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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The read-across substances were not toxic to algae when tested according to OECD guideline 201 (Alga, Growth Inhibition Test). Sorbitol was determined to possess a 72-hour growth rate EC50 and NOEC of >994 mg/L (active ingredient), and Maltitol was determined to possess a 72-hour growth rate EC50 and NOEC of >1040 mg/L (active ingredient). 

Key value for chemical safety assessment

Additional information

Metabolic data demonstrate that the notifiable substance, as well as the read-across substances [maltose, maltitol, sorbitol, wheat glucose syrup (WGS), and dextrin] share a common metabolic pathway as they are converted to D-glucose and/or sorbitol via hydrolysis of their glycosidic linkages by the intestinal brush border carbohydrases. On the basis of their common mono- and disaccharide metabolites, the properties of the notifiable substance, is expected to be similar to the read-across substances maltose, sorbitol, maltitol, WGS, and dextrin. Considering this, it is anticipated that exposure to any of the aforementioned saccharides would ultimately result in the formation of D-glucose and/or sorbitol. As such, maltose, sorbitol, maltitol, WGS, and dextrin may be used as appropriate surrogates for the notifiable substance, considering their common metabolic products.

Two studies addressing toxicity to aquatic algae and cyanobacteria are presented in the dossier. 

RA Sorbitol - Toxicity to aquatic algae and cyanobacteria - algae – 2005: Acute toxicity to Pseudokirchneriella subcapitata was assessed according to OECD guideline 201 (Alga, Growth Inhibition Test) and in accordance with GLP. Algae were exposed to the substance at a measured concentration of 1420 mg/L at 0 hours and 1400 mg/L at 72 hours. The study was performed under static conditions using 300 mL Erlenmeyer flasks (open) with an initial cell density of 10000 cells/mL. General observations were made at 0, 24, and 72 hours and microscopic examinations were made at 72 hours. The 72-hour biomass and growth rate EC50s and NOECs were determined to be >1420 mg/L (test material) or >994 mg/L (active ingredient).

 

RA Maltitol - Toxicity to aquatic algae and cyanobacteria - algae – 2005: Acute toxicity to Pseudokirchneriella subcapitata was assessed according to OECD guideline 201 (Alga, Growth Inhibition Test) and in accordance with GLP. Algae were exposed to the substance at a measured concentration of 1490 mg/L at 0 hours and 1420 mg/L at 72 hours. The study was performed under static conditions using 300 mL Erlenmeyer flasks (open) with an initial cell density of 10000 cells/mL. General observations were made at 0, 24, and 72 hours and microscopic examinations were made at 72 hours. The 72 hour biomass and growth rate EC50s and NOECs were determined to be >1490 mg/L (test material) or >1040 mg/L (active ingredient).