Tuna Serving (IMAGE) University of California - Santa Cruz Caption Tuna and other large fish contain significant amounts of mercury in its most toxic form (methylmercury). In a survey of college students, half of the tuna eaters reported eating three or more tuna meals per week, potentially exceeding the EPA's 'reference dose' for mercury. Credit Nick Gonzales Usage Restrictions For use only with news coverage of this research. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.