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Testing Of An Ultraviolet (UV)-Transparent Polymer-Based Passive Sampler for Rapid, Ultra-Low-Cost EDC Screening Applications
Citation:
Kibbey, T. C., L. Chen, D. A. Sabatini, M. MILLS, AND C. T. NIETCH. Testing Of An Ultraviolet (UV)-Transparent Polymer-Based Passive Sampler for Rapid, Ultra-Low-Cost EDC Screening Applications. Presented at SETAC New Orleans 30th Anniversary 2009, New Orleans, LA, November 19 - 23, 2009.
Impact/Purpose:
To test the method that was conducted at the EPA Experimental Stream Facility (ESF) in Milford, Ohio.
Description:
A new passive sampling method with rapid low-cost spectral detection has recently been developed. The method makes use of an ultraviolet (UV)-transparent polymer which serves as both a concentrator for dissolved compounds, and an optical cell for UV spectral detection. Because many endocrine disrupting chemicals (EDCs) and other contaminants of interest in natural waters have chromophores which absorb light in the UV range, their absorbance signatures can be detected once they have been concentrated in the polymer. The detection method uses spectral deconvolution and a spectral library to determine the concentrations of individual compounds partitioned into the polymer. Knowledge of partitioning coefficients and rate behavior allows calculation of aqueous concentrations. Preliminary laboratory testing of the method found very good selectivity in mixtures containing seven different EDCs. Detection limits varied by compound as a function of partition coefficient and UV absorbance. Although the detection limits of the hormones estradiol or estrone were too high for practical use, detection limits of a number of other compounds (e.g., triclosan, nonylphenol, phenanthrene, 2,6-ditert butyl-1-4-benzoquinone) were found to be very reasonable for screening applications. When coupled with low-cost CCD spectrophotometer detection, the method is accessible to stakeholders in emerging regions, or other applications where analytical cost is the primary limiter to water quality screening. The focus of this presentation will be on testing of the method that was conducted at the EPA Experimental Stream Facility (ESF) in Milford, Ohio. Initial testing examined detection of triclosan, while subsequent testing examined simultaneous detection of nonylphenol and triclosan. Initial tests indicated mass transfer and algae buildup problems when the sampler deployment methods were used, and no triclosan was detected. In the subsequent tests, modified deployment methods were used, and both nonylphenol and triclosan were detected. Results of the work highlighted the need for internal spiking standards in the polymer to more accurately calculate aqueous concentrations with varying mass transfer rates. Other ongoing field trials with the method will also be discussed.
