Making waves: The progress of management strategies for cleaning and rinsing of PFAS-impacted fire suppression systems.

Aircraft rescue firefighting (ARFF) vehicles often contain residual levels of per- and polyfluoroalkyl substances (PFAS) due to the global use of legacy and current use of aqueous film-forming foam (AFFF) for class B firefighting. However, numerous countries are transitioning to fluorine-free foam (F3) alternatives. There is, thus, an urgent need to develop efficient methods to rinse and clean interior ARFF surfaces thereby avoiding expensive replacement costs and preventing further discharge of PFAS to the environment.

Flexural rigidity of hawkmoth antennae depends on the bending direction.

To probe its environment, the flying insect controllably flexes, twists, and maneuvers its antennae by coupling mechanical deformations with the sensory output. We question how the materials properties of insect antennae could influence their performance. A comparative study was conducted on four hawkmoth species: Manduca sexta, Ceratomia catalpae, Manduca quinquemaculata, and Xylophanes tersa.

Application of Gaussian mixture models to quantify the upper background threshold for perfluorooctane sulfonate (PFOS) in U.S. surface soil.

Studies on the occurrence and environmental distribution of per- and polyfluoroalkyl substances (PFAS) have clearly demonstrated their ubiquity in surface soil as a result of historic and ongoing emissions from various manufacturing and industrial activities worldwide. Given global efforts to characterize and mitigate risk from point source-impacted sites, there is, thus, an urgent need to quantify nonpoint source threshold concentrations (i.e.

A review of innovative approaches for onsite management of PFAS-impacted investigation derived waste.

The historic use of aqueous film-forming foam (AFFF) has led to widespread detection of per- and polyfluoroalkyl substance (PFAS) in groundwater, soils, sediments, drinking water, wastewater, and receiving aquatic systems throughout the United States (U.S.).

Fluorine-Free Extinguishing of a Hydrocarbon Pool Fire with a Suspension of Glass Bubbles Grafted with Nanoscale Polymer Layers.

The current most efficient solution to extinguish liquid hydrocarbon (class B) pool fires involves fire-fighting foams containing fluorinated surfactants. However, fluorocarbon surfactants are unsafe due to their environmental persistence and negative toxicological/bioaccumulative impact. To this end, we show that fluorine-free aqueous suspensions of Glass Bubbles (GB) modified with hydrophilic polymer grafted layers can efficiently extinguish hydrocarbon pool fires.

Biotechnology to reduce logistics burden and promote environmental stewardship for Air Force civil engineering requirements.

This review provides discussion of advances in biotechnology with specific application to civil engineering requirements for airfield and airbase operations. The broad objectives are soil stabilization, waste management, and environmental protection. The biotechnology focal areas address (1) treatment of soil and sand by biomineralization and biopolymer addition, (2) reduction of solid organic waste by anaerobic digestion, (3) application of microbes and higher plants for biological processing of contaminated wastewater, and (4) use of indigenous materials for airbase construction and repair.

Polymeric Interlayer Strengthening with Boron Neutron Capture Radiation Treatment for Laminated Glass.

Polymer interlayer materials are utilized in laminated glass systems to provide increased resilience from blast incidents. The polymer chains within the interlayer material can benefit from material modifications that increase the crosslinking between adjacent chains. One theorized method of targeted crosslinking is made possible through a boron neutron capture process.

Mechanical Behavior of Laminated Glass Polymer Interlayer Subjected to Environmental Effects.

It is known that weathering action has a significant impact on polymer interlayer materials, and previous studies have evaluated certain aspects of weathering such as temperature, humidity, and UV radiation. In this paper, the environmental effect on the mechanical properties of the virgin and cured/processed polymer interlayer materials will be studied. Three polymer interlayer materials were focused, i.

Assessment of PFAS in collocated soil and porewater samples at an AFFF-impacted source zone: Field-scale validation of suction lysimeters.

Per- and polyfluoroalkyl substances (PFAS) measurable in soil porewater authoritatively represent the mobile mass fraction critical to accurate assessment of leaching from source zones. This study evaluated PFAS occurrence in lysimeter-collected porewater samples for two depth intervals at a decades-old aqueous film-forming foam (AFFF)-impacted field site quarterly for a year. Notably, site-wide Log (∑PFAS) concentrations did not significantly differ among sampling events despite highly variable sample yields due to a heterogeneous and dynamic soil moisture regime.

Field-Scale Demonstration of PFAS Leachability Following In Situ Soil Stabilization.

A field-scale validation is summarized comparing the efficacy of commercially available stabilization amendments with the objective of mitigating per- and polyfluoroalkyl substance (PFAS) leaching from aqueous film-forming foam (AFFF)-impacted source zones. The scope of this work included bench-scale testing to evaluate multiple amendments and application concentrations to mitigate PFAS leachability and the execution of field-scale soil mixing in an AFFF-impacted fire-training area with nearly 2.5 years of post-soil mixing monitoring to validate reductions in PFAS leachability.

Environmental Sources, Chemistry, Fate, and Transport of Per- and Polyfluoroalkyl Substances: State of the Science, Key Knowledge Gaps, and Recommendations Presented at the August 2019 SETAC Focus Topic Meeting.

A Society of Environmental Toxicology and Chemistry (SETAC) Focused Topic Meeting (FTM) on the environmental management of per- and polyfluoroalkyl substances (PFAS) convened during August 2019 in Durham, North Carolina (USA). Experts from around the globe were brought together to critically evaluate new and emerging information on PFAS including chemistry, fate, transport, exposure, and toxicity. After plenary presentations, breakout groups were established and tasked to identify and adjudicate via panel discussions overarching conclusions and relevant data gaps.

The Case for Direct Measures of Soil-to-Groundwater Contaminant Mass Discharge at AFFF-Impacted Sites.

Many entities around the world are initiating massive field campaigns to characterize the environmental distribution of per- and polyfluoroalkyl substances (PFAS), particularly at aqueous film-forming foam (AFFF) impacted sites where historic point-source discharges occurred at the ground surface. Concurrently, many regulatory agencies are publishing criteria used in practice to define the "nature and extent" of PFAS-impacted environmental media. Specific to the soil-to-groundwater transport pathway protective of the groundwater ingestion end point, these soil criteria (or screening values) are to date exclusively based on the traditional approach used for hydrophobic organics with a number of simplifying assumptions.

Investigating surface binding effects: antibacterial efficacy of bound 8-hydroxyquinoline against Staphylococcus aureus and Escherichia coli.

Aims: To investigate the binding of the antimicrobial compound 8-hydroxyquinoline (8HQ) to a material interface and to determine whether immobilization affects the antibacterial efficacy.

Methods And Results: The 8HQ derivative 5-carboxy-8-hydroxyquinoline (5C8HQ) was attached to silica beads through amide bond coupling at the carboxyl moiety of 5C8HQ. Attachment of 5C8HQ was confirmed using a combination of mass spectrometry, thermogravimetric analysis, colorimetric testing and Soxhlet extraction.

PFAS concentrations in soils: Background levels versus contaminated sites.

Per- and polyfluoroalkyl substances (PFAS) are contaminants of critical concern due to their persistence, widespread distribution in the environment, and potential human-health impacts. In this work, published studies of PFAS concentrations in soils were compiled from the literature. These data were combined with results obtained from a large curated database of PFAS soil concentrations for contaminated sites.

United states department of defense (DoD) real property repair, alterations, maintenance, and construction project contract data: 2009-2020.

Nearly one-half of all construction projects exceed planned costs and schedule, globally [1]. Owners and construction managers can analyze historical project performance data to inform cost and schedule overrun risk-reduction strategies. Though, the majority of open-source project datasets are limited by the number of projects, data dimensionality, and location.

Rapid Removal of Poly- and Perfluorinated Compounds from Investigation-Derived Waste (IDW) in a Pilot-Scale Plasma Reactor.

A pilot-scale plasma reactor installed into an 8 × 20 ft mobile trailer was used to rapidly and effectively degrade poly- and perfluoroalkyl substances (PFAS) from liquid investigation-derived waste (IDW; development and purge water from monitoring wells) obtained from 13 different site investigations at Air Force installations. In the raw water, numerous PFAS were detected in a wide concentration range (∼10-10 ng/L; total oxidizable precursors (TOP) ∼10-10 ng/L, total fluorine by combustion ion chromatography ∼10 to 5 × 10 ng F/L). The concentration of total PFAS (12 perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFSAs)) in the 13 samples ranged between 2.

Effect of anaerobic digester inoculum preservation via lyophilization on methane recovery.

A robust anaerobic digestion (AD) inoculum is key to a successful digestion process by providing the abundant bacteria needed for converting substrate to useable methane (CH). While transporting digester contents from one AD to another for digester startup has been the norm, transportation costs are high, and it is not feasible to transport wet inoculum to remote locations. In this study, the impact of preservation of AD inoculum via lyophilization was investigated for the purposes of digester startup and restabilization.

Enhanced reductive dechlorination of trichloroethene in an acidic DNAPL impacted aquifer.

A field pilot test was conducted using an emulsified vegetable oil (EVO) and colloidal magnesium hydroxide [Mg(OH)] formulation to enhance reductive dechlorination of dense non-aqueous phase liquid (DNAPL) trichloroethene (TCE) in an acidic (pH < 4), heterogeneous aquifer. The field test consisted of i) a single well injection test to evaluate Mg(OH) distribution and ii) installation of two EVO-Mg(OH) permeable reactive barriers (PRBs; PRB-1 & PRB-2) at varying distances downgradient of the DNAPL source area. Distribution of Mg(OH) was observed up to 2.

Partitioning of poly- and perfluoroalkyl substances from soil to groundwater within aqueous film-forming foam source zones.

Metadata from on-going site investigations at U.S. Air Force sites impacted by Aqueous Film-Forming Foam (AFFF) were used to evaluate primary factors that affect transport of poly- and perfluoroalkyl substances (PFAS) within source zones.

In situ bioremediation of 1,2-dibromoethane (EDB) in groundwater to part-per-trillion concentrations using cometabolism.

1,2-Dibromoethane (ethylene dibromide; EDB) is a probable human carcinogen that was historically added to leaded gasoline as a scavenger to prevent the build-up of lead oxide deposits in engines. Studies indicate that EDB is present at thousands of past fuel spill sites above its stringent EPA Maximum Contaminant Level (MCL) of 0.05 μg/L.

Microwave Enhancement of Autocatalytic Growth of Nanometals.

The desire for designing efficient synthetic methods that lead to industrially important nanomaterials has led a desire to more fully understand the mechanism of growth and how modern synthetic techniques can be employed. Microwave (MW) synthesis is one such technique that has attracted attention as a green, sustainable method. The reports of enhancement of formation rates and improved quality for MW driven reactions are intriguing, but the lack of understanding of the reaction mechanism and how coupling to the MW field leads to these observations is concerning.

1,4-Dioxane drinking water occurrence data from the third unregulated contaminant monitoring rule.

This study examined data collected from U.S. public drinking water supplies in support of the recently-completed third round of the Unregulated Contaminant Monitoring Rule (UCMR3) to better understand the nature and occurrence of 1,4-dioxane and the basis for establishing drinking water standards.