Lessons from Minamata mercury pollution, Japan - after a continuous 22 years of observation

Abstract

One of the most visible tragedies by industrial water pollution is Minamata disease, methylmercury poisoning caused by eating contaminated fish, which has killed more than 100 people and paralyzed several thousand people around Minamata Bay, Japan and the adjacent Yatsushiro Sea since 1956. The cause of Minamata disease was confirmed, not by analyzing environmental samples such as sediments (containing more than 600 ppm of Hg) or fish (at least 20 ppm) at the bay, but by symptoms of Minamata disease patients that resembled previous mercury poisoning reported in a European medical journal. Mercury dispersion was traced for 22 years to collect mercury concentration measurements in Yatsushiro Sea surface sediments at 24 fixed stations. The analytical results of mercury revealed four trends of mercury movement from the bay: 1) a rapid increase in Hg concentrations up to 1984; 2) a dramatic decrease in mercury concentrations after an artificial mercury decontamination project began in 1984; 3) a strange drop in mercury contents due to an historical rainfall in the region in 1982 and; 4) natural decontamination, which has been underway since 1985. The tragedy at Minamata has provided many lessons which have shaped the scientific field in environmental research, especially in the area of water quality.

Concentrations and Distribution of Mercury and Other Heavy Metals in Surface Sediments of the Yatsushiro Sea including Minamata Bay, Japan

“…The low concentrations of mercury in northern Yatsushiro Sea sediments may imply that mercury has not been migrated from Minamata bay to this area. The temporal trend of mercury concentrations in surface sediments of the Yatsushiro Sea was examined by comparing the concentrations determined in this study with those reported previously (Kudo and Miyahara 1986;Kudo et al 1998;Fig. 4).…”

“…As described earlier, mercury residues in southern Yatsushiro Sea sediments were greater than those in middle and northern Yatsushiro Sea samples collected in 2004. However, the mercury concentrations in southern sediments, St. H, and I have decreased since the Kudo et al (1998) and Kudo and Miyahara (1986) late 1980s and the early 1990s. These results suggest that the migration of mercury from Minamata bay has declined after the dredging project was completed in 1990.…”

Increased Bioavailability of Mercury in the Lagoons of Lomé, Togo: The Possible Role of Dredging

“…Mercury contamination and toxicity have long been of concerns during the last decades due to the occurrence of large-scale poisoning (Kudo et al 1998). Natural sources of Hg comprise weathering and degassing from water surfaces and land and volcanic eruption, while anthropogenic sources include metallurgical processes, fossil fuel burning, wood pulping, paint and chloro-alkali industries, battery production, pharmaceutical waste, and agriculture (Boening 2000;Mason et al 1994;Morel et al 1998).…”

Determination of methylmercury by solid-phase microextraction inductively coupled plasma mass spectrometry: a new sample introduction method for volatile metal species

“…2±7 The resulting biomagni®ca-tion of methylmercury can have dramatic consequences for top predators such as humans; the best-known example of this being the Minimata catastrophe in which over one hundred people died and many more suffered permanent disability from high-level exposure. 7 Although unfortunate, such events have catalyzed an increased interest in methylmercury toxicology and its biochemical mechanisms.…”