Chronic Exposure to a PFAS Mixture Resembling AFFF-Impacted Surface Water Decreases Body Size in Northern Leopard Frogs ().

Per- and polyfluoroalkyl substances (PFAS) occur in the environment as mixtures, yet mixture toxicity remains poorly understood. Aqueous film-forming foams (AFFFs) are a common source of PFAS. Our objective was to examine chronic effects of a complex PFAS mixture on amphibian growth and development.

Comparative Toxicity of Aquatic Per- and Polyfluoroalkyl Substance Exposure in Three Species of Amphibians.

Per- and polyfluoroalkyl substances (PFAS) are contaminants of concern due to their widespread occurrence in the environment, persistence, and potential to elicit a range of negative health effects. Per- and polyfluoroalkyl substances are regularly detected in surface waters, but their effects on many aquatic organisms are still poorly understood. Species with thyroid-dependent development, like amphibians, can be especially susceptible to PFAS effects on thyroid hormone regulation.

Dietary exposure and accumulation of per- and polyfluoroalkyl substances alters growth and reduces body condition of post-metamorphic salamanders.

Per- and polyfluoroalkyl substances (PFAS) are contaminants of concern due to their persistence, potential to bioaccumulate, and toxicity. While dietary exposure is the primary route of exposure for terrestrial species, data on dietary PFAS uptake and adverse effects are largely restricted to mammals. As such, substantial data gaps exist that hinder ecological risk assessment, including environmentally relevant exposure levels and taxa.

Reductive transformation of perfluorooctanesulfonate by nNiFe-Activated carbon.

Degradation of linear (L) and branched (Br) perfluorooctanesulfonate (PFOS) using nNiFe° particles supported on activated carbon (AC) and heat is demonstrated for the first time and with several lines of evidence. At 60 °C, PFOS degradation plateaued at 50 ± 6%, while at 50 °C, 94 ± 4.1 % PFOS transformed.

Sublethal Effects of Dermal Exposure to Poly- and Perfluoroalkyl Substances on Postmetamorphic Amphibians.

Studies of the toxicity of poly- and perfluoroalkyl substances (PFAS) on amphibians, especially after metamorphosis, are limited. We examined effects of dermal PFAS exposure (30 d) on survival and growth of juvenile American toads (Anaxyrus americanus), eastern tiger salamanders (Ambystoma tigrinum), and northern leopard frogs (Rana pipiens). Chemicals included perfluorooctanoic acid, perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and 6:2 fluorotelomer sulfonate (6:2 FTS) at 0, 80, 800, or 8000 ppb on a moss dry weight basis.

Chronic Per-/Polyfluoroalkyl Substance Exposure Under Environmentally Relevant Conditions Delays Development in Northern Leopard Frog (Rana pipiens) Larvae.

Per-/polyfluoroalkyl substances (PFAS) are pervasive in aquatic systems globally and capable of causing detrimental effects on human and wildlife health. However, most studies are conducted under artificial conditions that are not representative of environmental exposures. Environmental exposures are characterized by multiple routes of exposure, low aquatic PFAS levels, and greater environmental variability than laboratory tests.

Perfluorooctane Sulfonate (PFOS) Produces Dopaminergic Neuropathology in Caenorhabditis elegans.

Perfluorooctane sulfonate (PFOS) has been widely utilized in numerous industries. Due to long environmental and biological half-lives, PFOS is a major public health concern. Although the literature suggests that PFOS may induce neurotoxicity, neurotoxic mechanisms, and neuropathology are poorly understood.

Per- and polyfluoroalkyl substances in commercially available biosolid-based products: The effect of treatment processes.

Per- and polyfluoroalkyl substances (PFAS) have been used in a variety of consumer and industrial products and are known to accumulate in sewage sludge due to sorption and their recalcitrant nature. Treatment processes ensure safe and high-quality biosolids by reducing the potential for adverse environmental impacts such as pathogen levels; however, they have yet to be evaluated for their impact on the fate of PFAS. The objective of this study was to compare PFAS concentrations in four commercially available biosolid-based products that received different types of treatments: heat treatment, composting, blending, and thermal hydrolysis.

Developmental exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) selectively decreases brain dopamine levels in Northern leopard frogs.

Per- and polyfluoroalkyl substances (PFAS) are synthetic compounds that are a major public health concern due to widespread use, long environmental and biological half-lives, detection in most human plasma samples, and links to multiple adverse health outcomes. The literature suggests that some PFAS may be neurotoxic. However, there are major gaps in the literature with respect to how environmentally-relevant doses during development may influence the nervous system.

Larval amphibians rapidly bioaccumulate poly- and perfluoroalkyl substances.

Poly- and perfluoroalkyl substances (PFAS) are ubiquitous contaminants that can bioaccumulate in aquatic taxa. Amphibians are particularly vulnerable to contaminants and sensitive to endocrine disruptors during their aquatic larval stage. However, few studies have explored PFAS uptake rates in amphibians, which is critical for designing ecotoxicology studies and assessing the potential for bioaccumulation.

Alternate Reductants with VB12 to Transform C8 and C6 Perfluoroalkyl Sulfonates: Limitations and Insights into Isomer-Specific Transformation Rates, Products and Pathways.

Previous studies evaluating Vitamin B12 (VB12) with Ti(III)-citrate for potential use in in situ remediation of perfluorooctanesulfonate (PFOS) found that linear (L)-PFOS was unaltered. We explored if alternate reductants could overcome this limitation with a primary focus on nanoscale zerovalent zinc (nZn). Transformation over time with VB12-nZn was quantified at 22, 70, and 90 °C for PFOS, at 70 °C for perfluorohexanesulfonate (PFHxS), and VB12-nFe and VB12-Pd/nFe at 70 °C for PFOS.

Comparative analytical and toxicological assessment of methylcyclohexanemethanol (MCHM) mixtures associated with the Elk River chemical spill.

On January 9, 2014, a chemical mixture containing crude methylcyclohexanemethanol (MCHM) contaminated the water supply of Charleston, West Virginia. Although the mixture was later identified as a mix of crude MCHM and stripped propylene glycol phenyl ethers, initial risk assessment focused on 4-MCHM, the predominant component of crude MCHM. The mixture's exact composition and the toxicity differences between 4-MCHM, crude MCHM, and the tank mixture were unknown.

Gonadal intersex in smallmouth bass Micropterus dolomieu from northern Indiana with correlations to molecular biomarkers and anthropogenic chemicals.

Over the past decade, studies have shown that exposure to endocrine disrupting chemicals (EDCs) can cause gonadal intersex in fish. Smallmouth bass (Micropterus dolomieu) males appear to be highly susceptible to developing testicular oocytes (TO), the most prevalent form of gonadal intersex, as observed in various areas across the U.S.

Mixture toxicity of phostebupirim and cyfluthrin: Species-specific responses.

Currently, the potential impact of insecticide mixtures to nontarget organisms is largely unknown, and additional study is needed. The present study investigated the mixture toxicity of the organophosphate insecticide phostebupirim and the pyrethroid insecticide cyfluthrin using 4 nontarget species including Daphnia magna, Hyalella azteca, Pimephales promelas (fathead minnow), and Danio rerio (zebrafish). For each species, the toxicity of equipotent mixtures was compared with the expected toxicity estimated using the independent action (IA) and concentration addition (CA) models.

A simultaneous extraction method for organophosphate, pyrethroid, and neonicotinoid insecticides in aqueous samples.

A method was developed for the extraction and analysis of 2 organophosphate, 8 pyrethroid, and 5 neonicotinoid insecticides from the same water sample. A salted liquid-liquid extraction (LLE) was optimized with a solid-phase extraction (SPE) step that separated the organophosphates (OPs) and pyrethroids from the neonicotinoids. Factors that were optimized included volume of solvent and amount of salt used in the LLE, homogenization time for the LLE, and type and volume of eluting solvent used for the SPE.

Fate and effects of clothianidin in fields using conservation practices.

Despite the extensive use of the neonicotinoid insecticide clothianidin, and its known toxicity to beneficial insects such as pollinators, little attention has been given to its fate under agricultural field conditions. The present study investigated the fate and toxicity of clothianidin applied every other year as a corn seed-coating at 2 different rates, 0.25 mg/seed and 0.

Assessing the fate and effects of an insecticidal formulation.

A 3-yr study was conducted on a corn field in central Illinois, USA, to understand the fate and effects of an insecticidal formulation containing the active ingredients phostebupirim and cyfluthrin. The objectives were to determine the best tillage practice (conventional vs conservation tillage) in terms of grain yields and potential environmental risk, to assess insecticidal exposure using concentrations measured in soil and runoff water and sediments, to compare measured insecticidal concentrations with predicted concentrations from selected risk assessment exposure models, and to calculate toxicity benchmarks from laboratory bioassays performed on reference aquatic and terrestrial nontarget organisms, using individual active ingredients and the formulation. Corn grain yields were not significantly different based on tillage treatment.

Development of solid-phase microextraction to study dissolved organic matter--polycyclic aromatic hydrocarbon interactions in aquatic environment.

Solid-phase microextraction coupled with gas chromatography and mass spectrometry (SPME-GC-MS) was developed for the study of interactions between polycyclic aromatic hydrocarbons (PAHs) and dissolved organic matter (DOM). After the determination of the best conditions of extraction, the tool was applied to spiked water to calculate the dissolved organic carbon water distribution coefficient (K(DOC)) in presence of different mixtures of PAHs and Aldrich humic acid. The use of deuterated naphthalene as internal standard for freely dissolved PAH quantification was shown to provide more accuracy than regular external calibration.

Ecological bioavailability of permethrin and p,p'-DDT: toxicity depends on type of organic matter resource.

Hydrophobic organic contaminants readily partition from aqueous to organic phases in aquatic systems with past research largely focusing on sediment. However, within many aquatic systems, matrices such as leaf material and detritus are abundant and ecologically important, as they may represent a primary exposure route for aquatic invertebrates. The objectives of the present study were to examine partitioning and toxicity to Hyalella azteca among permethrin and p,p'-DDT contaminated sediment, leaf, and a sediment-leaf mixture.

Separation and identification of smokeless gunpowder additives by capillary electrochromatography.

This paper details a method for the separation and identification of fourteen organic compounds commonly found as constituents in commercial smokeless powders using a hexyl acrylate-based porous monolith. Capillary electrochromatography (CEC) coupled to UV and time of flight-mass spectrometry (TOF-MS) methods were both explored. The CEC-UV method provides an effective and efficient method for the detection of all components in the additive package of the powder.

Rapid and specific detection of urea nitrate and ammonium nitrate by electrospray ionization time-of-flight mass spectrometry using infusion with crown ethers.

Urea nitrate (UN) and ammonium nitrate (AN) are fertilizer-based explosives that are commonly used in improvised munitions and can have highly destructive effects. Because they are in the form of salts, their relatively low volatility makes them difficult to detect at trace levels. In addition, these salts readily undergo metathetic reactions in water to form urea, ammonium and nitrate, which are ubiquitous in the environment.

Trace analysis of urea nitrate by liquid chromatography-UV/fluorescence.

In this paper we have adapted a technique, previously used to determine the presence of urea in aqueous samples of wine and urine, to detect trace levels of urea nitrate explosives. The procedure involves the reaction of the uronium ion (protonated urea) with a fluorophore, xanthydrol. By modification of the procedure to utilize non-aqueous reagents, in neutral conditions, it can be made specific to the presence of the urea nitrate ion pair.