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STAR Grant R832738: Rapid Detection of Trace Endocrine Disrupting Chemicals in Complex Mixtures: A Full- Spectrum Deconvolution Technique with a UV-Transparent Passive Concentrator
Project Purpose:
The investigators aim to develop a method for rapid monitoring and detection of endocrine disrupting chemicals at trace concentrations in natural waters and test the method using samples of river water collected from sites where a USGS survey has previously detected multiple EDCs.
Project Description(s):
Objective:
The objective of this work is to develop a method for rapid monitoring and detection of endocrine disrupting chemicals at trace concentrations in natural waters, using a full spectrum deconvolution technique with simultaneous absorbance and fluorescence measurements. The method will be coupled with a novel ultraviolet (UV)-transparent polymer-based concentrator to be used as a passive sampling device. The UV-transparent polymer-based concentrator will serve both as a solid phase extraction medium to concentrate EDCs for analysis and exclude many compounds likely to interfere with detection (fines, macromolecules such as organic matter, ionic surfactants), and an analytical optical cell, allowing rapid EDC quantification without labor-intensive pre-concentration procedures.
Approach:
The proposed work will be accomplished through three main research tasks: 1. Development of a robust full-spectrum deconvolution technique for detecting individual EDC compounds in complex environmental mixtures; 2. Selection and characterization of one or more polymers, and design of the concentrator; and 3. Validation of the method with waters and wastewaters. Spectrophotometric measurements will be conducted using dual-channel fiber-optic CCD-array spectrophotometers equipped with custom designed cells to hold the UV-transparent polymer-based concentrators. The spectrophotometers will be configured for simultaneous fluorescence and absorbance measurements, and will be coupled with custom software for real-time data acquisition and analysis. Polymers for the concentrator will be selected from among the subset of polymers that combine significant UV transparency with hydrophobicity (largely silicones, fluorocarbons, or other advanced polymers), and will be fully characterized for EDC partitioning affinity and rate, as well as other critical physical properties. Compounds to be studied will include hundreds of EDCs and other compounds representing commonly detected compounds in natural waters, to provide an extensive library of spectra needed for accurate analyses.
Project Outcomes:
The results of this work will provide a powerful screening tool for rapid detection and quantification of EDCs in natural waters. The resulting tool will provide a means of rapidly assessing the risk of EDC exposure posed by a specific ground- or surface water, without the need for extensive sample preparation and preconcentration, allowing far more waters to be tested than would be possible with current methods. Preliminary results indicate that the tool will be highly selective, identifying the presence of specific compounds and families of compounds with excellent accuracy.
Contact
Susan Laessig at laessig.susan@epa.gov