息。尽管这些研究表明，废水和雨水中99%以上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仍然难以确定。该项目的总体目标是1)表征和确定与雨水和废水中的铜相互作用的有机配体，以及2)评估和量化这些人为金属结合配体对铜的化学形态和使用基于吸附的水处理工艺去除效果的影响。这项研究的成功完成将使社会受益，因为它将产生新的基本知识和经过验证的模型，以推动设计和实施更有效和更具成本效益的吸附剂和处理工艺，以便在废水和雨水排放到接收地表水系统之前消除废水和雨水中的重金属，如铜。将通过教育和外联活动，包括培训和指导俄勒冈州立大学的一名研究生，为社会带来更多好处。重金属与溶解有机质(DOM)的络合作用在控制它们从各种来源进入水生系统后的吸收、生物有效性和毒性方面起着关键作用。在组成方面，有证据表明，废水和雨水中的DOM在性质和金属结合特性上都不同于从地表水系统中分离出来的天然DOM。然而，对雨水和废水中存在的有机物的化学成分、分子特征和金属结合特性的详细了解仍然难以捉摸。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-有机结合对铜的化学形态的影响，以及使用活性碳和生物炭从这些人为废水中去除铜的效果。这项研究的指导假设是，废水和雨水中的铜结合配体池是人为或微生物起源的，与来自湖泊和河流等地表水系统的DOM中的天然配体相比，具有明显的金属结合特性。这项研究的具体目的是：(1)结合使用包括液相色谱(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仪(ESI-FT-MS)在内的多种分析工具，表征和鉴定废水和雨水中铜的结合配位体；(2)开发和验证新的铜化学形态模型，以解释废水和雨水中金属-有机络合作用；以及(3)评估金属-有机络合作用对使用常用水处理吸附剂如活性碳和生物炭从废水和雨水中去除铜的影响。这项研究的成功完成有可能产生变革性的影响，通过产生新的基本知识和经过验证的模型来推动实施基于化学形态的法规，以控制铜等重金属向地表水系统的排放，同时提供关键数据和模拟工具，指导基于吸附的工艺的设计和运行，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自来水公司的现有合作伙伴关系，将他们的研究成果传达并转化为该公司运营设施中重金属处理和去除的实践。此外，PIs建议利用俄勒冈州立大学现有的项目(例如，NSF资助的Louis Stokes少数群体参与联盟计划)来从代表不足的群体中招募本科生参与该项目。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.