Registration Dossier

Administrative data

Description of key information

Inorganic lead compounds do not exhit toxicity in acute toxicity tests with experimental animals.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
5 000 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Dose descriptor:
LC50
5 050 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
LD50
2 000 mg/kg bw

Additional information

Although lead can exert toxic effects upon multiple organ systems and body functions, this toxicity manifests under conditions of sub-chronic to chronic exposure that can range from months to years in duration. Acute toxicity is not observed in animals after oral or inhalation exposures up to the limit values of acute toxicity testing. Similarly, toxicity in humans after true acute exposures is limited and, when documented, is generally under conditions that yield sub-chronic or chronic exposures. This finding is not unexpected given the pharmacokinetics of lead uptake into the body. Lead uptake is generally quite low and heavily reliant upon easily saturable active transport mechanisms. Once saturation of these uptake mechanisms has occurred, uptake proceeds by inefficient passive diffusion. The uptake of lead is thus highly non-linear as a function of dose with uptake efficiency declining with the amount of lead administered to a test animal or an exposed human. Although toxic under chronic exposure situations, the acute toxicity of lead and inorganic lead compounds appears to be quite low.

These results can be assigned to lead silicate applying a read across based on a grouping of substances (Lead compounds).

Justification for classification or non-classification

Acute toxicity is not observed in animals after oral, inhalation or dermal exposures up to the limit values of acute toxicity testing. Similarly, toxicity in humans after true acute exposures is limited and, when documented, is generally under conditions that yield sub-chronic or chronic exposures. This finding is not unexpected given the pharmacokinetics of lead uptake into the body. Lead uptake is generally quite low and heavily reliant upon easily saturable active transport mechanisms. Once saturation of these uptake mechanisms has occurred, uptake proceeds by inefficient passive diffusion. The uptake of lead is thus highly non-linear as a function of dose with uptake efficiency declining with the amount of lead administered to a test animal or an exposed human. Although toxic under chronic exposure situations, the acute toxicity of lead and inorganic lead compounds appears to be quite low and does not require classification.