PhD/Lic Thesis
PhD/Lic Thesis
Identification and origin of potential background carcinogens: Endogenous isoprene and oxiranes, dietary acrylamide
Technical report
Ekotoxikologisk karakterisering av lakvatten från kommunalt avfallsupplag Examensarbete 15 poäng i marin ekotoxikologi (Handl. B.-E. Bengtsson & M. Breitholtz)
Scientific paper
Scrutinizing ACGIH risk assessments: The trichloroethylene case
carcinogenicity
,
cell
,
chemical reactivity
,
cohort
,
european union
,
exposure
,
mode
,
regulatory toxicology
,
risk management
,
threshold limit values
,
tumors
Background The American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values (TLVs)for occupational exposure to chemicals and physical agents have been very influential in the setting of occupational exposure limits in many countries. Methods Three ACGIH risk assessments of the chlorinated solvent trichloroethylene (TCE) [ACGIH (1989): 5th edition; ACGIH (1992): 5th edition. Revised Vol II; ACGIH (1996): Suppl. 6th edition] are compared to 26 other risk assessments made of the same chemical substance. The documents are compared in terms of their overall conclusions and the data selected for assessment. Results It is shown that these ACGIH risk assessment documents were based on incomplete and biased data sets. Conclusions The data on which the ACGIH [ACGIH (1996): Suppl. 6th edition] base their TCE risk assessment do not adequately reflect the available scientific knowledge about TCE toxicity and carcinogenicity. This may have influenced their conclusion that TCE is not carcinogenic in either animals or humans which stand out compared to contemporary risk assessments. (C) 2003 Wiley-Liss, Inc.
Presentation abstract
New ?biocide-free? antifouling paints are toxic.
antifouling paints
Presentation abstract
Ecotoxicological risk assessment of dioxin-like compounds in the Baltic.
assessment
,
dioxins
,
effects
Scientific paper
Model simulation of ultrafine particles inside a road tunnel
aerosol model
,
cfd model
,
emission factors
,
field experiment
,
size distributions
,
urban
,
vehicle
,
vehicle emissions
A monodispersive aerosol dynamic model, coupled to a 3D hydrodynamical grid model, has been used to study the dynamics of ultrafine particles inside a road tunnel in Stockholm, Sweden. The model results were compared to measured data of particle number concentrations, traffic intensity and tunnel ventilation rate. Coagulation and depositional losses to the tunnel walls were shown to be important processes during traffic peak hours, together contributing to losses of 77% of the particles smaller than 10nm and 41% of the particles of size 10-29nm. Particle growth due to water uptake or the presence of a micron-sized, resuspended particle fraction did not have any significant effect on the number of particles lost due to coagulation. Model simulation of particle number concentration response to temporal variations in traffic flow showed that constant emission factors could be used to reproduce the concentration variations of the particles larger than 29nm, while vehicle-speed-dependent factors are suggested to reproduce the variation of the smallest fractions. The emission factors for particle number concentrations estimated from the model simulation are in general higher and show a larger contribution from light-duty vehicles than what has been reported from a tunnel in California. The model study shows that combined measurements and model simulations in road tunnels can be used to improve the determinations of vehicle emission factors for ultrafine particles under realistic driving conditions. (C) 2003 Elsevier Science Ltd. All rights reserved.
Scientific paper
Eutrophication Effects on the Fate of Bleachery Discharges. In Environmental Impacts of Pulp and Paper Waste Streams. (Eds., T. Stuthridge, M. van den Heuvel, N. Marvin, A. Slade and J. Clifford).
anoxia
,
chlorinated compounds
,
eocl
,
eutrophication
,
hypoxia
,
interaction
,
laminated
,
sediment
Scientific paper
Extractable organic compounds in polyurethane foam with special reference to aromatic amines and derivatives thereof
Methods for determination of aromatic amines and related compounds in flexible toluene diisocyanate (TDI)-based polyurethane (PUR) foam were investigated. The foam was extracted using 0.1% (w/v) aqueous acetic acid (HAc). Extraction solutions were analysed and aromatic amines were determined as ethyl chloroformate (Et) and pentafluoropropionic acid anhydride (PFPA) derivatives. The determinations were performed using liquid chromatography (LC) and mass spectrometry (MS) detection with electrospray ionisation (ESI) or gas chromatography (GC)–MS with chemical ionisation monitoring negative ions (NCI). The Et derivatives were determined using LC–ESI+-MS with detection limit of 2 pg of toluenediamine (TDA). The PFPA derivatives were determined using LC–ESI−-MS or GC–NCI-MS with detection limits of 0.1 and 0.02 pg of TDA, respectively. Using trideuterium labelled TDA as internal standard, linear calibration curves were obtained in the range of 0.01–0.50 μg ml−1 (n=7), with correlation coefficients >0.999. When plotting calibration curves for TDA–PFPA derivatives determined using LC–MS against TDA–PFPA using GC–MS and TDA–Et using LC–MS, linear curves were obtained. The relative standard deviation (R.S.D.) for determination of TDA in foam extraction solutions were 13%. LC–MS determination of PFPA derivatives was more selective, as compared to LC–MS of Et derivatives.
In foam extraction solutions, 2,4- and 2,6-TDA, several isomers of methylenedianiline (MDA) and dimers of TDA/TDI were observed. 2,4-TDA and 4,4′-MDA are possible human carcinogens. Hydrolysis of the extraction solution revealed a large pool of TDA/TDI compounds and oligomers. The concentration of TDA in foam was affected by the extraction media, temperature and duration. The choice of derivatisation procedure also affected the determination of TDA. In extraction solutions from six different commercially available flexible foam qualities 2,4- and 2,6-TDA were found in the range of 0–7 and 0–6 μg g−1 foam, respectively. When flexible foam was heated, considerable higher concentrations of TDA were observed.
Scientific paper
Motilin-bicelle interactions: membrane position and translational diffusion
Technical report
Trängselavgifter i Stockholm ? Effekter på luftkvalitet år 2015.
no2
Scientific paper