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774 results on '"Malm, Olaf"'

204. Dolphins as indicators of micropollutant trophic flow in amazon basin

Author

Jr., José Lailson-Brito, Dorneles, Paulo R., Silva, Vera M. F. da, Martin, Anthony R., Bastos, Wanderley R., Azevedo-Silva, Claudio E., Azevedo, Alexandre F., Torres, Joao P. M., Malm, Olaf, Jr., José Lailson-Brito, Dorneles, Paulo R., Silva, Vera M. F. da, Martin, Anthony R., Bastos, Wanderley R., Azevedo-Silva, Claudio E., Azevedo, Alexandre F., Torres, Joao P. M., and Malm, Olaf

Abstract

This study presents an overview of the appropriateness of the use of Amazonian cetaceans as sentinel species for environmental contamination by micropollutants, such as organochlorines and mercury. Due to the top position in food webs occupied by cetaceans and to their long life-span, high micropollutant concentrations have been verifi ed in their tissues, what allows an amplifi cation of the determination capacity by different analytical procedures. Besides providing an analytical advantage, the continuous micropollutant determination in cetaceans has been useful: as a reference of pollutant availability to other organisms; to integrate a complex signal of pollution; to quantify the ecological signifi cance of a contamination. Therefore, published information on the concentrations of the quoted pollutants in the Amazonian cetaceans Inia geoffrensis (boto) and Sotalia fl uviatilis (tucuxi) were gathered herewith. Carrying out comparison with data from Brazilian coastal cetaceans, it became clear how high the levels observed in Amazonian aquatic mammals are. In this context, mercury deserves to be highlighted. Despite the little volume of information on the concentrations of mercury, polychlorinated biphenyls and dichlorodiphenyltrichloroethane in Amazonian cetaceans, the existing information already demonstrates that the levels observed mirror the environmental contamination by such pollutants in distinct Amazonian environments. Perspectives for future investigations are also discussed, including possible ways of overcoming obstacles related to sampling of Amazonian cetaceans. Keywords: Brazil, Amazon, cetacean, mercury, organochlorines.

Published
2008

206. Correction to First Determination of UV Filters in Marine Mammals. Octocrylene Levels in Franciscana Dolphins

Author

Gago-Ferrero, Pablo, primary, Alonso, Mariana B., additional, Bertozzi, Carolina P., additional, Marigo, Juliana, additional, Barbosa, Lupércio, additional, Cremer, Marta, additional, Secchi, Eduardo R., additional, Domit, Camila, additional, Azevedo, Alexandre, additional, Jr., José Lailson-Brito, additional, Torres, Joao P. M., additional, Malm, Olaf, additional, Eljarrat, Ethel, additional, Díaz-Cruz, M. Silvia, additional, and Barceló, Damiá, additional

Published
2013
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208. First Determination of UV Filters in Marine Mammals. Octocrylene Levels in Franciscana Dolphins

Author

Gago-Ferrero, Pablo, primary, Alonso, Mariana B., additional, Bertozzi, Carolina P., additional, Marigo, Juliana, additional, Barbosa, Lupércio, additional, Cremer, Marta, additional, Secchi, Eduardo R., additional, Azevedo, Alexandre, additional, Lailson-Brito Jr., José, additional, Torres, Joao P. M., additional, Malm, Olaf, additional, Eljarrat, Ethel, additional, Díaz-Cruz, M. Silvia, additional, and Barceló, Damià, additional

Published
2013
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210. Mercúrio em peixes - fontes e contaminação

Author

Kasper, Daniele, Botaro, Daniela, Albuquerque Palermo, Elisabete Fernandes, Malm, Olaf, Kasper, Daniele, Botaro, Daniela, Albuquerque Palermo, Elisabete Fernandes, and Malm, Olaf

Published
2007

212. Toxicologia das bifenilas policloradas

Author

Silva, Claudio Eduardo de Azevedo e, Torres, João Paulo Machado, Malm, Olaf, Silva, Claudio Eduardo de Azevedo e, Torres, João Paulo Machado, and Malm, Olaf

Published
2007

213. Guiana Dolphins ( Sotalia guianensis) and DR-CALUX for Screening Coastal Brazilian Environments for Dioxins and Related Compounds.

Author

Dorneles, Paulo, Lailson-Brito, José, Bisi, Tatiana, Domit, Camila, Barbosa, Lupércio, Meirelles, Ana, Carvalho, Vitor, Malm, Olaf, Azevedo, Alexandre, Brose, François, Das, Krishna, and Scippo, Marie-Louise

Subjects
DOLPHINS, TUCUXI, WATER pollution, MARINE ecology
Abstract

Guiana dolphin is the top predator of highest toxicological concern in Brazil and many studies on levels of persistent, bioaccumulative, and toxicant (PBT) pollutants have been performed on the species. However, due to high costs of the analyses, only one investigation comprised the determination of dioxins and related compounds (DRCs) in Guiana dolphin tissues. The dioxin responsive-chemically activated luciferase gene expression (DR-CALUX) cell bioassay was used in the present study for the analyses of hepatic samples from 28 male Guiana dolphins in order to screen estuarine environments for DRCs, comprising three regions (Northeastern, Southeastern, and Southern) and four states [Paraná (PR), Rio de Janeiro (RJ), Espírito Santo (ES), and Ceará (CE)] of Brazil. High bioanalytical equivalent (BEQ) concentrations [dioxins (pg BEQ/g lipid)] were found, varying from 1.94 to 15.6 pg BEQ/g. A significant negative correlation between BEQ concentrations and total length was found in Guiana dolphins from Brazil (all analysed dolphins). This pattern also was verified for RJ state, pointing to (1) chemically induced developmental disruption or to (2) increasing efficiency of the detoxifying activity with the growth of the animal. Comparison was performed with literature data and significantly higher BEQ levels were found in Brazilian Guiana dolphins than in those reported for North Sea harbour porpoises. Higher levels were found in Southeastern (the most PBT-contaminated area of the country) than in Southern region. However, it is not possible to affirm that Guiana dolphins are more contaminated by DRCs in SE than in S region, because individuals were lengthier in S than in SE region. Our results seem to have mirrored dolphin exposure to PCBs in Brazil according to the literature. Further studies are required for investigating the hypotheses 1 and 2 mentioned above. [ABSTRACT FROM AUTHOR]

Published
2016
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214. Mercury distribution in organs of fish species and the associated risk in traditional subsistence villagers of the Pantanal wetland.

Author

Ceccatto, Ana, Testoni, Magalei, Ignácio, Aurea, Santos-Filho, Manoel, Malm, Olaf, and Díez, Sergi

Subjects
MERCURY & the environment, FISH anatomy, HEALTH risk factors, ANTIQUITIES
Abstract

This study evaluated the risk to human health from mercury (Hg) exposure through fish consumption in the Pantanal, Brazil. In order to address these risks, Hg concentrations and accumulation patterns were determined in target organs of predatory fish ( Crenicichla lepidota and Pygocentrus nattereri). Levels of Hg were analysed during the two phases of the flood pulse (flood and drought) in fish from different local ecosystems, such as the Bento Gomes and Paraguay rivers. Although the former study area is directly affected by gold mining, a higher, but not significantly different, Hg concentration in fish was found compared with fish at the Paraguay River, which is regarded as pristine area. Moreover, no seasonal variability was found in either river. Although total mercury levels in fish did not exceed the maximum FAO/WHO threshold (0.5 μg g), according to dietary habits in riverine communities of the Pantanal (up to 6 oz of fish per day), there is reason for concern over the potential for deleterious health effects that could be caused by high Hg intake. In fact, the estimated daily intake in the present study ranged from 0.49 to 1.08 μg Hg kg day, for adults (including women of childbearing age) and children, respectively. Because of high Hg intakes in riverine groups, which exceed the recommended reference dose value, these communities could be considered at risk. Therefore, it is necessary to consider regulatory measures and public education regarding fish consumption, particularly in vulnerable groups (i.e. children, pregnant women and women of childbearing age). [ABSTRACT FROM AUTHOR]

Published
2016
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217. Natural and anthropogenically-produced brominated compounds in endemic dolphins from Western South Atlantic: Another risk to a vulnerable species

Author

Alonso, Mariana B., primary, Eljarrat, Ethel, additional, Gorga, Marina, additional, Secchi, Eduardo R., additional, Bassoi, Manuela, additional, Barbosa, Lupércio, additional, Bertozzi, Carolina P., additional, Marigo, Juliana, additional, Cremer, Marta, additional, Domit, Camila, additional, Azevedo, Alexandre F., additional, Dorneles, Paulo R., additional, Torres, João Paulo M., additional, Lailson-Brito, José, additional, Malm, Olaf, additional, and Barceló, Damià, additional

Published
2012
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218. Mercury in tropical and subtropical coastal environments

Author

Costa, Monica F., primary, Landing, William M., additional, Kehrig, Helena A., additional, Barletta, Mário, additional, Holmes, Christopher D., additional, Barrocas, Paulo R.G., additional, Evers, David C., additional, Buck, David G., additional, Claudia Vasconcellos, Ana, additional, Hacon, Sandra S., additional, Moreira, Josino C., additional, and Malm, Olaf, additional

Published
2012
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219. Pyrethroids: A new threat to marine mammals?

Author

Alonso, Mariana B., primary, Feo, Maria Luisa, additional, Corcellas, Cayo, additional, Vidal, Lara G., additional, Bertozzi, Carolina P., additional, Marigo, Juliana, additional, Secchi, Eduardo R., additional, Bassoi, Manuela, additional, Azevedo, Alexandre F., additional, Dorneles, Paulo R., additional, Torres, João Paulo M., additional, Lailson-Brito, José, additional, Malm, Olaf, additional, Eljarrat, Ethel, additional, and Barceló, Damià, additional

Published
2012
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223. Mercury-Selenium Relationships in Liver of Guiana Dolphin: The Possible Role of Kupffer Cells in the Detoxification Process by Tiemannite Formation

Author

Lailson-Brito, José, primary, Cruz, Renato, additional, Dorneles, Paulo Renato, additional, Andrade, Leonardo, additional, Azevedo, Alexandre de Freitas, additional, Fragoso, Ana Bernadete, additional, Vidal, Lara Gama, additional, Costa, Marianna Badini, additional, Bisi, Tatiana Lemos, additional, Almeida, Ronaldo, additional, Carvalho, Dario Pires, additional, Bastos, Wanderley Rodrigues, additional, and Malm, Olaf, additional

Published
2012
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233. Large emissions from floodplain trees close the Amazon methane budget

Author

Pangala, Sunitha R., Enrich-Prast, Alex, Basso, Luana S., Peixoto, Roberta Bittencourt, Bastviken, David, Hornibrook, Edward R. C., Gatti, Luciana V., Marotta, Humberto, Calazans, Luana Silva Braucks, Sakuragui, Cassia Mônica, Bastos, Wanderley Rodrigues, Malm, Olaf, Gloor, Emanuel, Miller, John Bharat, and Gauci, Vincent

Abstract

Wetlands are the largest global source of atmospheric methane (CH4), a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain, the largest natural geographic source of CH4in the tropics, consistently underestimate the atmospheric burden of CH4determined via remote sensing and inversion modelling, pointing to a major gap in our understanding of the contribution of these ecosystems to CH4emissions. Here we report CH4fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH4emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests and tropical peat swamp forests, representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (δ13C) of −66.2 ± 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 ± 1.8 to 21.2 ± 2.5 teragrams of CH4a year, in addition to the 20.5 ± 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a ‘top-down’ regional estimate of CH4emissions of 42.7 ± 5.6 teragrams of CH4a year for the Amazon basin, based on regular vertical lower-troposphere CH4profiles covering the period 2010–2013. We find close agreement between our ‘top-down’ and combined ‘bottom-up’ estimates, indicating that large CH4emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH4budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH4emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH4source when trees are combined with other emission sources.

Published
2017
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236. Organochlorine concentrations in franciscana dolphins, Pontoporia blainvillei, from Brazilian waters

Author

Lailson-Brito, José, primary, Dorneles, Paulo Renato, additional, Azevedo-Silva, Cláudio Eduardo, additional, Azevedo, Alexandre de Freitas, additional, Vidal, Lara Gama, additional, Marigo, Juliana, additional, Bertozzi, Carolina, additional, Zanelatto, Regina Célia, additional, Bisi, Tatiana Lemos, additional, Malm, Olaf, additional, and Torres, João Paulo Machado, additional

Published
2011
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241. Assessment of heavy metals in the particulate matter of two Brazilian metropolitan areas by using Tillandsia usneoides as atmospheric biomonitor

Author

Vianna, Nelzair A., primary, Gonçalves, Daniel, additional, Brandão, Flavia, additional, de Barros, Roberta P., additional, Filho, Gilberto M. Amado, additional, Meire, Rodrigo O., additional, Torres, João Paulo M., additional, Malm, Olaf, additional, Júnior, Argemiro D’Oliveira, additional, and Andrade, Leonardo R., additional

Published
2010
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244. Persistent toxic substances in the Brazilian Amazon: contamination of man and the environment

Author

Torres, João Paulo M., primary, Lailson-Brito, José, additional, Saldanha, Giselle C., additional, Dorneles, Paulo, additional, Silva, Cláudio Eduardo A. e, additional, Malm, Olaf, additional, Guimarães, Jean R., additional, Azeredo, Antônio, additional, Bastos, Wanderley R., additional, Silva, Vera Maria F. da, additional, Martin, Anthony R., additional, Cláudio, Luz, additional, and Markowitz, Steve, additional

Published
2010
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