Superfund Research Program
Developing and Evaluating Technology to Measure PAH Fate and Exposures
Project Leader: Kim A. Anderson
Grant Number: P42ES016465
Funding Period: 2009-2025
Significant progress has been made over the last year for this project. The Specific Aims remain largely unchanged and are:
- Further develop environmental exposure bio-analytical measurement technologies capable of quantitatively sequestering bioavailable contaminant concentrations.
- Utilize the zebrafish developmental model to test the relative potency of PSD extracts from current Superfund, urban, and undeveloped sites.
- Develop discriminatory chemical/physical fractions and constructions of PSD extracts from signatory biological responses in the zebrafish model.
- Develop discriminatory pattern recognition and multivariate regression assessments of co-varying components in PSD extracts and contaminant source type.
The development and validation of the first bio-analytical tool has been completed. The lipid-free passive sampler has been validated and field deployed at multiple Superfund sites during 2012 (including: Portland Harbor, McCormick and Baxter and Lower Duwamish Waterway) as well as complimentary studies using PSD in the Gulf of Mexico for the DWH oil spill and western Africa for pesticides. Three new types of silicone materials and several designs were laboratory and field tested, from these test a single silicone material was determined to best fit the research team's field and analytical needs. The researchers are now fabricating these in the laboratory for the next field season. The research team successfully developed technical approaches for the infusion of performance references compounds into all their PS materials so the technology would have in situ calibration applications. A proto-type sediment PSD was developed and field tested. The investigators have developed methods for PAH extraction and analysis of PAHs from the silicone PSD. In collaboration with Analytical Chemistry Research Support Core, the research team has developed a method for quinone and ketone-substituted PAHs (OPAHs) for the silicone extracts using both GCMS and LCMS for 24 target OPAHS. Both of these methods have recently been validated and analysis of field samples has begun. Personal passive sampler worn was also developed as part of the SRP research.
Significance: Two complimentary passive sampling materials have now been developed (polyethylene and silicone) from many materials and designs tested. The current designs permit the environmental characterization of semi-polar to non-polar superfund contaminants. They are easily co-deployed and extractions are complimentary and avoid carcinogenic/ hazardous extraction chemicals. Separate research for the wristband is underdevelopment and an (R01) has been submitted.
The developmental toxicity of the extracts was analyzed using the embryonic zebrafish bioassay. The passive samplers (BRIDGES) provided site-specific, temporally resolved information about environmental contaminant mixtures and their toxicity As well; they recently successfully integrated PSD extracts into the salmonella (TZ-98 with/without metabolic activation (S9+) (Ames) bio-assay.
Significance: The research team has successfully demonstrated a combined chemistry and biological high through put approach with the BRIDGES (passive sampler) tools.
The researchers are currently developing and employing multivariate regression assessment models with these rich datasets. While focusing mostly on the 35 PAHs representing a 2,000 data point set; the research team concurrently analyzed their extracts using their 1,201 screening method.
Significance: Multivariate modeling approaches were applied to paired chemical and toxic effects data sets to help unravel chemistry-toxicity associations. Modeling demonstrated a significant correlation between PAH concentrations and the toxicity of the samples and identified a subset of PAH analytes that were the most highly correlated with observed toxicity. Although this research highlights the complexity of discerning specific bioactive compounds in complex mixtures, it demonstrates methods for associating toxic effects with chemical characteristics of environmental samples.
A significant application of the SRP developed BRIDGES was employed before, during and after the Deepwater Horizon oil spill. A significant effort was initiated in spring of 2010 through fall of 2011 utilizing the passive samplers in four Gulf States. Water, air and sediment samples continue to be processed through the chemical and zebrafish model system. Researchers are continuing to process samples for OPAHs from this sample set. They have used multivariate regression assessments to model potential sources of the PSD extracts further demonstrating attributes of the BRIDGES approach.
Significance: Demonstration of BRIDGES (passive sampler) was dramatically demonstrated as a tool for environmental disaster characterization (temporal effects, spatial effects and for contaminants not a priori known).