Carbon black

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

no hazard identified

Marine water

Hazard assessment conclusion:

no hazard identified

STP

Hazard assessment conclusion:

no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:

no hazard identified

Sediment (marine water)

Hazard assessment conclusion:

no hazard identified

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Carbon black does not produce soluble (bio)available ionic and other carbon-bearing species in environmental media. Further, the poor solubility of carbon black is expected to determine its behaviour and fate in the environment, including its low potential for aquatic toxicity. In addition, carbon black can be considered environmentally and biologically inert and the potential of carbon black for aquatic toxicity can safely be assumed to be low.

Nanoforms of carbon black and by read-across non-nano forms of carbon black are not acutely and chronically toxic to aquatic organisms and do not meet classification criteria for acute and long-term aquatic hazard according to Regulation (EC) No 1272/2008.

According to the hazard classification criteria defined in Regulation (EC) No 1272/2008, nanoforms of carbon black and by read-across non-nano forms of carbon black are not acutely or chronically hazardous to aquatic organisms since observed acute EC/LC50 (algae, daphnia and fish) and chronic NOEC or EC10 (algae) values are well above > 100 mg/L and > 1 mg/L, respectively.

Section 8.4.2.2 of the ECHA guidance Part B: Hazard assessment (V 2.1; 2011) defines non-classified hazards as follows “If there are ecotoxicity data showing effects in aquatic organisms, but the substance is not classified as dangerous for the aquatic environment, an aquatic PNEC can nevertheless be derived thus indicating a hazard to the aquatic environment.” A limit test concentration has not been set to by ECHA to define a ‘non-classified hazard’. Further, dispersions of any material would ultimately affect aquatic organisms if the applied concentrations were elevated enough. Standard test guidelines such as the OECD test guidelines 201, 202, 215, 211 define limit test concentrations that depending on the guideline are the solubility limit or acute and chronic test limits of 100 and 10 mg/L, respectively. The OECD test limits and/or the solubility limit are considered for the evaluation if observed effects have to be regarded as ‘non-classified hazard’ in the environmental hazard assessment of non-nano- and nanoforms of carbon black.

In sum, nanoforms of carbon black and by read-across non-nano forms of carbon black are not acutely and chronically toxic to aquatic organisms since all effect values are unbounded and well above respective acute and chronic OECD test limits. Thus, nanoforms of carbon black and by read-across non-nano forms of carbon black are also not considered an “unclassified” aquatic hazard and an aquatic PNEC cannot be derived. In these circumstances there are also not unclassified hazards to the sediment and soil compartment because toxicity to aquatic organisms is used as an indicator of concern for sediment and soil organisms and a screening risk characterisation (using the equilibration partitioning method to derive a PNEC for sediment or soil) cannot be undertaken. Thus, carbon black nanoforms and by read-across non-nano forms of carbon black do not have a “non-classified hazard” potential in the aquatic, sediment and soil compartment.

Conclusion on classification

No classification as to environmental hazards required as follows:

Acute toxicity

Acute toxicity data of carbon black nanoforms are available for several freshwater species covering three trophic levels (fish, crustacea and algae). The Table below provides an overview of the effect values (all unbounded) for acute aquatic toxicity. The trophic level most sensitive cannot be identified as only unbounded EC/LC50 values are available for short-term effects on fish, crustacea and algae.

Table: Acute toxicity data of carbon black

Species	Effect	Effect concentration	Carbon black form	Reference
Fish	.	.	.	.
Danio rerio	mortality	96-h LC50 > 1000 mg/L (dispersion)	surface-treated nanoform	Hooftman, 1992
Danio rerio	mortality	96-h LC50 > 10000 mg/L (filtered)	surface-treated nanoform	Hooftman, 1992
Danio rerio	mortality	96-h LC50 > 1000 mg/L (dispersion)	untreated nanoform	Borgers & Gols, 1991
Leuciscus idus	mortality	96-h LC50 > 1000 mg/L (dispersion)	untreated nanoform	Dittrich, 1979
Invertebrates	.	.	.	.
Daphnia magna	mobility	24-h EC50 > 5600 mg/L (filtered)	surface-treated nanoform	Hooftman, 1992
Algae	.	.	.	.
Scenedesmus subspicatus	growth rate	72-h EC50 > 10,000 mg/L (dispersion)	untreated nanoform	Lebertz & Siegmund, 1999

 

In sum, LC/EC50 values for three trophic levels are unbounded and well above the classification cut-off value for acute (short-term) aquatic hazard Category 1 of 1 mg/L according to Regulation (EC) No 1272/2008, Table 4.1.0 (a). Thus, carbon black nanoforms do not meet classification criteria for acute (short-term) aquatic hazard.

Long-term toxicity

Chronic toxicity data are only available for algae (see Table below).

Table: Chronic toxicity data of carbon black

Species	Effect	Effect concentration	Carbon black form	Reference
Algae	.	.	.	.
Scenedesmus subspicatus	growth rate	72-h EC10 > 10,000 mg/L	untreated nanoform	Lebertz & Siegmund, 1999

 

In accordance with Figure 4.1.1 Categories for substances long-term (chronic) hazardous to the aquatic environment of Regulation (EC) No 1272/2008, if adequate chronic toxicity data are available for one or two trophic levels, both should be assessed:

• (a) chronic toxicity data according to criteria in Table 4.1.0 (b)
• (b) acute toxicity data for the other trophic level(s) according to criteria in Table 4.1.0 (b)(iii),

and the substance should be classified according to the most stringent outcome and the substance should be classified according to the most stringent outcome.

The EC10 value for chronic toxicity of one trophic level (algae) is unbounded and well above the classification cut-off value for long-term aquatic hazard of 1 mg/L according to Table 4.1.0 (b).

Respective LC/EC50 values for acute toxicity of three trophic levels are unbounded and well above the classification cut-off value for long-term aquatic hazard of 100 mg/L according to Table 4.1.0 (b) (iii).

According to 4.1.2.4 of Regulation (EC) No 1272/200, “ The system also introduces a "safety net" classification (referred to as Chronic 4) for use when the data available do not allow classification under the formal criteria for Acute 1 or Chronic 1 to 3 but there are nevertheless some grounds for concern.” However, other scientific evidence exists showing classification to be unnecessary. Since the chronic toxicity NOEC > water solubility and > 1 mg/L, the criteria for Category Chronic 4 are also not met.

Thus, nanoforms and by read-across non-nanoforms of carbon black do not meet classification criteria for long-term aquatic hazard. In sum, nanoforms of carbon black and by read-across non-nano forms of carbon black are not acutely and chronically toxic to aquatic organisms and do not meet classification criteria for acute and long-term aquatic hazard according to Regulation (EC) No 1272/2008.