Burning questions: Current practices and critical gaps in evaluating removal of per- and polyfluoroalkyl substances (PFAS) during pyrolysis treatments of biosolids.

Concerns surrounding potential health and environmental impacts of per- and polyfluoroalkyl substances (PFAS) are growing at tremendous rates because adverse health impacts are expected with trace-level exposures. Extreme measures are required to mitigate potential PFAS contamination and minimize exposures. Extensive PFAS use results in the release of diverse PFAS species from domestic, industrial, and municipal effluents to wastewater, which partition to biosolids throughout secondary treatment. Biosolids generated during municipal wastewater treatment are a major environmental source of PFAS due to prevailing disposal practices as fertilizers. Pyrolysis is emerging as a viable, scalable technology for PFAS removal from biosolids while retaining nutrients and generating renewable, raw materials for energy generation. Despite early successes of pyrolysis in PFAS removal, significant unknowns remain about PFAS and transformation product fates in pyrolysis products and emissions. Applicable PFAS sampling methods, analytical workflows, and removal assessments are currently limited to a subset of high-interest analytes and matrices. Further, analysis of exhaust gases, particulate matter, fly ashes, and other pyrolysis end-products remain largely unreported or limited due to cost and sampling limitations. This paper identifies critical knowledge gaps on the pyrolysis of biosolids that must be addressed to assess the effectiveness of PFAS removal during pyrolysis treatment.

Quantitation of Total PFAS Including Trifluoroacetic Acid with Fluorine Nuclear Magnetic Resonance Spectroscopy.

Fluorine nuclear magnetic resonance (19F-NMR) spectroscopy has been shown to be a powerful tool capable of quantifying the total per- and polyfluoroalkyl substances (PFAS) in a complex sample. The technique relies on the characteristic terminal -CF3 shift (-82.4 ppm) in the alkyl chain for quantification and does not introduce bias due to sample preparation or matrix effects. Traditional quantitative analytical techniques for PFAS, such as liquid chromatography-mass spectrometry (LC-MS) and combustion ion chromatography (CIC), contain inherent limitations that make total fluorine analysis challenging. Here, we report a sensitive 19F-NMR method for the analysis of total PFAS, with a limit of detection of 99.97 nM, or 50 µg/L perfluorosulfonic acid. To demonstrate the capabilities of 19F-NMR, the technique was compared to two commonly used methods for PFAS analysis: total oxidizable precursor (TOP) assay and LC-high resolution MS analysis for targeted quantification and suspect screening. In both cases, the 19F-NMR analyses detected higher total PFAS quantities than either the TOP assay (63%) or LC-MS analyses (65%), suggesting that LC-MS and TOP assays can lead to underreporting of PFAS. Importantly, the 19F-NMR detected trifluoroacetic acid at a concentration more than five times the total PFAS concentration quantified using LC-MS in the wastewater sample. Therefore, the use of 19F-NMR to quantify the total PFAS in highly complex samples can be used to complement classic TOP or LC-MS approaches for more accurate reporting of PFAS contamination in the environment.

Spatial distribution of pesticides, organochlorine compounds, PBDEs, and metals in surface marine sediments from Cartagena Bay, Colombia.

Cartagena Bay is an estuarine system located in the Caribbean Sea (Colombia, South America), that receives fresh water from Canal del Dique, which is connected to the Magdalena River, the most important river of Colombia, with some of the most prominent Colombian cities located in its watershed, which has a high sediment yield. An analysis of persistent organic pollutants and heavy metals was carried out on marine sediments from Cartagena Bay. Cartagena Bay sediments deployed the occurrence of total levels of pesticides (thiocarbamates, bromacil, triazines, organochlorines, and organophosphorus), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), in sediments ranging from 0.83-33.67 ng/g dry-weight, 0.05-0.34 ng/g dry-weight, and 0.06-19.58 ng/g dry-weight, respectively. Their concentrations were lower than those reported in NOAA Screening Quick Reference Tables. DDTs and PCBs are banned organochlorine compounds, since, even at low levels, their presence in sediments represents a threat to aquatic organisms and, therefore, to human health through the trophic chain. Sediments showed high concentrations of strontium (50-959.6 mg/kg). All metals evaluated in the marine sediments were found in the S6 sampling point; this was near tannery and hydrocarbon industries (Pb 37.1 mg/kg, Cr 137.2 mg/kg, Cd 1.7 mg/kg, Cu 64.4 mg/kg, As 13.1 mg/kg, Sr 318.9 mg/kg); these results exceeded the accepted values of threshold effect levels (TEL) used as an indicator of their potential risk on marine life.

Occurrence and transformation of veterinary antibiotics and antibiotic resistance genes in dairy manure treated by advanced anaerobic digestion and conventional treatment methods.

Manure treatment technologies are rapidly developing to minimize eutrophication of surrounding environments and potentially decrease the introduction of antibiotics and antibiotic resistant genes (ARGs) into the environment. While laboratory and pilot-scale manure treatment systems boast promising results, antibiotic and ARG removals in full-scale systems receiving continuous manure input have not been evaluated. The effect of treatment on ARGs is similarly lacking. This study examines the occurrence and transformation of sulfonamides, tetracyclines, tetracycline degradation products, and related ARGs throughout a full-scale advanced anaerobic digester (AAD) receiving continuous manure and antibiotic input. Manure samples were collected throughout the AAD system to evaluate baseline antibiotic and ARG input (raw manure), the effect of hygenization (post-pasteurized manure) and anaerobic digestion (post-digestion manure) on antibiotic and ARG levels. Antibiotics were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the ARGs tet(O), tet(W), sul1 and sul2 were analyzed by quantitative polymerase chain reaction (Q-PCR). Significant reductions in the concentrations of chlortetracycline, oxytetracycline, tetracycline and their degradation products were observed in manure liquids following treatment (p < 0.001), concomitant to significant increases in manure solids (p < 0.001). These results suggest sorption is the major removal route for tetracyclines during AAD. Significant decreases in the epimer-to-total residue ratios for chlortetracycline and tetracycline in manure solids further indicate degradation is desorption-limited. Moreover, sul1 and sul2 copies decreased significantly (p < 0.001) following AAD in the absence of sulfonamide antibiotics, while tetracyclines-resistant genes remained unchanged. A cross-sectional study of dairy farms utilizing natural aeration and liquid-solid separation treatments was additionally performed to compare levels of antibiotics and ARGs found in AAD with the levels in common manure management systems. The concentration of antibiotics in raw manure varied greatly between farms while minimal differences in ARGs were observed. However, significant (p < 0.01) differences in the levels of antibiotics and ARGs (except tet(W)) were observed in the effluents from the three different manure management systems.

Metagenomic profiling of historic Colorado Front Range flood impact on distribution of riverine antibiotic resistance genes.

Record-breaking floods in September 2013 caused massive damage to homes and infrastructure across the Colorado Front Range and heavily impacted the Cache La Poudre River watershed. Given the unique nature of this watershed as a test-bed for tracking environmental pathways of antibiotic resistance gene (ARG) dissemination, we sought to determine the impact of extreme flooding on ARG reservoirs in river water and sediment. We utilized high-throughput DNA sequencing to obtain metagenomic profiles of ARGs before and after flooding, and investigated 23 antibiotics and 14 metals as putative selective agents during post-flood recovery. With 277 ARG subtypes identified across samples, total bulk water ARGs decreased following the flood but recovered to near pre-flood abundances by ten months post-flood at both a pristine site and at a site historically heavily influenced by wastewater treatment plants and animal feeding operations. Network analysis of de novo assembled sequencing reads into 52,556 scaffolds identified ARGs likely located on mobile genetic elements, with up to 11 ARGs per plasmid-associated scaffold. Bulk water bacterial phylogeny correlated with ARG profiles while sediment phylogeny varied along the river's anthropogenic gradient. This rare flood afforded the opportunity to gain deeper insight into factors influencing the spread of ARGs in watersheds.

Challenges in the Measurement of Antibiotics and in Evaluating Their Impacts in Agroecosystems: A Critical Review.

Large quantities of antibiotics are used in agricultural production, resulting in their release to agroecosystems through numerous pathways, including land application of contaminated manure, runoff from manure-fertilized fields, and wastewater irrigation of croplands. Antibiotics and their transformation products (TPs) exhibit a wide range of physico-chemical and biological properties and thus present substantive analytical challenges. Advances in the measurement of these compounds in various environmental compartments (plants, manure, soil, sediment, and water) have uncovered a previously unrealized landscape of antibiotic residues. These advanced multiresidue methods, designed to measure sub-ng g concentrations in complex mixtures, remain limited by the inherent intricacy of the sample matrices and the difficultly in eliminating interferences that affect antibiotic detection. While efficient extraction methods combined with high sensitivity analysis by liquid chromatography/mass spectrometry can provide accurate quantification of antibiotics and their TPs, measured concentrations do not necessarily reflect their bioavailable fractions and effects in the environment. Consequently, there is a need to complement chemical analysis with biological assays that can provide information on bioavailability, biological activity, and effects of mixtures. Enzyme-linked immunosorbent assays (ELISA), often used as screening tools for antibiotic residues, may be useful for detecting the presence of structurally related antibiotic mixtures but not their effects. Other tools, including bioreporter assays, hold promise in measuring bioavailable antibiotics and could provide insights on their biological activity. Improved assessment of the ecological and human health risks associated with antibiotics in agroecosystems requires continued advances in analytical accuracy and sensitivity through improvements in sample preparation, instrumentation, and screening technologies.

Enhancing Extraction and Detection of Veterinary Antibiotics in Solid and Liquid Fractions of Manure.

Analysis of veterinary antibiotics in separated liquid and solid fractions of animal manures is vital because of wide variations in the composition of agriculturally applied manure. Differentiation of antibiotic concentrations is important between liquid and solid manures, as their sorption onto the solid fraction depends on physicochemical properties of each antibiotic and manure composition (e.g., organic content, pH) and because each fraction may be treated and reused differently. Here, an efficient and sensitive method for the analysis of 22 veterinary antibiotics in the liquid and solid fractions of manure is reported. Tetracycline (TC), macrolide, and sulfonamide antibiotics were extracted from liquid manure by liquid-liquid extraction (LLE) with methanol following acidification with acetic acid. Extraction from solids was performed by sonication with acetonitrile, methanol, and 0.1 M EDTA-McIlvaine buffer. Cleanup of extracts was achieved by solid-phase extraction with hydrophilic-lipophilic balance (HLB) cartridges or tandem amino (NH2) and HLB cartridges. Quantification of antibiotics was performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) under wrong-way-round (WWR) ionization for sulfonamides and TCs and right-way-round ionization for macrolides. Recoveries of 58 to 94.7% and 62 to 94.3% were obtained in liquid and solid manure, respectively. Method detection limits range from 1.2 to 12 ng L and 0.5 to 7.9 µg kg dry wt. in liquids and solids, respectively. This method allows for extraction and analysis of both mobile antibiotics in liquid phase and hydrophobic antibiotics adsorbed on the solids. Without separate analysis, antibiotic concentrations may be improperly estimated by analyzing whole manure, as reported in many studies to date.

Review on the occurrence and profiles of polybrominated diphenyl ethers in the Philippines.

The environmental occurrence of polybrominated diphenyl ethers (PBDEs) has been a subject of concern for the past decade because they are persistent, bioaccumulative, and toxic. These compounds have been listed as persistent organic pollutants (POPs) by the Stockholm Convention and are expected to disperse in the global environment even after their use and production. While the occurrence of PBDEs has been well characterized in environmental and biological samples from North America, Europe, and some Asian countries (i.e. China, Japan, and Korea), there is a scarcity of available data in developing Asian countries, such as the Philippines. Examination of PBDE contamination in the Philippine environment is particularly important because regulations have only recently been implemented on the production and use of PBDEs in this country. Additionally, the Philippines receives e-waste from Western countries, which is becoming a major source of organic contaminants in the tropical Asian regions. Ultimately, the Philippines may be a hot spot for contributing to on-going global PBDE pollution due to long-range atmospheric transport. This paper presents a review of the available literature on PBDEs in both environmental and biological samples collected from the Philippines. It is also intended to provide an overview on the levels and congener profiles of PBDEs in samples from the Philippines and to compare these data with other Asian countries. New data are presented on PBDE occurrence and congener profiles in fish commonly consumed by Filipinos and in particulate matter samples collected in Metro Manila, the capital of the Philippines. Both studies contribute to the available knowledge of PBDEs in the Philippines. We aim to stress the importance of future studies in countries receiving e-wastes, such as the Philippines, and suggest what future directions might be taken to enhance the available data on the presence of PBDEs in the Philippine environment.

Dynamic modeling predicts continued bioaccumulation of polybrominated diphenyl ethers (PBDEs) in smallmouth bass (Micropterus dolomiu) post phase-out due to invasive prey and shifts in predation.

Unprecedented food chain links between benthic and pelagic organisms are often thought to disrupt traditional contaminant transport and uptake due to changes in predation and mobilization of otherwise sequestered pollutants. A bioaccumulation model for polybrominated diphenyl ethers (PBDEs) is developed to simulate increases in biotic congener loads based upon trophic transfer through diet and gill uptake for a Lake Erie food chain including two invasive species as a benthic-pelagic link. The model utilizes species-specific bioenergetic parameters in a four-level food chain including the green alga Scenedesmus quadricauda, zebra mussels (Dreissena polymorpha), round goby (Appollonia melanostoma), and the smallmouth bass (Micropterus dolomiu). The model was calibrated to current biotic concentrations and predicts an increase in contaminant load by almost 48% in the upper trophic level in two years. Validation to archival data resulted in <2% error from reported values following a two-year simulation.

Risk score to predict serious bleeding in stable outpatients with or at risk of atherothrombosis.

AIMS: To develop a risk score to quantify bleeding risk in outpatients with or at risk of atherothrombosis. METHODS AND RESULTS: We studied patients in the REACH Registry, a cohort of 68 236 patients with/at risk of atherothrombosis. The outcome of interest was serious bleeding (non-fatal haemorrhagic stroke or bleeding leading to hospitalization and transfusion) over 2 years. Risk factors for bleeding were assessed using modified regression analysis. Multiple potential scoring systems based on the least complex models were constructed. Competing scores were compared on their discriminative ability via logistic regression. The score was validated externally using the CHARISMA population. From a final cohort of 56 616 patients, 804 (1.42%, 95% confidence interval 1.32-1.52) experienced serious bleeding between baseline and 2 years. A nine-item bleeding risk score (0-23 points) was constructed (age, peripheral arterial disease, congestive heart failure, diabetes, hypertension, smoking, antiplatelets, oral anticoagulants, hypercholesterolaemia). Observed incidence of bleeding at 2 years was: 0.46% (score < or = 6); 0.95% (7-8); 1.25% (9-10); 2.76% (> or = 11). The score's discriminative performance was consistent in CHARISMA and REACH (c-statistics 0.64 and 0.68, respectively); calibration in the CHARISMA population was very good (modified Hosmer-Lemeshow c(2) = 4.74; P = 0.69). CONCLUSION: Bleeding risk increased substantially with a score >10. This score can assist clinicians in predicting the risk of serious bleeding and making decisions on antithrombotic therapy in outpatients.