Charcoal

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Additional information

The screening test for reproduction/developmental toxicity in rats provides information on the possible health hazards likely to arise from repeated exposure over a relatively limited period of time. The method comprises a basic repeated dose toxicity study and a reproduction/developmental toxicity screening test. Therefore, the screening test can be used to provide initial information on possible effects on male and female reproductive performance.

However, the OECD screening test no. 422 for reproductive/developmental toxicity is not required, if the test item is not bioavailable.

At present, it is not expected that charcoal becomes systemically available at significant amounts as in the granulometry studies performed with three representative charcoal samples only a minor fraction was inhalable (particle sizes ≤100 µm) and more importantly only a negligible fraction was respirable (particle sizes ≤2 µm).

However, even if a limited bioavailability might become indicated based on the data that will be obtained in the suggested pharmacokinetic study(see IUCLID section 7.5.) this screening study is not needed based on the following arguments:

a) charcoal was not genotoxic in a battery of three genotoxic in vitro studies;

b) feeding of rats with charcoal like carbon fibre adsorbent compound was not associated with any signs of toxicity but reduced the incidence of carcinogenesis (Anisimov et al. 1998, 1999).

c) feeding of pregnant jaundiced female Gunn rats with a diet containing 10% activated charcoal was associated with improved embryonic survival (Davis et al. 1983). 58% of the treated, time-mated females were pregnant at necropsy, compared to none for the control females. 48% of the charcoal fed and 7% of the control females produced a live litter. The positive effect of charcoal was ascribed to a reduction in plasma bilirubin concentrations by as much as 40%.
In addition, in a reproduction study in White Leghorn hens, it was found that eggs from hens that received 3% of activated charcoal in their diet showed reduced yolk pigmentation, probably because the charcoal inhibited absorption of xanthophyll pigments contained in the diet from the gastrointestinal tract (Waibel et al. 1965). No other overt effects on reproduction were noted. 

Activated charcoal has been used for decades for the emergency treatment of acute oral poisoning or drug overdose at single doses of up to 50 g (Carbomix 2009, Kohle-Kompretten 2007, Ultracarbon 2010), repeated if necessary. There is no evidence to suggest that activated charcoal should not be used during pregnancy or lactation.

 

Short description of key information:
Studies on reproduction/developmental toxicity are not required (see "discussion" below).