Superfund Research Program
Sources, Fate, and Identification of Endocrine Disrupting Compounds in the Hudson
Project Leader: Bruce Brownawell
Grant Number: R01ES015451
Funding Period: 2006-2009
The goal of this study was to identify the sources of alkylphenol ethoxylate (APEO) metabolites and polybrominated (PBDE) flame retardants to the Hudson Basin and how those sources have changed over time. One of the most unique components of the project was to test the hypothesis that a group of largely sewage-derived superhydrophobic quaternary ammonium compounds (QACs, cationic surfactants) could prove useful for source allocation of targeted or not-target endocrine disrupting compounds (EDCs) in sediments of the lower Hudson Basin, where it was known that there was the potential for multiple inputs for many xenobiotic organic contaminants including PCBs, PBDEs, and metabolites of alkylphenol ethoxylates. The original compounds targeted as potential tracers were ditallowdimethylammonium compounds (DTDMAC), trialkylamines (TAMs) that exist as impurities of DTDMAC in commercial formulations, and benzalkonium compounds (BAC).
The research team’s work on QACs included:
- Successful demonstration of QACs as tracers for sources and evidence for differential fate of EDCs and other sediment associated organic and metal contaminants
- Research to better understand environmental factors and properties of QACs that control when and where they may be applied as useful tracers of sources and fate of other contaminants (e.g., results related to source histories, persistence, and the range of concentrations and compositions from different sewage sources)
- Studies on two QACs, for which researchers find very high relative concentrations in the environment that have increased at alarmingly fast rates over the past three decades (docosyltrimethylammonium or behentrimonium) or between 2003 and 2008 (dodecyltrimethylammonium).
The results with QACs provide insights into some of the weaknesses apparent in screening tools and approaches currently employed for identifying emerging contaminants.
The researchers have described a robust and comprehensive method for determination of targeted and non-targeted QAC analytes. The method overcomes problems identified with prior methods related to extraction efficiency, poor recoveries during sample preparation, and mass spectrometric blank problems. The impacts of this novel finding will have broader impact in the enormous field involved in the study of new generation ionic liquids (ILs), most of which contain quaternary ammonium cations.
The groundbreaking studies conducted with QACs in sediments, and more recently with in sewage sludges and biosolids, will stimulate new lines of research on these compounds as contaminants of potential environmental concern. The research team has demonstrated that QACs have great potential as tracers of contaminant sources, transport, and differential fate in sediments.