Arsenic in Seafood: Speciation Issues for Human Health Risk Assessment

ABSTRACT

Major sources of arsenic exposure for humans are foods, particularly aquatic organisms, which are called seafood in this report. Although seafood contains a variety of arsenicals, including inorganic arsenic, which is toxic and carcinogenic, and arsenobetaine, which is considered nontoxic, the arsenic content of seafood commonly is reported only as total arsenic. A goal of this literature survey is to determine if generalizable values can be derived for the percentage of total arsenic in seafood that is inorganic arsenic. Generalizable values for percent inorganic arsenic are needed for use as default values in U.S. human health risk assessments of seafood from arsenic-contaminated sites. Data from the worldwide literature indicate the percent of inorganic arsenic in marine/estuarine finfish does not exceed 7.3% and in shellfish can reach 25% in organisms from presumably uncontaminated areas, with few data available for freshwater organisms. However, percentages can be much higher in organisms from contaminated areas and in seaweed. U.S. site-specific data for marine/estuarine finfish and shellfish are similar to the worldwide data, and for freshwater finfish indicate that the average percent inorganic arsenic is generally < 10%, but ranges up to nearly 30%. Derivation of nationwide defaults for percent inorganic arsenic in fish, shellfish, and seaweed collected from arsenic-contaminated areas in the United States is not supported by the surveyed literature.

Key words:

• inorganic arsenic
• fish
• shellfish
• risk assessment
• speciation

ACKNOWLEDGMENTS

Portions of this work were sponsored by the U.S. Environmental Protection Agency (USEPA). The authors acknowledge early contributions to this work by Christine Chew (formerly of ICF Kaiser Engineers) and Richard Troast (retired from USEPA Office of Superfund Remediation and Technology Innovation).

The authors declare that they have no competing financial interests or ties. Any opinions, assertions, conclusions, or findings expressed herein are those of the authors and should not be construed as official USEPA policy or guidance unless so designated by other documentation. Any reference to products or methods herein does not constitute an endorsement of those products or methods by these authors, their employers, or by the U.S. federal government.

Notes

^a These data are from presumed or known contaminated areas. Limited data for a few species from reference sites indicated similar or higher percent inorganic/total arsenic than in the same species from contaminated areas in the same site assessment (Marrowstone Island, ATSDR 1998; Puget Sound, Johnson and Rose 2002), but not in shellfish (oysters) from the east coast, i.e., from Chesapeake Bay (0.4–1.0%) or the North Carolina coast (6.0–6.1%) as compared with those from the South Carolina coast (Valette-Silver et al. 1999, see above).