Lithium content of the ocean fish has been investigated for estimating the intake of lithium, which was known as an element being used to a medicine (lithium carbonate) for the remedy of manic-depressive psychosis. In this study, fish (184 samples) was classified commercially into three types; raw fish (n=95), dry fish (n=70) and canned fish (n=19). Lithium content was determined by flame photometry after the decomposition of a fish sample (∼ 2g) with the mixture of nitric and perchloric acids. In the raw fish, lithium content was obviously higher in a sardine group (264 ± 186 ng/g in the range of 67 ∼ 934 ng/g, n=51) than in the other fish group (38 ± 28 ng/g in the range of 11 ∼ 86 ng/g, n=44, at wet-weight basis). Especially in the sardine group, the content was higher in anchovy (407 ± 167 ng/g, n=25) than in others (e. g., big-eye sardine; 85 ± 12 ng/g, n=11 and Japanese pilchard; 157 ± 43 ng/g, n=6, at wet-weight basis). In addition to the sardine group (anchovy, pilchard, sardine and blue sprat) rich lithium was found in the head (40 ∼ 66% of total lithium), compared with the eyes (0.1 ∼ 1%), internal organ (1 ∼ 9%), body (10 ∼ 33%) and back bone (15 ∼ 36%) of the fish. On the other hand, in dry fish, lithium was rich in the anchovy of “Niboshi” (5390 ng/g, as mean, n=30, at dry-weight basis) among dry sardine; manufactured as “Niboshi”, “Tazukuri”, “Maruboshi”, “Namaboshi” and “Chirimen” named for depending on their different drying-treatments in Japan. Lithium content of raw anchovy, 407 ± 167 ng/g (n=25) at wet-weight basis, was converted to 1770 ± 727 ng/g (n=25) at dry-weight basis, and the value was close to 2440 ± 657 ng/g (n=9) of dry anchovy as “Tazukuri” at dry-weight basis. The lithium content of canned sardine soaked with oil (sardine fillet: 246 ± 135 ng/g, n=15, at wet-weight basis) was close to that with water (sardine fillet: 123 ± 62 ng/g, n=3, at wet-weight basis), and was almost equal to that of raw sardine group (264 ± 186 ng/g, n=51, at wet-weight basis). It was concluded that anchovy and sardine, regardless of raw, dry or canned fish and of different ocean of the fish collected, were good material for the intake of lithium.
