THE PRESENT MERCURY CONTENTS OF SCALP HAIR AND CLINICAL SYMPTOMS IN INHABITANTS OF THE MINAMATA AREA

A total of 191 fishermen and their family (32-82 years) living in some mercury-polluted areas along the Shiranui Sea volunteered for the pre sent study. They made a living by fishery and had formerly eaten the m ethyl mercury-contaminated fish and shellfish caught there. The questi onnaire on subjective symptoms, fish eating habits, and past living hi story was conducted on the subjects. In addition, they were clinically examined in detail by several neurologists and scalp hair was collect ed. With six exceptions, all the 185 subjects showed a normal total me rcury level in hair (<10 ppm). The ratio of methyl mercury to total me rcury was 79-94% on the average for each group examined, suggesting in direct contamination (perhaps through the food chain). Despite their l ow mercury level in scalp hair, however, the subjects showed various n eurological symptoms, particularly, sensory disturbance (such as the g love and stocking type), at a very high rate. Thus, it seems fair to s tate that, in addition to officially recognized Minamata disease patie nts, there still exist many people with atypical, slight Minamata dise ase on the coast of the Shiranui Sea. The current hair mercury level i s not necessarily useful as a criterion for diagnosing chronic Minamat a disease because of the long lapse of time. (C) 1998 Academic Press.