EAR-PF: Environmental source apportionment and soil-household dust relationships of urban metal pollutants across different regions and seasons

美国国家科学基金会（NSF）授予Matthew Dietrich博士EAR博士后奖学金，在Gabriel Filippelli教授的指导下，在印第安纳大学-普渡大学印第安纳波利斯分校（IUPUI）进行研究和科学推广活动。研究将侧重于了解城市土壤中重金属污染物与城市家庭粉尘之间的复杂关系，特别关注铅（Pb）。铅是一种有毒元素，尤其影响儿童，导致认知障碍等不利健康影响。美国仍有数十万儿童的血铅浓度对他们的发育有害，有色人种儿童受到的影响尤为严重。了解城市环境中铅和其他重金属的动员、运输和来源的研究还不发达，特别是在美国，这对于有效干预和解决环境正义问题至关重要。因此，通过使用两个截然不同的城市中心（美国印第安纳波利斯和澳大利亚悉尼）的社区成员，Dietrich博士将分析家庭灰尘和土壤样本，以更好地了解重金属污染物来自何处，以及季节、气候和地质变化如何影响灰尘和土壤中污染物的转移。创新的地球化学技术，如铜（Cu），锌（Zn）和铅同位素将有助于分配特定污染源贡献的比例，而高分辨率成像，如扫描电子显微镜（SEM）将有助于表征灰尘和土壤中的污染物颗粒。该项目的推广和社区参与至关重要，因为每个城市的当地社区成员将提供他们自己家庭的样本，这不仅提高了采样分辨率，而且使Dietrich博士能够直接向社区成员传达调查结果，以及他们在检测到污染时可以采取的行动步骤。此外，对提供样本的社区成员和更大的社区进行科学教育是该项目的重要组成部分。具体来说，与印第安纳波利斯市内的当地高中和IUPUI的本科生建立伙伴关系将有助于传播结果和增加抽样。所有数据最终将在www.mapmyenvironment.com上免费提供，为研究科学家和社区成员提供理想的可访问数据平台。通过使用来自美国印第安纳波利斯和澳大利亚悉尼的家庭灰尘和土壤，本研究将解决家庭规模的污染源分配和土壤-尘埃关系是否可以聚集在一起，以提供城市规模的有用趋势。在当地社区成员的帮助下收集的大量样本集提供了一个独特的机会，可以全面利用地球化学技术，在通常不容易获得的尺度上调查重金属污染。所使用的技术将是城市灰尘/土壤的全面地球化学特征（例如，矿物学，有机碳百分比），多种金属同位素（Pb， Zn和Cu）比率/多元统计（即主成分分析），以区分污染源末端成员（即土壤，房屋油漆，车辆磨损等）和儿童和成人经常接触的家庭灰尘。这些技术将有助于回答研究问题：(1)为什么一些金属，如Cu和Zn（而不是Pb）在灰尘中相对于土壤中的含量要高得多，不同的地理区域是否由于不同的矿物学、气候和其他地球化学特征而具有不同的土壤-家庭灰尘元素相关性？(2)在某些季节，家庭粉尘是否含有不同的同位素比率和不同的污染源？(3)悉尼和印第安纳波利斯之间是否存在区域性家庭粉尘同位素差异，这表明该地区的地质背景、气候或污染源存在差异？利用多金属同位素在不同时空尺度上进行多变量统计的新方法为更好地识别人类重金属暴露的最大威胁提供了一个新的和改进的整体框架。对城市环境中无机污染物循环的更深入了解最终将使干预方法更加有效，从而改善对污染补救的支持，特别是在受污染严重影响的地区。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。

An NSF EAR Postdoctoral Fellowship has been granted to Dr. Matthew Dietrich to conduct research and scientific outreach activities at Indiana University–Purdue University Indianapolis (IUPUI) under the mentorship of Professor Gabriel Filippelli. Research will be focused on understanding the complex relationships between heavy metal pollutants in urban soils and urban household dusts, with a particular focus on lead (Pb). Pb is a toxic element that especially affects children, leading to adverse health effects such as cognitive impairment. Hundreds of thousands of children in the U.S. still have blood Pb concentrations that harm their development, and this disproportionately affects children of color. Research in understanding mobilization, transport, and the sourcing of Pb and other heavy metals in urban environments is underdeveloped, particularly in the U.S., and is essential for efficient intervention and addressing environmental justice issues. Thus, through using community members in two contrasting urban centers, Indianapolis, U.S. and Sydney, Australia, Dr. Dietrich will analyze household dust and soil samples to better understand where the heavy metal pollutants are coming from and how seasonal, climatic, and geologic variability affects the transfer of pollutants in dusts and soils. Innovative geochemical techniques such as copper (Cu), zinc (Zn), and Pb isotopes will help with assigning proportions of specific pollutant source contributions, while high resolution imaging such as scanning electron microscopy (SEM) will help characterize pollutant particles in the dusts and soils. Outreach and community involvement in this project is essential, as local community members in each city will provide samples from their own households, which not only improves sampling resolution, but will allow Dr. Dietrich to directly communicate findings to the community members and the action steps they can take if pollution is detected. Additionally, scientific education to both community members supplying the samples and the greater community at large is an essential part of this project. Specifically, partnerships with local inner-city high schools in Indianapolis and undergraduate classes at IUPUI will help in both dissemination of results and additional sampling. All data will eventually be freely available at www.mapmyenvironment.com, providing the ideal platform for accessible data for both research scientists and community members alike.Through using household dusts and soils from homes in Indianapolis, U.S. and Sydney, Australia, this research will address whether pollution source apportionment and soil-dust relationships at the household scale can be agglomerated together to provide useful trends at the city scale. A large sample set collected with the help of local community members offers a unique opportunity to holistically utilize geochemical techniques to investigate heavy metal pollution at scales typically not easily accessible for research. The techniques utilized will be full geochemical characterization of urban dusts/soils (e.g., mineralogy, percent organic carbon), and multiple metal isotope (Pb, Zn and Cu) ratios/multivariate statistics (i.e., principal component analysis) to differentiate between pollutant source endmembers (i.e., soils, house paint, vehicle wear, etc.) and the household dust to which children and adults are routinely exposed. These techniques will help answer the research questions: (1) why are some metals such as Cu and Zn (but not Pb) much higher in dusts relative to soils, and do different geographic regions have differing soil-household dust element correlations because of differing mineralogy, climate, and other geochemical characteristics?, (2) do household dusts contain different isotopic ratios and therefore pollutant sources in some seasons compared to others?, and (3) is there regional household dust isotopic variation between Sydney and Indianapolis that points to variation in geogenic background, climate, or pollutant sources in an area? The novel approach of using multiple metal isotopes for source apportionment with multivariate statistics over different spatial and temporal scales provides a new and improved holistic framework for better identifying the greatest threats to human heavy metal exposure. Greater understanding of inorganic pollutant cycling in urban settings will ultimately enable more efficient intervention methods and thus improved support for pollution remediation, particularly in areas disproportionately affected by pollution.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.