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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

ErC50 (72 h) = 91 mg/L and NOErC (72 h) = 20 mg/L for Pseudokirchneriella subcapitata (OECD 201), read across

Key value for chemical safety assessment

EC50 for freshwater algae:
91 mg/L
EC10 or NOEC for freshwater algae:
20 mg/L

Additional information

No studies investigating the toxicity of sodium methylparaben (CAS No. 5026-62-0) to algae are available. Therefore, toxicity data of the corresponding acid methylparaben (CAS No. 99-76-3) are used as read across.

This read across approach is in accordance with Regulation (EC) No 1907/2006, Annex XI, 1.5. Grouping of substance and read across approach as is explained within the analogue justification in section 13. Except for different cations (hydrogen vs. sodium) the anions of both the source and target substance have identical chemical structures. Since dissociation of the sodium salt under environmental conditions (pH 4 - 9) yields the same ionic species as the acidic form of the substance, this read across can be considered as justified.

For the toxicity of the analogue read across substance methylparaben to algae two studies are available. The key study was carried out according to ISO 8692 and is published in a peer reviewed publication by the Danish Environmental Protection Agency (Madsen et al., 2001). Pseudokirchneriella subcapitata was used as test organism. No details on the analytics of the test substance in the test medium are included in the report. Based on nominal concentrations and growth rate, an ErC50 (72 h) of 91 mg/L and a NOErC (72 h) of 20 mg/L are reported. These values are used for assessment.

Additional data are included from a supporting study by the Ministry of the Environment of Japan (Anon., 1999). Testing with algae was carried out according to OECD guideline 201, no further details are available. An ErC 50 (72 h) of 56 mg/L and a NOErC (72 h) of 17 mg/L are reported.