National and regional trends in fentanyl seizures in the United States, 2017-2023.

BACKGROUND: Rates of synthetic opioid-related deaths over time and across regions have been compared within the US, but other indicator data could help inform prevention and harm reduction as well. We compared regional trends in fentanyl seizures to examine potential shifts in illicit fentanyl availability. METHODS: Annual trends in fentanyl seizures were examined using data from High Intensity Drug Trafficking Areas for the US overall and by region from 2017 through 2023. Multiple measures included the number of seizures, the number of powder seizures, the number of pill seizures, the total weight of seizures, the number of pills seized, and the percentage of the number of pill seizures relative to the number of total seizures. RESULTS: The percentage of seizures in pill form in the US increased from 10.3 % in 2017 to 49.0 % in 2023 (adjusted annual percentage change [AAPC]=25.2, 95 % CI: 17.6, 33.2), with 115.6 million individual pills seized in 2023. Pill weight related to total seizure weight also increased from 0.4 % to 54.5 % (AAPC=112.6, 95 % CI: 78.6, 153.2). In 2023, the plurality of seizures was in the West, in seven out of eight of our measures, with 77.8 % of seizures in the West being in pill form. Although the Midwest had lower prevalence of seizures than the West, there were notable increases in the Midwest in the number of pill seizures (AAPC=142.2, 95 % CI: 91.9, 205.8) and number of pills seized (AAPC=421.0, 95 % CI: 272.7, 628.4). Total weight of fentanyl seized increased the most in the West (AAPC=84.6, 95 % CI: 72.3, 97.8). CONCLUSIONS: The number and size of fentanyl seizures is increasing in the US, with the majority of seizures, especially in pill form, in the West. Continued monitoring of regional shifts in the fentanyl supply can help inform targeted prevention and public health response.

Public health surveillance of new psychoactive substances: recent developments.

PURPOSE OF REVIEW: New psychoactive substances (NPS) continue to emerge globally and present a threat to public health. This article summarizes the most recent literature on approaches for monitoring NPS use and adverse events related to use. RECENT FINDINGS: A variety of approaches have recently been employed for surveillance of NPS use and associated harms, including the use of toxicology testing of patients in emergency departments, surveys of sentinel populations, drug checking and syringe services programs, wastewater-based epidemiology, and retrospective analyses of clinical samples and toxicology reports. These studies cover a range of time periods and NPS examined across numerous countries. SUMMARY: Areas of particular interest for future research include the use of data from drug checking services to inform surveillance efforts of the illicit drug supply and the development of methods for wastewater-based monitoring of NPS. Studies that combine self-report data with toxicology testing in particular are important for capturing unintentional or unknown exposure to NPS including fentanyls and drugs like xylazine. Given the limitations associated with individual indicators of drug use and associated harms, the harmonization of multiple data sources can help present a more complete picture of both trends involving NPS to better inform public health responses.

Sequencing hour-level temporal patterns of polysubstance use among persons who use cocaine, alcohol, and cannabis: A back-translational approach.

BACKGROUND: Polysubstance use is highly prevalent among persons who use cocaine; however, little is known about how alcohol and cannabis are used with cocaine. We identified temporal patterns of cocaine+alcohol and cocaine+cannabis polysubstance use to inform more translationally relevant preclinical models. METHODS: Participants who used cocaine plus alcohol and/or cannabis at least once in the past 30 days (n=148) were interviewed using the computerized Substance Abuse Module and the newer Polysubstance Use-Temporal Patterns Section. For each day in the past 30 days, participants reported whether they had used cocaine, alcohol, and cannabis; if any combinations of use were endorsed, participants described detailed hourly use of each substance on the most "typical day" for the combination. Sequence analysis and hierarchical clustering were applied to identify patterns of timing of drug intake on typical days of cocaine polysubstance use. RESULTS: We identified five temporal patterns among the 180 sequences of reported cocaine polysubstance use: 1) limited cocaine/cocaine+alcohol use (53%); 2) extensive cannabis then cocaine+alcohol+cannabis use (22%); 3) limited alcohol/cannabis then cocaine+alcohol use (13%); 4) extensive cocaine+cannabis then cocaine+alcohol+cannabis use (4%); and 5) extensive cocaine then cocaine+alcohol use (8%). While drug intake patterns differed, prevalence of use disorders did not. CONCLUSIONS: Patterns were characterized by cocaine, alcohol, and cannabis polysubstance use and by the timing, order, duration, and quantity of episode-level substance use. The identification of real-world patterns of cocaine polysubstance use represents an important step toward developing laboratory models that accurately reflect human behavior.

Increases in the use of drug testing kits among nightclub and festival attendees in New York City who use ecstasy, 2017-2022.

INTRODUCTION: Ecstasy (3,4-methylenedioxymethamphetamine [MDMA]) is a drug commonly used by people who attend electronic dance music (EDM) events at nightclubs and dance festivals. Drug checking has gained popularity in recent years to test for adulterants, but epidemiology studies are needed to estimate potential shifts in prevalence of drug checking to further inform harm reduction efforts. METHODS: Adults entering randomly selected EDM events in New York City were surveyed in 2017 and 2022. Those reporting past-year ecstasy use were asked if they tested their ecstasy in the past year using a drug testing kit and whether they found out or suspected their ecstasy contained other drugs. We compared estimates between 2017 and 2022. RESULTS: In 2017, an estimated 23.1% had tested their ecstasy, and this estimate increased to 43.1% in 2022 (86.6% increase, p = 0.006). Among those who tested their ecstasy, in 2017, 31.2% always tested their drug, and this increased to 60.6% in 2022 (94.2% increase, p = 0.026). In 2017, 59.6% of those who tested their ecstasy reported finding out or suspecting their drug was adulterated, which decreased to 18.4% in 2022 (69.1% decrease, p < 0.001). Suspected methamphetamine adulteration in particular decreased, from 21.9% in 2017 to 3.6% in 2022 (83.6% decrease, p = 0.007). DISCUSSION AND CONCLUSIONS: The use of drug testing kits has increased among EDM event attendees who use ecstasy and, at the same time, among those who had tested their ecstasy, suspected adulteration has decreased. Continued interest in understanding ecstasy contents among this population suggests the need for formal drug checking services.

National and regional trends in seizures of shrooms (psilocybin) in the United States, 2017-2022.

BACKGROUND: Psilocybin, the principle psychoactive component in "shrooms", is regaining acceptance in therapeutic settings, leading to media coverage of medical benefits associated with use. Possession is also becoming increasingly decriminalized throughout the United States. There is a lack of data on prevalence of shroom use, but trends in law enforcement seizure data can provide one indicator of shroom availability in US communities. We determined whether seizures of shrooms have shifted between 2017 and 2022. METHODS: This study examined national and regional trends in counts and total weight of shroom seizures reported to High Intensity Drug Trafficking Areas in the US between 2017 and 2022 (N=4526). RESULTS: There were 402 seizures in 2017 compared to 1396 in 2022 with the plurality occurring in the Midwest (36.0%), followed by the West (33.5%). Between 2017 Quarter 1 (Q1) and 2022 Quarter 4 (Q4), the number of seizures increased by 368.9% (AQPC=7.0; 95 CI: 5.9-8.1) and there were significant increases in all four regions. In terms of weight, 226.0kg was seized in 2017 vs. 844.0kg in 2022, and the greatest total weight in seizures was in the West (1864.2kg, 42.6%), followed by the South (1831.9kg, 41.8%). Between 2017 Q1 and 2022 Q4, the total weight seized in the US increased by 2749.7% (AQPC=6.2, 95% CI: 0.3-12.4) and there were significant increases in all four regions. CONCLUSIONS: Seizures of shrooms have increased, suggesting that availability may be escalating; thus, increases in prevention efforts and harm reduction education are warranted.

A Qualitative Analysis of Emergency Medical Services (EMS) Personnel Experiences and Perceptions Responding to Drug Overdoses in the United States (US) During the COVID-19 Pandemic.

Background: The purpose of this work was to describe the experiences of EMS personnel in responding to drug overdose-related calls and the impact the pandemic has had to help better inform current response and treatment efforts. Methods: Semi-structured interviews were conducted with 99 EMS personnel across 18 areas throughout the United States that were designated as Early Warning Network sentinel sites by the National Institute on Drug Abuse-funded National Drug Early Warning System. Participants were asked about topics including the potential burdens from the pandemic and the opioid crisis. We coded the interview responses and identified themes through qualitative analysis. Multiple cycles of descriptive coding, recoding, subcoding, pattern-coding, and thematic coding of responses were conducted. Results: Responses were categorized into the following themes: 1) being over-worked from increased call volume; 2) increased risk for personal harm when responding to patients; 3) compassion fatigue due to long hours and repeat calls for the same people; 4) conflicting perceptions of the utility of naloxone; 5) the need for better treatment options to respond to opioid crisis on top of COVID-19. Conclusions: The burden of the substance use disorder (SUD) crisis on EMS personnel has been compounded by the COVID-19 pandemic. These reports from EMS personnel throughout the US can help inform policy and procedures to better protect the mental health of EMS personnel and to ensure better care for patients with SUD. These experiences and recommendations may be of use for other countries as substance use and COVID-19 are global health issues.

E-cigarette Use Among Community-Recruited Adults with a History of Asthma in North Central Florida.

Use of e-cigarettes have become an important public health concern in the US, particularly among those with health issues like asthma, which has remained high over the last decade. We examined associations between lifetime e-cigarette use and traditional cigarette use, cannabis use, and related health factors among community members with a history of asthma in North Central Florida. Data came from HealthStreet, a University of Florida community engagement program. Adults with a history of asthma (n = 1,475) were interviewed between 2014 and 2021. Bivariate and logistic regression analyses were conducted to examine differences between participants with and without a history of lifetime e-cigarette use. In this sample, lifetime prevalence of e-cigarette use was 19.9%. Over half of the sample reported ever smoking traditional cigarettes (54.4%) or cannabis (55.4%). Compared to those who identified as White, those who identified as Black/African American had lower odds for lifetime e-cigarette use (aOR = 0.30, 95% CI: 0.22, 0.42). Those reporting lifetime traditional cigarette use (aOR = 10.60, 95% CI: 6.93, 16.68) or cannabis use (aOR = 1.81, 95% CI: 1.27, 2.61) had higher odds for reporting lifetime e-cigarette use. Overall, among a community sample of adults with a history of asthma, nearly a fifth reported lifetime e-cigarette use. The use of e-cigarettes was most common among those with lifetime traditional cigarette use and cannabis use. Findings can inform prevention and intervention efforts in this population.

Characteristics of poisonings involving ketamine in the United States, 2019-2021.

BACKGROUND: The use of ketamine, a controlled dissociative anesthetic, has become more widespread in recent years with recreational/nonmedical use increasing and ketamine becoming more widely available in clinics to treat depression. AIMS: We examined recent trends in adverse effects related to ketamine use. METHODS: US National Poison Control data were examined, focusing on ketamine exposures among those aged ⩾13 between 2019 and 2021 (n = 758). We examined quarterly trends in exposure and delineated correlates of patients experiencing a major adverse effect or death. RESULTS: The number of reported exposures increased 81.1% from 2019 Quarter 1 through 2021 Quarter 4, from 37 to 67 (p = 0.018). The majority of patients were male (57.1%), and the plurality of cases involved intentional misuse or "abuse" (39.5%), followed by suspected suicide attempt (19.7%) and unintentional exposure (18.9%). A fifth (19.6%) experienced a major adverse effect or death. A third (33.4%) co-used other drugs; the drugs most commonly co-used were benzodiazepines (14.6%), alcohol (10.3%), and opioids (8.7%). Co-use of gamma-hydroxybutyrate (GHB; adjusted prevalence ratio (aPR) = 3.43, 95% confidence interval (CI): 1.57-7.46) and opioids (aPR = 2.44, 95% CI: 1.46-4.08) was associated with increased risk for a major adverse effect or death, as was injection-only administration (aPR = 2.68, 95% CI: 1.21-5.92). CONCLUSIONS: Although still rare, poisonings involving ketamine have increased in recent years. Polydrug use-particularly with opioids or GHB-appears to be a particular risk factor for more serious adverse effects. As prevalence of use increases, it is important to monitor adverse effects and co-occurring behaviors to inform timely prevention and harm reduction as needed.

Test-retest reliability of a new assessment to detect detailed temporal patterns of polysubstance use.

OBJECTIVE: While polysubstance use is highly prevalent among people who use drugs, the field lacks a reliable assessment that can detect detailed temporal patterns of polysubstance use. This study assessed the test-retest reliability of the newly developed Polysubstance Use-Temporal Patterns Section (PSU-TPS). METHODS: Participants who used cocaine plus alcohol and/or marijuana at least once in the past 30 days (n = 48) were interviewed at baseline and approximately 7 days later (retest) using the Substance Abuse Module and the PSU-TPS. Reliability of PSU-TPS measures of quantity, frequency, and duration of polysubstance use was examined using intra-class correlation coefficients (ICCs) and kappa tests. RESULTS: Excellent reliability was observed for frequencies of concurrent polysubstance use patterns in the past 30 days (ICC range: 0.90-0.94) and quantity of alcohol use (ICC = 0.83), and fair to good reliability was observed for duration of substance use (ICC range: 0.52-0.73). CONCLUSION: Detailed information regarding cocaine, alcohol, and marijuana polysubstance use in the past 30 days can be reliably measured with the PSU-TPS. Data on the order and timing of polysubstance use at the hourly level will improve our understanding of the implications of sequential and simultaneous use patterns, which can help inform treatment and prevention efforts.

Test-retest reliability and cross-cultural applicability of DSM-5 adopted diagnostic criteria for ketamine use disorders.

BACKGROUND: Despite increasing prevalence of nonmedical ketamine use globally, data on ketamine use disorders, which are classified in the DSM-5 under criteria for phencyclidine, are limited. This study assessed the reliability and applicability of DSM-based diagnostic criteria for ketamine use disorder. METHODS: Participants who used ecstasy were recruited through the Tri-City Study of Club Drug Use, Abuse, and Dependence in St. Louis, Miami, and Sydney. Those who reported using ketamine (lifetime use >5 times) were included in these analyses (n = 205). Participants were interviewed using the computerized Substance Abuse Module for Club Drugs (CD-SAM) at baseline and 7 days later for the reliability of diagnoses and individual diagnostic criteria. RESULTS: Overall, 29.3% met DSM-5 adopted criteria for ketamine use disorder at Time 1. Moderate to excellent test-retest reliability was observed consistently across study sites for any ketamine use disorder (κ = 0.57, Y = 0.61) and severe ketamine use disorder (κ = 0.62, Y = 0.79). Continued use of ketamine despite knowledge of physical or psychological problems was the most frequently endorsed individual criterion (59.0%), followed by reported withdrawal (30.2%) and physically hazardous use (29.8%). All individual criteria had acceptable reliability estimates (κ ≥ 0.41). CONCLUSIONS: Diagnoses of ketamine use disorder can be reliably evaluated using this fully structured diagnostic instrument's questions and algorithm. Ketamine-related withdrawal among people who use ketamine should be re-evaluated. Considering that after-effects of this dissociative anesthetic can last for many hours, it is important to explore a different timeframe for possible withdrawal effects.

Online surveillance of novel psychoactive substances (NPS): Monitoring Reddit discussions as a predictor of increased NPS-related exposures.

BACKGROUND: Novel psychoactive substances (NPS) present continuous and growing challenges for the scientific, medical, and interventional communities as emerging substances on recreational drug markets change national and international drug landscapes. NPS account for an increasing proportion of adverse events, hospitalizations, and deaths due to increasing potency and unanticipated biological effects compared to predecessors. This study evaluated the utility of drug use forums as an early indicator or predictor of impending intoxications with potentially harmful or lethal outcomes prior to their occurrences. METHODS: Eight NPS were selected for evaluation to assess the relationship between online mentions of drugs and their involvement in toxic exposures or overdoses. Mentions on Reddit drug forum discussions were tallied and toxicology testing results from forensic investigations in the US were assessed. The selected NPS covered several subclasses and a predetermined time range (2013-2020). They included carfentanil, U-47700, eutylone, flualprazolam, N-ethylpentylone, 5F-MDMB-PICA, isotonitazene, and brorphine. RESULTS: Seven NPS (excluding 5F-MDMB-PICA) appeared in discussions on Reddit prior to their implication in poisonings or intoxications. Distinct increases and decreases in number of mentions and number of exposures were observed. For most substances (n = 5, 63%), a rise in Reddit mentions was soon followed by a corresponding rise in toxicology positivity. Peak positivity for carfentanil and flualprazolam, however, preceded peak Reddit mentions. CONCLUSIONS: This study demonstrated the utility of social media sites, such as Reddit, as a predictor for future trends in NPS-related exposures. These results provide confirmation that activity on drug use forums in the virtual world can help predict changes in exposures associated with new or re-emerging NPS in the real world. The results warrant further evaluation as a strategy for inclusion in early warning systems.

Shifting awareness among electronic dance music party attendees that drugs may contain fentanyl or other adulterants.

BACKGROUND: Drugs like ecstasy, cocaine, and counterfeit prescription pills can contain fentanyl. We examined knowledge about potential adulteration/contamination of such drugs among people attending electronic dance music (EDM) parties. METHODS: Adults in New York City were surveyed entering randomly selected EDM parties during the summers of 2018 (n=1,029) and 2019 (n=559). Surveys assessed perceptions that: 1) ecstasy/Molly can contain adulterants more dangerous than MDMA, 2) cocaine can contain fentanyl, and 3) prescription pills from non-pharmacy sources can contain fentanyl. We compared prevalence of perceptions between 2018 and 2019. RESULTS: Prevalence of agreeing that cocaine can contain fentanyl increased from 42.1% to 58.6%, a 39.2% increase (p=.003). Increases in agreement were not significant regarding ecstasy potentially containing adulterants (55.0% vs. 59.0%) and non-pharmacy prescription drugs potentially containing fentanyl (46.8% vs. 52.9%). Those reporting past-year ecstasy use in particular reported increased agreement that ecstasy can be adulterated (from 52.9% to 80.0%, a 51.2% increase; p<.001) and those reporting past-year cocaine use reported increased agreement that cocaine can be adulterated (from 48.2% to 70.7%, a 46.7% increase; p=.016). CONCLUSIONS: Knowledge of potential adulteration or contamination of commonly used drugs in this high-risk scene is increasing. Continued education about possible drug contents is needed.

Prescription stimulant brand name recognition among a national sample of 10- to 18-year-old youth.

OBJECTIVE: The majority of prescription drugs, including prescription stimulants, are marketed using multiple brand names, doses, and formulations. There is limited research on the extent to which individuals correctly identify medication by brand name or packaging, but such identification is important for epidemiological studies especially among youth. Testing the ability of youth to identify medications was one aim of the National Monitoring of Prescription Stimulants Study, which focused on the prevalence of prescription stimulant use among youth. METHODS: Using the entertainment venue intercept method, youth 10 to 18 years of age (n = 11,048) were recruited across 10 metropolitan areas throughout the United States, shown pictures of eight formulations of prescription stimulants, and asked to identify them by name, dosage, and formulation. RESULTS: Overall, 27% of youth reported having seen one of the eight stimulant formulations and between 2% and 70% correctly identified name, dose, and formulation. Youths' reports of having seen and correctly identifying medication increased with age except for Daytrana® . Specifically, while 2.8% of youth reported using Adderall® in the past 30 days, only 71.4% correctly identified it. CONCLUSIONS: These results provide strong evidence of the need for more stringent methods for youth to report drug use.

Drug checking at dance festivals: A review with recommendations to increase generalizability of findings.

Dance festival attendees are at high risk for consuming adulterated drugs. In recent years, drug checking studies have been conducted at various dance festivals to provide valuable harm reduction information to attendees regarding drug content. We conducted a review of the literature to determine the generalizability of findings to the target population of interest-festival attendees at risk for using adulterated drugs. Six published studies involving drug checking at festivals were reviewed. All relied on self-selected samples and male attendees were overrepresented based on previous research. Test methods, drugs tested, definitions of adulteration, and prevalence of adulteration varied across studies. Prevalence of detection of adulterants ranged from 11% to 55%. While the drug checking services described appear to have been beneficial for participants, results have limited generalizability to the target population. We recommend that researchers expand beyond the self-selection model in future studies and utilize recruitment methods that involve random sampling techniques such as systematic random sampling, stratified random sampling, or time-space sampling within festivals. We also recommend that individuals approached are surveyed for demographic characteristics, planned drug use at the festival, and willingness to test their drugs. These methods would help determine how representative the sample is compared to the target population and allow for more generalizable estimates. In conclusion, as these valuable harm reduction services expand, it may be possible to reach a wider portion of the population at risk and to obtain more generalizable estimates of engagement, adulteration, and reactions to learning one possesses adulterated drugs. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Machine-learning approaches to substance-abuse research: emerging trends and their implications.

PURPOSE OF REVIEW: To provide an accessible overview of some of the most recent trends in the application of machine learning to the field of substance use disorders and their implications for future research and practice. RECENT FINDINGS: Machine-learning (ML) techniques have recently been applied to substance use disorder (SUD) data for multiple predictive applications including detecting current abuse, assessing future risk and predicting treatment success. These models cover a wide range of machine-learning techniques and data types including physiological measures, longitudinal surveys, treatment outcomes, national surveys, medical records and social media. SUMMARY: The application of machine-learning models to substance use disorder data shows significant promise, with some use cases and data types showing high predictive accuracy, particularly for models of physiological and behavioral measures for predicting current substance use, portending potential clinical diagnostic applications; however, these results are uneven, with some models performing poorly or at chance, a limitation likely reflecting insufficient data and/or weak validation methods. The field will likely benefit from larger and more multimodal datasets, greater standardization of data recording and rigorous testing protocols as well as greater use of modern deep neural network models applied to multimodal unstructured datasets.

Fecal indicator bacteria and virus removal in stormwater biofilters: Effects of biochar, media saturation, and field conditioning.

Stormwater biofilters are used to attenuate the flow and volume of runoff and reduce pollutant loading to aquatic systems. However, the capacity of biofilters to remove microbial contaminants remains inadequate. While biochar has demonstrated promise as an amendment to improve microbial removal in laboratory-scale biofilters, it is uncertain if the results are generalizable to the field. To assess biochar performance in a simulated field setting, sand and biochar-amended sand biofilters were periodically dosed with natural stormwater over a 61-week conditioning phase. Impact of media saturation was assessed by maintaining biofilters with and without a saturated zone. Biochar-amended biofilters demonstrated improved Escherichia coli removal over sand biofilters during the first 31 weeks of conditioning though media type did not impact E. coli removal during the last 30 weeks of conditioning. Presence of a saturated zone was not a significant factor influencing E. coli removal across the entire conditioning phase. Following conditioning, biofilters underwent challenge tests using stormwater spiked with wastewater to assess their capacity to remove wastewater-derived E. coli, enterococci, and male-specific (F+) coliphage. In challenge tests, biochar-amended biofilters demonstrated enhanced removal of all fecal indicators relative to sand biofilters. Additionally, saturated biofilters demonstrated greater removal of fecal indicators than unsaturated biofilters for both media types. Discrepant conclusions from the conditioning phase and challenge tests may be due to variable influent chemistry, dissimilar transport of E. coli indigenous to stormwater and those indigenous to wastewater, and differences in E. coli removal mechanisms between tests. Mobilization tests conducted following challenge tests showed minimal (<2.5%) observable mobilization of fecal indicators, regardless of media type and presence of a saturated zone. While our results emphasize the challenge of translating biochar's performance from the laboratory to the field, findings of this study inform biofilter design to remove microbial contaminants from urban stormwater.

Aqueous film forming foam and associated perfluoroalkyl substances inhibit methane production and Co-contaminant degradation in an anaerobic microbial community.

Aqueous film forming foams (AFFF) can contain gram per liter concentrations of per- and polyfluoroalkyl substances (PFAS) and are often released in large quantities directly to the environment as they are used to fight fires. AFFF composition is complex and contains many unknown PFAS in addition to ingredients such as hydrocarbons, solvents, and corrosion inhibitors. While biological effects of single PFAS have been studied, the effects of PFAS-containing mixtures, such as AFFF, are unknown. The effect of PFAS on microorganisms is also not well understood; nevertheless, we rely on microorganisms in locations containing elevated PFAS concentrations to perform certain functions, such as carbon cycling and co-contaminant degradation. This study focused on determining the functional consequences of AFFF and PFAS exposure in a microbial community in both the presence and the absence of a co-contaminant. AFFF, select PFAS, and a PFAS mixture were tested to determine the effect of AFFF on an anaerobic microbial community and the characteristics of the PFAS that drive toxicity in such mixtures. To study this, anaerobic digester communities were exposed to PFAS and a co-contaminant (2,4-dichlorophenol, DCP); methane production, as an indicator of toxicity and the community's ability to cycle carbon, and co-contaminant degradation were monitored. Results showed that PFAS and AFFF can alter the toxicity of DCP, inhibit DCP degradation, decrease the number of methanogens present, and change the microbial community structure. DCP was also able to decrease the toxicity of the PFAS perfluorooctane sulfonate (PFOS), possibly by changing the sorption of PFOS to the microorganisms present. Additionally, it was determined that while PFOS was responsible for AFFF toxicity, no single PFAS or simple PFAS mixture accurately accounted for the inhibition of DCP degradation caused by AFFF exposure.

Partitioning and Accumulation of Perfluoroalkyl Substances in Model Lipid Bilayers and Bacteria.

Perfluoroalkyl substances (PFAS) are ubiquitous and persistent environmental contaminants, yet knowledge of their biological effects and mechanisms of action is limited. The highest aqueous PFAS concentrations are found in areas where bacteria are relied upon for functions such as nutrient cycling and contaminant degradation, including fire-training areas, wastewater treatment plants, and landfill leachates. This research sought to elucidate one of the mechanisms of action of PFAS by studying their uptake by bacteria and partitioning into model phospholipid bilayer membranes. PFAS partitioned into bacteria as well as model membranes (phospholipid liposomes and bilayers). The extent of incorporation into model membranes and bacteria was positively correlated to the number of fluorinated carbons. Furthermore, incorporation was greater for perfluorinated sulfonates than for perfluorinated carboxylates. Changes in zeta potential were observed in liposomes but not bacteria, consistent with PFAS being incorporated into the phospholipid bilayer membrane. Complementary to these results, PFAS were also found to alter the gel-to-fluid phase transition temperature of phospholipid bilayers, demonstrating that PFAS affected lateral phospholipid interactions. This investigation compliments other studies showing that sulfonated PFAS and PFAS with more than seven fluorinated carbons have a higher potential to accumulate within biota than carboxylated and shorter-chain PFAS.