Grantee Research Project Results

Final Report: Development of Innovative Broad-Spectrum Analysis Methods for PFAS

EPA Contract Number: 68HERC20C0006
Title: Development of Innovative Broad-Spectrum Analysis Methods for PFAS
Investigators: Jackson, Randy E
Small Business: Seacoast Science, Inc.
EPA Contact: Richards, April
Phase: II
Project Period: November 1, 2019 through October 31, 2021 (Extended to October 31, 2022)
RFA: Small Business Innovation Research (SBIR) - Phase II (2019) Recipients Lists
Research Category: Urban Air Toxics , Small Business Innovation Research (SBIR) , Heavy Metal Contamination of Soil/Water , SBIR - Land Revitalization

Description:

Polyfluoroalkyl substances (PFAS) are used in food packaging, as coatings for cloth (e.g. Scotchgard), fire-fighting foams, electronics, and industrial and automotive components. Being perfluorinated species, they are engineered to breakdown slowly (half-life over 92 years in water), and thus persist for very long times. Their high water-solubility makes them especially dangerous, and much like perchloro- and trichloro-ethylene, i.e. PCE and TCE, they can enter and be transported by groundwater into the drinking water supply. According to the EPA, there are 156,000 public drinking water systems in the U.S. supplying most of the population's water, 82% of which serve the country. It is estimated that 65 million Americans may be at risk from PFAS in their drinking water, based on detection in 94 public water systems. In fact, on Feb. 8, 2018, the State of Ohio sued DuPont for releasing PFOA into the Ohio River.

The overall project objectives in this Phase II SBIR were: 1) optimization the PFAS analysis method in regard to the core cartridge technology, 2) modification of the Cyanalyzer to the PFAS Analyzer, 3) development of sample collection and sample preparation methods, and 4) performance testing and validation of the PFAS Analyzer.

Summary/Accomplishments (Outputs/Outcomes):

We synthesized 3 fluorometric reagents 7-O-tert-butyldiphenylsilyl-4-methylcoumarin, DFP1, RDF-1 for the detection of fluoride ions in water. Because of high variability, poor sensitivity to fluoride, and the inability to reproduce published data, we elected to use the commercially available UV-Vis active reagents lanthanum nitrate and alizarin fluorine blue for the analysis of fluoride which produced a narrow linear range of 5-20 µM.

Sample collection methods were developed for PFAS in water, soil, and sediment. Sample preparation focused on photocatalytic degradation of PFAS to fluoride using BOHP, active microdiffusion (based on the transfer of HF gas from the sample to a collection reservoir for spectrophotometric analysis) and SPE cleanup. Photocatalytic degradation using BOHP was successful yielding 10x amplification for PFOA but unsuccessful for PFOS. The PFAS Degradation Apparatus prototype was only slightly successful producing minimal degradation which may be due to differences in the illumination characteristics, orientation of the light source relative to the sample, or the temperature of the sample in each reaction setup. Active microdiffusion and SPE cleanup using a SCX were successful but optimization of the reaction parameters is necessary. Samples analyzed combining PFAS mineralization, SPE cleanup, and fluoride detection using LAFB was successful and data indicated that this process is viable and optimization of several of the analysis steps is necessary. 

Although we did not develop a fully functional PFAS Analyzer, we were able to modify the light sensing photodetector to function from 200 - 1100 nm that performs similarly to the original detector. We have identified two additional LED's that will work with the current instrument electronics and LAFB. In addition, we have proposed additional modifications to the PFAS Analyzer to allow UV-Vis based spectrophotometric detection.

Conclusions:

Overall, the microdiffusion based analysis method for PFAS in water, soil and sediment samples has an overall analysis time is 18 hrs the majority of this time is needed for photocatlytic degradation. Even though photocatalytic degradation is currently the limiting step, research into the degradation of PFAS, identification of additional degradation methods, and potentially the combination of methods and continued optimization still indicate that the PFAS Analyzer has the potential to be a first of its kind fieldable sensor. Future work will focus on the development of the PFAS Analyzer, the sample collection method, the sample preparation and cleanup methods, and the adaptation of these methods into a sample preparation system and the cartridge system for use in the PFAS Degradation Apparatus and the PFAS Analyzer.

The U.S. invests about $30 billion annually in water supply sanitation. Therefore, the most important markets for the proposed PFA analysis system are (1) municipal water facilities and (2) the environmental remediation, site surveyors, and others involved with detecting and identifying contaminants in soils and groundwater. Because large private companies like 3M generally hire environmental engineering consulting firms and the US military has substantial funding for investigation, remediation, research into new detection and clean-up technologies, and also hire environmental engineering firms, we concluded a partnership with a large environmental engineering firm contracted to investigate or remediate sites exposed to PFAS or a potential a startup that specializes in the field analysis of environmental samples with laboratory testing capabilities when further confirmatory testing is necessary are viable options for commercialization of the proposed PFAS Analyzer.

SBIR Phase I:

Development of Innovative Broad-Spectrum Analysis Methods for PFAS  | Final Report