Superfund Research Program
Mitigating Airborne PCB Emissions from Sediments with Black Carbon Materials and PCB-Degrading Biofilms
Project Summary (2020-2025)
Polychlorinated biphenyls (PCBs) are commonly encountered organic chemical pollutants of concern at Superfund sites, which are often found in river and lake sediments near areas of industrial and commercial activity. The Iowa Superfund Research Program (ISRP) has shown that airborne PCB emissions from open water associated with contaminated sediment sources could pose significant inhalation risk to nearby populations. This project's research is based on the critical need to develop, evaluate, and demonstrate innovative approaches to disrupt the flux of PCBs from sediments to the atmosphere at Superfund sites. The central hypothesis of this project is that black carbon materials containing PCB-degrading biofilms will enhance aerobic biodegradation of LC-PCBs in contaminated sediments, thereby decreasing their emission into the atmosphere. The team's hypothesis is based on preliminary studies showing that bioaugmentation of aerobic PCB degrading bacteria into soils catalyzes improved biodegradation of certain LC-PCB congeners. The team also shows that aerobic PCB-degrading bacteria form biofilms on black carbon materials, indicating their potential as delivery vehicles for introducing PCB-degrading bacteria into sediments. Guided by these preliminary data, the team will test their central hypothesis by: 1) optimizing tailored black carbon materials with sorptive and reactive properties toward LC-PCBs and the ability to host aerobic PCB-degrading biofilms; 2) evaluating the performance of black carbon materials containing aerobic PCB-degrading biofilms to lower LC-PCB concentrations in water and air under relevant environmental conditions; and 3) scaling up production of biofilm-coated black carbon materials to demonstrate the feasibility of decreasing airborne PCB flux from contaminated sediments at the mesocosm-scale. The team's work will rely on the support of ISRP cores for synthesis and analytical assessment of PCBs in study samples. The proposed research is innovative because the relationship between the removal of LC-PCB congeners from sediments and PCB emissions has not been studied. There are currently no developed or tested biotechnologies to decrease or prevent airborne PCB emissions from sediments. The project is relevant to the SRP mandates because the research team will develop advanced methods to decrease the amount and toxicity of PCBs in the environment. Outcomes of this project will benefit human health by reducing human exposure to airborne PCBs and realize economic benefits by demonstrating breakthrough alternative PCB remediation approaches that minimize expensive and disruptive measures such as dredging.