[Studies on the origin of the causative agent of Minamata disease. IX. Transition of the pollution of Minamata Bay and its neighbourhood].

Abstract

1) No new cases of Minamata disease have been found since 1961. However it was considered that a slight amount of the organomercury compound as the causative agent of the disease had been discharged from Minamata Factory until May, 1966, notwithstanding the completion of the waste treatment of the factory in January, 1961. In June, 1966, the system of waste treatment wsa revised. Then, the mercury content in the fish from the bay abruptly decreased.2) Methylmercury chloride was extracted as crystalline solids from the waste water discharged from the rectifying column of acetaldehyde plant, and a considerable amount of chloride appeared in in the same waste water.