About

Nicole Fahrenfeld is a professor whose research group focuses on environmental science, microbial biology, and chemical engineering. Her work involves studying microbial communities and their interactions within environmental systems, with an emphasis on water quality, contamination, and sustainable practices. She leads a research group that includes postdoctoral scholars, graduate students, and undergraduates, all engaged in projects related to environmental microbiology and engineering. Her contributions include advancing understanding of microbial processes in environmental contexts and developing solutions for environmental challenges.

Research topics

• Environmental science
• Environmental chemistry
• Ecology
• Environmental engineering
• Chemistry
• Geology
• Medicine
• Engineering
• Oceanography
• Pathology
• Biology
• Geotechnical engineering

Selected publications

• Differential morphological and physicochemical responses of polyvinyl chloride and Polyamide-12 micro- and nanoplastics to Fenton oxidation

  The Science of The Total Environment · 2025-12-20 · 1 citations

  articleOpen access

  Oxidative aging can modify the physicochemical properties of micro- and nanoplastics (MNPs), altering their environmental behavior and potential biological interactions. In this study, we investigated how a hydroxyl radical–driven Fenton oxidation process affects the morphology, size distribution, and surface chemistry of polyvinyl chloride (PVC) and polyamide-12 (PA-12) MNPs using multimodal characterization. Oxidation caused extensive aggregation and surface restructuring in PVC, whereas PA-12 retained greater colloidal stability but showed clear evidence of surface oxidation. Both polymers exhibited increases in oxygen-containing functional groups, along with polymer-specific elemental loss consistent with dechlorination in PVC and amide degradation in PA-12. These transformations indicate that oxidative aging can generate nanoscale debris, increase surface reactivity, and shift particle behavior in ways relevant to environmental fate and human exposure pathways. The results emphasize the importance of including chemically aged MNPs, rather than only pristine particles, in studies examining transport, sorption, and toxicological potential, particularly in contexts where advanced oxidation treatments are used. Overall, this work highlights polymer-specific differences in oxidative transformation and provides a foundation for future studies that connect degradation chemistry with exposure and risk assessment. • PVC and PA-12 micro/nanoplastics were oxidized via Fenton reaction to mimic aging. • PVC aggregated and roughened, while PA-12 stayed well-dispersed after oxidation. • Oxidized PVC size rose from ~350 nm to ~800 nm, increasing polydispersity. • PVC chlorine decreased and PA-12 nitrogen decreased after oxidation. • FTIR showed hydroxyl, ether, and carbonyl group formation from backbone oxidation.

  PublisherDOI

• Polymer weathering under simulated solar radiation and comparison to stormwater and estuarine microplastics

  Chemosphere · 2025-04-25 · 3 citations

  articleOpen accessSenior authorCorresponding

  Accurate spectral identification of weathered plastics and analyses that provide insight into environmental degradation and age are desirable for source tracking and understanding hazards. The objectives of this study were to (1) evaluate the kinetics of spectral changes for lab-weathered polymers and compare to spectra from environmental microplastics (MPs), and (2) assess the accuracy of spectral databases in identifying weathered polymers. For objective 1, polyethylene (PE) and polypropylene (PP) fragments were exposed to simulated solar radiation in water for 90 days. FTIR spectra were collected periodically and degradation was quantified using carbonyl and hydroxyl bond indices. Significant linear increases in carbonyl indices for PP, but not PE, were observed as a function of exposure time. Spectra (via principal component analysis) and bond indices from lab-weathered polymers were then compared to environmental MPs collected from urban stormwater and the Delaware Bay estuary. Estuarine PP carbonyl and hydroxyl indices varied as a function of spectral collection mode (i.e., ATR vs. transmission) and by sampling site, potentially indicating the bond indices provide insight into sources/fate/transport of PP and are worthy of further study. In contrast, no significant differences were observed for PP in stormwater samples, possibly due to the close proximity of collection locations. PE exhibited non-linear trends in bond indices in the laboratory study and showed no significant association with sampling location in environmental samples, suggesting these indices may be less useful for PE degradation analysis. For objective 2, 14 different polymers, eight of which were polymer blends, were exposed to simulated solar radiation for up to 90 days, in dry and wet conditions. FTIR spectra were collected periodically and analyzed with two spectral identification software. OpenSpecy achieved an 88 % true positive rate compared to siMPle's 57 % at a 70 % hit quality threshold. Expanding reference libraries, to include weathered polymers and polymer blends, could improve spectral identification accuracy, and manual interpretation of FTIR spectra is recommended for low-confidence matches.

  PublisherDOI

• Corrigendum to ‘Microplastic concentration, characterization, and size distribution in the Delaware Bay estuary’ [Chemosphere 361 (2024) 142523]

  Chemosphere · 2025-04-10

  erratumSenior author
  PublisherDOI

• Differential Morphological and Physicochemical Responses of Polyvinyl Chloride and Polyamide-12 Micro- and Nanoplastics to Fenton Oxidation

  ChemRxiv · 2025-09-29

  article

  Oxidative aging of micro- and nanoplastics (MNPs) alters their physicochemical properties and may influence their environmental persistence and biological interactions. Here, we investigated the effects of Fenton oxidation on 5µm sized polyvinyl chloride (PVC) and polyamide-12 (PA-12) MNPs using a multimodal characterization approach. Particles were treated with a Fenton reagent mixture (1 mM FeSO₄, 10 mM H₂O₂) at 40 °C for 2 hours to simulate oxidative conditions relevant to advanced water treatment and processes. Helium Ion Microscopy revealed that pristine PVC particles were aggregated and spherical, while oxidized PVC exhibited extensive aggregation and surface roughening. In contrast, PA-12 maintained a largely dispersed morphology post-oxidation, with moderate increases in surface texture. Dynamic light scattering measurements showed that the hydrodynamic diameter of PVC increased from 300–400 nm (pristine) to 700–900 nm (oxidized), with polydispersity index broadening and a new minor population emerging at 80–90 nm, indicating aggregation and polymer fragmentation. Oxidized PA-12 showed a stable size profile with minor peak shifts. X-ray photoelectron spectroscopy revealed a 150.0% increase in surface oxygen on PVC (from 8.2% to 20.5%) and a 126.5% increase on PA-12 (from 11.3% to 25.6%). PVC showed a 17.1% reduction in chlorine and PA-12 experienced a 62.9% nitrogen loss, consistent with dechlorination and amide degradation. Attenuated total reflectance Fourier-transform infrared spectroscopy confirmed these chemical transformations, showing new bands for hydroxyl (O–H stretch, ~3400 cm⁻¹), C–O (1000–1200 cm⁻¹), and possible CO₂-related species (~2300 cm⁻¹), alongside diminished amide II signals in oxidized PA-12. These findings demonstrate that Fenton oxidation induces significant morphological and chemical transformation in PVC and PA-12, with PVC exhibiting greater aggregation and surface restructuring, while PA-12 maintains greater colloidal stability but undergoes substantial surface oxidation and nitrogen loss. These oxidative transformations may enhance the surface reactivity, inflammatory potential, bioavailability, and ultimately influence the biological uptake, fate, and transport of MNPs in human exposure pathways, particularly through inhalation or ingestion. Our findings highlight the need to consider oxidation processes, such as those used in advanced water and wastewater treatment, in health risk assessments of plastic particles in both ambient and engineered settings.

  PublisherDOI

• Microplastic concentration, characterization, and size distribution in the Delaware Bay estuary

  Chemosphere · 2024-06-03 · 19 citations

  articleSenior authorCorresponding
  PublisherDOI

• Stormwater microplastic polymer types, particle sizes, and impact of techniques

  Open MIND · 2024-09-01

  articleSenior author

  Stormwater runoff is a pathway of entry for microplastics (MPs) into aquatic ecosystems. Understanding not only microplastic concentrations but also size distribution, morphology, and polymer profiles is desirable. A challenge is that subsampling is often required for analysis of environmental samples and the impact of subsampling on estimated MP concentrations and polymer diversity is poorly characterized. The objectives of this study were to (1) determine MP size, morphology, chemical composition, and loading across urban storm events and (2) the impact of subsampling on these observations for MP. Sampling was performed in two campaigns: the first based on NOAA methods with a wet peroxide oxidation and density separation and the second based on ASTM methods with a wet peroxide oxidation and cellulose digestion. MP analysis was performed via attenuated total reflectance (ATR) FTIR and/or FTIR-microscopy. MP concentrations (MP/L) were 86 ± 107 for 63-250 µm, 0.68 ± 0.36 for 250-500 µm, and 0.4 ± 0.24 for 500-2000µm or 0.99 ± 1.10 MP/L for 500-1000 μm and 0.41±0.30 MP/L for the 1000-5000 μm size ranges. Concentrations were comparable or greater and polymer richness was greater using the ASTM methods and larger sample volume. Varying the number of particles subsampled demonstrated the coefficient of variation for concentration (standard deviation/mean) for most samples was Also see: https://micro2024.sciencesconf.org/559566/document

  DOI

• Antibiotic Resistant Bacteria and Genes in Bioaerosols at Wastewater Treatment Plant: Should I Be Worried?

  Proceedings of the Water Environment Federation · 2024-10-01

  article1st authorCorresponding
  PublisherDOI

• Stormwater runoff microplastics: Polymer types, particle size, and factors controlling loading rates

  The Science of The Total Environment · 2024-04-16 · 19 citations

  articleOpen accessSenior authorCorresponding

  Stormwater runoff is a pathway of entry for microplastics (MPs, plastics <5 mm) into aquatic ecosystems. The objectives of this study were to determine MP size, morphology, chemical composition, and loading across urban storm events. Particles were extracted from stormwater samples collected at outfall locations using wet peroxide oxidation and cellulose digestion followed by analysis via attenuated total reflectance (ATR) FTIR. Concentrations observed were 0.99 ± 1.10 MP/L for 500–1000 μm and 0.41 ± 0.30 MP/L for the 1000–5000 μm size ranges. Seventeen different polymer types were observed. MP particle sizes measured using a FTIR-microscope camera indicated non-target size particles based on sieve-size classification, highlighting a potential source of error in studies reporting concentration by size class. A maximum MP load of 38.3 MP/m2 of upstream catchment was calculated. MP loadings had moderate correlations with both rainfall accumulation and intensity (Kendall τ = 0.54 and 0.42, respectively, both p ≤ 0.005). First flush (i.e. rapid wash-off of pollutants from watershed surfaces during rainfall early stages) was not always observed, and antecedent dry days were not correlated with MP abundance, likely due to the short dry periods between sampling events. Overall, the results presented provide data for risk assessment and mitigation strategies.

  PublisherDOI

• Lessons Learned from a Cross-Institutional Environmental Engineering and Science Faculty-to-Faculty Mentoring Program

  Environmental Engineering Science · 2024-01-11 · 2 citations

  article1st authorCorresponding

  A cross-institutional faculty mentoring program was initiated by the Association of Environmental Engineering and Science Professors to support junior faculty. Across three cohorts, 117 junior-faculty mentees and 68 senior-faculty mentors have participated in this program. The second cohort was asked to complete a written survey to assess the program through collection of quantitative and qualitative data. Mentees reported that university type, personality, research area, and parental status were important characteristics in their mentors; however, the mentors had less specific preferences. Both mentees and mentors generally agreed upon the importance of various areas of growth and satisfaction with the program. Suggestions for future iterations of the program included additional program structure.

  PublisherDOI

• Stormwater microplastic polymer types, particle sizes, and impact of techniques

  Zenodo (CERN European Organization for Nuclear Research) · 2024-09-01

  articleOpen accessSenior author

  Stormwater runoff is a pathway of entry for microplastics (MPs) into aquatic ecosystems. Understanding not only microplastic concentrations but also size distribution, morphology, and polymer profiles is desirable. A challenge is that subsampling is often required for analysis of environmental samples and the impact of subsampling on estimated MP concentrations and polymer diversity is poorly characterized. The objectives of this study were to (1) determine MP size, morphology, chemical composition, and loading across urban storm events and (2) the impact of subsampling on these observations for MP. Sampling was performed in two campaigns: the first based on NOAA methods with a wet peroxide oxidation and density separation and the second based on ASTM methods with a wet peroxide oxidation and cellulose digestion. MP analysis was performed via attenuated total reflectance (ATR) FTIR and/or FTIR-microscopy. MP concentrations (MP/L) were 86 ± 107 for 63-250 µm, 0.68 ± 0.36 for 250-500 µm, and 0.4 ± 0.24 for 500-2000µm or 0.99 ± 1.10 MP/L for 500-1000 μm and 0.41±0.30 MP/L for the 1000-5000 μm size ranges. Concentrations were comparable or greater and polymer richness was greater using the ASTM methods and larger sample volume. Varying the number of particles subsampled demonstrated the coefficient of variation for concentration (standard deviation/mean) for most samples was Also see: https://micro2024.sciencesconf.org/559566/document

  PublisherDOI

Recent grants

• CAREER: Controls on the host and transfer of hazardous genes

  NSF · $551k · 2019–2026

• UNS: Dynamics of Microbial Agents in Sewer Systems and Wet Weather Flow

  NSF · $369k · 2016–2021

• Collaborative Research: Terrestrial microplastic pollution: understudied sources, source tracking, and citizen science

  NSF · $210k · 2019–2025

Frequent coauthors

• Alessia Eramo

  Rutgers, The State University of New Jersey

  21 shared

• William R. Morales Medina

  Rutgers, The State University of New Jersey

  20 shared

• Amy Pruden

  Virginia Tech

  8 shared

• Georgia Arbuckle‐Keil

  Rutgers, The State University of New Jersey

  8 shared

• Sophia Blanc

  5 shared

• A.S. Deshpande

  5 shared

• Melissa Tu

  4 shared

• Sara Gallego

  Agroécologie

  4 shared