Beatriz Bicalho - Academia.edu (original) (raw)

Papers by Beatriz Bicalho

Research paper thumbnail of Prospecção de antibioticos e biocatalisadores

o presente trabalho foi organizado em 3 partes. A primeira delas compreende a investigacao por co... more o presente trabalho foi organizado em 3 partes. A primeira delas compreende a investigacao por compostos antimicrobianos em extratos de metabolitos secundarios de 15 fungos filamentosos isolados de abelhas (Trigona sp.). A aplicacao dos ensaios de bioautografia e concentracao inibitoria minima (CIM) a monitorizacao da atividade biologica resultou no isolamento de 4 substâncias conhecidas, sendo 2 quinonas isomericas (coclioquinona A e isococlioquinona A) de Drechslera dematioidea CCT 5631 e 2 dodecalactonas analogas (curvularina e E-desidrocurvularina) de Curvularia eragrostidis CCT 5634 e de Curvularia pallescens CCT 5654, as quais, em geral, apresentaram valores de CIM altos, relativamente a antibioticos padrao (cloranfenicol, ciclopiroxolamina). A segunda parte do trabalho trata da investigacao por haloperoxidases (HPOs) e por Baeyer-Villiger monoxigenases (BVMOs) em diferentes microrganismos. A atividade de HPO nao foi detectada nos experimentos realizados, os quais foram realizados com o indeno como substrato. Em contrapartida, utilizando cicloexanonas, BVMOs foram detectadas em Geotrichum candidum CCT 1205, Rhodotorula glutinis CCT 2182 e Rhodotorula minuta CCT 1751, ainda que nas reacoes com estes ultimos os porcentuais de conversao do substrato tenham sido baixos (:::; 10%) relativamente a G. candidum CCT 1205 (60 - 90%). O monitoramento de reacoes de biotransformacao simultâneas (mais de 1 substrato por microrganismo) foi introduzido com sucesso nesta etapa do trabalho, representando uma primeira acao de otimizacao do processo de triagem de biocatalisadores em microrganismos. A terceira e ultima parte do trabalho focaHsou a implementacao de triagens para biocatalisadores baseadas em fluorescencia. Os experimentos realizados proporcionaram deteccoes ineditas de BVMO em Trichosporon cutaneum CCT 1903 e de epoxido hidrolases em Pichia stipitis CCT 2617, T. cutaneum CCT 1903 e em Agrobacterium tumefaciens CCT 6515 Abstract

Research paper thumbnail of Desafios da qu�mica anal�tica frente �s necessidades da ind�stria farmac�utica

Research paper thumbnail of Blood Bag Plasticizers Influence Red Blood Cell Vesiculation Rate without Altering the Lipid Composition of the Vesicles

Transfusion Medicine and Hemotherapy, 2015

Background: Polyvinyl chloride (PVC) plasticized with di(2-ethylhexyl) phthalate (DEHP) is common... more Background: Polyvinyl chloride (PVC) plasticized with di(2-ethylhexyl) phthalate (DEHP) is commonly used for blood collection and storage. DEHP has protective effects on RBC membranes, but is also a toxin. Methods: A paired study was conducted to investigate the influence of DEHP and two alternative plasticizers, 1,2-cyclohexane-dicarboxylic acid diisononyl ester (DINCH) and nbutyryl-tri-n-hexyl citrate (BTHC), on the preservation of RBCs stored for 42 days in PVC pediatric bags. The RBC membrane was evaluated for supernatant hemoglobin (Hb), release of extracellular microvesicles (EVs), osmotic fragility, deformability, and lipid composition. Results: In BTHC-plasticized bags, the supernatant Hb increase during storage was 2 times greater than in DINCH-and DEHP-plasticized bags. By day 21, EV concentrations had doubled from day-5 levels in DINCH-and DEHP-, and trebled in BTHC-plasticized bags. RBC mean cell volumes were greater in BTHC-than in DINCH-or DEHP-plasticized bags (p < 0.001). Osmotic fragility differed significantly among plasticizers (p < 0.01). After day 21, RBC deformability decreased in all, but to a greater extent in the bags with BTHC. Phospholipid composition of RBCs and EVs was not different among plasticizers. Conclusion: Membrane stabilization capacity differed among the plasticizers. RBC in BTHC bags stored more poorly, while DEHP and DINCH bags offered better protection against vesiculation, osmotic stress, and Hb loss.

Research paper thumbnail of The effects of rejuvenation during hypothermic storage on red blood cell membrane remodeling

Transfusion, 2013

Our previous studies showed that hypothermic storage (HS) induces red blood cell (RBC) microparti... more Our previous studies showed that hypothermic storage (HS) induces red blood cell (RBC) microparticle (RMP) generation and changes in phosphatidylserine (PS) and CD47 expression on RBCs and RMPs. The aim of this study was to evaluate the effect of cold rejuvenation treatment at multiple time points during storage on these prehemolytic indicators of RBC membrane storage lesion. Leukoreduced RBC units in saline-adenine-glucose-mannitol were used to generate three groups: untreated controls, sham-treated units, and units treated with a cold (1-6°C) rejuvenation solution on Day 28, 35, or 42 of HS. Units were assessed for hemolysis, adenosine triphosphate (ATP) concentration, lipid composition, and RMP generation, as well as PS and CD47 expression throughout 49 days of HS. Rejuvenation treatment led to a significant increase in ATP concentration in all units, irrespective of treatment day. There were no significant differences between sham- and rejuvenation-treated RBC samples in the levels of PS externalization, CD47 expression, or the rate of RMP formation. RBCs rejuvenated on Day 28 were enriched in glycerophosphocholine (+23.5%), depleted in sphingomyelin (-14%), and slightly depleted in cholesterol (-3.5%). Cold rejuvenation in hypothermically stored RBCs affects the lipid composition of RBCs and respective RMPs in a time-dependent fashion.

Research paper thumbnail of Comparison of propolis from Apis mellifera and Tetragonisca angustula

Apidologie, 2003

High-temperature high-resolution gas chromatography (HT-HRGC) and HT-HRGC coupled to mass spectro... more High-temperature high-resolution gas chromatography (HT-HRGC) and HT-HRGC coupled to mass spectrometry (HT-HRGC-MS) were applied to the study of propolis collected by Apis mellifera and by Tetragonisca angustula, a stingless bee native to southeastern Brazil. With the exception of amino acids and erytrose/erythritol content, both propolis samples were quite similar in composition and in antimicrobial activity. Triterpenes were the most abundant compounds in the samples, comprising more then 35% of the total amount of each sample. propolis / Apis mellifera / Tetragonisca angustula

Research paper thumbnail of Application of High-Temperature Gas Chromatography−Mass Spectrometry to the Investigation of Glycosidically Bound Components Related to Cashew Apple ( Anacardium occidentale L. Var. nanum ) Volatiles

Journal of Agricultural and Food Chemistry, 2000

Free and bound volatile components of a Brazilian cashew apple variety (Anacardium occidentale L.... more Free and bound volatile components of a Brazilian cashew apple variety (Anacardium occidentale L. var. nanum) were obtained by simultaneous distillation-extraction (SDE) and XAD-2 adsorption. According to gas chromatography-mass spectrometry (GC-MS) analyses and retention indices, 62 free volatile constituents were characterized and quantified. They were esters (40%), terpenes (20%), hydrocarbons (14%), fatty acids (9%), aldehydes (8%), alcohols (3%), lactones (3%), ketones (1%), phenols (1%), and norisoprenoids (1%). The glycosidically bound volatile precursors were analyzed by high-temperature GC-MS, after room temperature silylation. Several conjugated alcohols and cinnamic acids were detected and reported as cashew apple glycosyl constituents for the first time.

Research paper thumbnail of In vitro mutagenicity of anti-inflammatory parsalmide analogues PA7, PA10, and PA31 triggered by biotransformation into hydroxy derivatives

European Journal of Medicinal Chemistry, 2006

In this study, the mutagenicity of the anti-inflammatory parsalmide [5-amino-N-butyl-2-(2-propyny... more In this study, the mutagenicity of the anti-inflammatory parsalmide [5-amino-N-butyl-2-(2-propynyloxy)-benzamide] analogues PA7 [5-amino-N-butyl-2-cyclohexyloxy-benzamide], PA10 [5-amino-N-butyl-2-phenoxy-benzamide] and PA31 [5-amino-N-butyl-2-(p-tolyloxy)-benzamide] was determined by an Ames Salmonella assay. The experiments were performed by preincubating the compounds in the absence and presence of a post-mitochondrial fraction (S9) of rat liver homogenate from phenobarbital/β-naphtoflavone treated rats. No mutagenic effect was observed after direct testing (no S9 added) in Salmonella typhymurium strains TA98, TA100, TA102, TA1535 and TA1537. However, in the presence of S9, the test substances triggered mutagenic responses in strains TA100 and TA98. PA31 presented the strongest mutagenic potential. The reversion rates in the presence of PA31 were about 2-19 fold higher than spontaneous mutation rates. In the presence of PA7, the reversion increased 2-14-fold over spontaneous rates. While PA10 showed a relatively mild mutagenic potential, as the number of revertants did not exceed 2.5 times the number of spontaneous mutations. Mass spectrometric analysis of the in vitro biotransformation showed that S9 converted (%), regioselectively, PA7 (19%), PA10 (7%) and PA31 (12%) into hydroxy-derivatives.

Research paper thumbnail of Pharmacokinetics of Dihydroergocristine and Its Major Metabolite 8- Hydroxy-Dihydroergocristine in Human Plasma

Current Drug Metabolism, 2005

Dihydroergocristine (DHEC) is a semi-synthetic drug mainly used for age-related cognitive impairm... more Dihydroergocristine (DHEC) is a semi-synthetic drug mainly used for age-related cognitive impairment. In this study, its major metabolite 8&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-hydroxy-dihydroergocristine (8&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-OH-DHEC) was produced in incubates of a bovine liver preparation using dihydroergocristine mesylate (DHECM) as substrate. Purification was achieved by flash silica gel column and reverse phase liquid chromatographies, and identification was based on accurate molecular mass measurements, mass fragmentation spectra and NMR ((1)H/(13)C) chemical shifts. By using the substance produced in vitro, a fast, sensitive, specific and robust LC/MS/MS method for the simultaneous determination of DHEC and its major metabolite in human plasma was developed and validated. Bromocriptine was used as internal standard and limits of quantification for DHEC and 8&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-OH-DHEC were 10 pg/ml and 20 pg/ml, respectively. Pharmacokinetic parameters were investigated on 12 male healthy volunteers to whom a single dose of 18 mg DHECM was administered in tablets (Iskevert). The peak of DHEC was 0.28 +/- 0.22 microg/l, the t(max) 0.46 +/- 0.26 h, the AUC(last) 0.39 +/- 0.41 microg/l.h and the terminal elimination half-life 3.50 +/- 2.27 h. The peak of 8&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-OH-DHEC was 5.63 +/- 3.34 microg/l, the t(max) 1.04 +/- 0.66 h, the AUC(last) 13.36 +/- 5.82 microg/l.h and the terminal elimination half-life 3.90 +/- 1.07 h. Dosing of 18 mg DHECM was well tolerated, causing no adverse events.

Research paper thumbnail of Identification and human pharmacokinetics of dihydroergotoxine metabolites in man: preliminary results

Biopharmaceutics & Drug Disposition, 2007

Dihydroergotoxine is a mixture of semi-synthetic ergot alkaloids mainly used for age-related cogn... more Dihydroergotoxine is a mixture of semi-synthetic ergot alkaloids mainly used for age-related cognitive impairment. In this study, dihydroergotoxine (30 microM) was added to incubates of rat and bovine liver microsomes, and the resulting major metabolites were identified as hydroxy-dihydroergocornine, hydroxy-dihydroergocryptine and hydroxy-dihydroergocristine on the basis of molecular mass measurements, determined with a time-of-flight mass spectrometer. The relevance of these to humans was then investigated by simultaneously monitoring dihydroergotoxine and its hydroxy-metabolites in human plasma by LC-MS/MS after oral dosing of dihydroergotoxine mesylate (27 mg) to a healthy volunteer (male, age 45, height 1.93 m, weight 103 kg). In this preliminary approach, the peaks (C(max)) of dihydroergocornine, dihydroergocryptine and dihydroergocristine were about 0.04 microg/l. The peaks (C(max)) of their hydroxy-metabolites were 0.98, 0.53 and 0.30 microg/l, respectively. In conclusion, in this preliminary approach it was found that hydroxy-dihydroergocornine, hydroxy-dihydroergocryptine and hydroxy-dihydroergocristine were one order of magnitude higher in concentration than their parents in human plasma.

Research paper thumbnail of Phospholipidomics reveals differences in glycerophosphoserine profiles of hypothermically stored red blood cells and microvesicles

Biochimica et Biophysica Acta (BBA) - Biomembranes, 2013

During their normal in vivo life cycle erythrocytes (red blood cells, RBCs) undergo biochemical c... more During their normal in vivo life cycle erythrocytes (red blood cells, RBCs) undergo biochemical changes leading to membrane microvesiculation and shedding. RBC microvesiculation also occurs in vitro under conditions of blood bank storage, so microvesicles (MVs) accumulate in the storage (preservation) medium over storage time. Considerable effort has been put into gaining a mechanistic understanding of the RBC microvesiculation process, as this is crucial to better understand RBC biology in disease and in health. Additionally, MVs accumulated in stored RBCs have been implicated in transfusion adverse inflammatory reactions, with chloroform extractable compounds, thus lipophilic, known to trigger the effect. However, because thin layer chromatography resolution of RBC and MV lipids has always enabled one to conclude high compositional similarities, in depth analysis of MV lipids has not been extensively pursued. Here we present an orbitrap mass spectrometry (MS) approach to compare the phospholipid composition of RBCs and MVs from leukoreduced, hypothermically (2-6°C) stored RBC units. We used shotgun MS analysis and electrospray ionization (ESI) intra-source separation, and demonstrated high similarity of compositional profiles, except for glycerophosphoserines (PS). Contrasting abundances of PS 38:4 and PS 38:1 characterized MV and RBC profiles and suggested that storage-associated microvesiculation possibly involves shedding of specific membrane rafts. This finding indicates that phospholipidomics could likely contribute to a better understanding of the RBC microvesiculation process.

Research paper thumbnail of Contemporary and Historical Atmospheric Deposition of Arsenic and Selenium in the Athabasca Bituminous Sands Region

Environmental Science & Technology, 2019

Selenium (Se) is one of the trace elements that is enriched in bitumen. To assess the importance ... more 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.

Research paper thumbnail of Trace elements in the Athabasca Bituminous Sands: A geochemical explanation for the paucity of environmental contamination by chalcophile elements

Chemical Geology, 2021

Abstract The Athabasca Bituminous Sands (ABS) in northern Alberta, Canada, represent one of the l... more Abstract The Athabasca Bituminous Sands (ABS) in northern Alberta, Canada, represent one of the largest reserves of hydrocarbons on the planet, yet there is remarkably little published data on the abundance of potentially toxic trace elements (TEs) in this resource. Here, we present the concentrations and review the relevance of 30 TEs in bulk samples of ABS as well as the organic and mineral fraction of representative samples. The distribution of TEs is dichotomous: they occur primarily in the organic fraction (Mo, Ni, Re, V and Se) or almost exclusively in the mineral fraction (virtually all of the other TEs). Except for Mo and Re, TEs in the ABS are depleted relative to the composition of the Upper Continental Crust (UCC), a reference level commonly used in quantifying the extent of contamination by TEs in the environment. Based on the published data available for comparison, TE concentrations in ABS are similar to those of sandstones, well below the average value for shale, and far below the values reported for organic-rich, black shales. The data presented here explains why recent studies of contamination of air, water, soil, plants in this region of northern Alberta, when viewed critically, reveal limited enrichments of chalcophile TEs, relative to crustal abundance. The abundance and distribution of TEs in the ABS also explains why atmospheric transport of TEs is largely restricted to the immediate region (

Research paper thumbnail of Bioaccumulation of Tl in otoliths of Trout-perch (Percopsis omiscomaycus) from the Athabasca River, upstream and downstream of bitumen mining and upgrading

Science of The Total Environment, 2019

• Concentrations of trace elements were determined in fish otoliths using ICP-QMS. • Compared to ... more • Concentrations of trace elements were determined in fish otoliths using ICP-QMS. • Compared to river water, Tl shows the greatest enrichment of any element. • Thallium dissolved in the Athabasca River is at natural, background levels. • The enrichment of Tl in the fish otoliths is a natural process. • There is no significant difference in enrichment upstream or downstream of industry.

Research paper thumbnail of A geochemical perspective on the natural abundance and predominant sources of trace elements in cranberries (Vaccinium oxycoccus) from remote bogs in the Boreal region of northern Alberta, Canada

Science of The Total Environment, 2019

Trace elements in native cranberry (Vaccinium oxycoccus) were compared with the underlying Sphagn... more Trace elements in native cranberry (Vaccinium oxycoccus) were compared with the underlying Sphagnum moss on which it grows, from two remote ombrotrophic (rain-fed) peat bogs in northern Alberta, Canada. The purpose of the comparison was to distinguish between dust inputs to the berries versus plant uptake from the substrate, and to determine the natural abundance of trace elements in native berries. Using Al as an indicator of the abundance of soil-derived mineral particles, the abundance of dust on the surface of the berries is 20 to 29× lower than that of the substrate (moss). Other lithophile elements (V, Cr, Co, Ga, Li and Y) show similar differences between moss and berry. The concentrations of Rb and Ba in berries were similar to moss and Sr within a factor of 3 to 4×, probably reflecting passive uptake of these lithophile elements by the plants, even though they have no known physiological function. Of the micronutrients examined (Mn, Fe, Ni, Cu, Zn and Mo), Cu and Mn were more abundant in berries than moss, Ni and Zn yielded similar concentrations in both whereas Fe followed by Mo showed the greatest concentration difference. For these micronutrients, uptake by the plants through their roots via the substrate (moss and peat) outweighs contributions from atmospheric dusts. In respect to potentially toxic "heavy metals", Pb concentrations in the moss (BMW, 89 ± 7.3 μg/kg; CMW, 93 ± 27 μg/kg) are below the natural, "background" values reported for ancient layers of Swiss peat from the mid-Holocene (N6000 years old). The Pb concentrations in the berries, however, are 19 to 47× lower than in the underlying moss indicating that Pb in the berries, like Al, is exclusively supplied by dust. Cadmium in the berries is at or above the level found in moss due to active uptake by the plants from the substrate, most likely because of the chemical similarity of this element to Zn. Silver, Sb and Tl in the berries were bLOD, but assuming that they are

Research paper thumbnail of Selenium and sulphur in Athabasca bituminous sands mineral and bitumen fractions

Research paper thumbnail of Spatial assessment of major and trace element concentrations from Lower Athabasca Region Trout-perch (Percopsis omiscomaycus) otoliths

Science of The Total Environment, 2018

Approximately 1/3 of elements analysed in otolith were below limits of detection. • Cu, Li and Pb... more Approximately 1/3 of elements analysed in otolith were below limits of detection. • Cu, Li and Pb differed among Lower Athabasca Region locations. • Patterns of variation did not support impacts of industrial footprint. • Differences between Alberta and Ontario otoliths likely reflect geology.

Research paper thumbnail of Determination of ultratrace (<0.1 mg/kg) elements in Athabasca Bituminous Sands mineral and bitumen fractions using inductively coupled plasma sector field mass spectrometry (ICP-SFMS)

Fuel, 2017

Abstract There is on-going concern regarding fugitive emissions of trace elements from mining and... more Abstract There is on-going concern regarding fugitive emissions of trace elements from mining and upgrading of the Athabasca Bituminous Sands (ABS) in northern Alberta, Canada, but remarkably few quantitative elemental data about the resource itself exists. By exploring advances in analytical techniques, an inductively coupled plasma sector field mass spectrometry (ICP-SFMS) method was developed for the determination of trace and ultratrace amounts ( 3 -HBF 4 yielded good recoveries (100 ± 20%) for Ag, As, Be, Bi, Cd, Mo, Ni, Pb, Re, Sb, Tl and V in certified reference materials (NIST 1635, NIST 2711). The distribution of elements within the ABS was dichotomous, with V, Ni, Mo and Re predominantly found in the organic fraction (bitumen) and Ag, As, Be, Bi, Cd, Pb, Sb, and Tl predominantly found in the mineral residue. Trace amounts of As and Pb (0.1–2.0 mg/kg), plus ultratrace amounts of Ag, Bi, Cd, Sb and Tl (

Research paper thumbnail of Peat Bogs Document Decades of Declining Atmospheric Contamination by Trace Metals in the Athabasca Bituminous Sands Region

Environmental science & technology, Jan 25, 2017

Peat cores were collected from five bogs in the vicinity of open pit mines and upgraders of the A... more Peat cores were collected from five bogs in the vicinity of open pit mines and upgraders of the Athabasca Bituminous Sands, the largest reservoir of bitumen in the world. Frozen cores were sectioned into 1 cm slices, and trace metals determined in the ultraclean SWAMP lab using ICP-QMS. The uppermost sections of the cores were age-dated with (210)Pb using ultralow background gamma spectrometry, and selected plant macrofossils dated using (14)C. At each site, trace metal concentrations as well as enrichment factors (calculated relative to the corresponding element/Th ratio of the Upper Continental Crust) reveal maximum values 10 to 40 cm below the surface which shows that the zenith of atmospheric contamination occurred in the past. The age-depth relationships show that atmospheric contamination by trace metals (Ag, Cd, Sb, Tl, but also V, Ni, and Mo which are enriched in bitumen) has been declining in northern Alberta for decades. In fact, the greatest contemporary enrichments of Ag...

Research paper thumbnail of Trace metals in the dissolved fraction (<0.45μm) of the lower Athabasca River: Analytical challenges and environmental implications

The Science of the total environment, Jan 16, 2016

Water samples were collected on the Athabasca River (AR), upstream and downstream from bitumen mi... more 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 abundan...

Research paper thumbnail of Peat bogs in northern Alberta, Canada reveal decades of declining atmospheric Pb contamination

Geophysical Research Letters, 2016

Peat cores were collected from six bogs in northern Alberta to reconstruct changes in the atmosph... more Peat cores were collected from six bogs in northern Alberta to reconstruct changes in the atmospheric deposition of Pb, a valuable tracer of human activities. In each profile, the maximum Pb enrichment is found well below the surface. Radiometric age dating using three independent approaches (14 C measurements of plant macrofossils combined with the atmospheric bomb pulse curve, plus 210 Pb confirmed using the fallout radionuclides 137 Cs and 241 Am) showed that Pb contamination has been in decline for decades. Today, the surface layers of these bogs are comparable in composition to the "cleanest" peat samples ever found in the Northern Hemisphere, from a Swiss bog~6000 to 9000 years old. The lack of contemporary Pb contamination in the Alberta bogs is testimony to successful international efforts of the past decades to reduce anthropogenic emissions of this potentially toxic metal to the atmosphere.

Research paper thumbnail of Prospecção de antibioticos e biocatalisadores

o presente trabalho foi organizado em 3 partes. A primeira delas compreende a investigacao por co... more o presente trabalho foi organizado em 3 partes. A primeira delas compreende a investigacao por compostos antimicrobianos em extratos de metabolitos secundarios de 15 fungos filamentosos isolados de abelhas (Trigona sp.). A aplicacao dos ensaios de bioautografia e concentracao inibitoria minima (CIM) a monitorizacao da atividade biologica resultou no isolamento de 4 substâncias conhecidas, sendo 2 quinonas isomericas (coclioquinona A e isococlioquinona A) de Drechslera dematioidea CCT 5631 e 2 dodecalactonas analogas (curvularina e E-desidrocurvularina) de Curvularia eragrostidis CCT 5634 e de Curvularia pallescens CCT 5654, as quais, em geral, apresentaram valores de CIM altos, relativamente a antibioticos padrao (cloranfenicol, ciclopiroxolamina). A segunda parte do trabalho trata da investigacao por haloperoxidases (HPOs) e por Baeyer-Villiger monoxigenases (BVMOs) em diferentes microrganismos. A atividade de HPO nao foi detectada nos experimentos realizados, os quais foram realizados com o indeno como substrato. Em contrapartida, utilizando cicloexanonas, BVMOs foram detectadas em Geotrichum candidum CCT 1205, Rhodotorula glutinis CCT 2182 e Rhodotorula minuta CCT 1751, ainda que nas reacoes com estes ultimos os porcentuais de conversao do substrato tenham sido baixos (:::; 10%) relativamente a G. candidum CCT 1205 (60 - 90%). O monitoramento de reacoes de biotransformacao simultâneas (mais de 1 substrato por microrganismo) foi introduzido com sucesso nesta etapa do trabalho, representando uma primeira acao de otimizacao do processo de triagem de biocatalisadores em microrganismos. A terceira e ultima parte do trabalho focaHsou a implementacao de triagens para biocatalisadores baseadas em fluorescencia. Os experimentos realizados proporcionaram deteccoes ineditas de BVMO em Trichosporon cutaneum CCT 1903 e de epoxido hidrolases em Pichia stipitis CCT 2617, T. cutaneum CCT 1903 e em Agrobacterium tumefaciens CCT 6515 Abstract

Research paper thumbnail of Desafios da qu�mica anal�tica frente �s necessidades da ind�stria farmac�utica

Research paper thumbnail of Blood Bag Plasticizers Influence Red Blood Cell Vesiculation Rate without Altering the Lipid Composition of the Vesicles

Transfusion Medicine and Hemotherapy, 2015

Background: Polyvinyl chloride (PVC) plasticized with di(2-ethylhexyl) phthalate (DEHP) is common... more Background: Polyvinyl chloride (PVC) plasticized with di(2-ethylhexyl) phthalate (DEHP) is commonly used for blood collection and storage. DEHP has protective effects on RBC membranes, but is also a toxin. Methods: A paired study was conducted to investigate the influence of DEHP and two alternative plasticizers, 1,2-cyclohexane-dicarboxylic acid diisononyl ester (DINCH) and nbutyryl-tri-n-hexyl citrate (BTHC), on the preservation of RBCs stored for 42 days in PVC pediatric bags. The RBC membrane was evaluated for supernatant hemoglobin (Hb), release of extracellular microvesicles (EVs), osmotic fragility, deformability, and lipid composition. Results: In BTHC-plasticized bags, the supernatant Hb increase during storage was 2 times greater than in DINCH-and DEHP-plasticized bags. By day 21, EV concentrations had doubled from day-5 levels in DINCH-and DEHP-, and trebled in BTHC-plasticized bags. RBC mean cell volumes were greater in BTHC-than in DINCH-or DEHP-plasticized bags (p < 0.001). Osmotic fragility differed significantly among plasticizers (p < 0.01). After day 21, RBC deformability decreased in all, but to a greater extent in the bags with BTHC. Phospholipid composition of RBCs and EVs was not different among plasticizers. Conclusion: Membrane stabilization capacity differed among the plasticizers. RBC in BTHC bags stored more poorly, while DEHP and DINCH bags offered better protection against vesiculation, osmotic stress, and Hb loss.

Research paper thumbnail of The effects of rejuvenation during hypothermic storage on red blood cell membrane remodeling

Transfusion, 2013

Our previous studies showed that hypothermic storage (HS) induces red blood cell (RBC) microparti... more Our previous studies showed that hypothermic storage (HS) induces red blood cell (RBC) microparticle (RMP) generation and changes in phosphatidylserine (PS) and CD47 expression on RBCs and RMPs. The aim of this study was to evaluate the effect of cold rejuvenation treatment at multiple time points during storage on these prehemolytic indicators of RBC membrane storage lesion. Leukoreduced RBC units in saline-adenine-glucose-mannitol were used to generate three groups: untreated controls, sham-treated units, and units treated with a cold (1-6°C) rejuvenation solution on Day 28, 35, or 42 of HS. Units were assessed for hemolysis, adenosine triphosphate (ATP) concentration, lipid composition, and RMP generation, as well as PS and CD47 expression throughout 49 days of HS. Rejuvenation treatment led to a significant increase in ATP concentration in all units, irrespective of treatment day. There were no significant differences between sham- and rejuvenation-treated RBC samples in the levels of PS externalization, CD47 expression, or the rate of RMP formation. RBCs rejuvenated on Day 28 were enriched in glycerophosphocholine (+23.5%), depleted in sphingomyelin (-14%), and slightly depleted in cholesterol (-3.5%). Cold rejuvenation in hypothermically stored RBCs affects the lipid composition of RBCs and respective RMPs in a time-dependent fashion.

Research paper thumbnail of Comparison of propolis from Apis mellifera and Tetragonisca angustula

Apidologie, 2003

High-temperature high-resolution gas chromatography (HT-HRGC) and HT-HRGC coupled to mass spectro... more High-temperature high-resolution gas chromatography (HT-HRGC) and HT-HRGC coupled to mass spectrometry (HT-HRGC-MS) were applied to the study of propolis collected by Apis mellifera and by Tetragonisca angustula, a stingless bee native to southeastern Brazil. With the exception of amino acids and erytrose/erythritol content, both propolis samples were quite similar in composition and in antimicrobial activity. Triterpenes were the most abundant compounds in the samples, comprising more then 35% of the total amount of each sample. propolis / Apis mellifera / Tetragonisca angustula

Research paper thumbnail of Application of High-Temperature Gas Chromatography−Mass Spectrometry to the Investigation of Glycosidically Bound Components Related to Cashew Apple ( Anacardium occidentale L. Var. nanum ) Volatiles

Journal of Agricultural and Food Chemistry, 2000

Free and bound volatile components of a Brazilian cashew apple variety (Anacardium occidentale L.... more Free and bound volatile components of a Brazilian cashew apple variety (Anacardium occidentale L. var. nanum) were obtained by simultaneous distillation-extraction (SDE) and XAD-2 adsorption. According to gas chromatography-mass spectrometry (GC-MS) analyses and retention indices, 62 free volatile constituents were characterized and quantified. They were esters (40%), terpenes (20%), hydrocarbons (14%), fatty acids (9%), aldehydes (8%), alcohols (3%), lactones (3%), ketones (1%), phenols (1%), and norisoprenoids (1%). The glycosidically bound volatile precursors were analyzed by high-temperature GC-MS, after room temperature silylation. Several conjugated alcohols and cinnamic acids were detected and reported as cashew apple glycosyl constituents for the first time.

Research paper thumbnail of In vitro mutagenicity of anti-inflammatory parsalmide analogues PA7, PA10, and PA31 triggered by biotransformation into hydroxy derivatives

European Journal of Medicinal Chemistry, 2006

In this study, the mutagenicity of the anti-inflammatory parsalmide [5-amino-N-butyl-2-(2-propyny... more In this study, the mutagenicity of the anti-inflammatory parsalmide [5-amino-N-butyl-2-(2-propynyloxy)-benzamide] analogues PA7 [5-amino-N-butyl-2-cyclohexyloxy-benzamide], PA10 [5-amino-N-butyl-2-phenoxy-benzamide] and PA31 [5-amino-N-butyl-2-(p-tolyloxy)-benzamide] was determined by an Ames Salmonella assay. The experiments were performed by preincubating the compounds in the absence and presence of a post-mitochondrial fraction (S9) of rat liver homogenate from phenobarbital/β-naphtoflavone treated rats. No mutagenic effect was observed after direct testing (no S9 added) in Salmonella typhymurium strains TA98, TA100, TA102, TA1535 and TA1537. However, in the presence of S9, the test substances triggered mutagenic responses in strains TA100 and TA98. PA31 presented the strongest mutagenic potential. The reversion rates in the presence of PA31 were about 2-19 fold higher than spontaneous mutation rates. In the presence of PA7, the reversion increased 2-14-fold over spontaneous rates. While PA10 showed a relatively mild mutagenic potential, as the number of revertants did not exceed 2.5 times the number of spontaneous mutations. Mass spectrometric analysis of the in vitro biotransformation showed that S9 converted (%), regioselectively, PA7 (19%), PA10 (7%) and PA31 (12%) into hydroxy-derivatives.

Research paper thumbnail of Pharmacokinetics of Dihydroergocristine and Its Major Metabolite 8- Hydroxy-Dihydroergocristine in Human Plasma

Current Drug Metabolism, 2005

Dihydroergocristine (DHEC) is a semi-synthetic drug mainly used for age-related cognitive impairm... more Dihydroergocristine (DHEC) is a semi-synthetic drug mainly used for age-related cognitive impairment. In this study, its major metabolite 8&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-hydroxy-dihydroergocristine (8&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-OH-DHEC) was produced in incubates of a bovine liver preparation using dihydroergocristine mesylate (DHECM) as substrate. Purification was achieved by flash silica gel column and reverse phase liquid chromatographies, and identification was based on accurate molecular mass measurements, mass fragmentation spectra and NMR ((1)H/(13)C) chemical shifts. By using the substance produced in vitro, a fast, sensitive, specific and robust LC/MS/MS method for the simultaneous determination of DHEC and its major metabolite in human plasma was developed and validated. Bromocriptine was used as internal standard and limits of quantification for DHEC and 8&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-OH-DHEC were 10 pg/ml and 20 pg/ml, respectively. Pharmacokinetic parameters were investigated on 12 male healthy volunteers to whom a single dose of 18 mg DHECM was administered in tablets (Iskevert). The peak of DHEC was 0.28 +/- 0.22 microg/l, the t(max) 0.46 +/- 0.26 h, the AUC(last) 0.39 +/- 0.41 microg/l.h and the terminal elimination half-life 3.50 +/- 2.27 h. The peak of 8&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-OH-DHEC was 5.63 +/- 3.34 microg/l, the t(max) 1.04 +/- 0.66 h, the AUC(last) 13.36 +/- 5.82 microg/l.h and the terminal elimination half-life 3.90 +/- 1.07 h. Dosing of 18 mg DHECM was well tolerated, causing no adverse events.

Research paper thumbnail of Identification and human pharmacokinetics of dihydroergotoxine metabolites in man: preliminary results

Biopharmaceutics & Drug Disposition, 2007

Dihydroergotoxine is a mixture of semi-synthetic ergot alkaloids mainly used for age-related cogn... more Dihydroergotoxine is a mixture of semi-synthetic ergot alkaloids mainly used for age-related cognitive impairment. In this study, dihydroergotoxine (30 microM) was added to incubates of rat and bovine liver microsomes, and the resulting major metabolites were identified as hydroxy-dihydroergocornine, hydroxy-dihydroergocryptine and hydroxy-dihydroergocristine on the basis of molecular mass measurements, determined with a time-of-flight mass spectrometer. The relevance of these to humans was then investigated by simultaneously monitoring dihydroergotoxine and its hydroxy-metabolites in human plasma by LC-MS/MS after oral dosing of dihydroergotoxine mesylate (27 mg) to a healthy volunteer (male, age 45, height 1.93 m, weight 103 kg). In this preliminary approach, the peaks (C(max)) of dihydroergocornine, dihydroergocryptine and dihydroergocristine were about 0.04 microg/l. The peaks (C(max)) of their hydroxy-metabolites were 0.98, 0.53 and 0.30 microg/l, respectively. In conclusion, in this preliminary approach it was found that hydroxy-dihydroergocornine, hydroxy-dihydroergocryptine and hydroxy-dihydroergocristine were one order of magnitude higher in concentration than their parents in human plasma.

Research paper thumbnail of Phospholipidomics reveals differences in glycerophosphoserine profiles of hypothermically stored red blood cells and microvesicles

Biochimica et Biophysica Acta (BBA) - Biomembranes, 2013

During their normal in vivo life cycle erythrocytes (red blood cells, RBCs) undergo biochemical c... more During their normal in vivo life cycle erythrocytes (red blood cells, RBCs) undergo biochemical changes leading to membrane microvesiculation and shedding. RBC microvesiculation also occurs in vitro under conditions of blood bank storage, so microvesicles (MVs) accumulate in the storage (preservation) medium over storage time. Considerable effort has been put into gaining a mechanistic understanding of the RBC microvesiculation process, as this is crucial to better understand RBC biology in disease and in health. Additionally, MVs accumulated in stored RBCs have been implicated in transfusion adverse inflammatory reactions, with chloroform extractable compounds, thus lipophilic, known to trigger the effect. However, because thin layer chromatography resolution of RBC and MV lipids has always enabled one to conclude high compositional similarities, in depth analysis of MV lipids has not been extensively pursued. Here we present an orbitrap mass spectrometry (MS) approach to compare the phospholipid composition of RBCs and MVs from leukoreduced, hypothermically (2-6°C) stored RBC units. We used shotgun MS analysis and electrospray ionization (ESI) intra-source separation, and demonstrated high similarity of compositional profiles, except for glycerophosphoserines (PS). Contrasting abundances of PS 38:4 and PS 38:1 characterized MV and RBC profiles and suggested that storage-associated microvesiculation possibly involves shedding of specific membrane rafts. This finding indicates that phospholipidomics could likely contribute to a better understanding of the RBC microvesiculation process.

Research paper thumbnail of Contemporary and Historical Atmospheric Deposition of Arsenic and Selenium in the Athabasca Bituminous Sands Region

Environmental Science & Technology, 2019

Selenium (Se) is one of the trace elements that is enriched in bitumen. To assess the importance ... more 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.

Research paper thumbnail of Trace elements in the Athabasca Bituminous Sands: A geochemical explanation for the paucity of environmental contamination by chalcophile elements

Chemical Geology, 2021

Abstract The Athabasca Bituminous Sands (ABS) in northern Alberta, Canada, represent one of the l... more Abstract The Athabasca Bituminous Sands (ABS) in northern Alberta, Canada, represent one of the largest reserves of hydrocarbons on the planet, yet there is remarkably little published data on the abundance of potentially toxic trace elements (TEs) in this resource. Here, we present the concentrations and review the relevance of 30 TEs in bulk samples of ABS as well as the organic and mineral fraction of representative samples. The distribution of TEs is dichotomous: they occur primarily in the organic fraction (Mo, Ni, Re, V and Se) or almost exclusively in the mineral fraction (virtually all of the other TEs). Except for Mo and Re, TEs in the ABS are depleted relative to the composition of the Upper Continental Crust (UCC), a reference level commonly used in quantifying the extent of contamination by TEs in the environment. Based on the published data available for comparison, TE concentrations in ABS are similar to those of sandstones, well below the average value for shale, and far below the values reported for organic-rich, black shales. The data presented here explains why recent studies of contamination of air, water, soil, plants in this region of northern Alberta, when viewed critically, reveal limited enrichments of chalcophile TEs, relative to crustal abundance. The abundance and distribution of TEs in the ABS also explains why atmospheric transport of TEs is largely restricted to the immediate region (

Research paper thumbnail of Bioaccumulation of Tl in otoliths of Trout-perch (Percopsis omiscomaycus) from the Athabasca River, upstream and downstream of bitumen mining and upgrading

Science of The Total Environment, 2019

• Concentrations of trace elements were determined in fish otoliths using ICP-QMS. • Compared to ... more • Concentrations of trace elements were determined in fish otoliths using ICP-QMS. • Compared to river water, Tl shows the greatest enrichment of any element. • Thallium dissolved in the Athabasca River is at natural, background levels. • The enrichment of Tl in the fish otoliths is a natural process. • There is no significant difference in enrichment upstream or downstream of industry.

Research paper thumbnail of A geochemical perspective on the natural abundance and predominant sources of trace elements in cranberries (Vaccinium oxycoccus) from remote bogs in the Boreal region of northern Alberta, Canada

Science of The Total Environment, 2019

Trace elements in native cranberry (Vaccinium oxycoccus) were compared with the underlying Sphagn... more Trace elements in native cranberry (Vaccinium oxycoccus) were compared with the underlying Sphagnum moss on which it grows, from two remote ombrotrophic (rain-fed) peat bogs in northern Alberta, Canada. The purpose of the comparison was to distinguish between dust inputs to the berries versus plant uptake from the substrate, and to determine the natural abundance of trace elements in native berries. Using Al as an indicator of the abundance of soil-derived mineral particles, the abundance of dust on the surface of the berries is 20 to 29× lower than that of the substrate (moss). Other lithophile elements (V, Cr, Co, Ga, Li and Y) show similar differences between moss and berry. The concentrations of Rb and Ba in berries were similar to moss and Sr within a factor of 3 to 4×, probably reflecting passive uptake of these lithophile elements by the plants, even though they have no known physiological function. Of the micronutrients examined (Mn, Fe, Ni, Cu, Zn and Mo), Cu and Mn were more abundant in berries than moss, Ni and Zn yielded similar concentrations in both whereas Fe followed by Mo showed the greatest concentration difference. For these micronutrients, uptake by the plants through their roots via the substrate (moss and peat) outweighs contributions from atmospheric dusts. In respect to potentially toxic "heavy metals", Pb concentrations in the moss (BMW, 89 ± 7.3 μg/kg; CMW, 93 ± 27 μg/kg) are below the natural, "background" values reported for ancient layers of Swiss peat from the mid-Holocene (N6000 years old). The Pb concentrations in the berries, however, are 19 to 47× lower than in the underlying moss indicating that Pb in the berries, like Al, is exclusively supplied by dust. Cadmium in the berries is at or above the level found in moss due to active uptake by the plants from the substrate, most likely because of the chemical similarity of this element to Zn. Silver, Sb and Tl in the berries were bLOD, but assuming that they are

Research paper thumbnail of Selenium and sulphur in Athabasca bituminous sands mineral and bitumen fractions

Research paper thumbnail of Spatial assessment of major and trace element concentrations from Lower Athabasca Region Trout-perch (Percopsis omiscomaycus) otoliths

Science of The Total Environment, 2018

Approximately 1/3 of elements analysed in otolith were below limits of detection. • Cu, Li and Pb... more Approximately 1/3 of elements analysed in otolith were below limits of detection. • Cu, Li and Pb differed among Lower Athabasca Region locations. • Patterns of variation did not support impacts of industrial footprint. • Differences between Alberta and Ontario otoliths likely reflect geology.

Research paper thumbnail of Determination of ultratrace (<0.1 mg/kg) elements in Athabasca Bituminous Sands mineral and bitumen fractions using inductively coupled plasma sector field mass spectrometry (ICP-SFMS)

Fuel, 2017

Abstract There is on-going concern regarding fugitive emissions of trace elements from mining and... more Abstract There is on-going concern regarding fugitive emissions of trace elements from mining and upgrading of the Athabasca Bituminous Sands (ABS) in northern Alberta, Canada, but remarkably few quantitative elemental data about the resource itself exists. By exploring advances in analytical techniques, an inductively coupled plasma sector field mass spectrometry (ICP-SFMS) method was developed for the determination of trace and ultratrace amounts ( 3 -HBF 4 yielded good recoveries (100 ± 20%) for Ag, As, Be, Bi, Cd, Mo, Ni, Pb, Re, Sb, Tl and V in certified reference materials (NIST 1635, NIST 2711). The distribution of elements within the ABS was dichotomous, with V, Ni, Mo and Re predominantly found in the organic fraction (bitumen) and Ag, As, Be, Bi, Cd, Pb, Sb, and Tl predominantly found in the mineral residue. Trace amounts of As and Pb (0.1–2.0 mg/kg), plus ultratrace amounts of Ag, Bi, Cd, Sb and Tl (

Research paper thumbnail of Peat Bogs Document Decades of Declining Atmospheric Contamination by Trace Metals in the Athabasca Bituminous Sands Region

Environmental science & technology, Jan 25, 2017

Peat cores were collected from five bogs in the vicinity of open pit mines and upgraders of the A... more Peat cores were collected from five bogs in the vicinity of open pit mines and upgraders of the Athabasca Bituminous Sands, the largest reservoir of bitumen in the world. Frozen cores were sectioned into 1 cm slices, and trace metals determined in the ultraclean SWAMP lab using ICP-QMS. The uppermost sections of the cores were age-dated with (210)Pb using ultralow background gamma spectrometry, and selected plant macrofossils dated using (14)C. At each site, trace metal concentrations as well as enrichment factors (calculated relative to the corresponding element/Th ratio of the Upper Continental Crust) reveal maximum values 10 to 40 cm below the surface which shows that the zenith of atmospheric contamination occurred in the past. The age-depth relationships show that atmospheric contamination by trace metals (Ag, Cd, Sb, Tl, but also V, Ni, and Mo which are enriched in bitumen) has been declining in northern Alberta for decades. In fact, the greatest contemporary enrichments of Ag...

Research paper thumbnail of Trace metals in the dissolved fraction (<0.45μm) of the lower Athabasca River: Analytical challenges and environmental implications

The Science of the total environment, Jan 16, 2016

Water samples were collected on the Athabasca River (AR), upstream and downstream from bitumen mi... more 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 abundan...

Research paper thumbnail of Peat bogs in northern Alberta, Canada reveal decades of declining atmospheric Pb contamination

Geophysical Research Letters, 2016

Peat cores were collected from six bogs in northern Alberta to reconstruct changes in the atmosph... more Peat cores were collected from six bogs in northern Alberta to reconstruct changes in the atmospheric deposition of Pb, a valuable tracer of human activities. In each profile, the maximum Pb enrichment is found well below the surface. Radiometric age dating using three independent approaches (14 C measurements of plant macrofossils combined with the atmospheric bomb pulse curve, plus 210 Pb confirmed using the fallout radionuclides 137 Cs and 241 Am) showed that Pb contamination has been in decline for decades. Today, the surface layers of these bogs are comparable in composition to the "cleanest" peat samples ever found in the Northern Hemisphere, from a Swiss bog~6000 to 9000 years old. The lack of contemporary Pb contamination in the Alberta bogs is testimony to successful international efforts of the past decades to reduce anthropogenic emissions of this potentially toxic metal to the atmosphere.