DIFFERENCES IN TOXICITY BETWEEN LEAD-OXIDES AND LEAD SILICATES

Epidemiological investigations have been performed on the toxicity of lead oxides and lead silicates. The results of the investigations document the higher toxicity of lead oxides compared to lead silicates. In agreement with other investigators, we found a ratio of atmospheric lead to blood lead (mu-g/m3 to mu-g/dl) of 3.0: 1. A ratio of 5.5: 1 could be established for lead silicates. The differences are statistically significant. There are no sex differences. It could be inferred from the ratio of atmospheric to blood lead values and with consideration of the frequency distribution of blood lead values at different atmospheric lead values that 0.05 mg/m3 atmospheric lead bound in the form of an oxide corresponds to about 2.9 mu-mol/l blood lead and 0.25 mg/m3 atmospheric lead bound as a silicate corresponds to about 1.93-mu-mol/l blood lead.