Browsing by Subject "PFAS"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Enhanced Adsorption of Perfluoro Alkyl Substances in Groundwater; Development of a Novel In-Situ Groundwater Remediation Method
    (2019-03) Aly, Yousof
    Per- and poly- fluoro alkyl substances (PFAS) are a class of highly persistent, toxic and bio-accumulative anthropogenic chemicals. Due to their wide range of application including non-stick cookware, water and stain resistant coatings, chrome plating and aqueous film forming foams (AFFF), the potential exposure pathways for humans are numerous. AFFF use and subsequent release often leads to groundwater contamination, which poses a risk for human health. Currently, there is a wide array of remediation methods capable of treating PFAS contamination. These pump and treat methods, however, face many limitations including inhibitory costs, harmful byproducts, feasibility and ease of deployment. An in place (in-situ) remediation method holds the advantage of being more cost-effective, easier to deploy and cope with post remediation. Current in-situ PFAS remediation is limited. This thesis explores the amendment of a natural soil by two cationic coagulants (polydiallyldimethylammonium chloride [PDM] and poly(epichlorohydrin-dimethyl) amine [PA]) in order to increase adsorption, and thus retention, of PFAS in groundwater, and possibly sequestering a plume. PFAS adsorption onto natural soil was increased significantly based on batch and column tests. The increase in PFAS adsorption was not due solely to increases in organic matter from the addition of adsorption enhancers. Therefore, the mechanism of PFAS-enhancer interaction was explored. 19Fluorine-NMR spectra indicated that perfluoro carboxylates (PFCAs) were strongly bound in solution when in a solution of PA and PDM. The use of a PFOS ion specific electrode (ISE) found the same result. Given that this is a proposed in-situ remediation method; the long term behavior of PFAS-enhancer binding interactions is an important question that needs answering. Weathering and biodegradation by bacteria native to natural soil were not capable of degrading PA and PDM. However, activated sludge was able to degrade enhancers. There was little PFAS release detected indicating again that PFAS are strongly bound in solution and that this binding interaction potentially reduces bioavailability of enhancers when bound with PFAS.
  • Thumbnail Image
    Item
    PFAS Forum: Cleanup and Upcoming Regulations: A Summary Report
    (Airport Technical Assistance Program (AirTAP) (Center for Transportation Studies, University of Minnesota), 2022-04) Airport Technical Assistance Program (AirTAP)
    Efforts to prevent and clean up PFAS discharges have been accelerating in recent years; state and federal regulatory agencies have been instituting policies that prioritize PFAS mitigation and require accountability from facilities that use the chemical. Because of their firefighting systems, airports will be included in these new policies. In practice, however, removing PFAS foams from airports and monitoring for contamination are logistically and financially difficult. To address these challenges, a forum held on April 5, 2022, in Rochester, Minnesota, gathered environmental experts, state and federal regulatory officials, and airport managers to discuss how best to transition away from PFAS. The event was sponsored by the MnDOT Office of Aeronautics and administered by the Airport Technical Assistance Program (AirTAP) at the U of M Center for Transportation Studies, in partnership with Minnesota's Local Air Service Action Committee (LASAC).
  • Thumbnail Image
    Item
    Potential Impacts of Per- and Polyfluoroalkyl Substance Contamination in Laboratory Materials and Model Organisms on Laboratory-based Studies
    (2021-12) Rushing, Julianna
    Per- and polyfluoroalkyl substances are persistent chemicals that present risks to human environmental health as a result of their ubiquitous nature. These compounds also impact laboratory based exposure and toxicology experiments through PFAS contamination in common materials used for aquatic laboratory exposure experiments. This thesis reviews literature surrounding PFAS bioaccumulation in aquatic organisms in laboratory exposure studies using several measures such as the bioaccumulation factor, bioconcentration factor, biomagnification factor, rate of uptake, and elimination rate. Lack of standardization in how the bioaccumulation factors were calculated creates challenges in statistical comparisons. This thesis also investigates potential PFAS contamination and impacts on aquatic laboratory based exposure experiments in habitat materials, fish feed, and aquaculture fish. Results suggest that PFAS contamination is present in common fish feed and can also be found in aquaculture fish. Unaccounted PFAS contamination in bioaccumulation and toxicity studies could confound results and ultimately influence environmental health recommendations.
  • Thumbnail Image
    Item
    Utilizing Waste Material From Minnesota For Stormwater Management Purposes
    (2024-05) Amoateng, Godbless
    Minnesota's mineral, forestry, agriculture, and industrial activities generate substantial by-products and waste. Strategies to reuse or recycle these can reduce landfill waste, enhance public health, conserve resources, and cut costs and emissions. Building on the frameworks by Johnson et al. (2017), Saftner et al. (2019), and Saftner et al. (2022), this project extended its scope across Minnesota to include materials like dredge sediment from Mississippi River, RCA (recycled concrete aggregate) and VersaLime. Researchers identified, selected, and characterized various waste, by-products, and commercial materials statewide and tested engineered soil mixes for roadway foundations, assessing their stormwater retention and support for native plants. Laboratory methods characterized these mixes, which were implemented and evaluated in situ. A preliminary environmental life cycle assessment was also conducted, quantifying the environmental impacts of the engineered soil mixtures. Results were compiled into a design guide for the Minnesota Department of Transportation (MnDOT) engineers.