The Study Team noticed early in the study the total arsenic levels were higher than the EPA screening level in most species and in all the study areas.  However, the screening level applies only to inorganic arsenic, while the initial analyses measured total (organic plus inorganic) arsenic.  The inorganic form is most toxic to humans. Fortunately, the proportion of inorganic arsenic is seafood is usually low, less than 10 percent.

These levels of arsenic are common in the marine environment and in seafood, and the arsenic is usually naturally occurring.

As the team compiled the data and recognized the high levels of total arsenic, it was decided to verify the proportion of inorganic arsenic.  Additional laboratory analyses were conducted to determine the forms of arsenic present in the seafood samples.