salmon could be consumed in amounts that provide at least 1 g/day of EPA/DHA per unit of noncarcinogenic risk (Foran et al., 2005b).
These analyses were conducted assuming salmon intake needed to provide 1 g/day of EPA/DHA. The authors interpreted the WHO intake recommendation for omega-3 fatty acids as corresponding to 2–3 g/day; this includes alpha-linolenic acid (ALA) intake, which is derived primarily from plant sources such as soy, flaxseed, and walnut oils (see Chapter 1). The analysis of Foran et al. (2005b) was based on the assumption that the 2–3 g/day of omega-3 fatty acids applied only to EPA/DHA and did not take ALA into consideration. The WHO (2003) recommendation for fish consumption is 1–2 servings per week; it assumes that this level of consumption would provide 200–500 mg of EPA/DHA, considerably less than the intake of 1 g/day EPA/DHA from fish that Foran et al. assumed. These analyses represent a “worst case” scenario in that it is assumed that consumption of salmon would be the sole source of omega-3 fatty acids. Further, it assumed that salmon would provide all omega-3 fatty acids (DHA, EPA, and ALA) and salmon is not a source of ALA. Their analysis was based on data obtained prior to the implementation of industry safety measures for the prevention of POP contamination of aquaculture products (Santerre, 2004). It is worth emphasizing that because the food supply is dynamic, benefit-risk analyses are not static (Willett, 2006).
Body burden can be defined as the total amount of a chemical in the human body or in human tissue from exposure to contaminants found in the environment (DeCaprio, 1997; Mendelsohn et al., 1998; IOM, 2003). CDC monitors over 200 contaminants with the aim of identifying baseline concentrations of specific substances and determining trends in body burdens among the general population (http://www.cdc.gov/biomonitoring/overview.htm; Kamrin, 2004). CDC reports (CDC, 2004; 2005b) include data on human exposure to approximately 150 compounds, including potential seafood contaminants such as lead, mercury, and many POPs. Technological advancements now afford the ability to detect minute levels of contaminants in human tissue, although detection of such contaminants does not indicate that a hazard or risk is present. For example, individuals regularly consuming fish from the Great Lakes were reported to have higher serum dichlorodiphenyl dichloroethene (DDE) concentrations (median 10 µg/L) compared to those who did not eat fish (1 µg/L); however, they did not show impaired motor function, impaired visuospatial function, or reduced memory and learning (Schantz et al., 1999; 2001; Rogan and Chen, 2005).
Body burdens for PCBs have been reviewed in studies of fish-consuming populations by the US EPA (US EPA, 2000a,c). The review did not show any