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Fort McMurray and the Athabasca oil sands region (AOSR) experienced major wildfires in 2016, but the impact of these on regional deposition of polycyclic aromatic hydrocarbons (PAHs) and trace elements has not been reported nor compared to industrial sources of these pollutants in the region. Living moss (Sphagnum fuscum) was collected in triplicate from five ombrotrophic bogs in the AOSR after the wildfires, and analyzed for PAHs and trace elements. These post-wildfire data were compared to data from previous years at the same sites, and also to remote reference bogs in Alberta and Ontario. Elevated post-wildfire concentrations and flux of naphthalene and fluorene were observed at all five bogs in the AOSR, but no consistent trend was evident for higher molecular weight PAHs or the sum of priority PAHs (∑ 13 PAH). Trace elements at most AOSR bogs were not elevated post-wildfire, except at one bog in the burned area (MIL), but even here the elements that were increased (1.7-5.6 × ) were likely of bitumen-origin (i.e., V, Ni, Se, Mo and Re). Significant post-wildfire correlations between PAHs and most trace elements suggested a common source, and few significant correlations were observed with retene, suggesting that wildfires were not the dominant source of most contaminants detected. Mass balance receptor models were used to apportion sources, indicating that the major sources of trace elements among five AOSR bogs post-wildfire were oil sands ore (mean 42%), haul road dust (17%), and petcoke (11%), whereas wildfire was always a minor source (3-4%). For PAHs at the most contaminated site (MIL), delayed petcoke (27%) and wildfire (25%) were the major sources, but the contribution of wildfire to PAHs at other sites was less or not discernable. Impacts of the 2016 wildfires on regional atmospheric deposition of major pollutants was less than from ongoing deposition of anthropogenic dust from oil sands activities., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Selenium (Se) is one of the trace elements that is enriched in bitumen. To assess the importance of atmospheric Se deposition from mining and upgrading of bituminous sands in northern Alberta, Canada, Sphagnum moss was obtained from 25 bogs near industrial operations. The average Se concentration in moss near industries (58 ± 13 μg/kg; n = 75) was greater than in remote sites in Alberta (29-50 μg/kg), but comparable to bogs in central regions of the province and lower than bogs in southern Ontario (121-244 μg/kg) or the west and east coasts (230-285 μg/kg). In bog vegetation and peat, arsenic (As) concentrations and accumulation rates are 10 times greater at the industrial site (MIL) compared to the control site (UTK), but this is proportional to the differences in scandium (a surrogate for mineral matter concentrations), which points to dust as the predominant As source. An age-dated peat core collected near industries revealed that both Se and As deposition have declined in recent years. A peat core from UTK provided a record of atmospheric deposition dating back over 2700 years, indicating that As and Se deposition in northern Alberta increased considerably in the early 19th century and then went into decline during ∼1950-1970.

Biopolymers derived from modified poultry feathers (KB) were developed to target a broad range of potentially toxic trace elements for their removal from synthetic wastewater and industrial process affected water. The chemical modifications increased surface functionality of KBs for enhanced metal adsorption. Unmodified KB (SM-03) added to synthetic wastewater spiked with nine transition and redox sensitive elements (30-50 μg L -1 each) removed >82% of Pb, Ni, Co and Zn, whereas modified KBs (SM-01 and SM-06) removed 68-100% of Se IV , V V and Cr VI . Similar results were observed when spiked process water was used. Experimental observation suggested chemical reduction of redox sensitive elements on the modified KB surfaces to their non-toxic/non-mobile redox states. Biopolymer SM-06 showed a maximum adsorption capacity of 17 mg g -1 for V V and 15 mg g -1 for Cr VI at ~20 °C. Due to the abundance of raw material and simplicity of the modifications presented here, modified KBs may serve as a useful option for large-scale water treatment., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Selenium in the lower Athabasca River (Alberta, Canada) is of concern due to potential inputs from the weathering of shallow bitumen deposits and emissions from nearby surface mines and upgraders. Understanding the source of this Se, however, is complicated by contributions from naturally saline groundwater and organic matter-rich tributaries. As part of a two-year multi-disciplinary study to assess natural and anthropogenic inputs, Se and its chemical speciation were determined in water samples collected along a ∼125 km transect of the Athabasca River and associated tributaries. Selenium was also determined in the muscle of Trout-perch (Percopsis omiscomaycus), a non-migratory fish species, that were sampled from selected locations. Dissolved (<0.45 μm) Se in the Athabasca River was consistently low in 2014 (0.11 ± 0.02 μg L -1 ; n = 14) and 2015 (0.16 ± 0.02 μg L -1 ; n = 21), with no observable increase from upstream to downstream. Selenate was the predominant inorganic form (∼60 ng L -1 ) and selenite was below detection limits at most locations. The average concentration of Se in Trout-perch muscle was 2.2 ± 0.4 mg kg -1 (n = 34), and no significant difference (p > 0.05) was observed between upstream and midstream (industrial) or downstream reaches. Tributary waters contained very low concentrations of Se (typically < 0.1 μg L -1 ), which was most likely present in the form of dissolved organic colloids., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Organic and inorganic colloids play important roles governing the speciation, transport, and bioaccessibility of trace elements in aquatic systems. These carriers are especially important in the boreal zone, where rivers that contain high concentrations of iron and organic matter are prevalent. The distribution of trace elements amongst different colloidal species (or "speciation profile") can therefore be useful as a fingerprint to detect different trace element sources and for tracking colloid transformations, with implications for bioaccessibility. Asymmetrical flow field-flow fractionation coupled to an inductively coupled plasma mass spectrometer was applied to detect the source of trace elements based on their speciation profile along a 125-km stretch of a large river in the Canadian boreal forest. Both the concentration and proportion of bound trace elements were increased by tributary inputs: bound As, Co, Fe, Mn, Pb, U, and Zn increased monotonically from upstream to downstream, increasingly resembling the speciation profile of tributaries. Principal component (PC) analysis also revealed tributary contributions of bound Cu, Ni, Th, V, and Y reflecting their higher concentrations in tributaries, and PC scores also increased monotonically from upstream-downstream. Monotonically decreasing concentrations of mainly ionic and small (i.e.

With growth of the Canadian oil sands industry, concerns have been raised about possible seepage of toxic oil sands process-affected water (OSPW) into the Athabasca River (AR). A sampling campaign in fall 2015 was undertaken to monitor for anthropogenic seepage while also considering natural sources. Naphthenic acids (NAs) and thousands of bitumen-derived organics were characterized in surface water, groundwater, and OSPW using a highly sensitive online solid phase extraction-HPLC-Orbitrap method. Elevated NA concentrations and bitumen-derived organics were detected in McLean Creek (30.1 μg/L) and Beaver Creek (190 μg/L), two tributaries that are physically impacted by tailings structures. This was suggestive of OSPW seepage, but conclusive differentiation of anthropogenic and natural sources remained difficult. High NA concentrations and bitumen-derived organics were also observed in natural water located far north of the industry, including exceedingly high concentrations in AR groundwater (A5w-GW, 2000 μg/L) and elevated concentration in a tributary river (Pierre River, 34.7 μg/L). Despite these evidence for both natural and anthropogenic seepage, no evidence of any bitumen-derived organics was detected at any location in AR mainstem surface water. The chemical significance of any bitumen-derived seepage to the AR was therefore minimal, and focused monitoring in tributaries will be valuable in the future.

Human and ecosystem health concerns for arsenic (As) in the lower Athabasca River downstream of Athabasca Bituminous Sands (ABS) mining (Alberta, Canada) prompted an investigation to determine its forms in surface and groundwater upstream and downstream of industry. Dissolved As species, together with total and particulate As, were used to evaluate the potential bioavailability of As in water as well as to decipher inputs from natural geological processes and ABS mining and upgrading activities. Water samples were collected from the river in October at 13 locations in 2014 and 19 locations in 2015, spanning up to 125 km. Additional samples were collected from groundwater, tributaries and springs. "Dissolved" (<0.45 μm) As was consistently low in the Athabasca River (average 0.37 ± 0.01 and 0.34 ± 0.01 μg L -1 in 2014 and 2015, respectively) as well as tributaries and springs (<1 μg L -1 ), with As(V) as the predominant form. The average total As concentration was higher in 2014 (12.7 ± 2.8 μg L -1 ) than 2015 (3.3 ± 0.65 μg L -1 ) with nearly all As associated with suspended solids (>0.45 μm). In 2014, when total As concentrations were greater, a significant correlation (p < 0.05) was observed with thorium in particles > 0.45 μm, suggesting that mineral material is an important source of As. Naturally saline groundwater contained low dissolved As (<2 μg L -1 ) and did not appear to be a significant source to the river. Arsenic in shallow groundwater near a tailings pond exceeded 50 μg L -1 predominantly as As(III) warranting further investigation., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Water samples were collected on the Athabasca River (AR), upstream and downstream from bitumen mines and upgrading facilities, to identify changes in water quality due to industrial activities in this region of northern Alberta, Canada. Starting upstream of Fort McMurray and proceeding downstream ca. 100km, waters were collected in duplicate at 13 locations on the main stem of the river, as well as 5 tributary streams, using ultraclean sampling protocols developed for polar snow and ice. To estimate potential bioaccessibility, trace elements of concern (Ag, Cd, Pb, Sb, Tl) were determined in the dissolved fraction (<0.45μm) along with metals known for their enrichments in bitumen (V, Ni, Mo, Re) and those found mainly in ionic (Li, Sr) or colloidal forms (Al, Co, Cr, Fe, Ga, Mn, Th, Y). Analyses were performed in the metal-free, ultraclean SWAMP lab using quadrupole and sector-field ICP-MS. Concentrations of Ag, Cd, Pb, Sb and Tl were extremely low, not significantly more abundant downstream of industry and probably reflect "background" values. In contrast, V, Ni, Mo and Re concentrations were all significantly (p<0.05) greater downstream of industry. However, chloride also increased downstream, due to natural inputs of saline groundwaters and it is unclear whether the increases in V, Ni, Mo and Re are due to natural or anthropogenic inputs to the river. Although it had been claimed that the industrial development of the Athabasca Bituminous Sands (ABS) is a significant source of Ag, Cd, Pb, Sb and Tl to the river, our study failed to find any evidence to support this. Here we provide a first, robust (accurate and precise) description of baseline values for these trace elements in the AR, and suggest that V, Ni, Mo and Re are more valuable tracers for environmental monitoring and source assessment., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Objective: To review the physiologic basis for normal and abnormal vagal reflexes arising from the pharynx, larynx, and esophagus, as well as the relevance of vagal reflexes to the pathogenesis of such clinically common cardiorespiratory responses as bradycardia, tachycardia, dysrhythmia, coronary angiospasm, bronchospasm, laryngospasm, prolonged apnea, and singultus (hiccups)., Data Sources: Pertinent articles and reviews were identified through a MEDLINE search (April 1966 to October 1991). Older studies and others not identified in the MEDLINE search were found through a manual search of the bibliographies of the retrieved articles., Study Selection: Experimental studies in both humans and animals, as well as case series and single case reports, were selected for evaluation and citation. In instances where a similar phenomenon was described in multiple independent reports, only studies that provided a novel finding or interpretation were cited. More authoritative book chapters and peer-reviewed summaries were also cited in support of commonly accepted principles., Data Extraction and Synthesis: Most of the clinical data are derived from case reports and small case series and are therefore anecdotal; equal weight was given to all such studies. Reports of conflicting observations or interpretations were clearly identified and were cited without exception., Conclusions: Stimulation of the upper aerodigestive tract can lead to clinically significant cardiorespiratory responses. Although the prevalence of and risk factors for such responses have not been established, we suggest that a pharyngeal, a laryngeal, or an esophageal source for abnormal cardiorespiratory responses be sought whenever a detailed clinical evaluation fails to reveal a cause, particularly when there are concurrent symptoms or signs of upper aerodigestive tract disease, such as dysphagia or gastroesophageal reflux.

Twenty patients with a remote history of poliomyelitis and recent or progressive dysphagia were evaluated with cinefluorography. Radiographic abnormalities were present in the pharynx in varying degrees in all but one of the patients. Findings included atrophy of the prevertebral soft tissues, unilateral or bilateral weakness of the tongue or soft palate, paresis or paralysis of the pharyngeal constrictor muscle, incomplete or absent epiglottic tilt, poor laryngeal elevation, poor laryngeal closure with laryngeal penetration, aspiration (often without a cough), and luminal narrowing at the cricopharyngeal level. Other structural lesions included a Zenker diverticulum in one patient, bilateral pharyngeal pouches in five, and a unilateral pouch in one. Additional structural lesions contributing to dysphagia were found in two other patients, including a focal stricture in the cervical esophagus in one patient and two stenotic rings in the distal esophagus in another. In four patients (one of whom had the Zenker diverticulum), the inferior constrictor muscle contracted forcibly above a prominent cricopharyngeus muscle, perhaps contributing to the formation of the diverticulum. It is important to examine postpolio patients with dysphagia carefully with dynamic imaging to assess the severity of decompensation and to detect other lesions that may be treatable. The information derived can be used to guide management.

Despite warnings against attributing dysphagia to psychological causes, the diagnoses of "psychogenic dysphagia" or "globus hystericus" have been previously applied to 13% of patients referred to the Johns Hopkins Swallowing Center. This paper reports the results of reevaluation of 23 patients previously diagnosed as having symptoms of psychogenic origin. The Swallowing Center evaluation documented an explanation for symptoms in 15 (65%). No cause of dysphagia could be documented in eight patients. All five patients with the "globus sensation" had a documentable abnormality of swallowing. Overall, nine patients had esophageal pathology, while six had pharyngeal disease. Five had structural lesions constricting the lumen, while 10 had motor dysfunction of either the pharynx or esophagus. Review of the referral records of these patients indicates the quality of prior evaluation for patients previously labeled as having a swallowing disorder of psychogenic origin is variable, and that once attribution of symptoms to psychogenic causes is made, the diagnosis is rarely reconsidered. We conclude that attribution of the diagnosis of psychogenic dysphagia should be made with caution, and only after thorough evaluation. Any change or progression of symptoms should prompt a careful re-evaluation.

Simultaneous disorders of the pharynx and esophagus are so frequent that the complete swallowing chain should be examined in all patients with dysphagia. Data are presented to support the concept that such simultaneous disorders represent related phenomena; the mechanism involves changes in cricopharyngeal function seen radiographically as cricopharyngeal prominence. If neurologic disease has been excluded, cricopharyngeal prominence may be the clue to esophageal disease. When cricopharyngeal prominence is found during dynamic imaging of the pharynx, intensive examination of the esophagus and a search for signs of compensation or decompensation in the pharynx should be undertaken.

The analysis of gastric motility makes possible the distinction between purely anatomic changes and those of a functional nature with or without associated morphologic alterations. Hence, through evaluation of gastric and duodenal motor function contributes significantly to the radiographic examination of the upper gastrointestinal tract.

A plastic holding device has been devised to allow in vitro computed tomography of term human placentas. Graded dilutions of iodinated contrast medium have been injected into the fetal placental circulation and into the intervillous space of placental lobules perfused with normal saline solution. Computed tomography in different orientations has imaged Borell's "jets" on the maternal side and cotyledonary vascular "puffs" on the fetal side of the placenta. Attenuation coefficients, before and after injection of contrast medium may be used for quantitative investigation of the physiological placental circulation and possibly for diagnosing placental pathology.

Experiments were done to test the hypothesis that emptying the gallbladder prior to intravenous cholangiography (IVC) would result in earler and better opacification of the gallbladder. Five dogs were studied on two separate days in a crossover experiment. Each dog had a standard IVC (15-minute infusion of meglumine iodipamide) 2.5 cc/kg of following a 14-16-hour fasting period. On one of the days, 0.3 mcg/kg of Ceruletide was intramuscularly administered to each dog 30 to 45 minutes prior to the iodipamide infusion. Films obtained at the end of infusion and at 20, 40, 60, and 90 minutes were evaluated independently by three radiologists. The results indicate that pretreatment with Ceruletide produces a significant (p less than 0.05) improvement in the quality of gallbladder opacification during the first 90 minutes following iodipamide infusion. We conclude that earlier and better opacification of the gallbladder during IVC can be obtained by prior emptying of the gallbladder with a cholecystokinetic agent.

Imaging maternal and fetal circulation during perfusion of isolated human placental lobules was performed. Radionuclide and contrast angiograms, specimen scans, and histologic preparations obtained on human material during in vitro investigations were compared to the results obtained in vivo on pregnant rhesus monkeys. The distribution of maternal blood flow within the placenta appeared similar in both human and rhesus studies. The 'spurts' of radiopaque medium shown on the contrast angiograms correlated with the appearance of areas of increased radioactivity. These 'hot spots' are located where the uteroplacental spiral arteries open into the intervillous space or where the perfusion cannulae irrigate the maternal side of the placenta. Time-radioactivity curves reached an early peak and remained the same as did their distribution on delayed scans. The 15 to 30 micron microspheres injected into the intervillous spaces are not removed onto the venous side by maternal flow through arteriovenous communications (or 'shunts') but are retained in localized areas of the intervillous space adjacent to the spiral arteries. Many of these microspheres adhere to the 'brush border' of the chorionic villi syncytiotrophoblast. These comparative studies confirm that rhesus monkeys and perfused human placental lobules are relevant models to investigate uteroplacental hemodynamics.

The technique of dynamic imaging of the pharynx and some supplementary maneuvers which can be tailored to the individual patient's needs are discussed in detail. An approach to the analysis of normal and abnormal swallowing studies is presented.

Under normal circumstances, the act of swallowing adjusts to varying demands of different bolus characteristics and different head and neck postures. When the swallowing mechanism is impaired by disease, adjustment is essential to compensate for the impairment and allow swallowing. Evidence of adjustment can be demonstrated by cineradiography which provides important clues to the presence of underlying disease. When adjustment to disease is inadequate, swallowing decompensates. In this case, gross changes in swallowing performance are evident from clinical evaluation and cineradiography.

Difficulty in swallowing is not an uncommon symptom. Approximately 10,000 persons choke to death every year in the United States, and at least 50% of patients in nursing homes have some difficulty eating or drinking. Dysphagia will become an increasing problem as the population continues to age, as more intensive resuscitative measures are applied, and as more aggressive head and neck surgery is performed. The practicing radiologist should be familiar with the examination technique and interpretation of swallowing studies.

Radiographic evaluation of the passage of a bolus from the mouth through the pharynx into the esophagus is based upon identification of specific anatomical landmarks and the integrated motion accomplished by the oral and pharyngeal muscles during swallowing. Twenty-six muscles and 6 cranial nerves must be coordinated to enable the safe performance of the complex physiological task of transporting liquids and firm food from the mouth into the esophagus. The following discussion and illustrations of pharyngeal anatomy and physiology are pertinent to an understanding of normal swallowing function.

Diagnostic imaging procedures are useful to analyze the complex mechanism of swallowing. They may be employed beneficially to answer specific questions of swallow coordination, and to distinguish between various forms of airway penetration. The pathophysiology of upper and lower airway involvement may be determined and visualized.

This paper describes the purpose and organization of a dedicated center at The Johns Hopkins Medical Institutions for the evaluation of swallowing problems. The multidisciplinary approach outlined will permit a better understanding and more accurate diagnosis of the functional or organic lesions affecting the swallowing mechanisms. Illustrative cases are presented.

This superbly illustrated article is an invaluable guide to the interpretation of double contrast pharyngograms.

Difficulty in swallowing is not an uncommon symptom. Approximately 10,000 persons choke to death every year in the United States, and at least 50% of patients in nursing homes have some difficulty eating or drinking. Dysphagia will become an increasing problem as the population continues to age, as more intensive resuscitative measures are applied, and as more aggressive head and neck surgery is performed. The practicing radiologist should be familiar with the examination technique and interpretation of swallowing studies.

Microfilariae of O. volvulus were recovered from the urine of 11% of the residents of a village in the Republic of Chad where onchocerciasis was holoendemic. A follow-up study of the same population 3 years after the original investigation revealed that microfilaruria was still present and that living microfilariae of O. volvulus could be recovered from small urine samples obtained by high catherization of the ureters. Radiological changes consistent with chronic pyelitis were found in 4 out of 14 persons with microfilaruria who were examined by retrograde pyelography. The recovery of microfilariae in the urine was associated with the intensity of the infection, as determined by counts of microfilariae in skin snips and the number of onchocercomata. A systematic comparison for differences between onchocerciasis patients with and without microfilaruria revealed that the microfilaruria patients had a low weight: height ratio, deficient antibody responses in indirect haemagglutination tests with O. volvulus antigen, elevated serum aminotransferase levels, and reduced systolic blood pressure.