Multi-Walled Carbon Nanotubes (MWCNT), synthetic graphite in tubular shape

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.43 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

1 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.043 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

100 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

insufficient hazard data available (further information necessary)

Sediment (marine water)

Hazard assessment conclusion:

insufficient hazard data available (further information necessary)

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no exposure of soil expected

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Only studies performed with Multi-Walled Carbon Nanotubes (MWCNT) meeting the form described in section 4.5 of the IUCLID dossier are considered to be relevant for this submission.

Although a large number of studies on MWCNT have recently been published, clear characterisation of the test materials including sample preparation is often missing although this is quite essential for ensuring reproducibility and reliability of a study. Importantly, modifications of some specific characteristics of the MWCNT tested such as variations in tube diameter or length distribution might give rise to differences in the (eco-)toxicological profile. 

Effects of different MWCNT seem to depend on the form (length) and physico-chemical properties (metal content, aggregation/agglomeration, surface chemistry, and functionalisation). Thus, for the time being a case-by-case approach is appropriate and the hazard assessment for MWCNT meeting the form described in section 4.5 of the IUCLID dossier is based solely on the information collected with this form of MWCNT. That is the reason why a comprehensive documentation is restricted to all available and relevant data on MWCNT meeting the form described in section 4.5 of the IUCLID dossier. That means on the other hand that the values used for any risk assessment should not be used for all MWCNT or for CNT in general, as the results obtained with one particular type of MWCNT may not necessarily be relevant for other CNT with other dimensions and properties.

However, the information on MWCNT not meeting the form described in section 4.5 of the IUCLID dossier (because the differences can be tracked back to the original papers or because the characterisation of the materials was unclear or incomplete) is also included in the IUCLID dossier but the entries are restricted to information on the data source.

Conclusion on classification

Classification and labelling according to aquatic toxicity data

Justification for classification or non classification:

Three acute tests have been performed with fish, daphnia and algae. No effects have been observed up to the highest concentrations tested (fish: 100 mg/L, daphnia: 100 mg/L, algae: 134 mg/L). In long-term tests, all NOECs are >1 mg/L, with the lowest NOEC from an algae study being 4.3 mg/L. Therefore, a classification related to H400 (GHS) is not required.

Classification and labelling according to degradation and bioconcentration

Justification for classification or non classification:

A classification related to hazard statement H400 (GHS) is not required as ready biodegradation tests are not applicable to inorganic substances. 

Furthermore, the partition coefficient log Pow cannot be determined and a log Pow > 3 is not expected.

For the same reason, hazard statements H410/H411/H412 according to the GHS regulation do not apply.