Registration Dossier

Administrative data

Link to relevant study record(s)

Description of key information


Benzene is readily absorbed following inhalation or oral exposure. Although it is also readily absorbed from the skin, a significant amount evaporates from the skin surface. Absorbed benzene is rapidly distributed throughout the body and tends to partition into fatty tissues. The liver serves an important function in benzene metabolism.

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential
Absorption rate - oral (%):
100
Absorption rate - dermal (%):
0.1
Absorption rate - inhalation (%):
50

Additional information

The toxicokinetics of benzene has been extensively studied and was recently reviewed by ATSDR (Toxicological profile for benzene, ATSDR, 2007). ATSDR concluded "Inhalation exposure is probably the major route of human exposure to benzene, although oral and dermal exposures are also important. Benzene is readily absorbed following inhalation or oral exposure. Although benzene is also readily absorbed from the skin, a significant amount of a dermal application evaporates from the skin surface. Absorbed benzene is rapidly distributed throughout the body and tends to partition into fatty tissues. The liver serves an important function in benzene metabolism, which results in the production of several reactive metabolites. Although it is widely accepted that benzene toxicity is dependent upon metabolism, no single benzene metabolite has been found to be the major source of benzene hematopoietic and leukaemogenic effects. At low exposure levels, benzene is rapidly metabolized and excreted predominantly as conjugated urinary metabolites. At higher exposure levels, metabolic pathways appear to become saturated and a large portion of an absorbed dose of benzene is excreted as parent compound in exhaled air. Benzene metabolism appears to be qualitatively similar among humans and various laboratory animal species. However, there are quantitative differences in the relative amounts of benzene metabolites”. The present analysis confirms the ATSDR statement. More specifically, human inhalation exposure is estimated to be approximately 50%, oral exposure assumed to be 100% (this value used for DN(M)EL calculations). Percutaneous absorption is estimated at 0.1% (Modjtahedi and Maibach, 2008) whereas a QSAR model determined a maximum value of 1.5% (Ten Berge, 2009).