Are Fish Consumption Advisories for the Great Lakes Adequately Protective from Chemical Mixture?

Background: North American Great Lakes are home to more than 140 types of fish and are famous for recreational and commercial fishing. However, presence of toxic substances has resulted in issuance of fish consumption advisories typically based on the most restrictive contaminant. Objectives: We investigate if these advisories, which typically neglect existence of a mixture of chemicals and their possible additive adverse effects, are adequately protective of health of humans consuming fish from the Canadian waters of the Great Lakes. Methods: Using recent fish contaminant monitoring data collected by the Government of Ontario, Canada, we simulated advisories using the most restrictive contaminant (one-chem) and multi-contaminant additive effect (multi-chem) approaches. The advisories from the two simulations were compared to examine if there is any deficiency in the currently issued advisories. Results: About half of the advisories presently issued are potentially not adequately protective. Of the Great Lakes, the highest percentage of advisories affected would be in Lake Ontario if an additive effect is considered. Many fish, which are popular for consumption such as Walleye, Salmon, Bass and Trout, would have noticeably more stringent advisories. Conclusions: Improvements in the advisories may be needed to ensure that the health of humans consuming fish from the Great Lakes is protected. In this region, total PCB and mercury are the major contaminants causing restriction on consuming fish, while dioxins/furans, toxaphene and mirex/photomirex are of a minor concern. Regular monitoring of most organochlorine pesticides and metals in fish can be discontinued. Environ Health Perspect DOI: 10.1289/EHP104 Advance Publication: Not Copyedited