PAH Remediation and Transformations

What We Do

The goal of our project is to identify technologies that can remove PAHs from the environment and Superfund sites, and minimize the formation of hazardous PAH breakdown products. As part of our work, we identify toxic products that are formed during remediation (removal) of PAHs at toxic waste sites. We use three different methods to determine if these breakdown products are toxic: computer modeling, the zebrafish assay, and targeted and non-targeted analyses.

Our project asks the following question

What is the role of metabolism in susceptibility for PAH-mediated toxicity and respiratory disease in humans?

Our project challenges the common assumption that contamination is reduced when parent PAHs degrade. The removal of PAHs (remediation) is very complex. Remediation processes can include chemical, physical and microbial-based approaches. Each of these processes can produce PAH breakdown products that may be more toxic than the parent compounds originally found in the environment.

Our Current Research

We have created a computational+experimental procedure to separate complex mixtures of parent PAHs and their breakdown products and identify the compounds that are responsible for bioactivity.
We have developed advanced analytical methods (GC-MS and LC-MS-QTOF) to measure the breakdown products that result during physical, chemical and biological treatment processes.
We have used the zebrafish assay to evaluate the toxicity of breakdown products from single PAHs or PAH mixtures.
We are studying the pathways of phenanthrene transformation with pure microbial cultures (such as the bacteria culture Mycobacterium sp. ELW1) and evaluating toxicity. The experimentally determined transformation pathways are compared to those predicted via computational analysis.
We are measuring PAH breakdown products of steam-treated Superfund soils using advanced analytical methods described by Trine et al. (2019).
Trine, L.S.D., Davis, E.L., Roper, C., Truong, L., Tanguay, R.L. and Simonich, S.L.M., 2019. Formation of PAH derivatives and increased developmental toxicity during steam enhanced extraction remediation of creosote contaminated superfund soil. Environmental science & technology, 53(8), pp.4460-4469.

Collaborations

We work with the PAH Fate and Exposure, Mechanisms of PAH Susceptibility, and Predicting the Toxicity of Complex PAH Mixtures projects and the Chemical Mixtures Core to obtain PAHs and mixtures found in the environment, and evaluate the toxicity of each PAH, PAH mixture, and subsequent metabolites using zebrafish screening. The proven advantages of the zebrafish model can provide the relative toxicity of real-world mixtures from Superfund sites in just a few days. Additionally, the zebrafish data are used to guide cleanup efforts at contaminated sites to better protect human health and the environment.
Through our work with the PAH Fate and Exposure and Mechanisms of PAH Susceptibility projects we are prioritizing which PAHs and PAH mixtures to assess.

Our Previous Research

We collected creosote contaminated soil samples from the Wyckoff-Eagle Harbor Superfund site and remediated with steam enhanced extraction (SEE) in a laboratory setting. The goal was to determine if this process reduced both parent PAHs and breakdown products. The process was effective in removing unsubstituted PAHs from contaminated soil, but other, potentially more toxic PAH derivatives may have formed.
We reviewed over 270 studies concerning the remediation of PAH-contaminated soil. We found that while 16 parent PAHs were commonly measured before and after remediation, only a fraction of the studies (n=33) included the measurement of PAH breakdown products. This work demonstrates the need for future remediation studies to consider PAH breakdown products and their potential toxicity following remediation.

Contact Info

The Superfund Research Center