2022/06/29 by Hartwig, Andrea, MAK Commission
#Blei #Bleiacetat #Bleichlorid #Bleidiacetat #Bleidichlorid #Bleidinitrat #Bleidistearat #Bleimonoxid #Bleinaphtenat #Bleinitrat #Bleioxid #Bleiphosphit #Bleiphthalat #Bleistearat #Bleisulfat #Genotoxizität #Humanstudien #Kanzerogenität #MAK value #MAK-Wert #Neurotoxizität #PBPK-Modell #PBPK-modell #Spitzenbegrenzung #anorganische Bleiverbindungen #carcinogenicity #genotoxicity #human studies #inorganic lead compounds #lead #lead acetate #lead chloride #lead diacetate #lead dichloride #lead dinitrate #lead distearate #lead monoxide #lead naphtenate #lead nitrate #lead oxide #lead phosphite #lead phthalate #lead stearate #lead sulfate #maximale Arbeitsplatzkonzentration #maximum workplace concentration #neurotoxicity #peak limitation
paper · doi:10.34865/mb743992d7_2ad
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated lead [7439-92-1] and its inorganic compounds (except lead arsenate and lead chromate) considering all toxicological end points. After repeated exposure of workers, lead and its inorganic compounds show specific target organ toxicity in the nervous system, kidneys, cardiovascular and haematological system. The most sensitive toxic effects of lead and its inorganic compounds are nervous system disorders. Lead-induced neurological effects are also observed in infants and children and may result in a lifelong reduction of neurological function at low blood lead levels. As lead has a long half-life in humans, the most reliable and specific parameter for determining the internal lead burden is the blood lead concentration. Thus, the BAT value (biological tolerance value) of 150°µg/l blood must not be exceeded and its use is to be preferred over an air limit value. Nevertheless, a maximum concentration at the workplace(MAK value) of 0.004°mg/m3 for the inhalable fraction was derived by applying an updated and well-validated physiologically based pharmacokinetic (PBPK) model. As the critical effect is systemic, lead has been assigned to Peak Limitation Category II with an excursion factor of 8 due to its long half-life. As it has been demonstrated unequivocally that lead induces damage to the human embryo or foetus and that these effects are to be expected even if the MAK and BAT values are not exceeded, lead has been assigned to Pregnancy Risk Group A. The carcinogenic effects of lead and its inorganic compounds have been demonstrated in animal studies, but the data in humans are inconclusive. The primary mechanism of action is non-genotoxic and genotoxic effects play no or at most a minor part provided that the MAK and BAT values are observed. Lead and its inorganic compounds have thus been classified in Carcinogen Category 4. Skin contact is not expected to contribute significantly to systemic toxicity, but oral absorption via hand-mouth contact continues to be a critical factor. A skin sensitization potential is not expected from the data available. There are no data for sensitization of the respiratory tract.