Minamata: The aftermath

摘要

The city of Minamata (Japan) was the host of the 6~(th)ICMGP in October 2001. This town is sadly associated with one of the worst case of mercury (Hg) poisoning worldwide as the industrial activities of the Chisso company caused a widespread Hg contamination of the Minamata Bay during the 1950's and 1960's, leading to severe intoxication cases among local populations. The Hg inputs to the bay were drastically reduced many years ago, and governmental authorities engaged in remedial to decontaminate and restore the quality of the environment. Nowadays, surrounding communities still largely enjoy and rely on local aquatic resources as a food source. Many of the Collaborative Mercuiy Research Network (Canada) researchers attended the conference and had the pleasure to share the traditional fish cuisine of their Japanese hosts. Two months later, thirteen of them agreed to have their hair tested for Hg content and variations in Hg concentrations in hair following the stay in Minamata was evaluated. Among the 13 researchers, 10 exhibited a significant increase (average of 50.1 pencent + - 59, or 904 ug Hg/kg hair), while the three other had a small decrease (average of-5.0 pencent + - 5) of the Hg hair content. Estimates based on different scenarios of averaged fish consumption during the stay, and metabolic rates lead us to evaluate that the approximate level of Hg in fish species consumed was between 0,2 and 1,6 ppm. If one considers acceptable the premises supporting these calculations, the main conclusion issuing from this experiment are that: 1) Hg levels of fish consumed in Minamata are still considerably high; 2) increasing fish consumption does significantly increase Hg intake.