FACTOR-ANALYTICAL OBSERVATION ON DOSE-RESPONSE RELATIONSHIP OF LEAD IN THE OCCUPATIONALLY NON-EXPOSED

Abstract

By the procedure of of factor analysis, the interrelationships of parameters relevant to lead exposure were statistically investigated. The parameters were clas-sified to three groups based on the results of these statistical analysis: the first group contained lead mobilized by CaEDTA and lead in blood, which were considered to be related to the body burden of lead; the second group, ALA-D in erythrocyte, δ-ALA in urine, coproporphyrin in urine and lead in urine, which should be the response to the body burden of lead; the third group, hemoglobin in blood.
It was supported that there might be specific biological reactions to lead in people free from occupational or accidental exposure to lead, though the extent of the reac-tions was supposed to be much less than that of occupationally-exposed lead workers. The influence of lead to blood hemoglobin level was not found under usual urban environments.
The biological significance seemed to be almost similar between lead in blood and lead mobilization test with the intravenous administration of CaEDTA from the view-point of dose-response relationship of lead. The regressions of urinary coproporphyrin and erythrocyte ALA-D activity on lead mobilized by CaEDTA or blood lead were supposed to be nearly linear in people free from occupational lead exposure.