Disodium 2,2'-(9,10-dioxoanthracene-1,4-diyldiimino)bis(5-methylsulphonate)

Endpoint summary

Description of key information

Short-term toxicity to aquatic invertebrates: EC₅₀ > 67 mg/l.

Toxicity to aquatic plants other than algae: E_rC₅₀ = 615 mg/l based on frond number.

Additional information

Short-term toxicity to aquatic invertebrates:

No studies on the "short term toxicity to aquatic invertebrates" are available for the substance in itself.

Nevertheless a study has been conducted an a similar substance. Further information are reported in the Read Across justification attached to section 13.

The short term toxicity to aquatic invertebrates was determined using the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test).

Although the test substance is soluble in pure (deionised) water (about 80 g/l), most of the test substance in the stock solution settled down and build a sediment at the bottom of the flask. This effect was possibly caused by a reaction of the test substance with the water hardness compounds in the test water. For the preparation of the test concentrations only the supernatant of the stock solution was taken (limit of the solubility). The reported results are related to the actual mean values of the analysed conentrations of the test article measured at the beginning and at the end of the test. No immobilization and abnormal behaviour of the Daphnia was observed in the controls. The NOEC value after 48 hours was determined to be 34 mg/l, the EC50 and the EC 100 value could not be calculated, but are clearly higher than 67 mg/l.

 

Toxicity to aquatic plants other than algae:

No studies are available for the substance in itself to fulfill this endpoint.

Nevertheless a study has been conducted on a similar substance. Further information are reported in the Read Across justification attached to section 13.

The inhibitory effects of the test substance the duckweed Lemna minor were investigated over a period of 7 days, based on the frond number and biomass (dry weight), following the guideline OECD 221.

The test solutions were prepared by respective dilutions of a stock solution in Swedish standard-Medium (SIS Medium).

The test was performed at 611, 193, 61.1, 19.3 and 6.11 mg/l nominal concentration of the test item, corresponding to 500, 158.1, 50.0, 15.8 and 5.00 mg/l of the active ingredient.

Three parallel test vessels were used for each test concentration of the test item and six vessels for the blank controls.

The test concentrations during the 7-day test period were determined by photometry at the beginning of the test, as well as after 3, 5 and 7 days of exposure. These analyses confirmed the right dosage of the test item, and showed that the concentrations of the loadings decreased over the whole 7-day test period after 7 days and did not remain within 80-120% range of the initial value (67, 69, 103, 90 and 86%, respectively, of the initial value). Therefore, the effective concentrations (E_rC₅₀ and E_yC₅₀) were assessed based on the geometric mean (GM) of the measured concentrations of the active ingredient.

The two endpoints frond number and biomass (dry weight) were investigated at days 3, 5 and 7, and each of them were assessed as growth rate and yield. The EC50 values obtained were:

E_rC₅₀ = 615 mg/l based on frond number

E_yC₅₀ = 197 mg/l based on frond number

E_rC₅₀ = 889 mg/l based on dry weight

E_yC₅₀ = 178 mg/l based on dry weight

 

Justification for classification or non-classification:

According to the CLP Regulation (EC n. 1272/2008), Part 4: Environmental Hazards, the substances can be classified for hazardous to the aquatic environment (fish toxicity) when the following criteria are met:

A) Acute (short-term) aquatic hazard:

Category Acute 1:

96 hr LC₅₀ (for fish) ≤ 1 mg/l and/or

48 hr EC₅₀ (for crustacea) ≤ 1 mg/l and/or

72 or 96 hr E_rC₅₀ (for algae or other aquatic plants) ≤ 1 mg/l

B) Long-term aquatic hazard

(iii) Substances for which adequate chronic toxicity data are not available

Category Chronic 1:

96 hr LC₅₀ (for fish) ≤ 1 mg/l and/or

48 hr EC₅₀ (for crustacea) ≤ 1 mg/l and/or

72 or 96 hr E_rC₅₀ (for algae or other aquatic plants) ≤ 1 mg/l

and the substance is not rapidly degradable and/or the experimentally determined BCF ≥ 500 (or, if absent, the logK_ow ≥ 4).

Category Chronic 2:

96 hr LC₅₀ (for fish) > 1 to ≤ 10 mg/l and/or

48 hr EC₅₀ (for crustacea) > 1 to ≤ 10 mg/l and/or

72 or 96 hr E_rC₅₀ (for algae or other aquatic plants) > 1 to ≤ 10 mg/l (Note 2)

and the substance is not rapidly degradable and/or the experimentally determined BCF ≥ 500 (or, if absent, the logK_ow ≥ 4).

Category Chronic 3:

96 hr LC₅₀ (for fish) > 10 to ≤ 100 mg/l and/or

48 hr EC₅₀ (for crustacea) > 10 to ≤ 100 mg/l and/or

72 or 96 hr E_rC₅₀ (for algae or other aquatic plants) > 10 to ≤ 100 mg/l

and the substance is not rapidly degradable and/or the experimentally determined BCF ≥ 500 (or, if absent, the logK_ow ≥ 4).

Category Chronic 4:

Cases when data do not allow classification under the above criteria but there are nevertheless some grounds for concern. This includes, for example, poorly soluble substances for which no acute toxicity is recorded at levels up to the water solubility (note 4), and which are not rapidly degradable in accordance with section 4.1.2.9.5 and have an experimentally determined BCF ≥ 500 (or, if absent, a logK_ow ≥ 4), indicating a potential to bioaccumulate, which will be classified in this category unless other scientific evidence exists showing classification to be unnecessary. Such evidence includes chronic toxicity NOECs > water solubility or > 1 mg/l, or other evidence of rapid degradation in the environment than the ones provided by any of the methods listed in section 4.1.2.9.5.

The LC₅₀ value calculated for the test substance on the "short-term toxicity to fish" was established to be 35 mg/l, therefore the substance, for this test, is classified as Category Chronic 3 (96 hr LC₅₀ (for fish) > 10 to ≤ 100 mg/l).

The LC₅₀ value calculated for the test substance on the "long-term toxicity to aquatic invertebrates" was established to be > 15 mg/l, with a LOEC value of 5 mg/l.

 

Based on the above results, the Daphnia study provides the lowest toxicity endpoint. This result is determined by the low limit of solubility of the tested substance (Similar Substance 02) in the test medium. There is a high probability that the toxicity level of the test substance is greater than 100 mg/l, which is the upper limit of classification.

However, using a conservative approach, the test substance has been classified as Category Chronic 4.