High-Fish Consumption and Risk Prevention: Assessment of Exposure to Methylmercury in Portugal

• Published in: Journal of Toxicology and Environmental Health, Part A Part A, 2008-01, Vol.71 (18), p.1279-1288
• Main Authors: Carvalho, C. M. L., Matos, A. I. N. M., Mateus, M. L., Santos, A. P. M., Batoréu, M. C. C.
• Format: Article
• Language: English
• Subjects: Adolescent; Animals; Child; Cross-Sectional Studies; Environmental Exposure - analysis; Female; Fishes; Food Contamination; Humans; Male; Methylmercury Compounds - analysis; Portugal; Risk Assessment; Seafood; Surveys and Questionnaires; Water Pollutants, Chemical - analysis
• ISSN: 1528-7394; 1087-2620
• DOI: 10.1080/15287390801989036

The aim of this study was to evaluate the exposure to methylmercury (MeHg) of potential populations at risk living in Portugal. To ascertain youth exposure, a questionnaire was distributed to 300 students of a middle secondary school in Sesimbra and to 429 students studying in Caneças, selected as the control population. The average number of fish meals consumed by person was 4.1 and 3 per week in Sesimbra and Caneças, respectively. The subpopulations of high intake (PHI) corresponding to those ingesting 7 or more fish meals per week were also analyzed separately, with 17% of the students belonging to the PHI of Sesimbra versus 6.1% in Caneças. Socioeconomic aspects such as relative's professional involvement with fisheries correlated with the higher intakes in Sesimbra. Fish samples were collected in the dock of Sesimbra and total mercury (Hg) was determined by flow injection cold vapor atomic fluorescence spectroscopy (FI-CV-AFS). The mean value found for nonpredators was 0.035 μg/g. Dogfish specimens surpassed the legislated limit for predator species and increased the predators mean to 1 μg/g. The cross-sectional data were integrated with the fish analysis results to estimate the population exposure to MeHg. The indices of risk calculated for youth reached values of 4.5, demonstrating the existence of risk to a part of the population exceeding the provisional tolerable weekly intake (PTWI) level mandated by WHO (1.6 μg/kg bw). The results indicate that monitoring of Hg levels in fish is mandatory and counseling should be provided to populations at risk, encouraging them to prevent the risk.