Author ORCID Identifier
0000-0003-3358-7189
Document Type
Dissertation
Date of Award
12-31-2022
Degree Name
Doctor of Philosophy in Environmental Science - (Ph.D.)
Department
Chemistry and Environmental Science
First Advisor
Mengyan Li
Second Advisor
Hao Chen
Third Advisor
Edgardo Tabion Farinas
Fourth Advisor
Alexei Khalizov
Fifth Advisor
Peter Jaffe
Sixth Advisor
Sandra Goodrow
Abstract
Per- and polyfluoroalkyl substances (PFASs), a class of emerging contaminants of concern, have attacked unprecedented attention given their prevalent detection and adverse health effects. Primary regulatory attention has been focused on PFOA, PFOS, and other perfluoroalkyl acids (PFAAs). Recent investigations revealed that fluorotelomer carboxylic acid (FTCAs), particularly 5:3 FTCA and 6:2 FTCA, were dominant in landfill leachates and other environmental matrixes. FTCAs are also found as common intermediates during the biotransformation of PFAA precursors. Unfortunately, FTCAs have higher bioaccumulating potential and are at least two orders more toxic than their corresponding PFCAs. However, information regarding the potentials and mechanisms of FCTA biotransformation remains elusive, underscoring the importance of a comprehensive and integral investigation at molecular, cellular, and community levels.
The first part of this dissertation is centered on developing a rapid, sensitive, and robust PFAS quantitative analysis system via Nano-ESI-HRMS, including target and non-target analysis. Nano-ESI HRMS reduced the running time to 1 5 min per sample and was verified as a sensitive and reliable quantitative method for synchronously analyzing 22 target PFAS compounds with limits of detection (LODs) ranging from 3.2 to 36.2 ng/L. Nano-ESI-HRMS was also successfully applied to AFFF formulations and wastewater samples for PFAS profiling.
The second part investigates the aerobic transformation potentials of 6:2 FTCA and 5:3 FTCA in activated sludges and Rhodococcus jostii RHA1 . Notably, 6:2 FTCA was fluoride-releasing pathways, while 5:3 FTCA were removed without releasing free fluoride in both activated sludge and RHA1. A novel monosaccharide-assisted fluorine transfer pathway was identified and proved for 5:3 FTCA biotransformation in activated sludge. The impact of FTCAs on activated sludge was studied to discern the shifting of the microbial communities and species that may contribute to the FTCA defluorination. Several FTCA transformation products (TPs) by RHA1 were identified by non-target analysis. Glutamic acid was found conjugating in 6:2 FTCA TPs.
Last but not least, 7 consortia from diverse sources were enriched and trained for stably defluorination and FTCA removal. A phylogenetic profile of potential FTCAs degraders and FTCAs co-metabolizers were characterized by microbial community analysis. Three genera (Hyphomicrobium, Methylorubrum, and Achromobacter) and five genera (Phenylobacterium, Xanthobacter, Methylotenera, Pseudomonas, and Rhodanobacter) were found highly responsible for the removal of 6:2 FTCA and 5:3 FTCA, respectively.
Recommended Citation
Wu, Chen, "Biotransformation and biodefluorination of fluorotelomer carboxylic acids" (2022). Dissertations. 1849.
https://digitalcommons.njit.edu/dissertations/1849
