Tuna Consumption and Tuna Mercury Concentration - Implications for Human Health

To our knowledge, no studies have analyzed tuna consumption levels, hair mercury, and knowledge in a population, let alone a high risk population such as college students that are provided tuna daily at dining facilities. We examined the relationship between tuna consumption, hair mercury levels, and knowledge of methylmercury exposure risk from tuna consumption in university students that were served tuna daily at university-run dining halls. Total mercury concentrations in tuna and hair samples were measured using atomic absorption spectrophotometry while tuna consumption levels and knowledge was assessed through surveys. Average hair total mercury levels in tuna consumers was higher than non-tuna consumers (0.443 µg/g ± 0.333 SD, n = 22 versus 0.113µg/g ± 0.100 SD, n = 32, respectively) (p < 0.0001, Mann-Whitney U), with tuna eaters exhibiting a positive relationship between self-reported tuna consumption and their hair total mercury levels (r = 0.852, p <0.0001, n = 22, linear regression). For tuna eaters, about half (46%) of the students self-reported eating > 3 tuna meals per week, potentially exceeding the U.S. Environmental Protection Agency’s reference dose for methylmercury of 0.1 µg/kgbw/day. Eight percent of study participants ate > 20 tuna meals per week, corresponding to hair total mercury levels > 1 µg/g - a level of concern. We also found that for tuna eating students, self-reported tuna consumption was negatively related to knowledge about risk of methylmercury exposure from tuna and confidence in their knowledge. Only one out of the 107 students surveyed illustrated knowledge about the United States Environmental Protection Agency’s recommended limit on tuna consumption, high confidence in their knowledge, and high awareness of the risk of mercury exposure from tuna consumption. Our study highlights the importance of education about the risks of tuna consumption, particularly in institutional settings where individuals have access to tuna products on a regular basis.