Biological Trace Element Research

, Volume 119, Issue 3, pp 195–211 | Cite as

Mercury–Selenium Species Ratio in Representative Fish Samples and Their Bioaccessibility by an In Vitro Digestion Method

  • Ana I. Cabañero
  • Yolanda Madrid
  • Carmen Cámara


The potential toxicity of mercury (Hg) content in fish has been widely evaluated by the scientific community, with Methylmercury (MeHg) being the only legislated species (1 mg kg−1, maximum concentration allowed in predatory fish). On the other hand, selenium (Se) is recognized to decrease its toxicity when both elements are simultaneously administrated. In the present paper, the total content of Se and Hg and their species in fish of high consumption, such as tuna, swordfish, and sardine, have been evaluated. The percentage of MeHg is higher than 90% of total Hg content. The results show that, for all of them, the Se/Hg ratio is significantly higher than one, being the maximum ratio for sardine. As only studying the bioaccessible fraction the extent of a toxic effect caused by an element can be predicted, the bioaccessibility of both analytes through an in vitro digestion method has been carried out. The results show that MeHg in all fishes is very low bioaccessible in both gastric and intestinal digestion. Because the MeHg bioaccessible fraction might be correlated to the Se content, the potential toxicity cannot be only related to the total Hg content but also to Se/Hg ratio.


Mercury Selenium MeHg Speciation Bioaccessibility 



The authors would like to thank to the Community of Madrid for the financial support through the program Analysic S505/AGR/0312 and to the CICYT for the project CTQ2005-02281/BQU.


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Copyright information

© Humana Press Inc. 2007

Authors and Affiliations

  • Ana I. Cabañero
    • 1
  • Yolanda Madrid
    • 1
  • Carmen Cámara
    • 1
  1. 1.Departamento de Química Analítica, Facultad de Ciencias QuímicasUniversidad Complutense de MadridMadridSpain

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