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Jonathan Verreault - One of the best experts on this subject based on the ideXlab platform.
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Lipid metabolites as indicators of body condition in highly contaminant-exposed belugas from the endangered St. Lawrence Estuary population (Canada).
Environmental research, 2020Co-Authors: Alexandre Bernier-graveline, Véronique Lesage, Robert Michaud, Jory Cabrol, Stéphane Lair, Maikel Rosabal, Jonathan VerreaultAbstract:Abstract The endangered St Lawrence Estuary (SLE) beluga population is declining and has shown no sign of recovery over the past decades despite several protective measures. Changes in the availability of food resources and exposure to Organohalogen contaminants have been suggested as potential factors limiting the recovery of this population. Studies on SLE belugas have suggested that contaminant exposure may perturb energy metabolism, however, whether this translates into changes in energy reserves (lipid composition) and body condition is unknown. The objective of this study was to investigate the relationships between body condition and concentrations of Organohalogens (polychlorinated biphenyls, organochlorine pesticides, and flame retardants) and a range of lipid metabolites (fatty acids, acylcarnitines, lysophosphatidylcholines, phosphatidylcholines, and sphingomyelins) in blubber samples collected from 51 SLE beluga carcasses recovered between 1998 and 2016 for which the cause of mortality was documented. Blubber Σ9fatty acid concentrations in SLE belugas significantly decreased between 1998 and 2016, suggesting a decline in energy reserves over the past two decades. Concentrations of several phosphatidylcholine analogues were greater in blubber of beluga males and/or females that were in poor body condition compared to those in good body condition. Moreover, concentrations of phosphatidylcholine acyl-alkyl C32:2 were greater in females that died from primary starvation (poor body condition). Greater concentrations of Σ12 emerging flame retardants were also found in blubber of SLE beluga females that were in poorer body condition. This study suggests that the use of membrane lipids including phosphatidylcholine concentrations may be a good indicator of body condition and energy reserve status in blubber of marine mammals.
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Metabolomic profiles of the endangered St. Lawrence Estuary beluga population and associations with Organohalogen contaminants.
The Science of the total environment, 2020Co-Authors: Antoine E. Simond, Magali Houde, Véronique Lesage, Robert Michaud, Jonathan VerreaultAbstract:Abstract The endangered beluga (Delphinapterus leucas) population residing in the St. Lawrence Estuary (SLE; Eastern Canada) is declining. The elevated tissue concentrations of a wide range of Organohalogen contaminants might play a role in the non-recovery of this whale population. Organohalogens have been reported to impair the regulation of several metabolic products from cellular reactions in mammals such as amino acids and fatty acids. The objective of this study was to investigate a suite of Organohalogens including polychlorinated biphenyls, organochlorine pesticides, short-chain chlorinated paraffins (SCCPs), polybrominated diphenyl ethers, and selected emerging flame retardants in blubber (biopsy) collected from 40 SLE male belugas, and their relationships to skin concentrations of targeted metabolites (i.e., 21 amino acids, 22 biogenic amines, 18 fatty acids, and 17 energy metabolites). A cluster analysis based on metabolomic profiles distinguished two main subgroups of belugas in the upper and lower sector of their summer habitat in the SLE. These results indicate that ecological factors such as local prey availability and diet composition played a role in shaping the metabolite profiles of belugas. Moreover, SCCP concentrations in SLE male belugas correlated negatively with those of four unsaturated fatty acids (C16:1ω7, C22:5ω3c1, C22:5ω3c2, and C22:6ω3), and positively with those of acetylornithine (biogenic amine). These findings suggest that biological functions such as lipid metabolism represent potential targets for Organohalogens in this population, and further our understanding on potential health risks associated with elevated Organohalogen exposure in cetaceans. Our results also underscore the necessity of considering ecological factors (e.g., diet and habitat use) in metabolomic studies.
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Associations between Organohalogen concentrations and transcription of thyroid-related genes in a highly contaminated gull population.
Science of The Total Environment, 2015Co-Authors: Romy Técher, Magali Houde, Jonathan VerreaultAbstract:A number of studies have reported altered circulating thyroid hormone levels in birds exposed either in controlled settings or in their natural habitat to ubiquitous Organohalogen compounds including organochlorines (OCs) and polybrominated diphenyl ether (PBDE) flame retardants. However, limited attention has been paid to underlying homeostatic mechanisms in wild birds such as changes in the expression of genes in the hypothalamic-pituitary-thyroid (HPT) axis. The objective of the present study was to investigate the relationships between hepatic concentrations of major Organohalogens (PBDEs and OCs), and circulating thyroid hormone (free and total thyroxine (T4) and triiodothyronine (T3)) levels and transcription of 14 thyroid-related genes in three tissues (thyroid, brain, and liver) of an urban-adapted bird exposed to high Organohalogen concentrations in the Montreal area (QC, Canada), the ring-billed gull (Larus delawarensis). Positive correlations were found between liver concentrations of several polychlorinated biphenyls (PCBs), PBDEs as well as chlordanes and total plasma T4 levels. Hepatic concentrations of several PBDEs were negatively correlated with mRNA levels of deiodinase type 3, thyroid peroxidase, and thyroid hormone receptor β (TRβ) in the thyroid gland. Liver PCB (deca-CB) correlated positively with mRNA levels of sodium-iodide symporter and TRα. In brain, concentrations of most PBDEs were positively correlated with mRNA levels of organic anion transporter protein 1C1 and transthyretin, while PCBs positively correlated with expression of TRα and TRβ as well as deiodinase type 2. These multiple correlative linkages suggest that Organohalogens operate through several mechanisms (direct or compensatory) involving gene transcription, thus potentially perturbing the HPT axis of this highly Organohalogen-contaminated ring-billed gull population.
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Organohalogen and metabolically-derived contaminants and associations with whole body constituents in Norwegian Arctic glaucous gulls
Environment international, 2007Co-Authors: Jonathan Verreault, Geir W. Gabrielsen, Soheila Shahmiri, Robert J LetcherAbstract:Abstract Comprehensive surveys of Organohalogen contaminants have been conducted in various tissues and blood of glaucous gulls ( Larus hyperboreus ), a top scavenger-predator species in Svalbard in the Norwegian Arctic. However, the physico-chemical properties of Organohalogens (e.g., type and degree of halogenation and the presence or absence of additional phenyl group substituents) that may influence toxicokinetics, and subsequently tissue-specific accumulation, have yet to be studied in this species. We investigated the concentrations, total body burdens, and compositional patterns of legacy chlorinated compounds (PCBs and chlordanes (CHLs)), metabolically-derived PCBs (methylsulfonyl (MeSO 2 )- and OH-PCBs), brominated flame retardants (polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), total-hexabromocyclododecane (HBCD)), and PBDE metabolites and/or naturally-occurring compounds with similar structures (MeO- and OH-PBDEs) in liver, blood and whole body homogenate samples of adult glaucous gulls ( n = 19) from Svalbard. Further, we examined the distribution of these Organohalogens and metabolites in relation to whole body composition of glaucous gulls, i.e., the total water, protein, lipid and mineral contents in whole homogenate carcasses. The total body burden of Organohalogens and metabolites in glaucous gulls ranged between 3.3 and 33.0 mg. Compound class distribution showed that the relative proportions of sum (Σ) OH-PCB and ΣOH-PBDE to the total Organohalogen concentrations were significantly highest in blood. Conversely, the ΣCHL and ΣPCB showed generally higher proportions in the lipid-rich liver as well as in whole body homogenates. No significant difference in the compositional patterns of individual congeners/compounds was found among tissues/blood, with the exception of the classes comprised of less polar brominated compounds (PBDEs, PBBs and total-(α)-HBCD). Total proteins isolated from the whole body homogenates of glaucous gulls were significantly associated to the proportions of ΣOH-PCB and ΣPBDE. A non-significant positive association was found between total lipids and the ΣPCB proportions. The present study suggests that both protein association and lipid solubility are important concomitant factors to be considered in the toxicokinetics and fate of contaminants as a function of chemical structure and properties, e.g., chlorination, bromination and the presence of other phenyl substituents such as OH group. An enhanced, selective retention of these Organohalogen classes in given tissues/body compartments may thus lead to site-specific toxicological actions and adverse effects in the highly-contaminated Svalbard glaucous gulls.
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Organohalogen contaminants and reproductive hormones in incubating glaucous gulls (Larus hyperboreus) from the Norwegian Arctic.
Environmental toxicology and chemistry, 2006Co-Authors: Jonathan Verreault, Robert J Letcher, Erik Ropstad, Ellen Dahl, Geir W. GabrielsenAbstract:Organohalogen contaminants detected globally in avian wildlife, including populations from the Arctic, have been related to various reproductive hormone potencies, and altered hormonal balance and functions. Besides legacy organochlorine (OC) substances, that is, polychlorinated biphenyls (PCBs) and OC pesticides and by-products, endocrine-disruptive properties have been defined for chemicals of new and emerging environmental concern, such as polybrominated diphenyl ethers (PBDEs) and metabolically derived products like methylsulfonyl (MeSO2)- and hydroxyl (OH)-PCBs. We investigated the relationships between plasma concentrations of selected legacy OCs, PBDEs, and MeSO2- and OH-PCB metabolites and the circulating reproductive hormones testosterone (T), 17β-estradiol (E2), and progesterone (P4) in incubating male and female glaucous gulls (Larus hyperboreus) from the Norwegian Arctic. Principal component and regression analyses demonstrated that P4 levels in male glaucous gulls were associated positively with variations of sum (∑) PCB, dichloro-diphenyl-trichloroethane (∑DDT), chlordane (∑CHL), and ∑PBDE concentrations, which were the most recalcitrant Organohalogens determined in glaucous gulls. No such relationship was found for female glaucous gulls as well as between concentrations of any of the selected Organohalogens and levels of T for both sexes. The E2 was not detected in any plasma samples. Present results were highly suggestive that exposure to high Organohalogen concentrations in glaucous gulls, particularly the most persistent compound classes, may have the potential to interfere with steroidogenesis and impinge on circulating P4 homeostasis. Because significant effects were found in males exclusively, it cannot be completely ruled out that male glaucous gulls are more sensitive than females to Organohalogen-mediated alteration of P4 synthesis and breakdown.
Michel Fournier - One of the best experts on this subject based on the ideXlab platform.
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immune functions in the fisher rat fed beluga whale delphinapterus leucas blubber from the contaminated st lawrence estuary
Environmental Research, 1999Co-Authors: P Lapierre, S De Guise, Derek C G Muir, Ross J Norstrom, Pierre Beland, Michel FournierAbstract:In order to assess the immunotoxic potential of food naturally contaminated with PCBs and other Organohalogens, Fisher rats were fed a diet in which the lipids originated from the blubber of either a highly polluted St. Lawrence beluga or a relatively uncontaminated Arctic beluga. After a period of 2 months, different immune functions were evaluated, including lymphoblastic transformation, natural killer cell activity, plaque-forming cells, phagocytosis, oxidative burst, and immunophenotyping. For all assays, rats fed a St. Lawrence beluga blubber diet or a mixture of Arctic and St. Lawrence beluga blubber diet were not different from control rats fed a diet containing Arctic beluga blubber. These results are inconsistent with the well-known immunosuppressive effects of organochlorines in numerous species and with the lesions suggestive of organochlorine-related immunosuppression that are observed in St. Lawrence belugas. The lack of observable immunotoxic effects in rats fed contaminated beluga blubber might be explained by antagonistic effects in the Organohalogen mixture, by a response specific to the rat, by a strain-related lack of sensitivity to organochlorines, or by insufficient dose due to the shortness of the exposure period or the route of exposure.
Eunsang Kwon - One of the best experts on this subject based on the ideXlab platform.
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Development and Application of a High-Precision Algorithm for Nontarget Identification of Organohalogens Based on Ultrahigh-Resolution Mass Spectrometry.
Analytical chemistry, 2020Co-Authors: Manabu Fujii, Eunsang KwonAbstract:Brominated and/or chlorinated organic compounds (referred to as Organohalogens) are frequently detected in natural and engineered environments. However, ultrahigh-resolution mass spectrometry (UHR-MS)-based nontargeted identification of Organohalogens remains challenging because of the coexistence of a vast number of halogenated and nonhalogenated organic molecules. In this study, a new algorithm, namely, the NOMDBP code, was developed to simultaneously identify Organohalogens and non-Organohalogens from the UHR-MS spectra of natural and engineered waters. In addition to isotopic patterns, for the first time, three optional filter rules [i.e., selection for minimum nonoxygen heteroatoms, inspection of the presence of newly formed halogenated disinfection byproducts (Xn-DBPs), and of their precursors] were incorporated into our code, which can accurately identify DBP-associated peaks and further elucidate Xn-DBP generation and transformation mechanisms. The formula assignment ratio against 2815 previously reported Organohalogens, and their 11,583 isotopologues exceeded 97%. Application of our algorithm to disinfected natural organic matter indicated that oxygen-containing Xn-DBP species accounted for a majority of the Xn-DBPs. Furthermore, brominated Xn-DBPs (Br-DBPs) were characterized by a higher degree of unsaturation compared to chlorinated Xn-DBPs. In addition to electrophilic substitution and electrophilic addition reactions, the decomposition/transformation pathway was found to be another important mechanism in Br-DBP formation. The results of this study highlight the superior potential of our code for the efficient detection of yet unknown Organohalogens (including Organohalogens bearing nonoxygen heteroatoms) in a nontargeted manner and for the identification of their generation mechanism occurring during the disinfection process.
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Development and Application of High-Precision Algorithm for Non-Target Identification of Organohalogens Based on Ultrahigh-Resolution Mass Spectrometry
2020Co-Authors: Manabu Fujii, Eunsang KwonAbstract:The brominated and/or chlorinated organic compounds (referred to as Organohalogens) are frequently detected in natural and engineered environments. However, the ultrahigh resolution mass spectrometry (UHR-MS)-based non-target identification of the Organohalogens remains challenging due to the presence of vast number of halogenated and non-halogenated organic molecules in the same aqueous sample. In this study, a new algorithm, namely NOMDBP Code, was developed, based on natural organic matter (NOM) chemistry, to simultaneously identify Organohalogens and non-Organohalogens from the UHR-MS spectra of natural and engineered waters. In addition to isotopic pattern extraction, for the first time, three optional filter rules (namely selection of minimum non oxygen heteroatoms, inspection of newly formed halogenated disinfection byproducts [X23 DBPs] and precursors) were incorporated in our code, which can accurately identify DBPs associated peaks and further elucidate the X-DBPs generation and transformation mechanisms. The formulae assignment rate against previously reported 2,815 unique Organohalogens and their 11,583 isotopologues was determined to be >97%. Application of our algorithm to disinfected NOM indicated that oxygen-containing X-DBPs species accounted for a majority of X-DBPs. Further, brominated X-DBPs (Br-DBPs) during disinfection process were characterized by higher degree of unsaturation compared to chlorinated X-DBPs (Cl-DBPs). Our algorithm also suggested that, in addition to electrophilic substitution and electrophilic addition reactions, the decomposition/transformation is another important mechanism in Br-DBPs formation. Results of this study highlight the superior potential of this code to efficiently detect yet- unknown Organohalogens (including Organohalogens with non-oxygen heteroatoms) in a non-target manner and identify their generation mechanism during the disinfection process
Barry C. Kelly - One of the best experts on this subject based on the ideXlab platform.
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associations of serum Organohalogen levels and prostate cancer risk results from a case control study in singapore
Chemosphere, 2016Co-Authors: Sin Eng Chia, Choon Nam Ong, Barry C. KellyAbstract:There is increasing evidence that elevated exposure to organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) may lead to an increased risk of prostate cancer. As part of a hospital-based case-control study of the Singaporean male population, we investigated associations between Organohalogen exposure and risk of prostate cancer. Trace residue concentrations of 74 Organohalogen contaminants, including several PCBs, OCPs and halogenated flame retardants (HFRs), were determined in serum samples (n = 120) using gas chromatography tandem mass spectrometry (GC-MS/MS). A variety of OCPs, PCBs and HFRs were detected in samples of both patients and controls. Mean concentrations of p,p' DDT, p,p' DDE, PCB 118, PCB 138, PCB 153 and PCB 187 were significantly higher (p 67th) were 5.67 (95% CI, 2.37-13.54) and 2.14 (95% CI, 0.99 to 4.66), respectively. The results suggest that exposure to DDTs and PCBs may be associated with prostate cancer risk in Singaporean males. No such association was observed for the Organohalogen flame retardants studied, including polybrominated diphenyl ethers (PBDEs). The study provides novel information regarding the occurrence, levels and potential associations with prostate cancer risk for several Organohalogen contaminants in the Singapore population. However, further investigation and analyses should be conducted to confirm these findings.
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Associations of serum Organohalogen levels and prostate cancer risk: Results from a case–control study in Singapore
Chemosphere, 2015Co-Authors: Sin Eng Chia, Choon Nam Ong, Barry C. KellyAbstract:There is increasing evidence that elevated exposure to organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) may lead to an increased risk of prostate cancer. As part of a hospital-based case-control study of the Singaporean male population, we investigated associations between Organohalogen exposure and risk of prostate cancer. Trace residue concentrations of 74 Organohalogen contaminants, including several PCBs, OCPs and halogenated flame retardants (HFRs), were determined in serum samples (n = 120) using gas chromatography tandem mass spectrometry (GC-MS/MS). A variety of OCPs, PCBs and HFRs were detected in samples of both patients and controls. Mean concentrations of p,p' DDT, p,p' DDE, PCB 118, PCB 138, PCB 153 and PCB 187 were significantly higher (p 67th) were 5.67 (95% CI, 2.37-13.54) and 2.14 (95% CI, 0.99 to 4.66), respectively. The results suggest that exposure to DDTs and PCBs may be associated with prostate cancer risk in Singaporean males. No such association was observed for the Organohalogen flame retardants studied, including polybrominated diphenyl ethers (PBDEs). The study provides novel information regarding the occurrence, levels and potential associations with prostate cancer risk for several Organohalogen contaminants in the Singapore population. However, further investigation and analyses should be conducted to confirm these findings.
Stéphane Bouchonnet - One of the best experts on this subject based on the ideXlab platform.
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formation and determination of Organohalogen by products in water part ii sample preparation techniques for analytical approaches
Trends in Analytical Chemistry, 2016Co-Authors: Aziz Kinani, Said Kinani, Stéphane BouchonnetAbstract:Abstract There is a crucial need of analytical methods allowing the characterization and/or the quantitation of known and unknown Organohalogen by-products (OXPBs) in water. This article is the second one (Part II) of a review trio dedicated to the formation and determination of Organohalogen by-products in water; it presents an overview of the sample preparation techniques generally used prior to OXPBs analysis and details their advantages and drawbacks. After a comparison of the water samples generally analyzed (natural water versus deionized water spiked with organic matter), this section deals with sample preservation, OXPBs enrichment and selective extraction.
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Formation and determination of Organohalogen by-products in water – Part II. Sample preparation techniques for analytical approaches
TrAC Trends in Analytical Chemistry, 2016Co-Authors: Aziz Kinani, Said Kinani, Stéphane BouchonnetAbstract:Abstract There is a crucial need of analytical methods allowing the characterization and/or the quantitation of known and unknown Organohalogen by-products (OXPBs) in water. This article is the second one (Part II) of a review trio dedicated to the formation and determination of Organohalogen by-products in water; it presents an overview of the sample preparation techniques generally used prior to OXPBs analysis and details their advantages and drawbacks. After a comparison of the water samples generally analyzed (natural water versus deionized water spiked with organic matter), this section deals with sample preservation, OXPBs enrichment and selective extraction.