Document Type
Dissertation
Date of Award
8-31-2022
Degree Name
Doctor of Philosophy in Environmental Engineering - (Ph.D.)
Department
Civil and Environmental Engineering
First Advisor
Lucia Rodriguez-Freire
Second Advisor
Jay N. Meegoda
Third Advisor
Taha F. Marhaba
Fourth Advisor
Wen Zhang
Fifth Advisor
Daniel E. Bunker
Sixth Advisor
Mengyan Li
Seventh Advisor
James F. White Jr.
Abstract
This dissertation is a comprehensive study of the mechanisms controlling per- and polyfluoroalkyl substances (PFAS) transformations and their transport in the environment, PFAS effects on plant growth and microbial community changes are critical in preventing or attenuating PFAS mobility and in predicting potential human exposure routes. The overarching goal of this project is to evaluate the distribution of PFAS in plants exposed to mixed contaminants, and their effects on the rhizosphere and in planta microbial community This main goal is achieved through the following research objectives: (1) Field investigation of PFAS contamination in New Jersey, (2) PFAS partition in soil and water, (3) PFAS partition in plants by hydroponic experiments using Arabidopsis thaliana, (4) Role of microbial plant endophytes on PFAS toxicity and uptake by plants in vitro experiment, (5) Role of PFAS plant resistome system.
For the first research objective, water, sediments, and plant samples are collected at four locations from north to south New Jersey. The highest water concentration is found in a spring downstream of a paint sludge disposal area (perfluorooctane sulfonic acid, PFOS 445 ng/L) near a superfund site, the highest sediment concentration is found near a landfill (PFOS 3.17-5.79 ng/g). and the highest plant concentration was found on the bank of a lake tributary (PFOS 22.79-24.90 ng/g) adjacent to an aqueous film-forming foam (AFFF) site. The concentrations of PFAS were analyzed to determine the distribution of PFAS in environmental compartments. Among all PFAS analyzed, PFOS is found the dominant PFAS species in soil, sediment, and plant samples.
The second research project investigates PFAS partition between soil and water by laboratory experiments by comparing the sorption capacities of perfluorooctanoic acid (PFOA) and PFOS on soils with different organic matter content, clay contents and soil type. It was found that more PFOS absorb onto soil than PFOA. More importantly, soil organic matter plays a more important role than clay for PFAS sorption.
The other three research objectives focus on PFAS partition in plants. Hydroponic experiments using Arabidopsis thaliana were conducted to assess the mechanisms of PFAS translocation; The result shows PFOA prefers accumulation in shoots, PFOS prefers accumulation in roots, and a direct relationship between PFAS solution concentration and plant uptake is observed. In Vitro experiments with Poa reptans seedlings with and without microbial endophytes are used to evaluate the plant response to PFAS toxicity and microbe interaction with roots, PFAS exposure resulted in damage to the root hairs and lack of internal cyclosis only in the absence of bacteria, and removal of root microorganisms significantly increases PFAS uptake by the plant. The last experiment analyzed the plant resistome system of Lemna minor after exposure to PFAS, all three plant experiments show that PFAS phytoaccumulation affects plant and microbiome health and changes the microbiome communities.
The ultimate goal of this project is to identify the main mechanisms that control PFAS transport and uptake fate in the environment, and to prevent human exposure, by limiting PFAS transport in the environment and to implement of remediation strategies to remove PFAS from contaminated areas.
Recommended Citation
Wang, Boran, "Per- and polyfluoroalkyl substances (pfas) distribution in contaminated soils and impact on rhizosphere and plant microbiota" (2022). Dissertations. 1925.
https://digitalcommons.njit.edu/dissertations/1925
