Assessing the photocatalytic effects of metal-oxide nanoparticles on marine organisms under environmentally-relevant light regimes

二氧化钛（TiO 2）纳米颗粒（NPs）是工业和消费品中使用最广泛的人造纳米材料之一，预计未来10年的环境负荷高达200万至600万吨。毒理学上，工程二氧化钛纳米颗粒已经得到了很好的研究，大多数工作正在进行细胞系，细菌和啮齿动物。报道的影响包括炎症、氧化应激和DNA损伤，但高度依赖于暴露方法以及NP的浓度和理化特性。其他研究已经检查了TiO 2纳米颗粒的光催化性能，作为氧化污染物，消毒饮用水或治疗肿瘤的一种方式。这些研究报告了各种光毒性效应，但通常使用的辐照度远高于水生环境中的辐照度。一些研究已经研究了自然光条件下TiO 2对淡水生物的光毒性，但在近岸海洋生物群落方面的工作基本上缺乏。我们认为，TiO 2纳米颗粒对浅水海洋生物的光毒性是一个被忽视的研究领域，这对于全面评估纳米技术的环境安全性至关重要。基于我们在海洋生物学、金属化学和海洋光学方面的丰富经验，我们开发了多项研究，研究了TiO 2在环境相关条件下的光催化效果。我们的项目符合纳米技术计划的环境健康和安全的预算限制，并代表了一个令人兴奋的研究领域，学生和PI将工作。具体来说，我们将研究：1）将纳米级TiO 2掺入天然存在的异质聚集体（即，海洋雪）; 2）对生活在海洋雪复合体中的重要微生物群体的光毒性; 3）通过海洋雪向两种近岸底栖滤食性动物的营养转移效率; 4）随后对这两种动物（一种半透明，一种不透明）的生理和细胞过程的光催化效应。海洋雪的形成）和环境相关的光机制，评估1）二氧化钛纳米颗粒对微生物群落和在海洋生态系统中起关键作用的底栖滤食性动物的光催化影响，和2）底栖生物的营养转移和生物利用度。确定纳米颗粒对关键的底栖生物群体的潜在有害影响不仅对比较目的很重要，而且对确定这些材料如何产生群落一级的影响也很重要。例如，对滤食性动物的毒性影响将损害它们的底栖-中上层耦合能力，进而极大地影响周围环境。我们的研究所产生的知识将感兴趣的监测机构与海鲜安全，监管机构谁是发展风险评估协议，科学家谁研究新兴污染物的分布，和工程师谁是设计“绿色”纳米技术。由于我们处于此类研究的前沿，我们的研究结果可能会立即产生海洋系统的重要数据，并有助于关于纳米粒子在环境中的潜在安全性的辩论。更广泛的影响：作为我们工作的自然延伸，我们将培训本科生和研究生跨生物学，化学和光学学科的概念和技术。我们的研究计划将被用作一种工具，让教育工作者和学生参与讨论近岸生态系统过程，以及纳米技术的好处和潜在危害。提供积极和有趣的学习机会，在早期的科学发现是至关重要的捕捉学习的热情。因此，我们将侧重于制定和实施创新的教材，宣传海洋环境对人类健康的重要性。教材将与非营利海洋科学教育组织新英格兰科学航行（NESS）合作设计。与NESS合作，我们将：1）制定课程计划，以引人入胜和易于理解的方式展示驱动沿海生态系统的基本原则，并探索新兴污染物与海洋和人类健康之间的联系; 2）培训NESS高级员工使用这些课程来促进生态素养，并吸引学生进入科学和工程领域。

CBET - 1336358 Titanium dioxide (TiO2) nanoparticles (NPs) are one of the most widely used manufactured nanomaterials in industrial and consumer products, with predicted environmental loads as high as 2,000,000 to 6,000,000 tons in the next 10 years. Toxicologically, engineered TiO2 NPs have been well studied with most work being performed on cell lines, bacteria, and rodents. The reported effects include inflammation, oxidative stress, and DNA damage, but are highly dependent on exposure method, and the concentration and physicochemical characteristics of the NPs. Other research has examined the photocatalytic properties of TiO2 NPs as a way of oxidizing contaminants, disinfecting drinking water, or treating tumors. These studies have reported various phototoxic effects, but typically use irradiances much higher than those found in aquatic settings. A few studies have examined the phototoxicity of TiO2 on freshwater organisms under natural light regimes, but work on near-shore marine communities is largely lacking. We argue that the phototoxicity of TiO2 NPs on shallow-water marine organisms is an overlooked area of research which is critical for a full assessment of the environmental safety of nanotechnology. Based on our extensive experience with a marine biology, metal chemistry and ocean optics, we have developed several lines of research that examine the photocatalytic effects of TiO2 under environmentally-relevant conditions. Our projects fit within the budgetary constraints of the Environmental Health and Safety of Nanotechnology program, and represent an exciting area of research in which students and PIs will work. Specifically, we will investigate: 1) incorporation of nanoscale TiO2 into naturally occurring hetero-aggregations (i.e., marine snow); 2) phototoxicity on important groups of microorganisms that live within the marine-snow complex; 3) trophic transfer efficiency via marine snow to two species of near-shore, benthic filter feeders; 4) subsequent photocatalytic effects on the physiology and cellular processes of these two animals (one translucent, one opaque).Intellectual Merit :The proposed work represents the first comprehensive study to consider common oceanographic processes (e.g., formation of marine snow) and environmentally-relevant light regimes in assessing 1) photocatalytic impacts of TiO2 NPs on microbial communities and benthic filter feeders that play key roles in marine ecosystems, and 2) trophic transfer and bioavailability to benthic organisms. Determining the potential deleterious effects of NPs on key groups of benthic organisms is not only important for comparative purposes, but also to determine how such materials might produce community level impacts. For example, toxic effects on filter feeders would compromise their capacity for benthic-pelagic coupling and, in turn, greatly impact the surrounding environment. Knowledge generated by our research will be of interest to monitoring agencies concerned with seafood safety, regulators who are developing risk-assessment protocols, scientists who study the distribution of emerging pollutants, and engineers who are designing "green" nanotechnology. As we are at the forefront of such research it is likely that our results will immediately yield important data for marine systems, and contribute to the debate regarding the potential safety of NPs in the environment.Broader Impacts :As a natural extension of our work we will train undergraduate and graduate students in concepts and techniques that cross the disciplines of biology, chemistry, and optics. Our research program will be used as a vehicle to engage educators and students in discussions about near-shore ecosystem processes, and the benefits and potential hazards of nanotechnology. Offering positive and entertaining learning opportunities for scientific discovery at an early age is crucial to capturing the enthusiasm for learning. Consequently, we will focus on developing and implementing innovative teaching materials that advocate the importance of marine environments to human health. The teaching materials will be designed in collaboration with New England Science & Sailing (NESS), a non-profit marine-science educational organization. In collaboration with NESS we will: 1) Develop lesson plans that demonstrate, in an engaging and understandable way, basic principles that drive coastal ecosystems, and explore the links between emerging pollutants and oceans and human health; 2) Train NESS senior staff to use these lessons to foster ecological literacy and draw students into science and engineering.