The MIT SRP Research Translation Core is pleased to share NextGen Protocols. Detailed experimental protocols used in SRP research are being shared so that the exact methods of each experiment can be linked to data sets produced by those experiments. The MIT SRP invites trainees from all SRP centers to use the website. The protocols on NextGen Protocols are intended to be fully descriptive of the experimental process to make it easier to reproduce results. This platform allows the researcher to explain every step they take with no limit on length. A key advantage to posting a NextGen Protocol is that video clips can be shared. Seeing how tricky steps are done is a great way to share methods. By facilitating reproducibility and allowing researchers to link their data to the protocol that produced it, NextGen Protocols aims to clarify and streamline the process of sharing complete methods widely.
MIT SRP In the News
MIT Homepage News Spotlight: Work from MIT SRP trainees Hélène Angot and Nicholas Hoffman was featured on the MIT Homepage. The article discussed their research with Prof. Noelle Selin (Project 2), studying the atmospheric transport and transformation of mercury and the impacts of mercury bioaccumulation in fish.
MIT SRP Citizen Science in the News: Abigail Harvey and Tchelet Segev, two Master’s students trained by Dr. Kathy Vandiver and supported by Harry Hemond, John Essigmann and Robert Croy, completed their Citizen Science Project focused on drinking water quality for the Passamaquoddy Tribe located in Maine. This citizen science project was initiated by the MIT Center for Environmental Health Sciences (CEHS) and supported by both the CEHS and the MIT Superfund Research Program. Tribe members expressed concern about their drinking water. Students learned how to design the study, and how to engage effectively with community members. Importantly, with coaching, the students led Community Meetings where the project and results were shared in a bidirectional fashion. Under the guidance of K. Vandiver, the students successfully engaged with ~20% of households (representing three towns and including Passamaquoddy Tribe members from Pleasant Point). Sampling methods were optimized and reported back to individuals and the Maine Environmental Department. The impact from this study included teaching people how to flush their water to reduce lead exposure. In addition, several homes were notified that their arsenic levels exceeded national standards. This opened the doors for those individuals to obtain safer water from other sources. This work served as an excellent pilot study in support of future Citizen Science projects directly related to the toxicants of study by the MIT Superfund Research Program. The study and its impact were described in several publications, including two Quoddy Tides Newspaper articles, and the NIEHS PEPH Newsletter.
Visit to Loring AFB Superfund Site
In August 2018, MIT SRP Program Director Prof. Bevin Engelward, Co-Director Prof. John Essigmann, and Community Engagement Core Leader Dr. Kathleen Vandiver traveled to the Loring Air Force Base Superfund site.
The former Loring AFB is contaminated with a variety of harmful chemicals, including PCBs, PAHs, and PFAS at different sites around the property. Following extensive remediation, the land was divided into parcels, one of which was given to the Aroostook Band of Micmacs. However, subsequent testing revealed that contamination remains at unsafe levels for food gathering or residences. There is also an advisory that fish should not be eaten due to dangerously high contamination by PCBs, and volatile organic chemicals continue to intrude into buildings left behind.
The MIT SRP team met with Peter Forbes of the US Air Force and Fred Corey’s team at the Micmac Environmental Lab to discuss the current status of the site and to explore the site on foot. The team gained improved understanding of the site’s geography and locations of contaminants, including in remediated areas. Tribal environmental concerns were discussed with Mr. Corey, and the team continues to work with both Mr. Corey and Mr. Forbes to develop specific plans for MIT-driven research. The team plans to return to collect soil, sediment and water samples to test for the presence of carcinogens, including N-Nitrosodimethylamine and polycyclic aromatic hydrocarbons, the focus of the MIT SRP.
Project 1 trainee Irene Hu successfully defended her thesis and will continue working with the SRP program as a postdoc. In the laboratory of Prof. Harry Hemond (Project 1), her research focused on the development and testing of a novel in situ sensor to measure benthic fluxes of key biogeochemicals, including pollutants at contaminated sites. Read more in her Trainee Spotlight here.
Project 4 trainee and RTC leader Dr. Jenny Kay was interviewed for a piece in the ASCO Post, published November 25, 2018. The ASCO Post has a circulation of ~35,000 health care experts. Ms. Kay described the relationships between inflammation and carcinogenesis, important aspects of MIT SRP biological research projects.
Projects 1 and 2 trainee Dr. Maggie He presented a talk at the American Chemical Society (ACS) National Meeting and Exposition. Her talk, "Functionalized carbon nanotubes for chemical sensor applications," described a chemiresistive sensor platform that will be adapted to sense NDMA and PAHs in the environment.
Project 2 trainee Dr. Hélène Angot received an Early Career Presentation Award for her poster, “Towards reduced human exposure to mercury: The need for near-term global action,” at the Joint 14th Annual iCACGP Quadrennial Symposium and at the 15th IGAC Science Conference in Takamatsu, Japan. Hélène Angot also published a manuscript entitled "Global and local impacts of delayed mercury mitigation efforts” in Environmental Science & Technology (https://doi.org/10.1021/acs.est.8b04542).
Project 4 trainee Lizzie Ngo graduated with her PhD under the supervision of Profs. Bevin Engelward and Leona Samson (Project 4). Dr. Ngo’s innovative work includes development of a novel platform for detecting bulky DNA lesions, which is being used for studies of PAHs in collaboration with other MIT SRP researchers. The assay exploits DNA repair trapping to convert undetectable bulky lesions into single strand breaks that can be detected using the CometChip platform. Dr. Ngo also developed another technology that can be used for higher throughput cytotoxicity quantitation. The “MicroColonyChip” platform exploits methods to create a microarray of mammalian cells. Cells are allowed to grow to form microcolonies with precise inter-colony distances. The sizes of the colonies are then measured using a combination of automated imaging and in-house software. Dr. Ngo discovered that the distribution of microcolony sizes give rise to exquisite sensitivity to chemical toxicity, rivaling the gold-standard colony forming assay and the popular Cell Titer-Glo assay. The approach is broadly useful to the MIT SRP and the manuscript, “Microcolony size distribution assay enables high-throughput cell survival quantitation,” was recently published in Cell Reports. In addition to these innovative projects, Dr. Ngo also developed methods for studying DNA repair in lymphocytes. In collaboration with Dr. Zachary Nagel of the Harvard School of Public Health, Dr. Ngo analyzed repair kinetics for 50 different people. She observed significant differences in the DNA repair kinetics among different individuals, pointing to the possibility that DNA repair may be a susceptibility factor for exposure-induced diseases. Dr. Ngo is now an Associate at Flagship Pioneering, located in Cambridge, MA.
Partnership with the Wilmington Environmental Restoration Committee
The Olin Chemical Superfund Site is located in Wilmington, MA. At Olin, from 1953 to 1970 wastes were discharged into lagoons, ponds, and a man-made area called Lake Poly. Prof. Bevin Engelward (Program Director) and Dr. Kathy Vandiver (Director of the Community Engagement Core) met with leadership from the Wilmington Environmental Restoration Committee (WERC) on July 26th 2018. Representatives from WERC included Suzanne Sullivan, Martha Stevenson, Liz Harriman, and Gary Mercer. WERC has been meeting regularly for over 15 years, so they have a great depth of knowledge regarding the Olin Chemical Superfund Site. The major concern of WERC is the presence of N-nitrosodimethylamine (NDMA), which is a chemical that causes cancer in animals and is a probable human carcinogen. NDMA was not directly generated by Olin activities, but rather it is created when chemicals dumped into the environment react with one another. At Olin, the chemical constituents needed to make NDMA are at high enough levels that NDMA has become a serious health concern.
The MIT team shared with WERC key research initiatives being undertaken to address the public health impact NDMA. NDMA can be metabolized in the body to form methyldiazonium ion, a highly reactive intermediate that can add methyl groups to the DNA, creating modified bases, including 7-methylguanine (7meG), 3-methyladenine (3meA) and O6-methylguanine (O6meG). These modified bases are of concern because these structural changes to the DNA can lead to cytotoxicity and mutagenicity. For example, 3meA is a lesion that inhibits DNA polymerases. As a result, replication forks can break down, creating a DNA double strand break that is both toxic and mutagenic. O6meG is a lesion that promotes mispairing, leading both to point mutations and to toxicity as a result of ineffective repair. The 3meA lesions are repaired primarily by the alkyladenine DNA glycosylase (AAG), while the O6meG lesions are repaired by methylguanine methyltransferase (MGMT). Members of the MIT SRP have created transgenic mice lacking these key DNA repair genes, where integrated transgenes enable analysis of DNA mutations. This puts the team in a strong position to study the effects of NDMA in vivo in animal models, work that is ongoing.
The WERC team shared with MIT their concerns regarding NDMA in the water. While there is a ‘holding area’, where much of the hazardous wastes at the Olin Site are sequestered, the holding area is known to be leaky. In particular, the base of the holding area is bedrock, but it is not clear that the bedrock is forming an impermeable barrier. Rather, there is evidence that the bedrock is fractured, which could allow NDMA to leak into surrounding areas and potentially contaminate nearby wells. WERC is concerned about these possible fractures, which are being investigated by the EPA.
When NDMA was discovered in well water, steps were taken to assure safe drinking water. Almost all the residents of Wilmington now have municipal water, and by avoiding use of well water, exposure has been greatly curbed. However, there are still homes that use well water. While some of these residents drink bottled water, there is still concern that NDMA in well water used for showering, washing dishes and washing clothing may be hazardous. This is an area of concern that the MIT team aims to explore further.
Predicting health impact of environmental contaminants for environmental justice communities in Eastern Maine: The longer mercury-controlling policies are delayed, the less effective they will be. Furthermore, the current administration is proposing to roll back existing regulations on mercury emissions. Mercury (Hg) is emitted into the atmosphere by multiple natural and anthropogenic sources (e.g., coal-fired power plants). Mercury is of global concern owing to its persistence in the environment, its ability to be transported far away from emission sources, and its bioaccumulation to toxic levels in food webs. Mercury emissions are addressed under the global 2017 Minamata Convention, which requires that countries control emissions from specific sources. Policymakers typically use models to evaluate their emissions-reducing plans. However, most of these models do not appropriately account for legacy emissions (recycling of previously deposited Hg) and the fact that today’s anthropogenic emissions are tomorrow’s legacy emissions. Hélène Angot, under the supervision of Prof. Noelle Selin (Project 2), developed an integrated modeling approach to account for legacy emissions given various emissions-reducing policy timelines (Angot H, Hoffman N, Giang A, Thackray CP, Hendricks AN, Urban N, Selin NE. Global and local impacts of delayed mercury mitigation efforts, Environmental Science & Technology, https://doi.org/10.1021/acs.est.8b04542). While the Minamata Convention urges that countries take action as soon as possible, its requirements for controlling sources allow for up to a 10-year delay. The MIT SRP team found that for every five-year delay, the impact of policy measures will be reduced by 14% on average. They also found that delays will have serious consequences in regions that are far from emission sources, such as tribal areas of Eastern Maine, and they discussed implications relevant to environmental justice concerns. The approach outlined in this work provides a new and straightforward methodology to better inform policy decision-making, as well as providing a platform for ongoing studies of MIT SRP contaminants of interest, including polycyclic aromatic hydrocarbons.
Development of Carbon Nanotube Sensors for the Detection of NDMA: In 2018, Maggie He, under the supervision of MIT Superfund Prof. Tim Swager (Projects 1 and 2), published the development of carbon nanotube sensors for the detection of γ-radiation (Zeininger L, He M, Hobson S, Swager T. Resistive and capacitive γ-ray dosimeters based on triggered depolymerization in carbon nanotube composites. ACS Sensors 3, 976–983, 2018, PMID: 29558118) and amines (Paoletti C, He M, Salvo P, Melai B, Calisi N, Mannini M, Cortigiani B, Bellagambi FG, Swager TM, Francesco FD, Pucci A. Room temperature amine sensors enabled by sidewall functionalization of single-walled carbon nanotubes. RSC Advance 8, 5578–5585, 2018). These publications describe the functionalization of single-walled carbon nanotubes with responsive units, poly(olefin sulfone)s and tetrafluorobenzoic acid, which can impart sensors with high sensitivity to γ-radiation and amines, respectively. These carbon nanotube chemiresistive sensors function at room temperature and have the advantage that they require very low power, provide real-time detection, are inexpensive, and can be made portable for field deployment. The design principles and techniques developed for this work provide a foundation for which the MIT SRP N-nitrosodimethylamine (NDMA) sensors will be designed and fabricated. Distributing portable sensors at contamination sites will allow SRP to obtain spatiotemporal concentrations of NDMA. This information will help nearby communities to minimize exposure and will be useful to optimize efforts for site remediation.
Recruiting under-represented members of our community to join the Superfund Research Program: Prof. Bevin Engelward (MIT SRP Program Director) attended the 2018 Annual Biomedical Research Conference for Minority Students (ABRCMS) in order to recruit under-represented members of our community to become involved in research related to environmental health, and in particular to tell them about the NIEHS Superfund Research Program. Over 4,000 faculty and students attend the ABRCMS meeting. Most of the attendees are undergraduates who are considering different options for graduate studies. This makes this meeting particularly effective for reaching out to promising students at an early stage in their career to encourage them to consider a career focused on public health. Prof. Engelward reached out to dozens of students to tell them about the SRP, and in particular about the research at MIT. Many students were not aware of environmental health research, and thus benefited from learning about the ongoing work at MIT and the mission of the NIEHS Superfund Research Program.
Trainee Spotlight: Irene Hu
Irene Hu, a former graduate student in Professor Harry Hemond’s group at MIT in the Department of Civil and Environmental Engineering, is studying the flux of contaminants between sediments and water. Specifically, her research focuses on the development and testing of novel in situ instrumentation to study the fate and transport of environmental biogeochemicals. As part of Project 1 of the MIT Superfund Research Program, Irene is developing a sensor to measure benthic (sediment-water) fluxes of chemicals in aquatic ecosystems, such as pollutants from contaminated sediments at Superfund and other sites. Knowledge of such pollutant fluxes—including the location of the most problematic areas, and how quickly they are releasing toxins—is critical in to remediation efforts, including assessment of exposures and prioritization of cleanup efforts.
The sensor being developed is based on the eddy correlation technique, which involves correlating fast, simultaneous, and co-located measurements of velocity and concentration. To date, eddy correlation measurements of benthic fluxes have mainly been used to measure dissolved oxygen fluxes, using a dissolved oxygen microelectrode. To expand the range of measurable biogeochemicals, Irene has developed a novel trimodal sensor capable of high-speed, high-resolution measurements of fluorescence, temperature, and conductivity. Coupled to a velocity sensor for eddy correlation measurements, this instrument can be used to measure benthic fluxes of fluorescing materials, heat, and salinity. Thus, it can be used to target sediment-water fluxes of fluorescing pollutants in contaminated groundwater. In addition, it can potentially be used to measure benthic fluxes of a wider range of contaminants by using one flux as a tracer for others. The instrument has so far been used to measure simulated benthic fluxes in a laboratory setting, and will be tested in the field in the spring.
Irene has an undergraduate degree in electrical engineering from Princeton University; as a premed, her interests also extended to chemistry and biology. After graduating, she worked for a few years as a financial management consultant in New York City. She returned to graduate school to study environmental engineering because she wanted to work on projects that would have a positive impact on our environment and public health. She is happy to have found at MIT a research group that allows her to utilize her electrical engineering background for environmental applications, and she appreciates the wide range of skills and knowledge she has developed by working on her project—including electronics, programming, chemistry, fluid dynamics, machine shop work and fieldwork.
Irene Hu successfully defended her dissertation this past October and will continue working with the MIT Superfund program as a postdoctoral associate. In her spare time, she enjoys cycling, ballroom dance, and ice skating.
Research Highlight: Modeling Atmospheric Transformation of PAHs
One of the goals of Project 2 for the MIT SRP is to analyze the chemical evolution of polycyclic aromatic hydrocarbons (PAHs) in the air near Superfund Sites. PAHs are common pollutants formed from incomplete combustion processes, and many are known or probable carcinogens. Their structure consists of two or more aromatic rings, an example of which is shown in Figure 1.
As part of the MIT SRP, the Kroll Lab at MIT is working to better understand what happens to PAHs during their chemical transformations in the atmosphere. This is important because PAHs are known to have negative impacts on human health, and so better understanding of their evolution in the atmosphere will inform how long they pose a threat after emission. Importantly, some reactions in the atmosphere produce reaction products that can be equally or more harmful than the parent PAH,1 yet these reaction products are not currently monitored. By studying PAH evolution over time, harmful byproducts of atmospheric reactions can be identified and suggested for routine monitoring.
Studying the evolution of PAHs in the atmosphere first requires an understanding of PAH emission. PAHs can be emitted in both the gas and particle phase depending on the size of the compound. PAHs in both phases are important, but larger PAH molecules mainly reside in the particle phase and are typically more harmful to human health than gas phase PAHs.2 For this reason, the work of the MIT SRP is mainly focused on particle phase PAHs. Once in the atmosphere, there are three predominant processes that affect their evolution, illustrated in Figure 2: 1) reaction with UV light produced by the sun, 2) reactions between particle phase PAHs and gas phase oxidants (i.e., heterogeneous reactions), and 3) the condensation of gas phase reactions. The relative importance of these pathways is determined by how quickly the process degrades the parent PAH and the types of reaction products that are formed. Fast degradation pathways of the parent PAH will decrease the health risk if the products formed from reaction are innocuous, but if the products formed are more harmful than the parent compound the reaction pathway becomes detrimental.
In order to determine which process is most impactful on human health, we have developed an experimental setup that can generate particle phase PAHs and simulate the three reaction pathways. Researchers measure PAH evolution using an Aerosol Mass Spectrometer (AMS) and Proton Transfer Reaction Mass Spectrometer (PTR) that can measure the concentration of individual PAHs and reaction products in the particle phase over time. To date this setup has been used to study heterogeneous reactions between particles and gas phase oxidants. Particle phase perylene, a representative PAH, has been created and reacted with two common atmospheric oxidants, hydroxyl radical (OH˙) and ozone (O3). Figure 3 shows the degradation of perylene by hydroxyl radical and ozone over time, and Figure 4 shows the reaction products products that are formed during perylene degradation by hydroxyl radical over time.
The reactions can be compared using the two factors mentioned previously, decay of parent PAH and formation of products. Results from the AMS show that the reaction of perylene with O3 in the atmosphere is initially faster than OH˙, but levels off after around one day of exposure while the reaction with OH˙ keeps going (Figure 3). This could mean that PAHs emitted in areas where heterogeneous reaction with O3 is the only process, only around 30% of the PAH will go away and the rest will remain a risk for human exposure. In terms of reaction products, similar products are formed in both reactions, but the products are formed more quickly from reaction with OH˙. This could mean that for PAHs that spend less than a day in the atmosphere, the products from reaction with OH˙ are of most concern to human health.
Future work on this project will include extending the experimental setup to other atmospheric processes and testing additional PAHs. This will begin to inform what processes are most important as well as identify potentially harmful byproducts. Beyond this, we aim to identify which chemical species of PAHs and degradation products have impacts on health. Collaboration with Projects 3, 4, and 5 of the MIT SRP will help identify the health risks of PAHs and their byproducts so that harmful ones can be suggested for routine monitoring.
 Finlayson-Pitts, B. J., & Pitts Jr, J. N. (1999). Chemistry of the upper and lower atmosphere: theory, experiments, and applications. Elsevier.
 Calvert, J. G., Atkinson, R., Becker, K. H., Kamens, R. M., Seinfeld, J. H., Wallington, T. H., & Yarwood, G. R. E. G. (2002). The mechanisms of atmospheric oxidation of the aromatic hydrocarbons. Oxford University Press.
EPA Region 1 Tribal Environmental Conference
Community Engagement Core leader Dr. Kathleen Vandiver and Research Translation Core leader Dr. Jennifer Kay attended the EPA Region 1 Tribal Environmental Conference in Jackman, ME on October 31-November 1, 2018. Goals of the visit included gaining an improved understanding of tribal environmental concerns, listening to tribal perspectives and histories, and learning about the future of New England climate, ecology, and environmental hazards. Drs. Vandiver and Kay spoke with a variety of New England tribal members as well as representatives from the EPA, NOAA, and UMass Amherst, learning a great deal about the state of New England’s tribal lands. The Passamaquoddy Tribe of Indian Township hosted the event, and they graciously opened their maple sugaring facility for the conference attendees to tour, sharing one of their successful environmentally sustainable economic ventures.
On October 4th and 5th, MIT SRP welcomed its External Advisory Committee and shared updates on trainee research and leadership activities. Prof. Akram Alshawabkeh of Northeastern, Prof. Ian Blair of UPenn, Prof. Rebecca Fry of UNC, Prof. John Durant of Tufts, Dr. Ljiljane Pasa-Tolic of PNNL, and Captain Michael Stover of the EPA formed the expert team to help guide ongoing development of the MIT SRP. Current research efforts were showcased at a trainee poster session, and Project PIs provided a summary of each Research Project to the team. Each Core leader also presented an overview of the activities undertaken to support interconnectedness within the MIT SRP as well as with other SRPs, the government, and community members. The EAC team provided valuable insight regarding ways to strengthen connections between research projects, to address future expectations for SRPs, and to guide future directions of the MIT SRP.