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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Key value for chemical safety assessment

EC50 for freshwater algae:
27 mg/L
EC10 or NOEC for freshwater algae:
15.2 mg/L

Additional information

Thioglycolic acid toxicity to algae has been investigated for Pseudokirchneriella subcapitata in a static test according to OECD guideline # 201. The EC50 -growth rate determined was 27 mg/L based on measured concentration in the test medium, as concentrations were not maintained throughout the test.

Thioglycolic acid can be therefore considered as harmful to algae (Thiébaud, 2001).

On the other hand, in 2005, the acute toxicity of Diammonium dithioglycolate to Scenedesmus subspicatus has been investigated by Mead and McKenzie through a test in accordance with OECD Guideline 201 and GLP requirements. Based on the results of this study, EC50 -growth rate determined was higher than 100 mg/L and NOEC was of 100 mg/L.

Dithiodiglycolic acid (respective the anion) is the main degradation product of thioglycolic acid when released in the environment occuring few hours after the release (Devaux, 2003 - Smolin and Fölsing, 2009).

On this basis one can confirm that thioglycolic acid toxicity to algae is moderate due to its relative short half-life in the environment. Moreover the degradation product obtained is not considered as harmful to algae.