Superfund Research Program
SRP Grantees Participate in Federal PFAS Information Exchange
On February 5 - 6, Superfund Research Program (SRP) grantees provided their expertise and perspectives during the Federal Information Exchange on per- and polyfluoroalkyl substances (PFAS) in Bethesda, Maryland. PFAS chemicals have received increasing attention because they have been found in several drinking water systems and have been linked to reproductive, developmental, liver, kidney, and immunological effects.
Hosted by the Toxics and Risks Subcommittee of the National Science and Technology Council, the workshop provided a forum to share emerging data and key knowledge gaps in the sources, pathways, treatment, and health effects of PFAS. SRP grantees Raymond Ball, Ph.D., Jennifer Guelfo, Ph.D., and Angela Slitt, Ph.D., participated in the workshop.
"The meeting was informative and underlined the magnitude of the PFAS problem," said Ball, president and principal engineer at the NIEHS-funded small business EnChem Engineering. As part of his SRP project, Ball's team is developing a technology to expedite the removal of PFAS from soil and groundwater.
The meeting opened with remarks from senior government officials, including NIEHS Director Linda Birnbaum, Ph.D., and the Centers for Disease Control and Prevention's National Center for Environmental Health Director Patrick Breysse, Ph.D. Following talks from researchers about new findings in their areas of expertise, federal employees and federally funded researchers participated in breakout sessions to discuss current scientific knowledge and future directions.
"The meeting provided a platform for researchers and employees across federal agencies to hear how each is engaged in science and decision-making regarding PFAS," said Guelfo, a researcher at the Brown University SRP Center. Her recent work has focused on using publicly available data to develop models that predict areas with potential PFAS groundwater contamination.
"Given that PFAS includes thousands of compounds, one recurring theme was the need for methods for prioritizing compounds and the need to understand the influence of mixtures," Guelfo added. "There was also a lot of discussion about developing standard methods for PFAS analysis."
In addition to discussions about routes of exposure and treatment methods, time was set aside to discuss the current understanding of the health effects of PFAS. Slitt, a grantee at the University of Rhode Island SRP Center, is studying whether PFAS exposure increases the risk for obesity-induced fatty liver disease and metabolic disorders.
In the final session, participants discussed risk assessment, consideration of data needs for protecting human health, and ongoing coordination and communication across federal agencies. The workshop was immediately followed by a closed Toxics and Risks Subcommittee meeting to discuss how these findings will inform agencies moving forward.
Improving Site Characterization to Assess Contaminant Removal
A computational model can be used to measure how different factors influence the removal of groundwater contaminants at hazardous waste sites, according to a study from the University of Arizona Superfund Research Program Center. Researchers led by Mark Brusseau, Ph.D., developed the predictive model and found that their contaminant estimates from the model compared well to measurements taken at a Superfund site.
Their model uses the relationship between reductions in contaminant discharge and removal as the metric to examine remediation efficiency. Characterization methods such as this may help researchers more easily understand factors that may impact the distribution of contaminants at a site, which can provide more information about the effectiveness of remediation efforts.
Building on these findings, the research team used the model to examine factors that influence contaminant removal in large groundwater contaminant plumes. Specifically, they looked at areas with low groundwater flow adjacent to large aquifer systems, which is common at many hazardous waste sites.
They found that the location of pump-and-treat wells, relative to contaminated water, can have a significant impact on how effectively contaminants are removed and how they persist in large groundwater systems. Based on well configuration, zones may be formed where contaminants remain stagnant, which reduces the effectiveness of pump and treat. This illustrates the need for dynamic system operations in which the system is routinely monitored and operational conditions are modified to maintain peak performance.
In a 2017 Risk e-Learning webinar, Brusseau described this work, as well as other efforts to improve characterization methods to understand the factors contributing to the persistence of contaminants in groundwater.
SRP Research Finds Ancestry-Based Differences in Telomere Length Genes
People with different ancestries may inherit telomere length differently, according to a new study from the Columbia University Superfund Research Program (SRP) Center. Telomeres are segments at the end of DNA, and telomere length plays an important role in aging and aging-related diseases. This study provides new information about the genes associated with telomere length across populations and highlights the importance of including diverse populations in genome-wide association studies (GWAS).
Although telomere length is a heritable trait, it still can vary considerably between individuals and populations, leading scientists to study how it is passed between generations. Previous studies that have investigated how telomere length is inherited have relied primarily on populations of European descent. In this study, researchers used samples from the Health Effects of Arsenic Longitudinal Study cohort in Bangladesh and found important ancestry-based differences in how telomere length might be passed on.
In addition to replicating some findings from other genome-wide association studies, such as those showing that gene regions called TERT and TERC are related to telomere length, the researchers also identified a new association. The study reports a link between telomere length and a gene region called RTEL1 and, importantly, a distinct second region of RTEL1 that had not been previously identified in relation to telomere length. This specific region of RTEL1 is common in South Asian populations but less so in other populations.