Abstract
The purpose of this paper is to determine the maximum permissible concentration of copper in mineral waters through internal use.
To each rabbit of 10 groups (each group consists of 2 rabbits) was administered for 30 days daily by a stomach tube 10cc of copper sulfate solution, the concentration of which were 19.2, 64, 192, 640, 19.2×102, 32×102, 64×102, 12.8×103, 32×103, 64×103mg/kg (7.5, 25, 75, 250, 750, 1.25×103, 2.5×103, 5×103, 12.5×103, 25×103mg/kg as copper) respectively.
Body weight, hemoglobin content, red, and white blood cell counts, serum total protein, alkaline phosphatase, choline-esterase, and diamine-oxidase activities of serum were determined weekly; and the liver, kidney, and spleen were examined histologically (H. E. staining and copper staining) after the treatment was over.
As for body weight, blood examinations and serum analysis, the groups administered under 640mg/kg of copper sulfate solution (250mg/kg as copper showed no abnormalities).
Histologically (H. E. staining only), the groups administered under 19.2×102mg/kg of copper sulfate solution (750mg/kg as copper) had no pathological findings.
The minimal concentration where copper pigment granules were proved histologically in the liver cells by copper staining was 64mg/kg of copper sulfate solution (25mg/kg as copper).
In the liver cells of the groups administered 19.2mg/kg of copper sulfate solution (7.5mg/kg as copper) was proved no copper pigment granule.
Therefore, when taken daily by oral use for 30 days, the maximum permissible dose of copper (not copper sulfate) in mineral water is estimated to be 10cc of 7.5mg/kg to a 2kg rabbit, or when compared by body weight, 250cc of 7.5mg/kg solution, and 0.625mg/kg if daily 3 litres are taken, to a human adult of 50kg body weight.
Only few of the Japanese mineral waters contain more than 7.5mg/kg of copper, so the internal use of the other mineral waters. 250cc daily for 30 days, will have no toxic effects by copper to human adults. As all the highly copper containing mineral waters of Japan belong to strongly acid vitriol or alum vitriol springs, dilution with water is inevitable at the time of drinking, so that generally not more than 20cc daily is used perorally. And when taken 25cc a day the maximum permissible concentration of copper containing waters will be 75mg/kg.
