Hazardous substances at Superfund sites are frequently remediated using thermal processes.
These processes produce particulate matter (PM), which can be found as a contaminate in soils or sediments and in air due to emissions from treatment facilities, or dust from additional remediation or containment activities. It is also widely assumed that the environmental and health effects of inhaled PM are due to the individual components of PM such as the particles, metals, or organic pollutants (i.e. chlorinated hydrocarbons (CHCs), polycyclic aromatic hydrocarbons (PAHs), etc.) or that the effects are simply additive. However, scientists at the Louisiana State University Superfund Research Center (LSU SRC) have shown that the pollutants and particles are complex mixtures that must be considered as a unified pollutant-particle system whose health and environmental impacts are due to surface-chemical reactions of its components.
The LSU SRC is comprised of researchers at LSU in Baton Rouge, the LSU Health Science Center in New Orleans, and the University of Tennessee Health Science Center in Memphis. The Center’s focus is on these newly-identified pollutant-particle systems, including environmentally persistent free radicals (EPFRs), that form during many combustion processes. The LSU SRC researchers are studying how EPFRs are formed, how they affect human health, and how to prevent their formation and reduce human exposures.
Stephania Cormier, PhD, of the Department of Pediatrics at UTHSC, currently serves as the Center’s director. She notes that because EPFRs are bound to the particles, they are difficult to detect and analyze and, as such, represent a previously unidentified and currently veiled environmental threat. As there are currently no rules or regulations for limiting or monitoring EPFRs in the environment, the studies from the LSU SRC will have important implications for guiding environmental and public health policy.
“We know that EPFRs are persistent in the environment for long periods of time (upwards of 12 hours). We also know that if inhaled they can persist and generate more radicals in the body through a cyclic reaction, causing major damage to your DNA, heart, and lungs. Our research aims to determine how EPFRs are formed, decay, and stabilized on the surface of airborne PM, the chemical reactivity in physiological conditions, and interaction of EPFRs with polyaromatic hydrocarbons associated with PM using advanced surface and chemical analysis techniques.
Since the airway is a major entry site for these particles from the environment, we also explore mechanisms of EPFR-induced cardiovascular and pulmonary dysfunction with the expectation of translation of data to humans,” says Cormier.
EPFRs are especially concerning when one considers their effects on newborns and kids. Recent studies have shown that infants and children may be especially sensitive to the toxic effects of EPFRs and other airborne PM. Dr. Cormier’s lab discovered that early life exposure is linked to long-term, persistent lung disease.
“My team reported that gestational exposures to EPFRs increases the likelihood for developing asthma later in life,” says Cormier. “In one study, we saw an increased allergic immune response after exposure to EPFRs ceased, but other types of immune responses were decreased. This EPFR-induced immunosuppression decreased the ability to fight infections – increasing influenza morbidity and mortality.”
The LSU SRC believes an important part of this process is communicating with the public, health care professionals and environmental researchers, regulators, and policy makers. Their ultimate goal is to protect human health and the environment by providing information to be used in risk-based decisions on treatment options for Superfund wastes.
The LSU Superfund Research Program is supported by the National Institute of Environmental Health Sciences Superfund Research Program grant number P42 ES013648.