| 11. |
- Fiedler, Heidelore, 1953-, et al.
(författare)
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PCDD, PCDF, and PCB in farm-raised catfish from southeast United States - Concentrations, sources, and CYP1A induction
- 1998
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 37:9-12, s. 1645-1656
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Tidskriftsartikel (refereegranskat)abstract
- Nine catfish fillets, three catfish nuggets, two feed samples, and one pond sediment were analyzed for PCDD, PCDF, and-PCB. Farm-raised catfish from Mississippi, Alabama, and Arkansas contained significant levels of 2,3,7,8-substituted PCDD and PCDF. In addition, a large number of non-2,3,7,8-substituted congeners were present in all samples. The catfish fillets and catfish nuggets also contained high concentrations of dioxin-like PCB, as well as a number of non-dioxin-like PCB. The TEQ based on PCDD and PCDF ranged from 9.5 to 43.0 pg/g lipid and the TEQ based on PCB ranged from 0.45 to 4.9 pg/g lipid for all catfish samples. The dioxin-like PCB contributed 4-16% to the total TEQ (PCDD/PCDF/PCB) for the catfish samples. The major source for the PCDD, PCDF, and PCB appears to be from feed and not from pond sediment. Immunoreactive CYP1A protein was elevated 2.5 fold in the pond-raised catfish compared to the aquarium-raised one. The results of this study suggest that the PCDD/PCDF are more important than the PCB in the CYP1A induction.
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| 12. |
- Fiedler, Heidelore, 1953-, et al.
(författare)
-
PCDD/PCDF, chlorinated pesticides and PAH in Chinese teas
- 2002
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 46:9-10, s. 1429-1433
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Tidskriftsartikel (refereegranskat)abstract
- Four samples of Chinese tea (two green teas, and two brick teas) were analyzed for their concentrations of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF), chlorinated pesticides and PAH. The infusions prepared from these teas were also analyzed for PCDD/PCDF. The levels of DDT and its metabolites in tea leaves were within the safety limit of 0.2 mg/kg. Rather high levels of total PAH were obtained in brick tea (1048-1162 mg/kg), when compared with green tea (497-517 mg/kg). In terms of PCDD/PCDF, the concentrations of green tea and brick tea differed by a factor of 16, while the concentrations of all infusions were within a factor of 2. The dioxin concentrations in green tea leaves can be explained through uptake of atmospheric PCDD/PCDF. The higher concentrations in the brick tea leaves are due the longer exposure time, and to certain extent, the use of old leaves, branches and roots when making the tea, and additional components such as soil particulates through contamination. Certain Chinese populations drinking a large amount of brick tea (>31 per day) indicated that individuals of these populations consume more tea than Europeans or North Americans result in a comparably higher intake of PCDD/PCDF. Tea consumption can attribute to up to 10% of the TDI recommended by WHO (only PCDD/PCDF considered, no PCB analyzed).
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| 13. |
- Fiedler, Heidelore, 1953-, et al.
(författare)
-
Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF) in food samples collected in southern Mississippi, USA
- 1997
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 34:5-7, s. 1411-1419
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Tidskriftsartikel (refereegranskat)abstract
- n 1994, we analyzed 43 foodstuff samples from local supermarkets in southern Mississippi, USA, for PCDD/PCDF. 2,3,7,8-Cl4DD could be quantified in 31 of these samples. On a lipid basis, levels in meat (0.53-1.10 pg I-TEQ/g) and dairy products (0.42-1.10 pg I-TEQ/g) were slightly lower than those reported from other industrialized countries. While levels in dairy samples from the United States and Europe are comparable, there is a difference in the contribution of individual congeners to the I-TEQ: for example, in milk samples from Germany approximately 40% of the I-TEQ is due to the presence of 2,3,4,7,8-Cl5DF while in the Mississippi samples this congener only contributes 16%. The highest concentrations of PCDD/PCDF in our study were detected in the farm-raised catfish (10.2-27.8 pg I-TEQ/g). A unique finding was that in addition to the 2,3,7,8-substituted PCDD/PCDF the catfish samples contained many non-2,3,7,8-substituted congeners. This is unusual because vertebrate animals selectively eliminate or metabolize the non-2,3,7,8-substituted congeners.
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| 14. |
- Fiedler, Heidelore, 1953-, et al.
(författare)
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QSAR generated octanol-water partition coefficients of selected mixed halogenated dibenzodioxins and dibenzofurans
- 1990
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 20:10-12, s. 1597-1602
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Tidskriftsartikel (refereegranskat)abstract
- We have calculated the values of pkow, water solubility, and Koc for chlorinated, brominated and mixed halogenated dibenzodioxins and dibenzofurans that have been identified in environmental samples. From the results it can be concluded that brominated and mixed halogenated dioxins and furans will show an ecological behaviour similar to that of the pure chlorinated compounds.
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| 15. |
- Fiedler, Heidelore, 1953-, et al.
(författare)
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Sources and sinks of dioxins : Germany
- 1992
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 25:7-10, s. 1487-1491
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Tidskriftsartikel (refereegranskat)abstract
- Combustion processes are known to produce dioxins and especially municipal waste incineration is thought to have the highest contribution to the general background. On the other hand the general acceptance of non-thermal waste treatment methods such as composting is much higher than incineration. The results of an estimation on the input of PCDD/PCDF to Germany show that besides the thermal processes so-called sinks for pollutants, such as sewage sludge, compost, and foliage represent a reservoir to release dioxins by use in agriculture.
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| 16. |
- Fiedler, Heidelore, 1953-
(författare)
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Sources of PCDD/PCDF and impact on the environment
- 1996
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 32:1, s. 55-64
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Tidskriftsartikel (refereegranskat)abstract
- PCDD/PCDF can be formed in a variety of industrial and thermal processes. Especially the combustion sources contribute to the ambient air levels. In addition to the well-investigated emissions from municipal waste incinerators dioxins were measured in the flue gases of other thermal emitters. It was found that some recycling plants can emit high concentrations of PCDD/PCDF. Ambient air concentrations monitored over several years have shown a clear seasonal trend with higher PCDD/PCDF levels in winter and lower concentrations during summer. Thus, results from short-term measurements cannot be used to calculate annual means for ambient air concentations or deposition rates. Dioxins, once concentrated in sewage sludge and compost can re-enter the environment when these ''reservoirs'' are applied onto agricultural and horticultural soils.
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| 17. |
- Hauk, A., et al.
(författare)
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Reduction of nitrated phenols : A method to predict half-wave-potentials of nitrated phenols with molecular modeling
- 1990
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 20:6, s. 717-728
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Tidskriftsartikel (refereegranskat)abstract
- The redox stability of 13 nitrated phenols was investigated using polarographic measured half-wave-potentials. These half-wave-potentials were compared with data from a semi-empirical quantum mechanic computer model. A good correlation was found between LUMO energy and the half-wave-potential for phenols, but for phenolates the correlation coefficient was lower, even when a multivariate regression model was used.
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| 18. |
- Heijerick, D. G., et al.
(författare)
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Bioavailability of zinc in runoff water from roofing materials
- 2002
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Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 47:10, s. 1073-1080
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Tidskriftsartikel (refereegranskat)abstract
- Corrosion and runoff from zinc-coated materials and outdoor structures is an important source for the dispersion of zinc in the environment. Being part of a large inter-disciplinary research project, this study presents the bioavailability of zinc in runoff water immediately after release from the surface of 15 different commercially available zinc-based materials exposed to the urban environment of Stockholm, Sweden. Runoff water was analysed chemically and evaluated for its possible environmental impact, using both a biosensor test with the bacteria Alcaligenes eutrophus (Biomet(R)) and the conventional 72 h growth inhibition test with the green alga Raphidocelis subcapitata. Chemical speciation modelling revealed that most zinc (94.3-99.9%) was present as the free Zn ion, the most bioavailable speciation form. These findings were confirmed by the results of the biosensor test (Biomet(R)) which indicated that all zinc was indeed bioavailable. Analysis of the ecotoxicity data also suggested that the observed toxic effects were due to the presence of Zn2+ ions. Finally, regression analysis showed that, for this type of runoff samples, the rapid screening biosensor was capable of predicting (a) the total amount of zinc present in the runoff samples (R-2 of 0.93-0.98; p < 0.05) and (b) the observed 72 h-EbC(50)s (R-2 of 0.69-0.97; p < 0.05).
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| 19. |
- Hutzinger, O., et al.
(författare)
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From source to exposure : Some open questions
- 1993
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 27:1-3, s. 121-129
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Tidskriftsartikel (refereegranskat)abstract
- PCDD/PCDF are trace contaminants in industrial and thermal processes, whose formation often cannot be avoided. Although the most important sources seem to be recognized within the last years new sources have been discovered. Very often only limited data are available. For the understanding of human exposure it is necessary to understand the pathways from the source to target organs or organisms. Environmental concentrations of dioxins have to be analyzed under ectoxicological aspects. Transfer and transformation mechanisms to be considered are: evaporation, deposition, erosion, photochemical degradation
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| 20. |
- Hutzinger, O., et al.
(författare)
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Sources and emissions of PCDD/PCDF
- 1989
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 18:1-6, s. 23-32
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Tidskriftsartikel (refereegranskat)abstract
- The main sources of polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF) have been found to be the following: 1. Combustion processes in large and small systems; 2. industrial processes of the chemical and other industries, and 3. dumps, accidents and residues. During the last years increasing attention has been paid to the emissions from mobile sources, e.g. automobile exhaust, and to private heating. Even though several theoretical and experimental investigations have been carried out to elucidate the formation mechanism of PCDD/PCDF, many questions still remain unanswered.
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