Clinical Picture and Risk Factors for Severity of SARS-CoV-2 and Dengue Coinfection in Children: Experience From a Tertiary Hospital in Vietnam.

Introduction Dengue is an infectious disease that is a burden in Asia-Pacific and Latin America. The COVID-19 pandemic in dengue-endemic areas has caused a "double burden" because of the possibility of coinfection, especially in children who are vulnerable to both COVID-19 and dengue. This study aimed to describe the characteristics and identify risk factors for the severity of the coinfection in Vietnamese children. Methods This was a retrospective cohort study, undertaken at Children's Hospital 1 (Ho Chi Minh City, Vietnam) during the fourth wave of the COVID-19 pandemic. All children under 16 years old who were admitted to the hospital from April 27, 2021 to June 30, 2022, and diagnosed with SARS-CoV-2 and dengue coinfection were included. Results From April 2021 to June 2022, a total of 31 patients with the coinfection were included, with 19 of them being male (61.3%). The median age was 10.8 years old (IQR, 5.1-14.1). Fourteen children (45.2%) had preexisting comorbidities, with the most common comorbidity being overweight/obesity (ten children). Nearly two-thirds of the children were diagnosed with dengue without/with warning signs (61.3%) and were classified as having mild COVID-19 (83.9%). The most frequently observed clinical characteristics were fever (n=29, 93.6%), followed by abdominal pain, vomiting, and petechiae. All patients had high serum ferritin, and 83.9% presented with thrombocytopenia. None of the cases died. Overweight/obesity, abdominal pain, and petechiae were factors independently associated with severe disease. Conclusion Most of the children had mild COVID-19 and disease progression similar to patients with dengue alone. However, some children may have severe COVID-19 and dengue coinfection. Obesity, abdominal pain, and petechiae were identified as independent risk factors for disease severity in pediatric cases. Further studies with multicenters and a larger sample size are needed to assess the coinfection more thoroughly.

Selectivity in the Formal [2 + 2 + 2] Cycloaromatization of Enyne-Allenes Generated by the Alder-ene Reaction from Triynes.

1,3-Diynyl propiolates undergo the Alder-ene reaction to generate enyne-allenes, which participate in the Diels-Alder reaction to provide products of a formal [2 + 2 + 2] cycloaromatization of three alkynes. Without an external alkyne, enyne-allene reacts with one of the alkyne moieties of 1,3-diynyl propiolate, whereas external alkynes can be used to trap enyne-allene to provide various arene products. The substituents on the dienophilic alkynes have a profound impact on their reactivity. In this Diels-Alder reaction, 1,3-diynes display higher reactivity than monoynes; thus, an excess amount (4-5 equiv) of external monoynes needs to be employed to get good product selectivity.

Introducing Casbah, Kronus, and MmasiCarm, Members of the Mycobacteriophage Subcluster B3.

Background: As part of a large science education effort, bacteriophages that lyse Mycobacterium smegmatis mc2155 continue to be discovered. Materials and Methods: Phages were isolated from soil samples from urban sites in the Northeastern United States. Their genomes were sequenced, assembled, and bioinformatically compared. Results: Three lytic siphoviruses belonging to subcluster B3 with high similarity to each other and other B3 mycobacteriophages were isolated. These phages contain double-stranded DNA genomes (68,754 to 69,495 bp) with high GC content (67.4-67.5%) and 102-104 putative protein coding genes. Notable features include a HicA-like toxin and 33 genes exclusive to subcluster B3. One phage had an intein in its terminase sequence. Conclusions: Genomic analyses of these phages provide insights into genome evolution and horizontal gene transfer (HGT). The networks for HGT are apparently vast and gene specific. Interestingly, a number of genes are found in both B3 and Gordonia DR phages.

Risk factors of postoperative complications and their effect on survival after laparoscopic gastrectomy for gastric cancer.

Background: The association between postoperative complications and long-term survival after laparoscopic gastrectomy (LG) for gastric cancer (GC) remains uncertain. This study aimed to determine the incidence and risk factors of postoperative complications and evaluate their impact on survival outcomes in patients undergoing LG. Methods: A retrospective study was conducted on 621 patients who underwent LG for gastric adenocarcinoma between March 2015 and December 2021. Postoperative complications were classified according to the Clavien-Dindo classification, with major complications defined as Grade III or higher. Logistic regression models with stepwise backward procedure were used to identify risk factors for complications. To assess the impact of postoperative complications on survival, uni- and multi-variable Cox proportional hazard models were used for overall survival (OS) and disease-free survival (DFS). Results: Overall rate of postoperative complications was 17.6% (109 patients); 33 patients (5.3%) had major complications. Independent risk factors for major complications were Charlson comorbidities index (OR [95% CI], 1.87 [1.09-3.12], p-value = 0.018 for each one score increase), and type of anastomosis (OR [95% CI], 0.28 [0.09-0.91], p-value = 0.029 when comparing Billroth II with Billroth I). Multivariable analysis identified major complications as an independent prognostic factor to reduce OS (HR [95% CI], 2.32 [1.02-5.30], p-value = 0.045) and DFS (HR [95% CI], 2.63 [1.37-5.06], p-value = 0.004). Other prognostic factors for decreased survival outcomes were tumor size, presence of invasive lymph nodes, and T4a stage. Conclusions: Major complications rate of LG for GC was approximately 5.3%. Charlson comorbidities index and type of anastomosis were identified as risk factors for major postoperative complications. Major complications were demonstrated to pose adverse impact on survival outcomes.

Limited Sampling Strategies Fail to Accurately Predict Mycophenolic Acid Area Under the Curve in Kidney Transplant Recipients and the Impact of Enterohepatic Recirculation.

BACKGROUND: Therapeutic drug monitoring for mycophenolic acid (MPA) is challenging due to difficulties in measuring the area under the curve (AUC). Limited sampling strategies (LSSs) have been developed for MPA therapeutic drug monitoring but come with risk of unacceptable performance. The authors hypothesized that the poor predictive performance of LSSs were due to the variability in MPA enterohepatic recirculation (EHR). This study is the first to evaluate LSSs models performance in the context of EHR. METHODS: Adult kidney transplant recipients (n = 84) receiving oral mycophenolate mofetil underwent intensive MPA pharmacokinetic sampling. MPA AUC0-12hr and EHR were determined. Published MPA LSSs in kidney transplant recipients receiving tacrolimus were evaluated for their predictive performance in estimating AUC0-12hr in our full cohort and separately in individuals with high and low EHR. RESULTS: None of the evaluated LSS models (n = 12) showed good precision or accuracy in predicting MPA AUC0-12hr in the full cohort. In the high EHR group, models with late timepoints had better accuracy but low precision, except for 1 model with late timepoints at 6 and 10 hours postdose, which had marginally acceptable precision. For all models, the good guess of predicted AUC0-12hr (±15% of observed AUC0-12hr) was highly variable (range, full cohort = 19%-61.9%; high EHR = 4.5%-65.9%; low EHR = 27.5%-62.5%). CONCLUSIONS: The predictive performance of the LSS models varied according to EHR status. Timepoints ≥5 hours postdose in LSS models are essential to capture EHR. Models and strategies that incorporate EHR during development are required to accurately ascertain MPA exposure.

Laparoscopic versus open total gastrectomy for T4a gastric cancer: a propensity score-matched analysis of long-term outcomes.

Evidence of implementation of laparoscopic total gastrectomy (LTG) for surgical T4a stage (sT4a) gastric cancer (GC) remains inadequate. This study aimed to compare short- and long-term outcomes of LTG versus open total gastrectomy (OTG) for sT4a GC. This retrospective cohort study was conducted using data from patients with sT4a GC underwent total gastrectomy from 2014 to 2020. Short-term outcomes included operative characteristics and postoperative complications. Long-term oncological outcomes focused on 3-, and 5-year overall survival (OS) and disease-free survival (DFS). Propensity score matching (PSM) was applied to reduce potential biases in baseline characteristics between groups. There was a total of 161 patients, in which 96 underwent LTG and 65 underwent OTG. After PSM, both groups consisted of 51 patients each, with balanced baseline characteristics. There were no significant differences between the two groups regarding blood loss, length of proximal resected margin, postoperative hospital stays, and overall and major postoperative complications. Most of the complications were classified as minor according to the Clavien-Dindo classification. Operating time was significantly longer in the LTG group (mean: 257 min vs. 231 min, p = 0.006). LTG was superior to OTG groups in time to flatus (mean: 3.0 days vs 3.9 days, p < 0.001). Five-year OS and DFS rates were similar between the two groups (44% and 33% vs. 43% and 28% in the LTG and OTG groups, respectively). Our findings indicate that LTG is a feasible and safe technique, exhibiting comparable long-term oncological outcomes to OTG for sT4a GC. LTG may be an acceptable alternative to OTG for the treatment of sT4a GC.

Fast analysis of short-chain and ultra-short-chain fluorinated organics in water by on-line extraction coupled to HPLC-HRMS.

A rapid on-line solid-phase extraction liquid chromatography high-resolution mass spectrometry (on-line SPE-LC-HRMS) method was developed to analyze 11 ultra-short and short-chain PFAS in surface water. Analytical optimization involved screening 7 chromatographic columns and 5 on-line SPE columns, as well as evaluating SPE loading conditions, filters, sample acidification, chromatographic mobile phases, and SPE loading mobile phases. The optimized method was then applied to 44 river water samples collected in Eastern Canada, including sites near airports with fire-training areas. Among the 11 targeted PFAS, the most frequently detected were trifluoroacetic acid (TFA, 4.6-220 ng/L), perfluorobutanoic acid (PFBA, 0.85-33 ng/L), perfluoropentanoic acid (PFPeA, 1.2-2100 ng/L), trifluoromethane sulfonic acid (TMS, 0.01-4.3 ng/L), and perfluorobutane sulfonic acid (PFBS, 0.07-450 ng/L). Levels of C3-C5 perfluoroalkyl carboxylic acids (PFCAs), C2-C4 perfluoroalkyl sulfonates (PFSAs) and n:3 polyfluoroalkyl acids (n = 2,3; n:3 acids) were significantly higher in water bodies near fire-training area sites compared with rivers in urban areas. In contrast, TFA, TMS, and 1:3 acid were not significantly elevated, likely reflecting atmospheric deposition or other diffuse sources for these compounds. Nontarget and suspect screening analysis revealed an abundance of other ultra-short and short-chain PFAS in AFFF-impacted water bodies. Perfluoroalkyl sulfonamides (FASA, C2, C3, and C5), perfluoroalkyl sulfonamide propanoic acids (FASA-PrA, C1-C2) and n:3 acids (n = 1, 4, and 5) were detected for the first time in environmental surface waters.

Role of indocyanine green fluorescence imaging for evaluating blood supply in the gastric conduit via the substernal route after McKeown minimally invasive esophagectomy.

BACKGROUND: Anastomotic leakage (AL) is a determining factor of morbidity and mortality after esophagectomy. Adequate perfusion of the gastric conduit is crucial for AL prevention. This study aimed to determine whether intraoperative angiography using indocyanine green (ICG) fluorescence improves the incidence of AL after McKeown minimally invasive esophagectomy (MIE) with gastric conduit via the substernal route (SR). METHODS: This retrospective cohort study included 120 patients who underwent MIE with gastric conduit via SR for esophageal cancer between February 2019 and April 2023. Of 120 patients, 88 experienced intraoperative angiography using ICG (ICG group), and 32 patients experienced intraoperative angiography without ICG (no-ICG group). Baseline characteristics and operative outcomes, including AL as the main concern, were compared between the 2 groups. In addition, the outcomes among patients in the ICG group with different levels of fluorescence intensity were compared. RESULTS: The ICG and no-ICG groups were comparable in baseline characteristics and operative outcomes. There was no significant difference between the 2 groups regarding the rate of AL (31.0% vs 37.5%; P = .505), median dates of AL (9 vs 9 days; P = .810), and severity of AL (88.9%, 11.11%, and 0.0% vs 66.7%, 16.7%, and 16.7% for grades I, II, and III, respectively; P = .074). Patients in the ICG group with lower intensity of ICG had higher rates of leakage (24.6%, 39.3%, and 100% in levels I, II, and III of ICG intensity, respectively; P = .04). CONCLUSION: The use of ICG did not seem to reduce the rate of AL. However, abnormal intensity of ICG fluorescence was associated with a higher rate of AL, which implies a predictive potential.

Billroth-II modified with hinged anti-peristaltic afferent loop versus Roux-en-Y reconstruction after distal gastrectomy for gastric cancer: A propensity-score match analysis.

BACKGROUND: This study aimed to evaluate the effectiveness of modified Billroth-II with a hinged anti-peristaltic afferent loop by comparing it with the Roux-en-Y method. METHODS: We retrospectively analyzed 344 patients with gastric cancer who underwent distal gastrectomy between 2016 and 2021. Propensity score matching was conducted to balance baseline characteristics. RESULTS: After propensity score matching, there were 117 patients in each group. The Billroth-II group was significantly better regarding operating time (184.7 vs 225.3 minutes), postoperative hospital stays (7.9 vs 9.2 days), and time to semi-solid diet tolerance (2.8 vs 3.8 days). The Billroth-II group demonstrated comparable results with the Roux-en-Y group in weight loss, hemoglobin changes, reflux esophagitis, food residue, and gastritis severity. Presentation of bile in gastric remnant was significantly higher in the Billroth-II group (42.9% vs 10.3%). CONCLUSION: There were no significant differences in functional outcomes between Billroth-II and Roux-en-Y reconstructions. The Billroth-II was superior to Roux-en-Y in operating time, hospital stays, and time to semi-solid diet tolerance. The Billroth-II could be considered an acceptable alternative reconstruction after distal gastrectomy.

Reactivity of Enyne-Allenes Generated via an Alder-Ene Reaction.

Tandem transformations of 1,3-diynyl propiolate derivatives are described. The Alder-ene reaction generates an enyne-allene, which undergoes a formal 1,7-H shift or a Diels-Alder reaction, depending on the substituent on the alkyne. A terminal or aryl-substituted alkyne promotes a 1,7-H shift to generate a new enyne-allene, which undergoes a Myers-Saito cycloaromatization followed by a 1,5-H transfer-mediated cyclization to form highly functionalized benzo-fused 6-membered cycles. The reactivity of the preformed enyne-allene shows comparable reactivity profiles.

Comparison of substernal and posterior mediastinal route of reconstruction after minimally invasive esophagectomy for esophageal cancer.

BACKGROUND: Substernal (ST) and posterior mediastinal (PM) routes are the two most common for reconstruction after esophagectomy with cervical anastomosis. Recent evidence showed similar outcomes between the routes; thus, the superior choice remained controversial. This study aimed to compare the short-term outcomes of the ST to the PM route for reconstruction after esophagectomy for esophageal cancer (EC). METHOD: This retrospective cohort study included 132 patients who underwent McKeown minimally invasive esophagectomy (MIE) with gastric conduit for EC between March 2015 and December 2022. Among these, 89 and 43 patients received the ST route and PM route for reconstruction, respectively. Short-term outcomes including operative characteristics, postoperative morbidity, and mortality were evaluated. RESULT: There was no conversion from ST to PM route. The ST group had longer operating time (375 min vs. 341 min). Oral feeding initiation, postoperative hospital stays, and overall complication rates were comparable in the two groups. The rate and severity of anastomotic leakage were similar between the groups. The ST group had a significantly lower incidence of postoperative ICU admission and pneumonia compared to the PM group (5.6% vs. 16.3% and 19.1% vs. 37.2%, respectively). Azygos vein bleeding, obstruction at feeding jejunostomy site, and conduit-trachea fistula were severe complications that only occurred in PM route. CONCLUSION: ST route was superior to PM route in term of postoperative ICU admission and pneumonia. This route may prevent severe complications that only occur in PM route. ST route can be favorable option for reconstruction after McKeown MIE for EC.

Stomach-partitioning versus conventional gastrojejunostomy for unresectable gastric cancer with gastric outlet obstruction: A propensity score matched cohort study.

BACKGROUND: Stomach partitioning gastrojejunostomy (SPGJ) was introduced to deal with delayed gastric emptying (DGE). This study aimed to compare the short- and long-term outcomes of SPGJ versus conventional gastrojejunostomy (CGJ). METHOD: This cohort study analyzed 108 patients who underwent gastrojejunostomy for unresectable gastric cancer: 70 patients underwent SPGJ, and 38 patients underwent CGJ between 2018 and 2022. Propensity score-matched (PSM) analysis was used to balance the baseline characteristics. RESULTS: After PSM, there were 26 patients in each group. SPGJ group had significantly lower incidence of DGE (3.8% vs. 34.6%), vomiting (3.8% vs. 42.3%), and prokinetics requirement (11.5% vs. 46.2%). SPGJ group had significantly shorter time to solid diet tolerance (4.1 days vs. 5.7 days) and postoperative hospital stay (7.7 days vs. 9.3 days). There was no significant difference in relapse reinterventions, gastric outlet obstruction (GOO) recurrence, conversion surgery, and survival outcomes. CONCLUSIONS: SGPJ was associated with lower rate of DGE, prokinetics requirement, and shorter time of solid diet tolerance compared to CGJ in the treatment of unresectable gastric cancer patients with GOO.

Tracking down pharmaceutical pollution in surface waters of the St. Lawrence River and its major tributaries.

A reconnaissance survey was undertaken to evaluate the occurrence and risks of 27 pharmaceuticals and metabolites in the St. Lawrence watershed. Surface water samples were collected over a five-year period (2017-2021) along a 700-km reach of the St. Lawrence River as well as 55 tributary rivers (overall N = 406 samples). Additionally, depth water samples and sediments were collected near a major wastewater effluent. Caffeine, diclofenac, and venlafaxine were the most recurrent substances (detection rates >80 %), and extremely high levels were found near a municipal effluent (e.g., ibuprofen (860 ng/L), hydroxyibuprofen (1800 ng/L) and caffeine (7200 ng/L)). Geographical mapping and statistical analyses indicated that the St. Lawrence River water mass after the Montreal City effluent was significantly more contaminated than the other water masses, and that contamination could extend up to 70 km further downstream. This phenomenon was repeatedly observed over the five years of sampling, confirming that this is not a random trend. A slight increase in contamination was also observed near Quebec City, but concentrations rapidly declined in the estuarine transition zone. Tributaries with the highest pharmaceutical levels (ΣPharmas ∼400-900 ng/L) included the Mascouche, Saint-Régis, and Bertrand rivers, all located in the densely populated Greater Montreal area. When flowrate was factored in, the top five tributaries in terms of mass load (ΣPharmas ∼200-2000 kg/year) were the Des Prairies, Saint-François, Richelieu, Ottawa, and Yamaska rivers. All samples met the Canadian Water Quality Guideline for carbamazepine. Despite the large dilution effect of the St. Lawrence River, a risk quotient approach based on freshwater PNEC values suggested that four compounds (caffeine, carbamazepine, diclofenac, and ibuprofen) could present intermediate to high risks for aquatic organisms in terms of chronic exposure.

Optimizing time, cost, and carbon in construction: grasshopper algorithm empowered with tournament selection and opposition-based learning.

The global construction industry plays a pivotal role, yet its unique characteristics pose distinctive challenges. Each construction project, marked by its individuality, substantial value, intricate scale, and constrained adaptability, confronts crucial limitations concerning time and cost. Despite contributing significantly to environmental concerns throughout construction activities and infrastructure operations, environmental considerations remain insufficiently addressed by project managers. This research introduces an improved rendition of the muti-objective grasshopper optimization algorithm (MOGOA), termed eMOGOA, as a novel methodology to tackle time, cost, and carbon dioxide emission trade-off problems (TCCP) in construction project management. To gauge its efficacy, a case study involving 29 activities is employed. eMOGOA amalgamates MOGOA, tournament selection (TS), and opposition-based learning (OBL) techniques to enhance the performance of the original MOGOA. The outcomes demonstrate that eMOGOA surpasses other optimization algorithms, such as MODA, MOSMA, MOALO and MOGOA when applied to TCCP. These findings underscore the efficiency and relevance of the eMOGOA algorithm within the realm of construction project management.

Kinematic alteration in three-dimensional reaching movement in C3-4 level cervical myelopathy.

OBJECT: This study aimed to compare the reaching movement between two different spinal cord compression level groups in cervical myelopathy (CM) patients. METHODS: Nine CM patients with maximal cord compression at the C3-4 level (C3-4 group) and 15 CM patients with maximal cord compression at the C4-7 level (C4-7 group) participated in the study. We monitored three-dimensional (3D) reaching movement using an electronic-mechanical whack-a-mole-type task pre-and post-operatively. Movement time (MT) and 3D movement distance (MD) during the task were recorded. An analysis of variance for split-plot factorial design was performed to investigate the effects of compression level or surgery on MT and MD. Moreover, we investigated the relationship between these kinematic reaching parameters and conventional clinical tests. RESULTS: The 3D reaching trajectories of the C3-4 group was unstable with higher variability. The C3-4 group showed longer MT (p < 0.05) and MD (p < 0.01) compared with the C4-7 group both before and after surgery. Moreover, MT was negatively correlated with the Japanese Orthopedic Association score only in the C3-4 group (r = - 0.48). CONCLUSION: We found that spinal cord compression at the C3-4 level had a negative effect on 3D reaching movement and the kinematic alteration influenced the upper extremity performance. This new knowledge may increase our understanding of kinematic alteration in patients with CM.

Multimodal analysis of methylomics and fragmentomics in plasma cell-free DNA for multi-cancer early detection and localization.

Despite their promise, circulating tumor DNA (ctDNA)-based assays for multi-cancer early detection face challenges in test performance, due mostly to the limited abundance of ctDNA and its inherent variability. To address these challenges, published assays to date demanded a very high-depth sequencing, resulting in an elevated price of test. Herein, we developed a multimodal assay called SPOT-MAS (screening for the presence of tumor by methylation and size) to simultaneously profile methylomics, fragmentomics, copy number, and end motifs in a single workflow using targeted and shallow genome-wide sequencing (~0.55×) of cell-free DNA. We applied SPOT-MAS to 738 non-metastatic patients with breast, colorectal, gastric, lung, and liver cancer, and 1550 healthy controls. We then employed machine learning to extract multiple cancer and tissue-specific signatures for detecting and locating cancer. SPOT-MAS successfully detected the five cancer types with a sensitivity of 72.4% at 97.0% specificity. The sensitivities for detecting early-stage cancers were 73.9% and 62.3% for stages I and II, respectively, increasing to 88.3% for non-metastatic stage IIIA. For tumor-of-origin, our assay achieved an accuracy of 0.7. Our study demonstrates comparable performance to other ctDNA-based assays while requiring significantly lower sequencing depth, making it economically feasible for population-wide screening.

High Persistence of Novel Polyfluoroalkyl Betaines in Aerobic Soils.

Some contemporary aqueous film-forming foams (AFFFs) contain n:3 and n:1:2 fluorotelomer betaines (FTBs), which are often detected at sites impacted by AFFFs. As new chemical replacements, little is known about their environmental fate. For the first time, we investigated the biotransformation potential of 5:3 and 5:1:2 FTBs and a commercial AFFF that mainly contains n:3 and n:1:2 FTBs (n = 5, 7, 9, 11, and 13). Although some polyfluoroalkyl compounds are precursors to perfluoroalkyl acids, 5:3 and 5:1:2 FTBs exhibited high persistence, with no significant changes even after 120 days of incubation. While the degradation of 5:3 FTB into suspected products such as fluorotelomer acids or perfluoroalkyl carboxylic acids (PFCAs) could not be conclusively confirmed, we did identify a potential biotransformation product, 5:3 fluorotelomer methylamine. Similarly, 5:1:2 FTB did not break down or produce short-chain hydrogen-substituted polyfluoroalkyl acids (n:2 H-FTCA), hydrogen-substituted PFCA (2H-PFCA), or any other products. Incubating the AFFF in four soils with differing properties and microbial communities resulted in 0.023-0.25 mol % PFCAs by day 120. Most of the products are believed to be derived from n:2 fluorotelomers, minor components of the AFFF. Therefore, the findings of the study cannot be fully explained by the current understanding of structure-biodegradability relationships.

Percutaneous aspiration and absolute ethanol sclerotherapy in the treatment of symptomatic bronchogenic cyst.

Surgical treatment is indicated for both symptomatic and asymptomatic bronchogenic cysts. The goal of treatment is total removal of the cyst. Percutaneous aspiration and absolute ethanol sclerotherapy is an effective, minimally invasive, and safe alternative method. We present the case of a 74-year-old woman with a symptom of persistent dry cough for 5 months. Plain and contrast-enhanced chest computed tomography revealed a large superior mediastinal cyst that could be easily accessed percutaneously. The cyst was treated by aspiration and ethanol sclerotherapy under ultrasound guidance and fluoroscopy. The patient was discharged a day later without complications. Chest CT at 6 months follow-up showed complete regression of the cyst.

PFAS in fish from AFFF-impacted environments: Analytical method development and field application at a Canadian international civilian airport.

Methods targeting anionic per- and polyfluoroalkyl substances (PFAS) in aquatic biota are well established, but commonly overlook many PFAS classes present in aqueous film-forming foams (AFFFs). Here, we developed an analytical method for the expanded analysis of negative and positive ion mode PFAS in fish tissues. Eight variations of extraction solvents and clean-up protocols were first tested to recover 70 AFFF-derived PFAS from the fish matrix. Anionic, zwitterionic, and cationic PFAS displayed the best responses with methanol-based ultrasonication methods. The response of long-chain PFAS was improved for extracts submitted to graphite filtration alone compared with those involving solid-phase extraction. The validation included an assessment of linearity, absolute recovery, matrix effects, accuracy, intraday/interday precision, and trueness. The method was applied to a set of freshwater fish samples collected in 2020 in the immediate vicinity (creek, n = 15) and downstream (river, n = 15) of an active fire-training area at an international civilian airport in Ontario, Canada. While zwitterionic fluorotelomer betaines were major components of the subsurface AFFF source zone, they were rarely detected in fish, suggesting limited bioaccumulation potential. PFOS largely dominated the PFAS profile, with record-high concentrations in brook sticklebacks (Culaea inconstans) from the creek (16000-110,000 ng/g wet weight whole-body). These levels exceeded the Canadian Federal Environmental Quality Guidelines (FEQG) for PFOS pertaining to the Federal Fish Tissue Guideline (FFTG) for fish protection and Federal Wildlife Diet Guidelines (FWiDG) for the protection of mammalian and avian consumers of aquatic biota. Perfluorohexane sulfonamide and 6:2 fluorotelomer sulfonate were among the precursors detected at the highest levels (maximum of ∼340 ng/g and ∼1100 ng/g, respectively), likely reflecting extensive degradation and/or biotransformation of C6 precursors originally present in AFFF formulations.

Target and nontarget screening of PFAS in drinking water for a large-scale survey of urban and rural communities in Québec, Canada.

Limited monitoring data are available regarding the occurrence of emerging per- and polyfluoroalkyl substances (PFAS) in drinking water. Here, we validated an analytical procedure for 42 PFAS with individual detection limits of 0.001-0.082 ng/L. We also evaluated how different sample pH conditions, dechlorinating agents, and storage holding times might affect method performance. PFAS were analyzed in tap water samples collected at a large spatial scale in Quebec, Canada, covering 376 municipalities within 17 administrative regions. Target and nontarget screening revealed the presence of 31 and 23 compounds, respectively, representing 24 homolog classes. Overall, 99.3% of the tap water samples were positive for at least one PFAS, and the Æ©PFAS ranged from below detection limits to 108 ng/L (95th percentile: 13 ng/L). On average, Æ©PFAS was 12 times higher in tap water produced from surface water than groundwater; however, 6 of the top 10 contaminated locations were groundwater-based. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) had high detection rates (88% and 80%, respectively). PFOS (median: 0.15 ng/L; max: 13 ng/L) and PFOA (median: 0.27 ng/L; max: 8.1 ng/L) remained much lower than current Health Canada guidelines but higher than USEPA's interim updated health advisories. Short-chain (C3-C6) perfluoroalkyl sulfonamides were also recurrent, especially the C4 homolog (FBSA: detection rate of 50%). The 6:2 fluorotelomer sulfonyl propanoamido dimethyl ethyl sulfonate (6:2 FTSO2PrAd-DiMeEtS) was locally detected at ∼15 ng/L and recurred in 8% of our samples. Multiple PFAS that are most likely to originate from aqueous film-forming foams were also reported for the first time in tap water, including X:3 and X:1:2 fluorotelomer betaines, hydroxylated X:2 fluorotelomer sulfonates, N-trimethylammoniopropyl perfluoroalkane sulfonamides (TAmPr-FHxSA and TAmPr-FOSA), and N-sulfopropyl dimethylammoniopropyl perfluoroalkane sulfonamidopropyl sulfonates (N-SPAmP-FPeSAPS and N-SPAmP-FHxSAPS).