Relationship between mercury content of hair and amount of fish consumed.

A GREATER amount of mercury has been found in the scalp hair of the Japanese than in the scalp hair of Americans living either in Japan or in the United States (1). The reason has been attributed to the abnormal exposure of the Japanese to mercurial pesticides used for agricultural purposes. Recent investigations to determine the amount of mercury in human scalp hair have suggested a positive correlation with the intake of alkylmercury compound in foods (2, 3). Several observations on the amount of methylmercury in marine products also have been reported (4, 5). Consequently, arguments concerning the allowable concentration of mercury in foods have arisen (6). While extensive studies of the amount of mercury in marine products have not yet been reported, data on the mercury content of a limited number of species of fish and shellfish eaten by the Japanese are given in table 1. We have attempted to study how the mercury compound in marine products influences mercury metabolism in the bodies of persons living in different environments who have different food habits. The design of the study was influenced by the following premises. 1. The mercury content of scalp hair will increase according to the intake of methylmercury compounds (2). 2. Fish caught in an area where alkylmercury compounds are known to pollute the water contain a large amount of mercury (7); 40 to 90 percent of the fish's total mercury content is composed of methylmercury compound. 3. It is recognized that fish caught in unpolluted natural waters contain a certain amount of methylmercury compound. The amount fluctuates according to the size and age of the fish and as yet undetermined biological characteristics of fish.