Estimation and validation of mercury intake associated with fish consumption in an EPIC cohort of Spain

Objective: To estimate mercury intake due to fish consumption among the individuals from Gipuzkoa participating in the European Prospective Investigation into Cancer (EPIC), and to validate the estimation of mercury exposure through diet, by measuring blood mercury level. Design and setting: The population for the EPIC Gipuzkoa cohort was recruited from 1992 to 1995. Each individual's diet was assessed regarding habitual intake over the previous year, using the diet history method. Blood samples were taken at the time of the interview. The mercury content of the fish species consumed was supplied by the Food Chemical Surveillance Programme in the Basque Country. Subjects: For the estimation, 8417 volunteers, men and women, aged 35-65 years, of the EPIC cohort; for the validation, a random sample of 120 individuals stratified by fish intake was taken. Results: The validation study confirmed the relationship between fish consumption and mercury intake, as well as between fish consumption and mercury in erythrocytes. 99.9% of individuals have intakes below 75% of the Provisional Tolerable Weekly Intake (PTWI) of mercury established by the World Health Organization. But the limit dosage recommended by the United States Environmental Protection Agency, measured by the average risk index, would be exceeded often. Conclusions: No individual from the cohort would exceed the PTWI of mercury. Nevertheless, owing to the amount of fish consumed, certain individuals would have mercury intakes approaching the recommended limits. With a view to the future, we believe mercury in fish must continue to be monitored closely in order to assess the risks for the population.