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Arsenic Speciation in Problematic Seafood Matrices: the Importance of a Species Specific Mass Balance

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Abstract:Arsenic has two major exposure routes: dietary and drinking water ingestion. Dietary exposures can easily exceed those typically associated with drinking water but the risk associated with these exposures is strongly influenced by the toxicity of the arsenicals present in the sample. For instance, a major source of dietary arsenic is seafood but 90+% of the "extractable" arsenicals can be non-toxic; therefore, species specific information is essential in estimating the risk associated with dietary exposures. A source of uncertainty associated with estimating dietary risks is the limited availability of species specific data on target foods.

One of the analytical problems associated with arsenic speciation (species specific detection) in dietary samples is the need to extract the arsenicals from the solid dietary matrix. In many cases, the predominant "extractable" arsenical associated with seafood has been non-toxic arsenobetaine, but in certain seafood matrices the "extractable" arsenicals may be less than 50% of the total arsenic. This raises questions about the toxicity of the "unextractable" arsenicals and the potential for underestimating the risk (i.e., exposure) based on this analytical extraction bias. These low extraction efficiencies can be further complicated by unchromatographable arsenicals. The net result is the unextractable and unchromatographable fraction sequentially decrease the available speciation information.

This presentation will focus on the use of tetramethylammonium hydroxide as an extraction solvent in seafood samples collected in the Pacific Northwest clams, mussels, and oysters). This presentation will address the conversion of unchromatographable species to chromatographable arsenosugars and how this influences the overall speciation recovery and in turn the ability to assess the risk from these matrices.
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Citation:Creed, J. T., P. A. Gallagher, J. A. Shoemaker, C. A. Schwegel, B. M. Gamble, and A. N. Parks. Arsenic Speciation in Problematic Seafood Matrices: the Importance of a Species Specific Mass Balance. Presented at International Conference on Arsenic Exposure and Health Effects (SEGHA), San Diego, CA, July 14-17, 2002.
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Contact: Mary P. O'Bryant - (919)-541-4871 or obriant.mary@epa.gov
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Division: Microbiological & Chemical Exposure Assessment Division
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Branch: Chemical Exposure Research Branch
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Product Type: Abstrct/Oral
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Presented: 07/14/2002
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Related Entries:
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Bullet Item Speciation of Arsenic in Dietary and Dietary Composite Samples to Provide a More Complete Assessment of Arsenic Exposure from Dietary Sources
spacer Relationship Reason:   A Project of the Product
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Bullet Item Speciation of Arsenic in Dietary and Dietary Composite Samples to Provide a More Complete Assessment of Arsenic Exposure from Dietary Sources
spacer Relationship Reason:   A Project of the Product
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Last Updated on Monday, October 22, 2007
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