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Sökning: WFRF:(de Boer Jacob)

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1.
  • Schael, S, et al. (författare)
  • Precision electroweak measurements on the Z resonance
  • 2006
  • Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
  • Forskningsöversikt (refereegranskat)abstract
    • We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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2.
  • Schael, S., et al. (författare)
  • Electroweak measurements in electron positron collisions at W-boson-pair energies at LEP
  • 2013
  • Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 532:4, s. 119-244
  • Forskningsöversikt (refereegranskat)abstract
    • Electroweak measurements performed with data taken at the electron positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3 fb(-1) collected by the four LEP experiments ALEPH, DELPHI, 13 and OPAL, at centre-of-mass energies ranging from 130 GeV to 209 GeV. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose Einstein correlations between the two W decay systems arising in WW production, are searched for and upper limits on the strength of possible effects are obtained. The data are used to determine fundamental properties of the W boson and the electroweak theory. Among others, the mass and width of the W boson, m(w) and Gamma(w), the branching fraction of W decays to hadrons, B(W -> had), and the trilinear gauge-boson self-couplings g(1)(Z), K-gamma and lambda(gamma), are determined to be: m(w) = 80.376 +/- 0.033 GeV Gamma(w) = 2.195 +/- 0.083 GeV B(W -> had) = 67.41 +/- 0.27% g(1)(Z) = 0.984(-0.020)(+0.018) K-gamma - 0.982 +/- 0.042 lambda(gamma) = 0.022 +/- 0.019. (C) 2013 Elsevier B.V. All rights reserved.
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3.
  • Beal, Jacob, et al. (författare)
  • Robust estimation of bacterial cell count from optical density
  • 2020
  • Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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4.
  • Niemi, MEK, et al. (författare)
  • 2021
  • swepub:Mat__t
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5.
  • Aad, G, et al. (författare)
  • 2015
  • swepub:Mat__t
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6.
  • Engert, Andreas, et al. (författare)
  • The European Hematology Association Roadmap for European Hematology Research : a consensus document
  • 2016
  • Ingår i: Haematologica. - Pavia, Italy : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 101:2, s. 115-208
  • Tidskriftsartikel (refereegranskat)abstract
    • The European Hematology Association (EHA) Roadmap for European Hematology Research highlights major achievements in diagnosis and treatment of blood disorders and identifies the greatest unmet clinical and scientific needs in those areas to enable better funded, more focused European hematology research. Initiated by the EHA, around 300 experts contributed to the consensus document, which will help European policy makers, research funders, research organizations, researchers, and patient groups make better informed decisions on hematology research. It also aims to raise public awareness of the burden of blood disorders on European society, which purely in economic terms is estimated at (sic)23 billion per year, a level of cost that is not matched in current European hematology research funding. In recent decades, hematology research has improved our fundamental understanding of the biology of blood disorders, and has improved diagnostics and treatments, sometimes in revolutionary ways. This progress highlights the potential of focused basic research programs such as this EHA Roadmap. The EHA Roadmap identifies nine 'sections' in hematology: normal hematopoiesis, malignant lymphoid and myeloid diseases, anemias and related diseases, platelet disorders, blood coagulation and hemostatic disorders, transfusion medicine, infections in hematology, and hematopoietic stem cell transplantation. These sections span 60 smaller groups of diseases or disorders. The EHA Roadmap identifies priorities and needs across the field of hematology, including those to develop targeted therapies based on genomic profiling and chemical biology, to eradicate minimal residual malignant disease, and to develop cellular immunotherapies, combination treatments, gene therapies, hematopoietic stem cell treatments, and treatments that are better tolerated by elderly patients.
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7.
  • Kanai, M, et al. (författare)
  • 2023
  • swepub:Mat__t
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8.
  • Brandsma, Sicco H., et al. (författare)
  • Two organophosphorus flame retardants, resorcinol bis (diphenylphosphate)(PBDPP) and bisphenol A bis (diphenylphosphate) (BPA-BDPP) used as alternatives for BDE209 detected in dust
  • 2013
  • Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 1086-931X .- 1520-6912 .- 0013-936X .- 1520-5851. ; 47:24, s. 14434-14441
  • Tidskriftsartikel (refereegranskat)abstract
    • Resorcinol bis(diphenylphosphate) (RBDPP) and bisphenol A bis(diphenylphosphate) (BPA-BDPP) are two halogen-free organophosphorus flame retardant (PFRs) that are used as an alternative for the decabromodiphenyl ether (Deca-BDE) technical mixture in TV/flatscreen housing and other electronic consumer products.' In this study, dust samples were collected from various microenvironments in The Netherlands (houses, cars), Greece.(houses), and Sweden (apartments, cars, furniture stores, electronics stores) and analyzed for RBDPP and BPA-BDPP. Additionally, the dust samples from The Netherlands were analyzed for decabromodiphenyl ether (BDE-209) for comparison and for TPHP, which is a byproduct in the RBDPP and BPA-BDPP technical products. BPA-BDPP was detected in almost all dust samples from The Netherlands, Greece, and Sweden. Highest concentrations were found in dust samples collected on electronic equipment from all three countries with BPA-BDPP levels ranging from <0.1 to 1300 mu g/g and RBDPP levels from <0.04 to 520 mu g/g. RBDPP and BPA-BDPP levels in dust collected further away from the electronics (source) were usually lower. BDE-209 levels in The Netherlands dust samples collected on and around the electronics were similar and much lower than the BPA-BDPP/RBDPP levels, indicating that the electronics were not the source of BDE-209. Strong positive correlations were found between TPHP concentrations and those of RBDPP (r = 0.805) and BPA-BDPP (r = 0.924), probably due to TPHP being a byproduct in commercial RBDPP and BPA-BDPP mixtures in electronics. To our knowledge, this is the first time that RBDPP and BPA-BDPP were detected in dust samples from Europe.
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9.
  • Brits, Martin, et al. (författare)
  • Brominated and organophosphorus flame retardants in South African indoor dust and cat hair
  • 2019
  • Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 253, s. 120-129
  • Tidskriftsartikel (refereegranskat)abstract
    • Flame retardants (FRs), such as brominated flame retardants (BFRs) and organophosphorus flame retardants (OPFRs), are diverse groups of compounds used in various products related to the indoor environment. In this study concentrations of eight polybrominated diphenyl ethers (PBDEs), two alternative BFR5 and ten OPFRs were determined in indoor dust (n = 20) and pet cat hair (n = 11) from South Africa. The OPFRs were the major FRs, contributing to more than 97% of the total FR concentration. The median Sigma(10)OPFRs concentrations were 44,800 ng/g in freshly collected dust (F-dust), 19,800 ng/g in the dust collected from vacuum cleaner bags (V-dust), and 865 ng/g in cat hair (C-hair). Tris(1-chloro-2-propyl) phosphate (TCIPP) was the dominant OPFR in the dust samples with median concentrations of 7,010 ng/g in F-dust and 3,590 ng/g in V-dust. Tris(2-butoxyethyl) phosphate (TBOEP) was the dominant OPFR in C-hair, with a median concentration of 387 ng/g. The concentrations of Sigma 8PBDEs were higher in F-dust than in V-dust. BDE209 was the dominant BFR in all three matrices. Bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEH-TEBP) and 2-ethylhexyl-2,3,4,5- tetrabromobenzoate (EH-TBB) showed notable contributions to the BFR profile in cat hair. A worst-case dust exposure estimation was performed for all analytes. The estimated TCIPP daily intake through dust ingestion was up to 1,240 ng/kg bw for toddlers. The results indicate that OPFRs are ubiquitous in South African indoor environment. Indoor dust is a major source of human exposure to environmental contaminants. This can for example occur through hand-to-mouth contact of toddlers, and is an important route of exposure to currently used FRs accumulated on dust particles. The presence of FRs, in particular high concentrations of OPFRs, suggests that children and indoor pet cats may have greater exposure to FRs than adults.
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10.
  • Brits, Martin, et al. (författare)
  • Comprehensive two-dimensional gas chromatography coupled to high resolution time-of-flight mass spectrometry for screening of organohalogenated compounds in cat hair
  • 2018
  • Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1536, s. 151-162
  • Tidskriftsartikel (refereegranskat)abstract
    • The coupling of comprehensive two-dimensional gas chromatography with high-resolution time of-flight mass spectrometry offers the best separation efficiency combined with accurate mass measurements over a wide mass range. The tremendous power of this screening tool is illustrated by trace qualitative screening analysis of organohalogenated compounds (OHCs) in pet cat hair. Tentative identification was supported by mass spectral database searches and elemental formula prediction from the experimentally determined accurate mass data. This screening approach resulted in the first tentative identification of pentabromoethylbenzene, decabromodiphenyl ethane, hexabromocyclododecane, trisbromoneopentyl alcohol, tris(2-chloroethyl) phosphate and tris(2-chloroisopropyl)phosphate in the South African indoor environment. A total of seventy-two OHCs were identified in the samples and include known flame retardants, such as polybrominated diphenyl ethers, and legacy contaminants such as polychlorinated biphenyls and organochlorine, organophosphorous and pyrethroid pesticides. The results obtained from cat hair indicate that these pets are exposed to complex mixtures of OHCs and the detection of these compounds suggests that non-invasive cat hair samples can be used to model indoor exposure with reference to external deposition of OHCs present in the air and dust surrounding people. Toddlers share the same environment as pet cats and therefore also the same health risks.
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11.
  • Brits, Martin, et al. (författare)
  • Critical review of the analysis of brominated flame retardants and their environmental levels in Africa
  • 2016
  • Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 164, s. 174-189
  • Forskningsöversikt (refereegranskat)abstract
    • World-wide, the prevalence of brominated flame retardants (BFRs) is well documented for routine analysis of environmental and biological matrices. There is, however, limited information on these compounds in the African environment and insufficient information on the analytical approaches used to obtain data. This paper presents a review on BFR levels in the African environment and the various analytical methodologies specifically applied in Africa for polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls and alternative-BFRs. The analyses include liquid sample preparation using liquid-liquid and solid phase extraction and solid sample preparation involving Soxhlet extraction, with ultrasound-assisted extraction increasingly being applied. Instrumental detection techniques were limited to gas chromatography coupled with electron capture detector and electron impact ionisation with single quadrupole mass spectrometers. Information on congener profile prevalence in indoor dust, soil, aquatic environment (water, sediment, and aquatic organisms), eggs, wastewater treatment plant compartments, landfills (leachate and sediment) and breast milk are presented. Although PBDEs were inconsistently detected, contamination was reported for all investigated matrices in the African environment. The manifestation in remote regions indicates the ubiquitous prevalence and long-range transport of these compounds. Levels in sediment, and breast milk from some African countries were higher than reported for Asia and Europe. Due to limited data or non-detection of alternative-BFRs, it is unclear whether banned formulations were replaced in Africa. Most of the data reported for BFR levels in Africa were obtained in non-African laboratories or in South Africa and formed the basis for our discussion of reported contamination levels and related methodologies.
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12.
  • Brits, Martin, et al. (författare)
  • Short-, medium-, and long-chain chlorinated paraffins in South African indoor dust and cat hair
  • 2020
  • Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 238
  • Tidskriftsartikel (refereegranskat)abstract
    • Polychlorinated n-alkanes or chlorinated paraffins (CPs) contain a magnitude of structural isomers and are categorized as short-chain (SCCPs), medium-chain (MCCPs), and long-chain (LCCPs) CPs, according to the carbon chain lengths. In this study the Sigma SCCPs, Sigma MCCPs, and Sigma LCCP concentrations are reported for South African indoor dust and pet cat hair. The median concentrations of the Sigma CPs (C-9-C-37) ranged from 33 to 663 mu g/g for freshly collected dust (FD), 36-488 mu g/g for dust collected from household vacuum cleaner bags (VD), and 1.2-15 mu g/g for cat hair (CH) samples. MCCPs were the dominant CP group, followed by SCCPs and LCCPs. The Sigma MCCP concentration ranged from 13 to 498 mu g/g in dust and 0.6-6.5 mu g/g in cat hair. SCCPs with shorter carbon chains and lower chlorine substitution were observed in cat hair. LCCPs with carbon chains > C(20)were detected in dust and hair samples, possibly indicating the use of wax grade LCCP formulations. Non-traditional Kendrick mass defect plots were used to obtain information on the magnitude of CPs and provide evidence of possible interfering compounds. This is the first report on the occurrence of SCCPs, MCCPs, and LCCPs in the South African indoor environment. 
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13.
  • Gaziano, Liam, et al. (författare)
  • Mild-to-moderate kidney dysfunction and cardiovascular disease : Observational and mendelian randomization analyses
  • 2022
  • Ingår i: Circulation. - : Wolters Kluwer. - 0009-7322 .- 1524-4539. ; 146:20, s. 1507-1517
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: End-stage renal disease is associated with a high risk of cardiovascular events. It is unknown, however, whether mild-to-moderate kidney dysfunction is causally related to coronary heart disease (CHD) and stroke.METHODS: Observational analyses were conducted using individual-level data from 4 population data sources (Emerging Risk Factors Collaboration, EPIC-CVD [European Prospective Investigation into Cancer and Nutrition-Cardiovascular Disease Study], Million Veteran Program, and UK Biobank), comprising 648 135 participants with no history of cardiovascular disease or diabetes at baseline, yielding 42 858 and 15 693 incident CHD and stroke events, respectively, during 6.8 million person-years of follow-up. Using a genetic risk score of 218 variants for estimated glomerular filtration rate (eGFR), we conducted Mendelian randomization analyses involving 413 718 participants (25 917 CHD and 8622 strokes) in EPIC-CVD, Million Veteran Program, and UK Biobank.RESULTS: There were U-shaped observational associations of creatinine-based eGFR with CHD and stroke, with higher risk in participants with eGFR values <60 or >105 mL·min-1·1.73 m-2, compared with those with eGFR between 60 and 105 mL·min-1·1.73 m-2. Mendelian randomization analyses for CHD showed an association among participants with eGFR <60 mL·min-1·1.73 m-2, with a 14% (95% CI, 3%-27%) higher CHD risk per 5 mL·min-1·1.73 m-2 lower genetically predicted eGFR, but not for those with eGFR >105 mL·min-1·1.73 m-2. Results were not materially different after adjustment for factors associated with the eGFR genetic risk score, such as lipoprotein(a), triglycerides, hemoglobin A1c, and blood pressure. Mendelian randomization results for stroke were nonsignificant but broadly similar to those for CHD.CONCLUSIONS: In people without manifest cardiovascular disease or diabetes, mild-to-moderate kidney dysfunction is causally related to risk of CHD, highlighting the potential value of preventive approaches that preserve and modulate kidney function.
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14.
  • Harrad, Stuart, et al. (författare)
  • Indoor Contamination with Hexabromocyclododecanes, Polybrominated Diphenyl Ethers, and Perfluoroalkyl Compounds : An Important Exposure Pathway for People?
  • 2010
  • Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 44:9, s. 3221-3231
  • Forskningsöversikt (refereegranskat)abstract
    • This review underlines the importance of indoor contamination as a pathway of human exposure to hexabromocyclododecanes (HBCDs), polybrominated diphenyl ethers (PBDEs), and perfluoroalkyl compounds (PFCs). There is ample evidence of substantial contamination of indoor dust with these chemicals and that their concentrations in indoor air exceed substantially those outdoors. Studies examining the relationship between body burden and exposure via indoor dust are inconsistent while some indicate a link between body burdens and PBDE and HBCD exposure via dust ingestion, others find no correlation. Likewise, while concentrations in indoor dust and human tissues are both highly skewed, this does not necessarily imply causality. Evidence suggests exposure via dust ingestion is higher for toddlers than adults. Research priorities include identifying means of reducing indoor concentrations and indoor monitoring methods that provide the most ""biologically-relevant"" measures of exposure as well as monitoring a wider range of microenvironment categories. Other gaps include studies to improve understanding of the following: emission rates and mechanisms via which these contaminants migrate from products into indoor air and dust; relationships between indoor exposures and human body burdens; relevant physicochemical properties; the gastrointestinal uptake by humans of these chemicals from indoor dust; and human dust ingestion rates.
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15.
  • Kierkegaard, Amelie, 1955- (författare)
  • PBDEs in the Environment : Time trends, bioaccumulation and the identification of their successor, decabromodiphenyl ethane
  • 2007
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Polybrominated diphenyl ethers (PBDEs) are important chemical flame retardants, but also environmental pollutants. Their bromine substitution lends them a different bioaccumulation behaviour than the better studied organochlorines.The contamination of a Swedish lake with lower brominated BDEs was assessed by a retrospective study of pike. The concentrations of tetra- to hexaBDEs increased exponentially up to the mid-1980s and then decreased slowly, possibly reflecting the voluntary reduction in production/usage of the chemicals. Methoxylated PBDEs were found to be present in similar concentrations to the PBDEs, but originated from different sources. The large size of the bromine atom was believed to result in negligible absorption of higher brominated BDEs in wildlife, thus explaining the low levels observed in fish despite high levels in e.g. sediment. However, it was shown that the fully brominated BDE, BDE209, was absorbed to a small extent via the diet. Once absorbed, it was reductively debrominated to lower brominated BDE congeners. Debromination was also observed in dairy cows exposed to higher brominated BDEs in their natural diet. Moreover, the molecular size restricted the transfer of higher brominated BDEs to milk. In contrast to PCBs and lower brominated BDEs, there was no equilibrium between adipose tissues and milk fat, and with increasing bromine substitution a progressively smaller fraction of the ingested PBDEs was transferred to the milk.This thesis highlights differences in uptake, metabolism and excretion for PBDEs compared to the well characterized organochlorines. A knowledge that is useful for risk assessments given the ongoing use of these compounds. Furthermore, a representative of the next generation brominated flame retardants, decabromodiphenyl ethane, a replacement for the BDE209 technical product, was identified for the first time in the environment.
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16.
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17.
  • Bergman, Åke, et al. (författare)
  • A novel abbreviation standard for organobromine, organochlorine and organophosphorus flame retardants and some characteristics of the chemicals
  • 2012
  • Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 49, s. 57-82
  • Forskningsöversikt (refereegranskat)abstract
    • Ever since the interest in organic environmental contaminants first emerged 50 years ago, there has been a need to present discussion of such chemicals and their transformation products using simple abbreviations so as to avoid the repetitive use of long chemical names. As the number of chemicals of concern has increased, the number of abbreviations has also increased dramatically, sometimes resulting in the use of different abbreviations for the same chemical. In this article, we propose abbreviations for flame retardants (FRs) substituted with bromine or chlorine atoms or including a functional group containing phosphorus, i.e. BFRs, CFRs and PFRs, respectively. Due to the large number of halogenated and organophosphorus FRs, it has become increasingly important to develop a strategy for abbreviating the chemical names of FRs. In this paper, a two step procedure is proposed for deriving practical abbreviations (PRABs) for the chemicals discussed. In the first step, structural abbreviations (STABs) are developed using specific STAB criteria based on the FR structure. However, since several of the derived STABs are complicated and long, we propose instead the use of PRABs. These are, commonly, an extract of the most essential part of the STAB, while also considering abbreviations previously used in the literature. We indicate how these can be used to develop an abbreviation that can be generally accepted by scientists and other professionals involved in FR related work. Tables with PRABs and STABs for BFRs, CFRs and PERs are presented, including CAS (Chemical Abstract Service) numbers, notes of abbreviations that have been used previously, CA (Chemical Abstract) name, common names and trade names, as well as some fundamental physicochemical constants.
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18.
  • Björklund, Jonas, 1967- (författare)
  • Gas chromatography and mass spectrometry of polybrominated diphenyl ethers
  • 2003
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The aim of this thesis has been to develop accurate and sensitive analytical methods for the determination of polybrominated diphenyl ethers (PBDEs). It focuses on the development and optimization of gas chromatographic and mass spectrometric analysis of PBDE.PBDEs are widely used as additative flame retardants and an increasing environmental occurrence and persistence rise concern about these compounds as environmental contaminants. However, the chemical and physical properties of the PBDEs yield a number of problems associated with the analysis of these compounds. This thesis provides an overview of the gas chromatographic separation system used for determination of PBDE and suggestions of improvements of the analytical methods. It is shown that by careful selection and optimization of the injection technique, the column system and the detection technique, the precision of the analytical method for PBDEs is significantly improved.To increase sensitivity and overcome some of the problems associated with sample preparation, large volume injection technique is recommended. Both large volume programmable temperature vaporizing (PTV) injection and the loop type injector has been optimized and evaluated with respect to the PBDEs. It is also demonstrated that the GC injection technique most commonly used for PBDE analysis, discriminate the high molecular weight congeners such as the decabrominated diphenyl ether congener (BDE-209).The dimensions and the type of GC column system strongly affect the yield of the PBDE. Degradation in the GC system of high molecular weight polybrominated diphenyl ether (BDE) congeners, especially BDE-209, is also dependent on the residence time in the column system. There is a large difference in performance between columns with supposedly similar stationary phase and by selecting a short narrow bore columns it is possible to dramatically decrease the degradation of high molecular weight PBDEs.Mass spectrometric properties of BDE-209 is presented, and carbon 13 labeled BDE-209 is evaluated and proposed as internal surrogate standard for the determination of BDE-209 in mass spectrometric detection in electron capture negative ionization (ECNI) mode.
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19.
  • Björnsdotter, Maria, 1989-, et al. (författare)
  • Bisphenol A and replacements in thermal paper : A review
  • 2017
  • Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 182, s. 691-706
  • Tidskriftsartikel (refereegranskat)abstract
    • Thermal paper contains potentially toxic compounds such as bisphenol A (BPA), which is used as a color developer. BPA has been reported in thermal paper in concentrations up to 42,600 Kg g(-1). The exposure to BPA via dermal transfer has been recently discussed as a significant contribution to the overall human exposure and the estimated daily intake (EDI) has been reported up to 218 mu g d(-1). BPA has been also detected in recycled paper with concentrations up to 46 n g(-1). Due to the fact that BPA is a known endocrine disruptor and migrates from materials, regulatory restrictions have been established to prevent risks for the human health. As a consequence, structural analogues, such as bisphenol S (BPS) have been introduced into the market. Little is known about the presence and toxicity of these emerging replacements, and concern has risen about them. The present review gives an overview of the occurrence and levels of BPA and replacements in thermal paper. BPA is still the most common color developer found in thermal paper, followed by BPS. The analytical methods used for quantification of BPA and BPA replacements in paper products are also reviewed. BPA is transferred from thermal paper products to the finger pads upon handling it. Paper-skin transfer followed by penetration of BPA depends on conditions (e.g. greasiness of fingers and use of hand cream). It is, however, still debated whether thermal paper as a source for human exposure contributes significantly to the overall internal BPA exposure.
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20.
  • Björnsdotter, Maria, 1989-, et al. (författare)
  • Presence of diphenyl phosphate and aryl-phosphate flame retardants inindoor dust from different microenvironments in Spain and the Netherlandsand estimation of human exposure
  • 2018
  • Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 112, s. 59-67
  • Tidskriftsartikel (refereegranskat)abstract
    • Phosphate flame retardants (PFRs) are ubiquitous chemicals in the indoor environment. Diphenyl phosphate (DPHP) is a major metabolite and a common biomarker of aryl-PFRs. Since it is used as a chemical additive and it is a common impurity of aryl-PFRs as well as a degradation product, its presence in indoor dust as an additional source of exposure should not be easily ruled out. In this study, DPHP (and TPHP) are measured in indoor dust in samples collected in Spain and in the Netherlands (n = 80). Additionally, the presence of other emerging aryl-PFRs was monitored by target screening. TPHP and DPHP were present in all samples in the ranges 169-142,459 ng/g and 106-79,661 ng/g, respectively. DPHP concentrations were strongly correlated to the TPHP levels (r = 0.90, p < 0.01), suggesting that DPHP could be present as degradation product of TPHP or other aryl-PFRs. Estimated exposures for adults and toddlers in Spain to TPHP and DPHP via dust ingestion (country for which the number of samples was higher) were much lower than the estimated reference dose (US EPA) for TPHP. However, other routes of exposure may contribute to the overall internal exposure (diet, dermal contact with dust/consumer products and inhalation of indoor air). The estimated urinary DPHP levels for adults and toddlers in Spain (0.002-0.032 ng/mL) as a result of dust ingestion were low in comparison with the reported levels, indicating a low contribution of this source of contamination to the overall DPHP exposure. Other aryl-PFRs, namely cresyl diphenyl phosphate (CDP), resorcinol bis(diphenyl phosphate) (RDP), 2-ethylhexyl diphenyl phosphate (EDPHP), isodecyl diphenyl phosphate (IDP) and bisphenol A bis(diphenyl phosphate) (BDP), were all detected in indoor dust, however, with lower frequency.
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21.
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22.
  • de Boer, Jacob, et al. (författare)
  • Global interlaboratory assessments on PCBs, organochlorine pesticides and brominated flame retardants in various environmental matrices 2017/2019
  • 2022
  • Ingår i: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 295
  • Tidskriftsartikel (refereegranskat)abstract
    • In support of the United Nations Environment Programme (UNEP) global monitoring plan under the Stockholm Convention contributing laboratories were offered to take part in a series of interlaboratory assessments on persistent organic pollutants (POPs). The results of two rounds of these assessments are reported. The target compounds were polychlorinated biphenyls, organochlorine pesticides, polybrominated diphenylethers, one polybrominated biphenyl and hexabromocyclododecane diastereomers. The matrices distributed were a test solution, fish, sediment, human milk, and air extracts. The number of participants in each round was well over 100, showing the interest of laboratories worldwide. The results showed that many laboratories still struggle to obtain acceptable standard deviations of around 25% for their determinations. In particular for organochlorine pesticides serious improvement in quality is required. Acceptable results were obtained for the air extracts and for the determination of polybrominated diphenylethers in various matrices.
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23.
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24.
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25.
  • Fiedler, Heidelore, Dr. 1953-, et al. (författare)
  • Assessment of four rounds of interlaboratory tests within the UNEP-coordinated POPs projects
  • 2022
  • Ingår i: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 288
  • Tidskriftsartikel (refereegranskat)abstract
    • Since 2005, the United Nations Environment Programme (UNEP) has supported developing countries with capacity building, including on-site training courses and provision on laboratory materials and consumables, and analysis of samples from Africa, Asia-Pacific and Latin America and the Caribbean (GRULAC) in designated expert laboratories. In order to check the performance of laboratories analyzing persistent organic pollutants (POPs) and giving trust into chemical analytical results, four rounds of interlaboratory assessments (ILs) were organized between 2010 and 2019. These were open to all POPs laboratories. In total, 41 575 z-scores, as indicators of performance, were generated in these four ILs; of these, 8912 were from laboratories in countries supported by UNEP projects and 3923 were from expert laboratories; these together constitute 31% of the total. 69% of all z-scores came from laboratories not participating in the UNEP projects, especially from China, who recognized the importance of such exercises for quality control at an early stage. The results showed that POPs analytical capacity has increased over the years, but some gaps could not be closed especially not when LC-MS/MS equipment is essential such as for PFAS and congener-specific HBCD. Use of mass spectrometers provides better results than ECD instruments due to the broad spectrum of organochlorine pesticides to be analyzed under the Stockholm Convention. The main conclusion for all laboratories is that interlaboratory assessments provide important and objective snapshots of performance for the laboratories themselves and for external clients. The methods used in any interlaboratory testing should be the same as during routine analysis between such tests.
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26.
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27.
  • Fiedler, Heidelore, Dr. 1953-, et al. (författare)
  • Bi-ennial Global Interlaboratory Assessment on Persistent Organic Pollutants – Fourth Round 2018/2019
  • 2021
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • The fourth Bi-ennial Global Interlaboratory Assessment on Persistent Organic Pollutants (POPs) was organized in 2018. After invitation to participate in this fourth round of the proficiency test, 148 laboratories from 62 countries had registered. In comparison to the 3rd round in which 175 laboratories had registered, this was somewhat lower. However, again several new laboratories (participating for the first time) joined this exercise. The test materials included test solutions of analytical standards, the abiotic matrices included sediment, air (extract) and water and the biotic matrices were fish, human milk and human plasma. The results for the 23 groups of POPs that were listed in the annexes of the Stockholm Convention until 2013 and in addition hexachlorobutadiene, pentachlorobenzene, alpha-HCH, beta-HCH, gamma-HCH, alpha-endosulfan, beta-endosulfan, endosulfan sulfate were assessed. This resulted in a report with a wealth of information on POP analysis and a huge dataset from which the laboratories can evaluate their own methods and performance.The Global Monitoring Plan (GMP) of the Stockholm Convention requires that POP laboratories must be capable – at any time – to analyse samples for POPs within a variation of ±25%. Based on this target error of 25%, the statistical model used provided z-scores based on which the performance of each laboratory for each analyte in each matrix can be assessed.The results show a scattered picture and in comparison, with previous rounds, the performance of many laboratories receded. For a number of analytes, in particularly for organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), the performance was disappointing. In addition, several laboratories which had been trained within UNEP’s or other’s capacity building projects and have participated in this scheme for three or four times did not meet the expectations. Relatively low concentrations of OCPs in the test materials and a low fat content in the fish matrix could have played a role. However, these materials are realistic and non-spiked test materials.A large number of laboratories only analysed a few matrices and especially the standard test solutions, where it was expected that after four rounds of this study, the capacity of the laboratories would have been extended to the analysis of most POPs and the performance would steadily improve. The standard test solution results were often disappointing as well.More experienced laboratories showed a good to very good performance for chlorinated dibenzodioxins and dibenzofurans and dioxin-like (dl)-PCB, and for PBDE, PFASs and HBCD (alpha-HBCD in fish and gamma-HBCD in sediment). The toxaphene results were encouraging for the test solutions but in a next round, test materials need higher concentrations of toxaphene to enable a realistic test.This interlaboratory assessment on POPs remains to be among the largest ever organised. Given the overwhelming interest in this study and the need for a substantial increase in quality for many laboratories, it is strongly advised to continue with this study on a bi-ennial basis.
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28.
  • Fiedler, Heidelore, Dr. 1953-, et al. (författare)
  • Interlaboratory assessments for dioxin-like POPs (2016/2017 and 2018/2019)
  • 2022
  • Ingår i: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 288:Pt 1
  • Tidskriftsartikel (refereegranskat)abstract
    • In the two rounds of the UNEP-coordinated 'Biennial interlaboratory assessments of POPs laboratories, which were implemented in 2016/2017 and 2018/2019, 56 and 46 laboratories submitted results for dioxin-like persistent organic pollutants (dl-POPs). Test matrices consisted of solutions of analytical standards and naturally contaminated sediment, air extract, fish and human milk. Performance assessment using z-scores so that satisfactory performance corresponded to 2 z = ±25%, which is recommended for laboratories submitting data to the global monitoring plan of the Stockholm Convention on POPs. Participation has shown that analytical capacity for analyzing dl-POPs exist in all UN regions; however, in Africa and Central and Eastern European countries capacities are (very) limited; in Latin America capacity is increasing. The presence of dioxin laboratories is not limited to industrialized or OECD countries but also present in developing countries such as China, Brazil, Egypt, Thailand, or Vietnam. Laboratories using established methods based on gas chromatographs coupled to high-resolution mass spectrometers (sector field instruments only) by far had the best results. Among the test samples, human milk and especially fish in the last round posed severe problems to all laboratories so that performance has to improve, especially in foodstuff at (very) low concentrations.
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29.
  • Fiedler, Heidelore, Dr. 1953-, et al. (författare)
  • Persistent organic pollutants in air across the globe using a comparative passive air sampling method
  • 2024
  • Ingår i: TrAC. Trends in analytical chemistry. - : Elsevier. - 0165-9936 .- 1879-3142. ; 171
  • Tidskriftsartikel (refereegranskat)abstract
    • For the global monitoring plan (GMP) established under the Stockholm Convention on Persistent Organic Pollutants (POPs), passive air samplers (PAS) equipped with polyurethane foam disks (PUFs) were recommended for generating comparative results on the presence of POPs in countries. One representative sampling location was designed in each of the 42 countries and the PAS/PUFs exposed for three months to collect POPs during 2017–2019. The PUFs were analyzed in three laboratories according to their chemical nature and concentrations reported per PUF and 90 ± 3 days of exposure. In total, 381 PUFs were analyzed for organochlorine pesticides (OCPs), industrial chlorinated POPs, dioxin-like POPs (dl-POPs), brominated flame retardants (BFRs), and perfluoroalkane substances (PFAS). Concentrations typically varied by a factor of up to three for a POP and often within the same geographic region or other denominator such as similar latitudes or altitudes. Maximum values were found for DDT (895 ng/PUF) in Africa, but the highest medium value was in the Latin American countries. Also, polychlorinated biphenyls (PCB) and hexachlorobenzene (HCB) were most abundant across all parameters assessed. Noteworthy were high values in single countries, such as DDT in the Solomon Islands, toxaphene in Mexico, β-HCH and lindane in Tanzania, hexachlorobutadiene and hexabromocyclododecone in Mongolia, deca-BDE and PFOS in Zambia. Although we had two sampling locations at very high altitudes, >2000 m, we could determine increasing POPs concentrations with increasing altitudes only for HCB but not for other POPs. A general dependency on latitudes with higher concentrations towards the north and south pole could not be found, although the most northern station in Mongolia had two of the maxima and elevated values for some legacy POPs.
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30.
  • Fiedler, Heidelore, Dr. 1953-, et al. (författare)
  • Preliminary trends over ten years of persistent organic pollutants in air : Comparison of two sets of data in the same countries
  • 2023
  • Ingår i: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 324
  • Tidskriftsartikel (refereegranskat)abstract
    • In two series of ambient air measurement campaigns to support the implementation of the global monitoring plan (GMP) component of the Stockholm Convention on Persistent Organic Pollutants (POPs), passive air samplers (PAS) using polyurethane foams were implemented by the United Nations Environment Programme (UNEP). With the same laboratories responsible for the chemical analyses of the different groups of POPs, a total of 423 PUFs were analyzed for organochlorine pesticides (OCPs) including hexachlorobenzene (HCB) and polychlorinated biphenyls (PCB); 242 for dioxin-like POPs. For trend analysis, to compare amounts of POPs in the PUFs during the first phase in 2010/2011 and the second phase from 2017 to 2019, only results were assessed that were generated in the same country and for the same POP in both campaigns. Finally, there were 194 PUFs available for OCPs (GMP1 = 67 and GMP2 = 127), 297 for PCB (GMP1 = 103, GMP2 = 194), 158 for polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDD, PCDF) (GMP1 = 39, GMP2 = 119), and 153 for dl-PCB (GMP1 = 34, GMP2 = 119). Indicator PCB and dioxin-like POP were quantified in all countries at all times; decreases of about 30% based on median values were determined. A 50% increase was found for HCB. By scale, DDT remained with the highest values, although more than 60% decrease was found; mainly due to smaller values in the Pacific Islands. Our assessment showed that on relative scale - per PUF - trend analysis was achieved and that such approach should be undertaken at regular intervals, not necessarily on an annual basis.
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31.
  • Fiedler, Heidelore, Dr. 1953-, et al. (författare)
  • The Stockholm Convention : A Tool for the Global Regulation of Persistent Organic Pollutants
  • 2019
  • Ingår i: Chemistry International. - : Walter de Gruyter. - 0193-6484 .- 1365-2192. ; 41:2, s. 4-11
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of the Stockholm Convention on Persistent Organic Pollutants (POPs) is to eliminate persistent organic chemicals worldwide by either prohibiting their production and use or gradually reducing them. The Stockholm Convention was adopted in 2001 and entered into force in 2004, 90 days after receiving the 50th instrument of ratification. The Parties to the Convention have to regularly report progress in implementation of their measures taken to achieve the goals. The Convention has a mechanism to add more compounds; today 28 POPs are covered, 16 more than the initial ones.
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32.
  • Fridén, Ulrika E., 1973- (författare)
  • Sources, emissions, and occurrence of chlorinated paraffins in Stockholm, Sweden
  • 2010
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Chlorinated paraffins (CPs) are ubiquitous environmental contaminants. They fulfill all of the criteria (persistent, toxic, and subject to long-range transport) for persistent organic pollutants (POPs) according to the United Nations Economic Commission for Europe (UNECE). CPs are also under consideration for inclusion in the Stockholm Convention on POPs. Their presence has been shown in various environmental matrices in the industrialized parts of the world, as well as in remote regions such as the Arctic. The aim of this thesis was to increase the limited knowledge of the presence of CPs in the environment, their sources to the environment, and the resulting human exposure. An analytical procedure for the determination of CPs in environmental samples based on gas chromatography coupled to electron capture detection (GC-ECD) has been developed. GC-ECD is a relatively inexpensive instrument that is fast and easy to operate. These advantages open up the possibility for a comprehensive screening of the occurrence of CPs in the environment, including developing countries. Furthermore, the occurrence of CPs in ambient air and in indoor air and dust was studied. Elevated CP concentrations in indoor air (<5-210 ng/m3) were observed compared to ambient air (0.7-33 ng/m3), which is indicative of the presence of indoor emission sources. Indoor air and dust concentrations were used to estimate the human exposure to CPs via the indoor environment. Comparison of the estimates to available dietary intake estimates indicated that the indoor exposure pathways are not negligible. CP concentrations in ambient air from urban Stockholm were higher than in rural Aspvreten, Sweden. This indicates the presence of additional (emission) sources in urban areas compared to rural sites. Additionally, a seasonal variation of air concentrations was observed at both locations, suggesting temperature dependent emission sources for CPs. These observations were supported by a substance flow analysis of CPs performed for Stockholm. This study estimated the major emission sources of CPs to the Stockholm environment to be emissions from painted surfaces and in-place sealants.
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33.
  • Haglund, Peter, et al. (författare)
  • GCxGC-ECD a promising method for the determination of dioxins and dioxin-like PCBs in food and feed
  • 2008
  • Ingår i: Analytical and Bioanalytical Chemistry. - : Springer. - 1618-2642 .- 1618-2650. ; 390:7, s. 1815-1827
  • Tidskriftsartikel (refereegranskat)abstract
    • There is a need for cost-efficient alternatives to gas chromatography (GC)–high-resolution mass spectrometry (HRMS) for the analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) in food and feed. Comprehensive two-dimensional GC–micro electron capture detection (GC×GC-μECD) was tested and all relevant (according to the World Health Organisation, WHO) PCDD/Fs and PCBs could be separated when using a DB-XLB/LC-50 column combination. Validation tests by two laboratories showed that detectability, repeatability, reproducibility and accuracy of GC×GC-μECD are all statistically consistent with GC-HRMS results. A limit of detection of 0.5 pg WHO PCDD/F tetrachlorodibenzo-p-dioxin equivalency concentration per gram of fish oil was established. The reproducibility was less than 10%, which is below the recommended EU value for reference methods (less than 15%). Injections of vegetable oil extracts spiked with PCBs, polychlorinated naphthalenes and diphenyl ethers at concentrations of 200 ng/g showed no significant impact on the dioxin results, confirming in that way the robustness of the method. The use of GC×GC-μECD as a routine method for food and feed analysis is therefore recommended. However, the data evaluation of low dioxin concentrations is still laborious owing to the need for manual integration. This makes the overall analysis costs higher than those of GC-HRMS. Further developments of software are needed (and expected) to reduce the data evaluation time. Combination of the current method with pressurised liquid extraction with in-cell cleanup will result in further reduction of analysis costs.
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34.
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35.
  • Hinsley, Amy, et al. (författare)
  • A review of the trade in orchids and its implications for conservation
  • 2018
  • Ingår i: Botanical journal of the Linnean Society. - : OXFORD UNIV PRESS. - 0024-4074 .- 1095-8339. ; 186:4, s. 435-455
  • Forskningsöversikt (refereegranskat)abstract
    • Orchids are one of the largest plant families and are commercially traded for a variety of purposes, including as ornamental plants, medicinal products and food. These markets involve thousands of species, which may be traded legally or illegally, sustainably or unsustainably, and take place at local, national or international scales. In this review, we provide the first overview of commercial orchid trade globally and highlight the main types that involve wild-collected plants. Much of this trade is the result of illegal harvest meaning that it is little documented and is absent from official statistics, at the same time as being of growing conservation concern. We discuss the associated legal-regulatory context, identify key conservation challenges and highlight four key priorities for addressing these challenges. These are to (1) research trade dynamics and the impacts of harvest; (2) strengthen the legal trade of orchids; (3) adopt measures to reduce illegal trade; and (4) raise the profile of orchid trade among policy makers, conservationists and the public.
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36.
  • Lal, Vincent, et al. (författare)
  • Capacity building for persistent organic pollutant (POP) analysis in the Pacific and POP trends in the Pacific Islands
  • 2013
  • Ingår i: TrAC. Trends in analytical chemistry. - : Elsevier BV. - 0165-9936 .- 1879-3142. ; 46, s. 173-177
  • Tidskriftsartikel (refereegranskat)abstract
    • This article gives an overview of activities relating to the establishment of a regional center of excellence for testing persistent organic pollutants (POPs) in the Pacific Island Region. It highlights the areas of analytical procedures that needed improvement to perform trace-level POP testing in human-breast milk. It describes the actions taken by the POP expert group of the United Nations Environment Programme (UNEP) Chemicals during inspection visits and in setting up analytical procedures and proficiency tests to achieve acceptable levels of results for testing POPs regionally. It also describes results of early studies on POPs in human-breast milk in several Pacific Island countries, which generally show relatively low levels.
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37.
  • Ouyang, Xiyu, et al. (författare)
  • Non-target analysis of household dust and laundry dryer lint using comprehensive two-dimensional liquid chromatography coupled with time-of-flight mass spectrometry
  • 2017
  • Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 166, s. 431-437
  • Tidskriftsartikel (refereegranskat)abstract
    • Household dust and laundry dryer lint are important indoor environmental matrices that may have notable health effects on humans due to chronic exposure. However, due to the sample complexity the studies conducted on these sample matrices until now were almost exclusively on the basis of target analysis. In this study, comprehensive two-dimensional liquid chromatography coupled with time-of flight mass spectrometry (LC x LC-ToF MS) was applied, to enable non-target analysis of household dust as well as laundry dryer lint for the first time. The higher peak capacity and, good orthogonality of LC x LC, together with reduced ion suppression in the MS enabled rapid identification of environmental contaminants in these complex sample matrices. A number of environmental contaminants were tentatively identified based on their accurate masses and isotopic patterns, including plasticizers, flame retardants, pesticides, drug metabolites, etc. The identity of seven compounds: tris(2-butoxyethyl) phosphate, tris(2-chloropropyl) phosphate, n-benzyl butyl phthalate, dibutyl phthalate, tributyl phosphate, triethyl phosphate and N, N-diethyl-meta-toluamide was confirmed using two-dimensional retention alignment and their concentrations in the samples were semi-quantitatively determined.
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38.
  • Rebryk, Andriy, 1989- (författare)
  • Comprehensive non-target screening to find and identify new biomagnifying organic contaminants in Baltic Sea top consumers
  • 2022
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The development of industrial processes in the 19th and 20th centuries, in particular oil refining, resulted in a huge discovery and subsequent large-scale production of a variety of chemicals. These useful chemicals supposedly made the everyday lives of people easier and better by, for instance, controlling the spread of diseases such as malaria, through the use of DDT and other organochlorine pesticides (OCPs).During the 1970s and following decades, it was hypothesized and later shown, that these, and other “helpful chemicals” such as polychlorinated biphenyls (PCBs), played a crucial role in the steep population decline observed for multiple species in the Baltic Sea. They were classified as anthropogenic (man-made) hazardous substances (AHSs). Many AHSs can be stored in fatty tissues of the organisms and magnify in species at high trophic levels (predators) of the food web, as a result of persistence and transfer from lower-level organisms (prey). This process is called biomagnification and is characterized by biomagnification or trophic magnification factors (BMFs or TMFs, respectively). AHSs can be roughly divided into known chemicals of concern, such as persistent organic pollutants (POPs), and contaminants of emerging concern (CECs), that include novel flame retardants, polymer additives, and many more. Both the production and use of a number of AHSs have been regulated since the 1970s. To understand the outcome of the regulations, retrospective analysis of samples from different years, a time-trend study, is often utilized.The main aim of this work was to develop a non-selective sample extraction, purification, and analysis method, and then find and identify as many biomagnifying contaminants as possible. To assess both biomagnification and temporal trends of a wide range of chemical contaminants in a given Baltic Sea food web, non-target screening (NTS) was used. A clean-up method was established and tested with a satisfactory outcome: processed extracts were pure enough for gas chromatography-mass spectrometry (GC-MS) analysis. Also, accompanying NTS data processing workflows were developed. Application of these resulted in BMFs for more than 100 contaminants (Paper I). The data processing workflow was refined for faster detection of chemicals that demonstrate temporal trends and/or biomagnify. It was possible to detect and tentatively identify more than 300 legacy POPs and CECs with statistically significant temporal trends in three Baltic top consumers (Paper II). Adjusted NTS workflows were used to reveal more than 250 compounds that possessed trophic magnification properties (Paper III). Inspired by the discovery of a novel flame retardant Dechlorane 602 (Paper I), a suspect screening for dechlorane-related compounds and their transformation products was carried out. A total of 31 compounds were detected and tentatively identified, many of which showed significant temporal trends and biomagnification (Paper IV). A number of compounds reported in Papers I–IV were tentatively identified for the first time in wildlife. In addition, the papers provide valuable spectral and retention information for the researchers in the field.In conclusion, this thesis presents useful GC-MS-based NTS workflows and biomagnification or time-trend data for a plethora of organic contaminants in the Baltic Sea food web. The data can contribute to i) the assessment of the influence pollutants have on the ecosystem and ii) various mitigation actions for AHSs, such as evaluating dechloranes for regulation under the Stockholm Convention on POPs, helping in the fight for a better environment and future.
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39.
  • Rimayi, Cornelius, et al. (författare)
  • Contaminants of emerging concern in the Hartbeespoort Dam catchment and the uMngeni River estuary 2016 pollution incident, South Africa
  • 2018
  • Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 627, s. 1008-1017
  • Tidskriftsartikel (refereegranskat)abstract
    • A quantitative assessment of pollutants of emerging concern in the Hartbeespoort Damcatchment area was conducted using liquid chromatography-tandem mass spectrometry LC-MS/MS) to establish the occurrence, source and distribution of 15 environmental pollutants, including 10 pharmaceuticals, 1 pesticide and 4 steroid hormones. Seasonal sampling was conducted in the Hartbeespoort Lake using sub-surface grab sampling to determine the lake's ecological status and obtain data for establishment of progressive operational monitoring. The Jukskei River, which lies upstream of the Hartbeespoort Dam, was sampled in the winter season. Five year old carp Cyprinus carpio) and catfish Clarias gariepinus) were also sampled from the Hartbeespoort Dam to study bioaccumulation in biota as well as to estimate risk associated with fish consumption. In the Jukskei River, the main source of 11 emerging pollutants EPs) was identified as raw sewage overflow, with the highest Sigma 11 EP concentration of 593 ng L-1 being recorded at the Midrand point and the lowest Sigma 11 EP concentration of 164 ng L-1 at the N14 site located 1 km downstream of a large wastewater treatment plant. The Jukskei River was found to be the largest contributor of the emerging contaminants detected in the Hartbeespoort Dam. In the Hartbeespoort Dam EP concentrations were generally in the order efavirenz > nevirapine > carbamazepine > methocarbamol > bromacil > venlafaxine. Water and sediment were sampled from the uMngeni River estuary within 24 h after large volumes of an assortment of pharmaceuticalwaste had been discovered to bewashed into the river estuary after flash rainfall on 18 May 2016. Analytical results revealed high levels of some emerging pollutants in sediment samples, up to 81 ng g(-1) for nevirapine and 4 ng g(-1) for etilefrine HCL. This study shows that efavirenz, nevirapine, carbamazepine, methocarbamol, bromacil and venlafaxine are contaminants that require operational monitoring in South African urban waters.
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40.
  • Rimayi, Cornelius, et al. (författare)
  • Effects of environmentally relevant sub-chronic atrazine concentrations on African clawed frog (Xenopus laevis) survival, growth and male gonad development
  • 2018
  • Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 199, s. 1-11
  • Tidskriftsartikel (refereegranskat)abstract
    • Sub-chronic toxicity of environmentally relevant atrazine concentrations on exposed tadpoles and adult male African clawed frogs (Xenopus laevis) was evaluated in a quality controlled laboratory for 90 days. The aim of this study was to determine the effects of atrazine on the survival, growth and gonad development of African clawed frogs. After exposure of tadpoles to atrazine concentrations of 0 (control), 0.01, 200 and 500 mu g L-1 in water, mortality rates of 0, 0, 3.3 and 70% respectively were recorded for the 90 day exposure period. Morphometry showed significantly reduced tadpole mass in the 500 mu g L-1 atrazine exposed tadpoles (p < 0.05). Light microscopy on testes of adult frogs exposed to the same atrazine concentrations using hematoxylin and eosin (H&E) and Van Gieson staining techniques revealed gonadal atrophy, disruption of germ cell lines, seminiferous tubule structure damage and formation of extensive connective tissue around seminiferous tubules of frogs exposed to 200 mu g L-1 and 500 mu g L-1 atrazine concentrations. Ultrastructural analysis of the cellular organelles using transmission electron microscopy (TEM) revealed significant amounts of damaged mitochondria in testosterone producing Leydig cells as well as Sertoli cells. Biochemical analysis revealed reduced serum testosterone levels in adult frogs at all exposure levels as well as presence of six atrazine metabolites in frog serum and liver. The results indicate that atrazine concentrations greater than the calculated LC50 of 343.7 mu g L-1 cause significant mortality in tadpoles, while concentrations >= 200 mu g L-1 adversely affect reproductive health of adult frogs and development of tadpoles sub-chronically exposed to atrazine.
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41.
  • Rimayi, Cornelius, et al. (författare)
  • Seasonal variation of chloro-s-triazines in the Hartbeespoort Dam catchment, South Africa
  • 2018
  • Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 613, s. 472-482
  • Tidskriftsartikel (refereegranskat)abstract
    • Seasonal variation of eight chloro-s-triazine herbicides and seven major atrazine and terbuthylazine degradation products was monitored in the Hartbeespoort Dam catchment using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS/MS). Lake, river and groundwater were sampled from the Hartbeespoort Dam catchment over four seasons and the downstream Jukskei River was monitored during the winter season. Triazine herbicide concentrations in the Hartbeespoort Dam were in the order atrazine > simazine > propazine > ametryn > prometryn throughout the four seasons sampled. Triazine herbicide concentrations in the Hartbeespoort Dam surface water were highest in summer and gradually decreased in successive seasons of autumn, winter and spring. Terbuthylazine was the only triazine herbicide detected at all sampling sites in the Jukskei River, though atrazine recorded much higher concentrations for the N14 and Kyalami sites, with concentrations of 923 and 210 ng L-1 respectively, compared to 134 and 74 ng L-1 for terbuthylazine. Analytical results in conjunction with river flow data indicate that the Jukskei and Crocodile Rivers contribute the greatest triazine herbicide loads into the Hartbeespoort Dam. No triazine herbicides were detected in the fish muscle tested, showing that bioaccumulation of triazine herbicides is negligible. Atrazine and terbuthylazine metabolites were detected in the fish muscle with deethylatrazine (DEA) being detected in both catfish and carp muscle at low concentrations of 0.2 and 0.3 ng g(-1), respectively. Desethylterbuthylazine (DET) was detected only in catfish at a concentration of 0.3 ng g(-1). With atrazine herbicide groundwater concentrations being >130 ng L-1 for all seasons and groundwater Sigma triazine herbicide concentrations ranging between 527 and 367 ng L-1, triazine compounds in the Hartbeespoort Dam catchment may pose a risk to humans and wildlife in light findings of endocrine and immune disrupting atrazine effects by various researchers.
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42.
  • Rimayi, Cornelius, et al. (författare)
  • Source characterisation and distribution of selected PCBs, PAHs and alkyl PAHs in sediments from the Klip and Jukskei Rivers, South Africa
  • 2017
  • Ingår i: Environmental Monitoring & Assessment. - : Springer Science and Business Media LLC. - 0167-6369 .- 1573-2959. ; 189:7
  • Tidskriftsartikel (refereegranskat)abstract
    • A study of the distribution of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) utilising 16 priority PAHs, benzo(e) pyrene, perylene, 19 alkylated PAHs and 31 ortho substituted PCBs in South Africa is presented. It was aimed to (a) deduce characteristic contamination patterns for both PCBs and PAHs and (b) provide the first comprehensive dataset for establishment of source characterisation of PCBs and PAHs. This is in line with new South African legislation on mandatory monitoring of PCB and PAH emissions. Bar charts, principal component analysis (PCA) and biplots were utilised to identify signature contamination patterns and distribution of PCBs and PAHs within the Jukskei and Klip Rivers. Sediments from the Jukskei and Klip River catchments both showed distinct contamination signatures for hexa to nonachlorinated PCBs, characteristic of contamination by Aroclor 1254 and 1260 technical mixtures. PCB signature patterns in order of abundance were 138 > 180 > 206 > 153 > 187 > 149 and 138 > 153 > 180 > 149 > 187 > 110 > 170 for the Jukskei and Klip River sediments, respectively. The upstream Alberton point had the highest Sigma 31 PCB and Sigma (parent+alkyl) PAH concentrations in the Klip River of 61 and 6000 mu g kg(-1) dry weight (dw), respectively. In the Jukskei River, the upstream Marlboro point had the highest Sigma 31 PCB concentration of 19 mu g kg(-1) dw and the N14 site recorded the highest Sigma(parent+alkyl) PAH concentration of 2750 mu g kg(-1) dw. PAH concentrations in both the Jukskei and Klip Rivers were significantly higher than the PCB concentrations. Fluoranthene, phenanthrene and pyrene were found in the highest concentrations in both the Jukskei and Klip River sediments. Both the Jukskei and Klip River sediments showed trends of a mixed pyrogenic-petrogenic PAH source contamination.
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43.
  • Rotander, Anna, 1978- (författare)
  • Monitoring persistent organic pollutants (POPs) in sub-Arctic and Arctic marine mammals, 1984 - 2009
  • 2011
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The Arctic has become an important indicator region for assessing persistence and bioaccumulation properties of persistent organic pollutants (POPs). This thesis is aimed at evaluating the occurrence of persistent halogenated POPs in seven species of sub-Arctic and Arctic marine mammals over a 25-year period. The emphasis is on studying temporal variations in concentration of three categories of POPs, including naturally occurring organobromine compounds. Polybrominated diphenyl ethers (PBDEs), Metoxylated diphenyl ethers (MeO-PBDEs), and polychlorinated naphtalenes (PCNs) were extracted from blubber tissue and analyzed by GC/MS. Polyfluoroalkyl substances (PFAS) were extracted from livers and analyzed by LC-MS/MS. Although restricted by the number of pooled samples, survey points, and species available from the specimen banks, the results showed some interesting contamination patterns. Overall, pollutant concentrations showed signs of declining or levelling out, indicating a decrease in POP exposure in the studied areas in recent years. However, increasing levels of long-chain fluorinated compounds (PFCAs) present in most species is a finding of concern, and implies that a continuous monitoring of these compounds is important. Interestingly, a shift over time in the relative abundance of PFOS isomers in ringed seals was observed, indicating a change in exposure to PFOS in recent years. In many of the investigated species the MeO-PBDE levels equalled or exceeded the levels of PBDEs, showing that MeO-PBDEs can be major contributors to the organobromine load in marine mammal species. No apparent relation was found between PBDE and MeO-PBDE levels, adding further support for a natural origin of MeO-PBDEs.
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44.
  • van der Veen, Ike, et al. (författare)
  • Assessment of the per- and polyfluoroalkyl substances analysis under the Stockholm Convention - 2018/2019
  • 2023
  • Ingår i: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 313
  • Tidskriftsartikel (refereegranskat)abstract
    • The comparability of laboratories for the analysis of per- and polyfluoroalkyl substances (PFAS) was assessed in the fourth round (2018/2019) of a series of interlaboratory assessments coordinated by the United Nations Environment Programme (UNEP) in support of the Stockholm Convention quality assurance activities as to persistent organic pollutants (POPs) laboratories reporting data under this Convention. The participating laboratories were asked to analyse PFAS concentrations in a test solution of the target compounds, in the four core matrices of the global monitoring plan (GMP), human milk, human plasma, an air extract, and water, and in a sediment and a fish matrix. 39 participating laboratories submitted PFAS data for one or more test materials. The majority of the participating laboratories originated from the Asia-Pacific region, and from the 'Western European and other groups' (WEOG). Only one laboratory from the group 'Latin America and Caribbean' (GRULAC), and two from the Central and Eastern Europe (CEE) region submitted results. None of the African laboratories submitted data. The coefficients of variation (CVs) varied from 7% to 24% (mean 14%) for the test solution. Mean CVs for all matrices, except for the human plasma test material (18%), were above the satisfactory limit of 25%. The highest mean CV was found for human milk (61%). In total 1457 z-scores were assigned of which 64% were satisfactory (|z| < 2). Instrumentation used was mainly high-performance liquid chromatography (HPLC), in combination with various mass spectrometric (MS) techniques, in most cases tandem MS (MS/MS). Additional PFAS beyond perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), which are listed at the Stockholm Convention POPs list, as well as water as a matrix for PFAS only and human plasma were added as a service for the laboratories.
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45.
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46.
  • van der Veen, Ike, et al. (författare)
  • Development and validation of a method for the quantification of extractable perfluoroalkyl acids (PFAAs) and perfluorooctane sulfonamide (FOSA) in textiles
  • 2016
  • Ingår i: Talanta. - : Elsevier BV. - 0039-9140 .- 1873-3573. ; 147, s. 8-15
  • Tidskriftsartikel (refereegranskat)abstract
    • In textiles, like outdoor clothing, per- and polyfluoroalkyl substances (PFASs) are often used for durable water repellency (DWR) of the final products. The analytical performance to determine the concentration of these chemicals available for exposure to humans and to the environment need to be established. Here a method for the extraction and analysis of one class of PFASs, namely perfluoroalkyl acids (PFAAs), in outdoor clothing was developed and validated. The PFAAs which were validated, included perfluoroalkyl carboxylic acids (PFCAs) (C4-C14), and perfluoroalkane sulfonic acids (PFSAs) (C4, C6, C7, C8). In addition, perfluorooctane sulfonamide (FOSA) was included in this study. The method was based on an organic solvent extraction and analysis by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). No further cleaning was needed. Two commonly used organic solvent compositions were evaluated for the optimal extraction, i.e. methanol and acetone/acetonitrile (80:20, v/v), and the number and duration of the sequential extractions were optimized. Results showed that two sequential extractions with 5 mL methanol and an extraction time of 30 min gave an optimal performance with an extraction efficiency of >90%. The influence of matrix on the quantification of PFAAs was studied. This indicated ion suppression due to different matrix effects or sorption behavior to specific textile samples. Validation of the entire method showed overall recoveries of>80% and relative standard deviations (RSDs) of<9% (n=3) for repeatability and <20% (n=3) for reproducibility. This is the first validation of an analytical method for the analysis of extractable PFCAs, PFSAs and FOSA associated to textiles, which is of high importance due to the regulation of PFAAs in textile.
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47.
  • Van Der Veen, Ike, et al. (författare)
  • Fate of Per- and Polyfluoroalkyl Substances from Durable Water-Repellent Clothing during Use
  • 2022
  • Ingår i: Environmental Science and Technology. - : American Chemical Society. - 0013-936X .- 1520-5851. ; 56:9, s. 5886-5897
  • Tidskriftsartikel (refereegranskat)abstract
    • To make outdoor clothing water- or dirt-repellent, durable water-repellent (DWR) coatings based on side-chain fluorinated polymers (SFPs) are used. During use of outdoor clothing, per- and polyfluoroalkyl substances (PFASs) can be emitted from the DWR to the environment. In this study, the effects of aging, washing, and tumble drying on the concentration of extractable PFASs in the DWR of perfluorohexane-based short-chain SFPs (FC-6 chemistry) and of perfluorooctane-based long-chain SFPs (FC-8 chemistry) were assessed. For this purpose, polyamide (PA) and polyester (PES) fabrics were coated with FC-6- and FC-8-based DWRs. Results show that aging of the coated fabrics causes an increase in concentration and formation of perfluoroalkyl acids (PFAAs). The effect of aging on the volatile PFASs depends on the type of fabric. Washing causes a decrease in PFAA concentrations, and in general, volatile PFASs are partly washed out of the textiles. However, washing can also increase the extractable concentration of volatile PFASs in the fabrics. This effect becomes stronger by a combination of aging and washing. Tumble drying does not affect the PFAS concentrations in textiles. In conclusion, aging and washing of fabrics coated with the DWR based on SFPs release PFASs to the environment.
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48.
  • van der Veen, Ike, et al. (författare)
  • The effect of weathering on per- and polyfluoroalkyl substances (PFASs) from durable water repellent (DWR) clothing
  • 2020
  • Ingår i: Chemosphere. - : Elsevier Ltd. - 0045-6535 .- 1879-1298. ; 249
  • Tidskriftsartikel (refereegranskat)abstract
    • To assess the effects of weathering on per- and polyfluoroalkyl substances (PFASs) from durable water repellent (DWR) clothing, thirteen commercial textile samples were exposed to elevated ultra violet (UV) radiation, humidity, and temperature in an aging device for 300 h, which mimics the lifespan of outdoor clothing. Before and after aging, the textile samples were extracted and analysed for the ionic PFASs (perfluoroalkyl acids (PFAAs), perfluorooctane sulfonamide (FOSA)) and volatile PFASs (fluorotelomer alcohols (FTOHs), acrylates (FTACs) and methacrylates (FTMACs)). Results showed that weathering can have an effect on PFASs used in DWR of outdoor clothing, both on the PFAS profile and on the measured concentrations. In most weathered samples the PFAA concentrations increased by 5- to more than 100-fold, while PFAAs not detected in the original textiles were detected in the weathered samples. DWR chemistries are based on side-chain fluorinated polymers. A possible explanation for the increase in concentration of the PFAAs is hydrolysis of the fluorotelomer based polymers (FTPs), or degradation of the FTOHs, which are used in the manufacturing of the FTPs. The concentrations of volatile PFASs also increased, by a factor up to 20. Suggested explanations are the degradation of the DWR polymers, making non-extractable fluorines extractable, or the transformation or degradation of unknown precursors. Further research is needed to unravel the details of these processes and to determine the transformation routes. This study shows that setting maximum tolerance limits only for a few individual PFASs is not sufficient to control these harmful substances in outdoor clothing.
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49.
  • van Leeuwen, Stefan P. J., et al. (författare)
  • Struggle for quality in determination of perfluorinated contaminants in environmental and human samples
  • 2006
  • Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 40:24, s. 7854-7860
  • Tidskriftsartikel (refereegranskat)abstract
    • The first worldwide interlaboratory study on the analyses of 13 perfluorinated compounds (PFCs) in three environmental and two human samples indicates a varying degree of accuracy in relation to the matrix or analyte determined. The ability of 38 participating laboratories from 13 countries to determine the analytes in the various matrices was evaluated by calculation of z-scores according to the Cofino model. The PFCs which were reported most frequently by the laboratories, and assessed with the most satisfactory agreement, were perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). In general, the level of agreement between the participating laboratories decreased in the following order: PFC standard solution (76% satisfactory z-scores of <[2]1 for PFOS) < human blood (67%) < human plasma (63%) < fish liver extract (55%) < water (31%) < fish tissue (17%). This shows that relative good agreement between laboratories was obtained for the study of standard and human matrices. For the fish extract, most laboratories underestimated the actual PFOS concentration due to matrix effects. The results for the fish tissue and water are also poor, indicating that the extraction and cleanup steps require further improvement. It was concluded that the PFC determinations in various matrices are not yet fully mastered.
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