Food Safety and Environmental Stewardship Program

Although it is known that legacy toxicants, such as polycyclic aromatic hydrocarbons (PAHs), can be introduced into meats via smoke curing, little is known about their prevalence in smoked salmon prepared using traditional Native American smoking techniques. This work sought to characterize the effect of traditional Native American fish smoking methods on dietary exposure to 33 legacy and emerging substituted PAHs and identify possible risks to human health. Salmon smoking events were carried out by Tribal researchers at the Confederated Tribes of the Umatilla Indian Reservation in collaboration with Oregon State University Superfund Research Program researchers. Fresh caught Chinook salmon were smoked using two commonly used smoking structures (tipi or shed) and two types of traditionally used woods (apple or alder). For the purposes of exposure pathway and risk assessment, all salmon samples were prepared as if to be eaten. Additionally, 20 non-smoked spring-run Chinook salmon were analyzed for background PAH content along with three commercially available smoked salmon. Salmon samples were subsequently analyzed for PAHs. Potential carcinogenic and non-carcinogenic risks to human health were evaluated using Relative Potency Factor and Hazard Index approaches. 

Across all smoking methods, individual PAH loads ranged between < 2 – 3,800 μg/kg, where non-carcinogenic, carcinogenic, emerging, and legacy PAHs generally accounted for 95%, 5%, 20% and 80% of the total PAH load respectively. It was found that neither smoking structure nor wood type accounted for differences in smoked salmon PAH content. However, carcinogenic and non-carcinogenic PAH loads in traditionally smoked salmon were 40 – 430 times higher than PAH loads measured in fresh caught non-smoked salmon and commercial smoked salmon. Exposure to the levels of carcinogenic PAHs measured in traditionally prepared smoked salmon could result in excess life-time cancer risks between 1E-5 and 1E-4 at a daily consumption rate of 5 g/d and could approach 1E-2 at 300 g/d. Exposure to non-carcinogenic PAHs could result in hazard indexes of 0.005 at 5 g/d and approach 0.3 at 300 g/d. Levels of PAHs present in smoked salmon prepared using traditional Native American methods potentially pose elevated cancer risks if consumed at high consumption rates over many years. Study results were shared with the Tribes and are currently being evaluated in order to design a culturally specific Tribal message.