Yellow PE 3260

Toxicity to aquatic algae and cyanobacteria

Description of key information

In conclusion, a modified algal test has clearly demonstrated that the observed growth inhibition effect of the test item on Pseudokirchneriella subcapitata was caused only by an indirect effect, the light filter effect in the colored test solutions. Thus, a toxic effect of the test item on the algal cells can be excluded up to the highest test concentration of 100 mg/l. For this substance, the following values considering the growth rate were determined: EC50 (72 h) > 100 mg/L and NOEC (72 h) = 3.2 mg/L. A previous test with Scenedesmus subspicatus gave a result of EC50 (72 h) is 12.5 mg/L based on biomass and 66.5 mg/L based on growth rate. For conservative reasons (worst-case) the value used for CSA is ECr50(72h)=66.5 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

66.5 mg/L

EC10 or NOEC for freshwater algae:

3.2 mg/L

Additional information

The influence of the substance on the growth of the green alga Scenedesmus subspicatus was investigated in a study based on the OECD Guideline No. 201 and the EEC Directive 92/69 Part C.3 (Gruetzner, 1996), that was modified to differentiate between a reduced growth of algae due to direct inhibitory effects of the test article on the algal cells and a reduced growth of algae due to an indirect effect caused by the light absorption of the colored test solutions.

The growth inhibition effect of the substance on Scenedesmus subspicatus was to a great extent caused by the indirect effect, i.e. the light absorption of the colored test solutions. Nevertheless, at the two highest test concentrations of 32 and 100 mg/|, a direct inhibitory effect of the substance on the algae growth cannot be excluded.

In the test with Scenedesmus subspicatus an 72h EC50 of 12.5 mg/L based on biomass and 66.5 mg/L based on growth rate was reported. The NOEC for both endpoints is 3.2 mg/L and the LOEC is 10 mg/L.

 

The results of this test contributed to the classification of the notified substance which is classified as Aquatic Chronic 3 (H412). The substance is included in the Annex VI of CLP Regulation with a Harmonized Classification Aquatic Chronic 3.

 

In a second test (Peither, 2004) the influence of the substance on the growth of the green alga Pseudokirchneriella subcapitata  was investigated. The test method was also based on the OECD Guideline No. 201 with same modifications as in the study of Gruetzner, 1996. In the study of Peither, 2004 the same growth inhibition of the substance was observed when the algae grew in test water without test item, but under reduced light intensities by the filter effect of the colored test media as in the second parallel experimental part, where the algae grew in the test media with dissolved test item. Thus, in conclusion, this modified algal test has clearly demonstrated that the observed growth inhibition effect of the test item on Pseudokirchneriella subcapitata was caused only by an indirect effect, the light filter effect in the colored test solutions. Thus, a toxic effect of the test item on the algal cells can be excluded up to the highest test concentration of 100 mg/L, and for this substance, the following values considering the growth rate were determined: ECr50 (72 h) > 100 mg/L and NOEC (72 h) = 3.2 mg/L.

 

According to the results of the study of Peither, 2004 the substance is not classified as Aquatic Chronic 3. However, due to the substance has a Harmonized Classification as Aquatic Chronic 3 and for conservative reasons (worst-case), the value used for the chemical safety assessment is ECr50(72h)=66.5 mg/L.