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Description of key information

Little carbon black is found in Peyer`s patches after oral exposure. It is unlikely that the insoluble particles are capable of skin penetration.
Uptake and retention of carbon black particles in lung macrophages have been observed following inhalation. In rats, clearance of carbon black particles from the respiratory tract is delayed at lung burdens equal or greater than 0.5 – 1.0mg carbon black / g lung or 7mg carbon black / m3 (“lung overload”). Hamsters have more efficient clearance mechanism than rats or mice. Lung overload is an important issue in the interpretation of inhalation toxicological studies. It is an open question whether data from studies under overloading conditions are useful for the prediction of health effects in man. PAHs and other organics are tightly adhered to the carbon black particles and are not bioavailable.

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential
Absorption rate - oral (%):
0.01
Absorption rate - dermal (%):
0.001
Absorption rate - inhalation (%):
1

Additional information

Commercially produced carbon black in contact with lung fluid is unlikely to de-agglomerate or disaggregate into smaller aggregates or primary particles. Uptake and retention of carbon black particles in lung macrophages have been observed following inhalation. In rats, clearance of carbon black particles from the respiratory tract is delayed at lung burdens equal or greater than 0.5 – 1.0mg carbon black / g lung or 7mg carbon black / m3 (“lung overload”). Hamsters have more efficient clearance mechanism than rats or mice. Studies of the mechanisms of cellular uptake suggest an endocytosis-mediated mechanism of internalization as aggregates in cytosolic vesicles. No aggregates have been found in mitochondria or nuclei. Translocation of carbon black after dermal exposure to other organs is unlikely.