2-ethylhexanoic acid, monoester with propane-1,2-diol

Endpoint summary

Description of key information

The most sensitive organisms from the reliable short-term toxicity studies were invertebrates with a 48 -hr EC50 of 11.77 mg/l (Muckle, 2020). The long-term toxicity studies indicated similar toxicity between all three trophic levels including a NOEC from the fish study of >1.33 mg/l, an EC10 from the invertebrate study of 4.11 mg/l and an EC10 for algal growth inhibition of 7.44 mg/l.

Additional information

Several reliable (Klimisch 1 or 2) short-term and long-term toxicity studies in fish, invertebrates, algae, and microorganisms have been conducted for the test substance (FX511) and are included in this dossier.  The term key studies are summarised below.  

 

Acute toxicity studies

The key study (GLP; Klimisch 1) for fish acute toxicity is by Muckle (2020) for Danio rerio resulting in a LC50 of 46.66 mg/l (measured TWA). This value is taken as the short-term toxicity in fish endpoint for FX511. A supporting study by Fougler et. al, (1995) conducted a reliable (Klimisch 2) study according to OECD 203 methods. Rainbow trout,Oncorhynchus mykiss were exposed to nominal concentration of 10 mg/L FX511 for 96 hrs under semi-static conditions.The 96-h LC50 was >10 mg/L, based on mortality.

The key study (GLP; Klimisch 1) for invertebrate acute toxicity is by Muckle (2020) for Daphnia magna resulting in a LC50 of 11.77 mg/l (mobility; measured geometric mean). This value is taken as the short-term toxicity in invertebrates endpoint for FX511.

The key study (GLP; Klimisch 1) for algal toxicity is by Muckle (2020) for Desmodesmus subspicatus resulting in a EC50 of 62.87 mg/L (growth rate; measured geometric mean). This value is taken as the algal toxicity endpoint for FX511.

Chronic toxicity studies

The key study (GLP; Klimisch 1) for fish early life stage toxicity is by Muckle (2020) for Danio rerio resulting in a NOEC of >1.33 mg/l (hatchability; measured TWA). This value is taken as the long-term toxicity in fish endpoint for FX511.

The key study (GLP; Klimisch 1) for invertebrate chronic toxicity is by Muckle (2020) for Daphnia magna resulting in a EC10 of 4.11 mg/l (offspring mortality; measured TWA). This value is taken as the long-term toxicity in invertebrates endpoint for FX511.

The key study (GLP; Klimisch 1) for algal toxicity is by Muckle (2020) for Desmodesmus subspicatus resulting in a EC10 of 7.44 mg/L (growth rate; measured geometric mean). This value is taken as the algal toxicity endpoint for FX511.

 

A reliable toxicity study with microorganisms is available for FX511 and is included in this dossier. Clark (2012) conducted a reliable (Klimisch 1) GLP compliant study according to OECD 209 methods. Activated sludge was exposed to FX511 at nominal concentrations of 100, 180, 320, 560 and 1000 mg/L for 3 hours. The effect of the test item on the respiration of activated sewage sludge resulted in a 3-hour EC50 value of 590 mg/L. The NOEC after 3 hours exposure was 180 mg/L. Consequently, this value will be taken for the toxicity of FX511 to microorganisms endpoint.