Mercury - adverse effects, Japan - epidemiology, Methylmercury Compounds - analysis, Mercury - analysis, Methylmercury Compounds - metabolism, Humans, Mercury Poisoning - pathology, Middle Aged, Hair - chemistry, Hair - metabolism, Male, Mercury - metabolism, Mercury Poisoning - etiology, Mercury Poisoning - epidemiology, Scalp, Aged, 80 and over, Adult, Fem...