Resumo

CANEDO-LOPEZ, Y  e  MACIAS-ZAMORA, JV. Polychlorinated dibenzo-p-dioxins and dibenzofurans in fish from four different regions of Mexico. Cienc. mar [online]. 2007, vol.33, n.2, pp.217-227. ISSN 0185-3880.

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs), known commonly as dioxins, have been recognized as ubiquitous environmental contaminants. Among those, the 2,3,7,8-substituted congeners, the most toxic compounds, were measured in fish tissue (Caranx caninus, Caranx hippos and Chirostoma estor estor) from three marine regions and one freshwater lagoon in Mexico. Samples were commercially available and were acquired between September and December 2005 in Ensenada (Pacific Ocean), El Barril (Gulf of California), Carmen City (Gulf of Mexico) and Patzcuaro Lake (central Mexico). The fish samples were analyzed using gas chromatography/high resolution mass spectrometry. Mean concentrations of total PCDDs/Fs ranged from 0.3 to 1.6 pg g^-1 wet weight and were in the following order: Patzcuaro > Carmen City > El Barril > Ensenada. A particular congener profile was found for every studied region, but OCDD and OCDF were relatively important congeners at all the sites. On a wet weight basis, the total concentrations of PCDDs/Fs and their toxic equivalents (TEQs) found in this study were lower or in the same range as those for other sites around the world, but on a lipid weight basis, TEQs from the Patzcuaro samples were higher than some other sites. Dioxin intake was calculated considering fillet portions of 200 g using our results, and none of the fish sampled in this study reached the tolerable daily intake established by the World Health Organization. To our knowledge, this is the first report to document PCDD/F levels in fish from Mexico.

Palavras-chave : polychlorinated dibenzo-p-dioxins; polychlorinated dibenzofurans; fish; Caranx caninus; Caranx hippos; Chirostoma estor estor; Mexico.

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