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| Registros recuperados: 11 | |
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| Antoine, N.; Jansegers, I.; Holsbeek, L.; Joiris, C.R.; Bouquegneau, J.-M.. |
| In the North Sea, the contamination level of Cd in porpoises, Zn and Cu in seabirds and Hg in both appear to be very high. The other studied metals (Cr, Ti, Fe, Pb) concentrations are comparable to literature. Seabirds and porpoises are located at top of the food chains, however their use as bioindicators of the contamination level of the ecosystem they are feeding on remains debatable. Actually many differences appear in both the contamination level and the storage and detoxification mechanisms from a species to another. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aves [Birds]; Phocoenidae [porpoises]. |
| Ano: 1992 |
URL: http://www.vliz.be/imisdocs/publications/237547.pdf |
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| Holsbeek, L.; Siebert, U.; Joiris, C.R.. |
| Heavy metal concentrations (total and organic Hg, Ti, Cr, Cu, Zn, Cd and Pb) were determined in the muscle, liver and kidney of 36 dolphins stranded on the French Atlantic coast between 1977 and 1990: 29 common dolphins Delphinus delphis, five bottlenose dolphins Tursiops truncatus and two striped dolphins Stenella coeruleoalba. Total Hg concentration in the liver increased with age, while relative methylmercury concentration decreased, reflecting the existence of a slow demethylation process. To a lower extent, a similar pattern was observed in the kidney and muscle. No age-related increase was found for other heavy metals, although the highest levels for Cd and Cr were always found in adults. No difference in contamination could be detected between the... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=6844 |
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| Joiris, C.R.; Tapia, G.; Holsbeek, L.. |
| Beached seabirds, mainly common guillemots Uria aalge, were collected on the Belgian coast during winter from 1990 to 1995. Concentrations of total and organic mercury, and of organochlorines (PCBs and pesticides) were determined in muscle, liver and kidney. They were high compared to summer data (up to one order of magnitude), and increased during winter. This increase is not due to changes of total body weight nor polar lipid content, and thus reflects an actual increase of the seabirds' contamination while wintering in the southern North Sea. The observed annual cycle can be understood by assuming differences in prey contamination: higher during winter in the southern North Sea ecosystem than during summer in the Atlantic water ecosystem. |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1997 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=6846 |
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| Joiris, C.R.; Holsbeek, L.; Laroussi, M.N.. |
| This paper reports concentrations of total mercury and methylmercury in muscle, liver and gonads of two sardines (Sardinella aurita, n=184 and Sardina pilchardus, n=87) from three coastal areas off Tunisia. Mercury concentration in muscle and liver showed significant positive correlation with fish length (i.e. with age). The relative methylmercury concentration was high and constant in muscle (>85% MeHg), and was decreasing with age in liver (from 50% to 20%), which might reflect the existence of a slow demethylation process. From the geographic point of view, Hg concentration was similar in the northern and eastern areas (0.32 µg g-1 dw in muscle for Sardinella aurita, 0.41 for Sardina pilchardus), but significantly lower in the southern zone (0.19 and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sardina pilchardus; Sardinella aurita [round sardinella]. |
| Ano: 1999 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=6838 |
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| Joiris, C.R.; Holsbeek, L.; Bossicart, M.; Tapia, G.. |
| Four sperm whales (three subadult males stranded on the Belgian coast, a fourth older male found dead at sea) were analysed for total mercury, methylmercury and organochlorines. All four were part of a total of 24 sperm whales that stranded on the North Sea coasts over a period of six months, a highly unusual phenomenon. Total mercury levels ranged from 0.5 µg/g fw in kidney and 1 in muscle, up to 15 in liver. The finding of at least 90% of the mercury in its inorganic form confirms the existence of detoxification mechanisms in the liver of cetaceans. PCB concentrations in muscle, liver, kidney and blubber ranged from 10 to 25 µg/g lipids. These results are in the same order of magnitude as literature data, which however does not imply that there is no... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Detoxification Mercury Social behaviour Stranding ANE; Belgium ANE; North Sea; Southern Bight. |
| Ano: 1997 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=837 |
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| Baeyens, W.F.J.; Leermakers, M.; Molina, R.; Holsbeek, L.; Joiris, C.R.. |
| Aqueous distillation is a common initial step in the determination of monomethyl mercury (MMHg) in a variety of matrices. However, recently it was observed that during distillation, MMHg may be generated from inorganic mercury and induce in some cases significant analytical errors. Therefore we investigated a number of alternative analytical techniques for the determination of MMHg in sediments and biological tissues: (1) headspace-GC-AFS and some variants; (2) acid extraction-solvent extraction-GC-AFS; (3) acid extraction-solvent extraction-GC-ECD. Methods (2) and (3) showed MMHg generation when an inorganic Hg spike was added to the sediment sample. The headspace method yielded MMHg results in agreement with the reference values for biological and... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1999 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=6829 |
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| Holsbeek, L.; Joiris, C.R.; Debacker, V.; Ali, B.I.; Roose, P.; Nellissen, J.P.; Gobert, S.; Bouquegneau, J.-M.; Bossicart, M.. |
| Seven male sperm whales stranded on the southern North Sea coast during the 1994/95 winter were analysed for stable pollutant concentrations in muscle, liver, kidney and blubber: heavy metals (total and organic Hg, Se, Zn, Pb, Ni, Cd, Fe, Cr, Cu and Ti), organochlorines (PCBs and pesticides) and polycyclic aromatic hydrocarbons (PAHs), High concentrations of Cd (up to 300 mu g/g dw in kidney), Hg (up to 130 mu g/g dw in liver) and PCBs (up to 5 mu g/g dw in blubber) were detected, but not considered as the direct cause of mortality, while their possible indirect influence on the health status and/or behaviour of the North Atlantic sperm whale population is discussed. |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1999 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=6837 |
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| Registros recuperados: 11 | |
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