Choline hydroxide

Endpoint summary

Additional information

General consideration

The ecotoxicological potential of Choline hydroxide was not investigated experimentally. In order to fulfil all relevant endpoints, read-across is intended to Choline chloride (CAS 67-48-1). The substances possess a great structural similarity and therefore it is obvious that the physico-chemical, toxicological and ecotoxicological properties are likely to be similar. For a detailed justification and further information about this procedure, please refer to the separate read-across statement (Chemservice S.A., 2013).

The aquatic toxicity of the read-across substance Choline chloride was investigated experimentally towards all required trophic levels (fish, invertebrate and algae) and microorganisms. Based on the good water solubility of the test substance, no solvents, pretreatments and/or other adaptions had to be taken into account.

Information concerning toxicity towards any other aquatic organisms is not available. However, these are no mandatory requirements in accordance to REACH Regulation (EC) 1907/2006.

 

Toxicity to fish

The freshwater fish Leuciscus idus was exposed to Choline chloride for 96 hours (BASF AG, 1988). The experiment was conducted equivalent to the German Guideline DIN 38412 (1982). After a range-finding study (LC50(96h) > 10000 mg/L), two concentration were fixed as followed: 5000 mg/L and 10000 mg/L. The concentrations exceeded the normal upper limit for acute studies because it was the aim to test higher concentrations for classification of hazards to water. The LC50(96h) was determined to be > 10000 mg/L and the NOEC(96h): 10000 mg/L. Based on the chemical safety assessment (CSA), long-term testing for fish is not triggered since the obtained results indicate that Choline chloride is not toxic even at the highest concentration tested. This endpoint is waived in accordance to REACH, Annex IX, Section 9.1.6, column 2.

 

Toxicity to invertebrates

Daphnia magna was used as test organism in two different experiments in order to investigate the short- as well as the long-term toxicity of the read-across substance Choline chloride. The short-term experiment was conducted according to EU Method C.2. (1984; BASF AG, 1988). Test concentrations were chosen as followed: 0 (control), 31.25, 62.50, 125, 250 and 500 mg/L. Four replicates of each concentration were included. No toxicity was observed even at the highest concentration tested. Therefore, the final results were reported as: EC0(48h): 125 mg/L, EC50(48h) ≥ 500 mg/L and EC100(48h) ≥ 500 mg/L.

Long-term results are reported for Choline chloride from the Ministry of Environment (MOE) Japan (1999) as followed: LC50(21d) > 95.50 mg/L (parental mortality), EC50(21d): 58.9 mg/L (95 % CL: 37.7 - 83.7 mg/L), NOEC(21d): 30.2 mg/L and LOEC(21d): 95.5 mg/L. This experiment was conducted according to OECD Guideline 211 and the test concentrations were chosen as 0, 3.2, 10, 32 and 100 mg/L.

 

Toxicity to algae

BASF AG (1989) investigated the toxicity towards algae of Choline chloride according to the German guideline DIN 38412 L9. Scenedesmus subspicatus was used as test organism. Test concentrations were chosen as followed: 0 (control), 10, 25, 50, 100, 250 and 500 mg/L.

All EC50 values based on growth rate as well as on biomass, are > 500 mg/L. This applies for exposure durations of 72 h as well as of 96 h.

 

Toxicity to microorganisms

The toxicity of Choline chloride towards Pseudomonas putida was investigated according to German standard DIN 38412 Part 8 (BASF AG, 2003). The test concentrations were 0 (control), 50, 100, 150, 200, 250 and 300 mg/L and the following results were obtained: EC10(17h): 112.90 mg/L, EC50(17h): 132.80 mg/L and EC90(17h): 278.20 mg/L, respectively.