In this study, we measured the activity of the erythrocyte pyrimidine 5'-nucleotidase(P5N) for 83 workers exposed to lead in their workplace, and analyzed the correlation of the activity with other biological exposure indices of lead. The measurement was performed by using a high performance liquid chromatography (HPLC) with a reverse phased ODS column.

The results are as follows;

1. The correlation of the erythrocyte P5N activity with the concentration of blood lead(PbB) was shown to be statistically significant (r=-0.71, p=0.0001).

2. For a group of subjects whose PbB was less than 10microgram/dl, the erythrocyte P5N activity was 14.9+/-1.5 micromole uridine/h/g Hb.

3. For medical surveillance, this study suggests the erythrocyte P5N activity of 12 micromole uridine/h/g Hb is equivalent to 40 microgram/dl of PbB.

4. The correlation coefficients of the erythrocyte P5N activity with other biological exposure indices of lead such as PbB, ZPP, ALA-U, PBU, CP-U, ALAD, and log ALAD were -0.71, -0.64, -0.57, -0.51, -0.50, 0.46 and 0.64, respectively.

5. The correlation coefficients of the PbB with other biological exposure indices of lead for ALAD, P5N, ZPP, PBU, CP-U, and ALA-U were -0.76, -0.71, 0.68, 0.59, 0.42, and 0.41, respectively. The erythrocyte P5N activity can be used as a reliable biological exposure index of lead.