Superfund Research Program
Phytoremediation to Degrade Airborne PCB Congeners from Soil and Groundwater Sources
Project Leader: Jerald L. Schnoor
Grant Number: P42ES013661
Funding Period: 2006-2020
Project Summary (2015-2020)
The overall goal of this project is to provide engineering research for the remediation of sites containing typical airborne polychlorinated biphenyl (PCB) congeners that may expose humans. Specifically, it is to determine whether plants can provide in situ phytoremediation of lesser-chlorinated PCB congeners from soil and groundwater sources like the municipal wastewater lagoon at Altavista, Virginia. Thus, the Project focuses on PCB congeners of higher volatility, which comprise significant mass, toxicity and persistence in the environment. Plants can uptake PCB congeners from soil and sediments, intercept semi-volatile congeners from the air onto the waxy cuticle of leaves and bark, and metabolize contaminants within plant tissues. In addition, plants can stimulate rhizosphere bioremediaton of PCBs by providing the habitat, redox potential, and substrates necessary for microbial biodegradation in the root zone. The significance of this project is to provide the scientific and engineering basis for development of land management strategies that can be used to intervene and clean PCB-contaminated sites. Researchers are:
- Identifying plant metabolites of selected PCB congeners (PCB 11, 52, 77, 101, 126, 153) that are semivolatile, persistent, and toxic; and also the uptake/selectivity/metabolism of chiral compounds (PCB 91 and 95).
- Elucidating the regulation of metabolism of PCBs by poplar plants (Populus trichocarpa) at the epigenetic and transcriptional levels.
- Identifying microorganisms and functional genes associated with PCB dechlorination in enrichment cultures derived from PCB-contaminated soil and in un-enriched PCB-contaminated sediment.
- Characterizing PCB-induced changes by plants and their associated rhizosphere microorganisms at a contaminated site (Altavista, Virginia) and in contaminated sediments using gene sequencing and transcriptomic responses.
The researchers are identifying plant metabolites and microbial dechlorination processes in rhizosphere soils and sediments. Project researchers strive to understand the biochemical mechanisms necessary for full-scale phytoremediation of PCBs and the subsequent reduction of exposure at contaminated sites.