Research & Literature Reviews - PFAS & Biosolids/Residuals
updated November 12, 2020
NEW! NEBRA Literature Review: Sources of PFAS Contamination Impacting Farms
by Michael Rainey, for NEBRA
NEBRA Literature Review: Sources of PFAS Contamination Impacting Farms, September 2020
Appendix II: Compiled Abstracts and Notes, September 2020
Calculating PFAS in Soils - Spreadsheet, September 2020, by Michael Rainey & Andrew Carpenter
NEBRA Literature Review: PFAS & Wastewater Residuals (v. 2.0)
by Michael Rainey, for NEBRA, with input from Ned Beecher
June 2018, updated November 2019 (v. 2.0)
NEBRA Literature Review: PFAS & Wastewater Residuals, updated November 2019
Appendix A: Compendium of Abstracts & Notes, updated November 2019
Bibliography (spreadsheet), updated November 2019
PFAS & Biosolids Literature Review- Updated, slides presented January 31, 2020 by Michael Rainey
Slides PDF
Webinar: NEBRA PFAS Literature Review & Updates, recorded, January 31, 2020
Additional notable research, 2020
PFAS in Biosolids, Soils, & Groundwater - a Southern Arizona Field Study by Ian Pepper, Ph.D., et al., University of Arizona
Dr. Linda Lee, Purdue Univ., discusses the science and data of PFAS in biosolids, Words On Water, WEF, Feb. 3, 2020
PFAS Levels in Precipitation, National Atmospheric Deposition Program, presentation to Wisconsin PAC, Jan. 16, 2020
Letcher et al., 2020: https://doi.org/10.1016/j.jhazmat.2020.122044
This significant paper measuring side-chain PFAS in Canadian biosolids may raise concerns. But it is not surprising. Side-chain PFAS chemicals, like other PFAS, are in our daily lives, and our exposures are far greater there than from biosolids. The one and only concern is potential leaching to groundwater, and these S1 and S2 side-chain compounds can degrade to PFOA, PFOS, etc. that are being regulated. That means the best way to understand if there is any risk is to measure PFOA, PFOS, and any other PFAS of concern (including side-chain PFAS) in groundwater at many land application sites; that will provide the necessary information to determine whether land application creates impacts at levels near regulatory standards.ABSTRACT: High concentrations of the main components in Scotchgard™ fabric protector products (pre-2002 and post-2002; side-chain fluorinated polymer surfactants, S1 and S2, respectively) were detected in biosolids samples from twenty pan-Canadian wastewater treatment plants (WWTPs). Based on mass spectrometric analysis, S1 and S2 can be named as side-chain perfluorooctane sulfonamide-urethane polymer and side-chain perfluorobutane sulfonamide-urethane polymer, respectively. S1 (with C8F17 side-chain) concentrations ranged from 1.08–105 ng/g d.w. and S2 (with C4F9 side-chain) concentrations ranged from 37.5–2051 ng/g d.w., which were much higher than that of other commonly monitored perfluoroalkyl substances (PFAS). S1 and S2 concentrations were significantly correlated (p<0.001; r2 = 0.6142) indicating similar source origins. A negative linear correlation was observed (p < 0.05) between concentrations of S1 (or S2) with the volume of WWTP treated wastewater per day per person (m3/person/day). The total concentration of 22 other PFAS ranged from 4.93 to 92.6 ng/g d.w., and approximately thirty times lower than S1 and S2 concentrations. The calculated elemental fluorine concentrations of ƩFS1&S2 were generally much higher than the sum of the other PFAS. PFAS concentrations in biosolids are likely underestimated without consideration of S1 and S2.
Environmental Working Group reviewed biosolids and PFAS, including tabulating representative data on PFAS in biosolids, August 2020: https://www.ewg.org/news-and-analysis/2020/08/feeding-waste-cycle-how-pfas-disposal-perpetuates-contamination
NEBRA: Supporting Research on PFAS & Biosolids/Residuals
Since 2017, NEBRA has been urging field research at selected, representative real-world biosolids land application sites to determine if, and to what extent, routine biosolids land application is impacting groundwater (and surface water) at levels of potential concern. In 2017, NEBRA teamed with NH DES and the University of NH to develop a research proposal. NH DES decided not to fund the project. U. S. EPA has initiated a field research project at Boise, ID, and NEBRA believes this will be one of the most useful research efforts to date.
NEBRA has provided letters of support and joined teams for research project grant applications to U. S. EPA, U. S. Dept. of Agriculture, and Water Research Foundation (WRF), some of which have been successful. NEBRA is involved in…
WRF 5042 - Assessing Poly- and Perfluoroalkyl Substance Release from Finished Biosolids (Charles Schaeffer, CDM Smith; Linda Lee, Purdue Univ.; and Ned Beecher, NEBRA - co-Principal Investigators)
U. S. EPA PFAS Impacts in Rural Communities (Purdue University, Dr. Linda Lee, PI): https://www.epa.gov/newsreleases/epa-awards-nearly-5-million-new-research-managing-pfas-agricultural-and-rural
See also:
EPA ORD - PFAS Research Plan Update, Aug. 2019
PFAS Research Updates, short slide presentation to the USDA W3170 Annual Meeting, June 24, 2019
NEBRA Research Proposal (draft): Measuring PFAS at Biosolids Field Sites, March 2018 & January 2019
NEBRA Summary of PFAS Research Proposal with UNH (draft), December 2017
2019 research finds microbial degradation of PFOA and PFOS, breaking carbon-fluorine chains:
“ABSTRACT: Incubations with pure and enrichment cultures of Acidimicrobium sp. strain A6 (A6), an autotroph that oxidizes ammonium to nitrite while reducing ferric iron, were conducted in the presence of PFOA or PFOS at 0.1 mg/L and 100 mg/L. Buildup of fluoride, shorter-chain perfluorinated products, and acetate was observed, as well as a decrease in Fe(III) reduced per ammonium oxidized. Incubations with hydrogen as a sole electron donor also resulted in the defluorination of these PFAS. Removal of up to 60% of PFOA and PFOS was observed during 100 day incubations, while total fluorine (organic plus fluoride) remained constant throughout the incubations. To determine if PFOA/PFOS or some of their degradation products were metabolized, and since no organic carbon source except these PFAS was added, dissolved organic carbon (DOC) was tracked. At concentrations of 100 mg/L, PFOA/PFOS were the main contributors to DOC, which remained constant during the pure A6 culture incubations. Whereas in the A6 enrichment culture, DOC decreased slightly with time, indicating that as defluorination of PFOS/PFOA occurred, some of the products were being metabolized by heterotrophs present in this culture. Results show that A6 can defluorinate PFOA/PFOS while reducing iron, using ammonium or hydrogen as the electron donor.”
