1,2-dihydroxyanthraquinone

Ecotoxicological Summary

Conclusion on classification

In order to determine the classification for hazardous properties related to the aquatic environment, the criteria of the Regulation (EC) No 1272/2008 (CLP) version 2016 in Annex I were accurately followed.

Short-term (acute) aquatic hazard:

For classification, acute toxicity data are available for aquatic invertebrates (Daphnia) and algae:

Daphnia: EC50 (48h) = 1.58 mg/L

Lemna: EC50 (7 days, frond number) = 5.5 mg/L

The criteria in Table 4.1.0 (a) of Annex I of the CLP Regulation were applied.

The lowest EC50 value was observed for Daphnia, which is hence the most sensitive species. According to Table 4.1.0 (a) the substance should not be classified for acute aquatic hazard, as the lowest EC50 value is 1.58 mg/L, which is above the cut-off for classification of 1 mg/L.

Note that the EC50 as determined in PAR light was used as key value for assessment. The aquatic toxicity of the test material increases after photomodification. The EC50 (Lemna) after photomodification is 1.5 mg/L, which is still above the cut-off for classification. Hence, the derived classification is not changed when using this conservative approach.

Long-term (chronic) aquatic hazard:

For chronic classification, there are only chronic data available for one trophic level, aquatic plants (Lemna). As described in Figure 4.1.1 in the CLP regulation (EC No 1272/2008, version 2016), the most stringent outcome of classification according to Table 4.1.0 (b) (i) or (ii) and (iii) should be used.

Table 4.1.0 (b) (i):

The substance is not readily biodegradable, hence Table 4.1.0 (b) (i) applies.

The LOEC (7 days, frond number) was 0.05 mg/L, which is in the range of cut-off values for classification as chronic category 1: ≤ 0.1 mg/L. Therefore, according to this table, the substance should be classified for chronic aquatic toxicity, category 1.

Similarly, the key value used for classification and labelling is the LOEC determined in PAR light. Using the LOEC as determined after full photomodification, i.e. 0.01 mg/L would not change the classification.

The available Lemna study only reports LOEC and EC50 values. Although, NOEC or EC10 values are preferred for deriving the classification, the LOEC was used nevertheless for deriving the classification. Since the classification derived was chronic aquatic toxicity, this approach does not impact the conclusion.

Table 4.1.0 (b) (iii):

Classification based on available acute data available for the other trophic levels and environmental fate data:

Daphnia: EC50 (48h) = 1.58 mg/L

Lemna: EC50 (7 days, frond number) = 5.5 mg/L

Log Kow = 2.91

The substance is not readily biodegradable.

Based on the criteria Table 4.1.0 (b) (iii), the substance should be classified as chronic aquatic toxic, category 2 since the lowest EC50 value for daphnia is > 1 and ≤ 10 mg/L and the substance is not readily biodegradable.

Again, using the EC50 value after full photomodification does not influence the classification.

Most stringent chronic classification:

The conclusion of both assessment is that the substance should be classified for chronic aquatic hazard, category 1.

Based on the chronic LOEC value of 0.05 mg/L an M-factor for chronic toxicity of 1 applies.