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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

EC10 = 122 mg/L

Key value for chemical safety assessment

EC50 for microorganisms:
164 mg/L
EC10 or NOEC for microorganisms:
122 mg/L

Additional information

For the data endpoint “Toxicity to microorganisms” one read across study is available.

Read across from Docusate Sodium which contains 8 C-atoms in a C6 -chain in both of its alkyl rests to CAS 2373 -38 -8 (which contains 6 C-atoms in a C4 -chain) is considered appropriate based on the similarity of the molecules and since none of the OECD 209 tests for the OECD 209 indicated toxicity to microorganisms in teh di-ester group. From tests with daphnids and fish it is known that longer C-chains result in higher toxicity. Therefore read across to Docusate Sodium is considered to be conservative. A further risk factor does not need to be taken into account.

The study from Elementis (Schöberl 1993) was classified as Klimisch 1 key study. In this study the growth inhibition of formulated product (which contains 64.2% Docusate Sodium) to Pseudomonas putida MIGULA was determined in a 16 h static GLP Pseudomonas growth inhibition test. The test design was based on the DIN 38412.The nominal test concentrations were 0 (control), 40, 80, 160, 240, 320 and 400 mg formulated product/L, corresponding to 0 (control), 25.7, 51.4, 102.7, 154.1, 205.4 and 256.8 mg Docusate Sodium/L. Five control replicates and 3 replicates from each test solution were set up. Dose verification analysis was not performed. In order to determine the growth of the cultures, the optical density was measured by photometry at 436 nm. The optical density was determined at 0 hours in the control and about 16 hours after start of the exposure in the control and all test solutions. The EC10 and EC 50 values were calculated by regression of the log transformed concentration vs. probit transformed percent inhibition relative to the average control density. Two experiments were preformed. In the first experiment, the EC10 and EC50 were 121 and 164 mg Docusate Sodium/L, respectively. In the second experiment, the EC10 and EC50 were 123 and 164 mg Docusate Sodium/L, respectively. The mean values for the of the calculated EC10 and EC50 values of both experiments deviated at the maximum of less than 1 % from their mean values and hence, both experiments can be considered to be reliable. The 16 -hour EC10 is 122 mg Docusate Sodium/L and the EC50 is 164 mg Docusate Sodium/L. This study is considered to be acceptable for the risk assessment.

Therefore, the EC10 (122 mg Docusate Sodium/L) and EC50 (164 mg Docusate Sodium/L) reported by Elementis (Schöberl 1993) (Klimisch 1 key study) will be used for the risk assessment.