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

Abstract

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.

This work was supported by Project POCTI/41741/ESP/2001—Risk Assessment of Methylmercury Exposure: Integrated actions through the food chain. Eixo 2, medida 2.3 POCTI do QCA III (componentes Feder e OE) and Portuguese-Spanish Integrated Actions (2001/2002 NºE-13/01). The collaboration of Pedro Margarido and Gilberto Silva from DSHPV was vital for the attainment of representative samples of fish. Prof. Mário Figueiredo and Prof. Hortência Caramona from the executive councils of the Sesimbra and Caneças, respectively, are gratefully acknowledged for their acceptance and collaboration on the questionnaires distribution.

Notes

JO CE. 2001. Jornal Oficial das Comunidades Europeias NºL77 (466/2001CE). Decisão da Comissão das Comunidades Europeias de 8 Março de 2001.

JO UE. 2006. Jornal Oficial da União Europeia Nº L 364/5 (regulamento 1881/2006). Decisão da Comissão das Comunidades Europeias de 19 de Dezembro de 2006.