A Comparative Review of Passive Sampling to Conventional Metrics for Evaluating Sediment Remediation Efficacy
Citation:
Grundy, J., R. Burgess, AND M. Lambert. A Comparative Review of Passive Sampling to Conventional Metrics for Evaluating Sediment Remediation Efficacy. Battelle International Conference on the Remediation and Management of Contaminated Sediments, Austin, TX, January 09 - 12, 2023.
Impact/Purpose:
Around the country there are hundreds of very polluted sites. These sites are contaminated with a range of pollutants including industrial chemicals and toxic metals. Many of these sites are called ‘Superfund’ sites because of the high levels of pollution. In order to limit the negative effects of such sites on human and ecological health, over time, these sites are cleaned-up and the pollutants removed or covered-over to reduce exposure to the environment. Determining the success of these clean-ups can be challenging. In recent years, a technology called passive sampling has been applied as a tool for measuring how well the cleans-up have performed. This presentation will provide an evaluation of the use of the passive sampling tool for assessing cleanup success at sites in the United States and globally, and it will compare results from passive sampling to more conventional metrics, such as bulk sediment concentration and sediment-to-water flux. Recommendations from this evaluation will be used by environmental managers to select the most effective clean-up procedures based on the passive sampling information.
Description:
Background/Objectives: Contaminated sediments are present at 36% of active National Priority List sites in the United States, and remediation of these sediments to reduce human health or ecological risk can be costly and complex. Over the last few decades, passive sampling devices (PSDs) have become valuable additions to the toolkit of remedial project managers to improve the characterization of contaminant transport and assessment of risk at sediment sites, and to evaluate the effectiveness of remedial actions. This study has two aims: (1) to identify sites where PSDs have been used to support cleanup efforts, and (2) assess how PSD-derived remedial endpoints compared to conventional metrics. Approach/Activities: We searched the peer-reviewed literature using the Web of Science and ProQuest databases. Additionally, we screened conference proceedings (Battelle Sediments, SETAC, and NEMC), ESTCP/SERDP reports, and queried an internal U.S. EPA database of Superfund site documents to identify additional sites where PSDs have been used to determine effectiveness of sediment remediation. Results/Lessons Learned: Authors of over 130 articles, reports, and conference presentations have used PSDs to support sediment remediation projects at over 100 sites in the US, Europe, and Asia. Generally, there were four categories of use for PSDs to support remedial investigations: (1) freely dissolved concentrations, (2) site-specific partition coefficients, (3) bioaccumulation evaluations, and (4) mass flux estimates between site media. Most studies focused on hydrophobic organic contaminants, namely PAHs and PCBs, highlighting the advances and growing acceptance of polymeric PSDs. Roughly 20% of studies used diffusive gradient in thin film (DGT) devices for heavy metals, indicating these tools are often utilized when this class of contaminants are of concern. Of the peer-reviewed literature, about 1/3 of articles solely used PSDs to determine remedial efficacy, highlighting the advances, utility, and growing acceptance of polymeric PSDs. In the other articles, the most common conventional metrics investigated alongside PSDs were bioaccumulation (33%), pore water grab samples (16%), toxicity (15%), and water column grab samples (15%). Generally, remedial efficacy investigated through PSD endpoints correlated with conventional methods, but poor agreement was found in some cases (e.g., when PSDs sampled different sediment depths than what biota were exposed to). Results of this review support the continued and potential expanded use of PSDs for a range of applications supporting decision-making at sites undergoing remediation.
