Bioaccumulative toxins are a class of persistent compounds with a high resistance to degradation and are not eliminated through metabolism. Simply put, they build up in tissues without breaking down, and tend to be more concentrated higher in the food chain (something known as bioconcentration). The most well-known example is DDT. Seafood is the primary source by which humans ingest bioaccumulative toxins, as contaminants wash into the waterways and permeate the environment in which aquatic organisms live and feed. For this reason, as the Alaska Seafood Marketing Institute concluded, “The best way to ensure the lowest levels of contaminants is to eat fish known to have low levels, such as Alaska-caught fish.”