2-ethylhexanoic acid, iron salt

Endpoint summary

Description of key information

Aquatic toxicity studies of 2-ethylhexanoic acid, iron salt are not available. Thus, read-across to the assessment entities soluble iron substances and 2-ethylhexanoic acidis applied since the ions of 2-ethylhexanoic acid, iron salt determine its fate and toxicity in the environment. Whereas iron species are rapidly removed from environmental solutions as insoluble precipitate at oxic conditions and moderate pH, 2-ethylhexanoic acid is rather soluble.

 

Iron

Iron is relatively immobile under most environmental conditions mainly due to the very low solubility of iron (III) hydroxides. Regarding iron toxicity in aquatic environments, relevant effects of soluble iron salts towards algae, invertebrates and fish were not identified. Instead, bioavailability of the essential element iron is often considered to be a limiting factor for optimal growth and development of aquatic organisms. Thus, iron as essential element for living organisms has a very low potential for toxicity to freshwater and saltwater organisms.

 

2-ethylhexanoic acid

Acute data are available from studies for three trophic levels: algae, invertebrates and fish

- a 72-h ErC50 of 49.3 mg/L was identified for the algae Desmodesmus subspicatus (acc. To DIN 38412 part 9)

- a 48-h EC50 of 85.4 mg/L represents the lowest value identified for the invertebrate species Daphnia magna

- an unbounded value of > 100 mg/L (96-h LC50) was identified for the freshwater fish species Oryzias latipes based on data of an analogous substance (sodium 2-ethylhexanoate). Further studies of 2-ethylhexanoate with the freshwater fish species Oncorhynchus mykiss, Lepomis gibbosus and Leuciscus idus resulted in 96-h LC50 values > 100 mg/L

 

In sum, 2-ethylhexanoic acid has a low potential for acute aquatic toxicity.

 

Chronic data are available from studies for algae, aquatic invertebrates and microorganisms:

- a 72-h EC10 of 32.0 mg/L was identified for the green algae Desmodesmus subspicatus (acc. To DIN 38412 part 9)

- 21-d NOEC values of 18 mg/L and of 25.0 mg/L were identified for Daphnia magna.

- a 17-h EC10 of 71.7 mg/L was identified for the inhibition of bacterial growth (Pseudomonas putida)

 

In sum, 2-ethylhexanoic acid has a very low potential for chronic aquatic toxicity to algae and invertebrates and appears to be of low toxicity to microorganisms.

  

2-ethylhexanoic acid, iron salt

The aquatic hazard assessment is based on 2-ethylhexanoate as the toxic moiety of 2-ethylhexanoic acid, iron salt. Therefore, existing aquatic toxicity effect concentrations of 2-ethylhexanoic acid are recalculated for 2-ethylhexanoic acid, iron salt based on the maximum 2-ethylhexanoate content of 2-ethylhexanoic acid, iron salt of 92%.

 

Acute data:

- a 72-h ErC50 of 53.6 mg/L for the algae Desmodesmus subspicatus (acc. To DIN 38412 part 9)

- a 48-h EC50 of 92.8 mg/L represents the lowest value for the invertebrate species Daphnia magna

- an unbounded value of > 108.7 mg/L (96-h LC50) for the freshwater fish species Oryzias latipes. Further studies of 2-ethylhexanoate with the freshwater fish species Oncorhynchus mykiss, Lepomis gibbosus and Leuciscus idus resulted in 96 -h LC50 values > 108.7 mg/L.

 

Chronic data:

- a 72-h EC10 of 34.8 mg/L for the green algae Desmodesmus subspicatus (acc. To DIN 38412 part 9)

- 21-d NOEC values of 19.6 mg/L and of 27.2 mg/L for Daphnia magna.

- a 17-h EC10 of 77.9 mg/L for the inhibition of bacterial growth (Pseudomonas putida)