Carbon black

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Endpoint-specific read-across justification" attached under section 13.2

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 5 600 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Description of key information

A No Observed Effect Concentration (NOEC) of 3200 mg/L was found for short-term toxicity in a GLP guideline study with a nanoform of the substance. As a preliminary range-finding study showed that the Daphnia magna were possibly physically hampered by particles, and as the presence of particulate matter is not recommended in the OECD TG 202 for Daphnia tests, the final test was carried out on a water accommodated filtrate.

The nano- and non-nanoforms have the same chemical composition, are both highly insoluble in water and differ only in the size distributions of their constituent particles with the majority of particles being larger than 100 nm in the case of "non-nanoform carbon black". Because 100 nm is the regulatory threshold for "nano", but not based on a steep change in biological activity, no differences in the toxicity between the non-nanoform and the nanoforms are expected. Therefore, the read across is justified and the non-nanoform of carbon black is not expected to cause acute toxicity to aquatic invertebrates. This conclusion is in line with and supported by other ecotoxicity data, e.g. data on acute toxicity in fish which shows no apparent influence of constituent particle sizes or surface area on toxicity.