Storage method for blood that provides stability of erythrocyte 5-aminolevulinic acid dehydratase of carp Cyprinus carpio when used as an indicator of water lead pollution

5-Aminolevulinic acid dehydratase (ALA-D) in the blood of carp Cyprinus carpio has been certified for use as an indicator of water lead pollution. The present study was undertaken in order to find storage conditions for blood samples which provide stability of, and allow a standarized expression unit for ALA-D activity, since the provision of these is essential for accurately assessing water lead pollution in a field survey, when using carp ALA-D extensively as the indicator enzyme of water lead pollution. Carp blood ALA-D levels were stable for at least 4 days when the blood was stored in a refrigerator (4°C), an ice bath, or a dry-ice bath. The three expression units of ALA-D activity, that is, per ml of RBC, ml of blood, and g of Hb, were found to be related as follows: nmol PBG/ml RBC/h = 3.6xnmol PBG/ml blood/h = 0.256xnmol PBG/g Hb/h.