Charcoal

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Assessment based on existing toxicological data

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Charcoal

EC Number:

240-383-3

EC Name:

Charcoal

Cas Number:

16291-96-6

Molecular formula:

C

IUPAC Name:

Charcoal

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): no bioaccumulation potential based on study results

Executive summary:

The test material charcoal (EC no 240-383-3) is a UVCB substance which consists of the following main constituents: carbon amorphous, ash, volatile material of undetermined composition and moisture. There may be some trace elemental impurities dependent on the origin / source of the wood from which it is made. It is a black solid which can compose of fine - powder, medium - granules and coarse grades – granules, lumps and briquettes. Occupational exposure may occur during production (removal from kiln) and sizing/bagging. In literature studies, observation and established knowledge it is confirmed that charcoal is essentially insoluble in water and most usual solvents. Solubility of charcoal was also assessed to be insoluble in bodily fluids such as gastric fluid and alveolar fluid.

Particle size of commercial charcoal is variable but is generally found in either lump, briquette, or extruded forms. Charcoal can be activated and used in smaller particulate form in filters but the particle size distribution (PSD) will be dependent on the end use and therefore it is not possible to give a typical PSD for this end point. However it is fair to say that whilst some dust will be generated in products sold on the market through surface erosion, that the most likely exposure to dust would be during manufacturing and bagging.

In an acute inhalation study the 4 hr LC50 (single 4-h nose-only exposure) to charcoal dust by rats followed by a 14-day observation period at a dose level 5 mg/L was not associated with mortality or any test item-related toxicological findings on the male and female animals. The LC50 is considered to be > 4.97 mg/L (max dose achieved). As such although charcoal dust has the potential to be inhaled it does not appear to exhibit inhalation toxicity at a high dose in the rat. Occupational exposure to airborne charcoal dust in charcoal-producing plants would not be expected to be in the ultrafine or nano particle range. Since the test material has a low solubility in artificial alveolar fluid it is considered the inhaled test material will not be absorbed. 

There is no evidence that charcoal or activated charcoal is orally toxic. In fact all evidence suggests that it is beneficial in certain circumstances as a treatment for removing toxins from the stomach and gastric tract.

Carbon black (a read-across substance for charcoal) was found not to be irritating to the skin and eyes of rabbits in tests performed similar to current OECD guidelines. As superficial foreign bodies, charcoal particles may be slightly irritating mechanically and may cause discoloration of lids and conjunctivae in humans. There is no information to suggest that charcoal might be a skin sensitiser.

In conclusion, the test material has a low potential for any absorption by oral ingestion and dermal absorption.

Since the test material has a low potential for absorption by any route it means that the test material will not be readily bioavailable. The majority of any test material that is ingested orally is likely to pass through the gastrointestinal (GI) tract unchanged and be excreted in the faeces. Any small amount of constituents from the test material that are absorbed by the gut will enter the essential elemental pool along with those that are absorbed from the daily nutritional requirement of elements and therefore are not considered to be of any toxicological significance.  

Charcoal has not been tested in guideline studies for its effects on fertility, reproduction and the developing organism. Based on the available toxicokinetic principles, it is very unlikely that charcoal particles will reach the reproductive organs, the embryo or the fetus under in vivo conditions. No adverse effects on reproduction and development would therefore be expected.

In Conclusion: Charcoal has been demonstrated not to have any toxic effect on human health or the environment