Derivation of a biological limit value (BLV) for inorganic lead based on lead-induced genotoxicity in workers using the benchmark dose approach (BMD)

Background: Safe exposure levels for industrial chemicals are a prerequisite to the safety of workers in occupational settings. Methods: The application areas of the benchmark dose (BMD) approach have tremendously increased in recent years. Quantitative analyzes of dose-response relationships of genotoxic chemicals are among these application areas too. This study investigates the applicability of sister chromatid exchange (SCE) frequencies in lymphocytes of lead-exposed workers to derive a biological limit value (BLV) for inorganic lead. To this end, our previously published occupational lead exposure data were pooled and re-examined by using the BMD approach. Subsequently, we determined the point of departure (POD) value for lead-induced SCE frequencies in lymphocytes. Accordingly, the blood lead concentrations and SCE frequencies in lymphocytes of 26 control and 108 lead exposed male voluntary workers employed in a battery manufacturing plant were subjected to BMD modeling to determine the BMD confidence interval (BMD-CI). Results: According to our data set, benchmark dose lower bound (BMDL) of 6.55 mu g Pb/dL blood for the SCE frequencies in lymphocytes of lead-exposed workers has been obtained. Conclusion: The blood lead concentration of 6.55 mu g/dL might be proposed as the BLV for lead and its inorganic lead compounds based on our dataset.