Minamata

TABLE 15.8 Freąuency of Symptoms Experienced by People at Minamata Suffering from Methylmercury Poisonong

Symptom    Post-natal

	Congenital	Children	Adults
	%	%	%
Mental disturbance	100	100	71
Disturbed coordination	100	100	80-90
Disturbed gait	100	100	82
Disturbed speech	100	94	88
Disturbed hearing	5	67	85
Constricted visual field	?	100	100
Impaired chewing &	100	89	94
swallowing Enhanced tendon reflexes	82	72	38
Pathological reflexes	54	50	12
Irwoluntary movements	73	0	0
Salivation	77	56	24
Forced laughing	27	29	-

TABLE 15.9 Outbreaks of Methylmercury Poisoning in Recent Times

Datę	Place	Effect	Source of mercury
1953-60's	Minamata	>3000 cases	CH3Hg^+ and other mercury products
	Japan	100 deaths	from a plastics factory
1956	Iraq	100 cases	From eating CH3Hg^+ treated grain
1960	Iraq	1000 cases	From eating CH3Hg+ treated grain
1963-65	Guatemala	45 cases	From eating CH3Hg^+ treated grain
1965	Niigata	669 cases	CH3Hg^+ and other mercury products
	Japan	55 deaths	from a plastics factory
1967	Ghana	150 cases	From eating CH3Hg* treated grain
1969	Pakistan	100 cases	From eating CH3Hg* treated grain
1970^/s	Canada		Mercury from chloroalkali cells in paper manufacture
1971-72	Iraq	6350 cases 459 deaths	From eating CH3Hg^+ treated grain

Fig. 15.5 Relationship between signs and symptoms of mercury toxicity and body burden of mercury at the onset of symptoms. Sources; Bakir et al., 1973

[7], Suzuki, 1979 [103].