Superfund Research Program
Indoor Air Concentration Dynamics and Vapor Intrusion
Project Leader: Eric M. Suuberg
Grant Number: P42ES013660
Funding Period: 2009-2021
This research project supports three different activities centered on characterization of exposure routes to organic chemicals of concern.
Property Measurements on Organic Compounds of Concern. The researchers continued to obtain thermodynamic data of relevance to environmental scientists modeling fate and transport of organic chemicals of concern. In 2011, they published papers on the properties defining the behavior of tar materials of concern at many contaminated sites. They have also given attention to the thermodynamic properties of halogenated aromatics, including publishing on polybrominated diphenyl ethers (PBDEs), a class of flame retardants of increasing environmental health concern. This portion of the project is motivated by practical aspects related to a need for the kinds of property data being measured in order to understand how these materials can move in the environment. Such data can also be useful in design of thermally-based remediation strategies for contaminated soils — they allow answering the question of just how severe heat treatment needs to be in order to remove the contaminants from the soil.
Vapor Intrusion Modeling. The research group continues to develop models that can guide the investigation and assessment of contaminated sites on which there is concern regarding entry of vapor contaminants into structures built atop those sites. The effort at Brown has been primarily aimed at developing a computational fluid dynamics methodology to permit those involved with such sites to better understand the processes occurring on the sites. Their aim has been to show how readily available commercial mathematical modeling packages can be used to show key aspects of the vapor intrusion process. They have used these methods to publish papers illustrating when simpler, widely used modeling packages (e.g., Johnson and Ettinger, as implemented by the EPA) are successful/unsuccessful in capturing relevant behavior. This modeling effort has been supplemented by a field study now based at the University of Massachusetts - Dartmouth (through an ARRA supplement) in which data from a site in Massachusetts are being examined in the context of these models.
Evaluation of Passive Samplers for Establishing the Bioavailability of Contaminants in Sediments. Another supplement-funded project involves collaboration with the EPA ORD/NHEERL Atlantic Ecology Division Laboratory in Narragansett, Rhode Island. This project has considered the relative performance of different polymer-based passive samplers for establishing the bioavailability of contaminants in sediments. Normally, to gauge the ecological and potential human health hazard associated with uptake by marine organisms of contaminants from sediments, certain standard organisms were employed in testing regimens. Often field testing with organisms has been difficult due to other, uncontrolled environmental factors that confounded the analysis of the data. By use of various polymer model systems, the variability associated with use of organisms can be avoided. In this project, three common materials or device types—PE, POM, and SPME—were compared under identical actual field conditions. The results obtained pointed to the specificity of certain types of samplers for certain types of compounds (e.g., PAH and PCB uptakes are higher in PE as compared to POM, but the reverse was true for PBDE).