Designating Seafood a Health Alert

How Environmental Defense calculates consumption advice

Wherever possible, Environmental Defense Fund calculates health advisories for fish and shellfish profiled on the Seafood Selector. We base our health advisories on data from more than 200 government databases and scientific studies on seafood contaminants, and determine how many meals per week it is safe to eat a particular type of fish.

We update our database whenever new studies become available; nevertheless, the majority of the data are for wild-caught, rather than farmed, fish and shellfish. (For more information on freshwater and sport fish advisories, visit EPA's National Listing of Fish Advisories.) We focus primarily on mercury and PCBs — common environmental contaminants in seafood that are a focus of government data collection efforts. We also look for data on dioxins and certain pesticides, although levels of these contaminants are less frequently monitored in seafood.

Our scientists designate a type of fish a Health Concern if eating that fish once per week (roughly the U.S. average consumption level) poses an unacceptable health risk according to the Environmental Protection Agency¹ (see technical information for more details). Any fish designated a Health Concern for adults is, by default, also a 'Health Concern' for children.

Mercury is especially toxic to fetuses and young children, and EPA's approach is designed to protect both women of childbearing age and children. Therefore, our consumption advice generally errs on the side of safety for men and older women. PCBs, dioxins and pesticides are also documented neurotoxins; however we use EPA's more conservative assessment of cancer risks from these chemicals, as it results in the most protective advice for both adults and children.

Our assumptions

EPA's methodology allows us to calculate health advisories based on gender, age, body weight and portion size. We set our recommendations for men, women, young children and older children using the following assumptions:

If your weight or portion size (or those of people you feed) differs considerably from those listed above, please adjust the consumption advice accordingly. For example, larger portions contain more contaminants, so fewer meals may be eaten safely every month. Similarly, people weighing less should consume fewer meals per month than those recommended.

To determine consumption advice for teenagers (ages 13-17), use the set of assumptions above that most closely approximates their weight and portion size. If none of these apply, estimate consumption advice between that for older children and adults.

Given the variety of ways in which seafood is prepared and the fact that not all contaminants are reduced by cooking, we did not assume any contaminant loss from fish preparation.

1. Any fish with a 'Health Concern' advisory can not qualify for our 'Best Eco-Choices' list. At the present time, this applies to Spanish mackerel and wild striped bass. Although these fisheries demonstrate good management and responsible fishing practices, we conclude that the high contaminant levels in these species prevent us from recommending them to consumers.

Posted: 03-Dec-2008; Updated: 03-Dec-2008