| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Carp blood ALA-D was certified for use as an indicator of water lead pollution. In order to use ALA-D extensively for assessing water lead pollution, it is necessary to find a method which does not require HgCl_2 for the determination of ALA-D,and storage conditions for the blood which permit stability of and a standarized expression unit of ALA-D activity.
The results are summarized as follows :
1) In the case of a modified method which did not use HgCl_2, the reaction mixture was mixed and then left to stand for 10 min following the addition of 7% TCA solution. This was then repeated twice.
2) Carp blood ALA-D was stable for at least 4 days when the blood was stored at 4ﾟC,in an ice bath or in a dry-ice bath. The three expression units of ALA-D activity, that is, per erythrocyte (RBC) , blood, and hemoglobin (Hb) , were related as follows :
nmol PBG/ml RBC/h=3.6*nmol PBG/ml blood/h=0.256*nmol PBG/g Hb/h
Fish blood ALA-D has been usuful as an effective short-term indicator for evaluating t
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he chronic toxicity of water lead on fish. Conseqently, the validity of the environmental standard value of water lead in Japan (10 ppb) was evaluate from a 20-d exposure test.
The results are summarized as follows :
3) Judging from the inhibitory degree of the ALA-D,the lead standard value is a concentration that may cause chronic toxicity to carp.
When we tried to survey water lead pollution in the fresh waters of northern Kyushu using carp, the carp were difficult to collect, however, crucian carp (Carassius auratus langsdorfii) could be collected easily. Accoringly a 3-wk exposure test of crucian carp to water lead was undertaken in order to evaluate the suitability of fish blood ALA-D as an indicator of water lead pollution.
The results are summarized as follows :
4) Blood ALA-D activity reflects the degree of lead contamination that crucian carp have suffered, and decreased to about 30% of that of control fish when the fish were exposed for 3 wks to water lead at a concentration of 10 ppb. Crucian carp blood ALA-D is useful as a indicator of water lead pollution.
At present we are planning to assess the actual conditions of water lead pollution in areas of fresh water in northern Kyushu using crucian carp blood ALA-D. Less
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