Strontium bis(2-ethylhexanoate)

Endpoint summary

Description of key information

In assessing the aquatic toxicity of strontium 2-ethylhexanoate, read-across to the assessment entities soluble strontium substances and 2-ethylhexanoic acid is applied since the ions of strontium 2-ethylhexanoate determine its aquatic toxicity.

Strontium

Reliable aquatic toxicity data of strontium ions and strontium substances are available from GLP-conform guideline studies covering three trophic levels (algae, daphnia, fish) and microorganisms.

Acute aquatic toxicity:

- An unbounded 72-h ErC50 value of > 47.1 mg Sr/L was identified for the growth rate of algae (Pseudokirchneriella subcapitata)

- An unbounded value of > 56.3 mg Sr/L and a bounded acute value of 125 mg Sr/L were identified for the freshwater invertebrate species Daphnia magna with the latter being well above the OECD test limit.

- An unbounded value of > 56.34 mg Sr/L was identified for the freshwater fish species Danio rerio

- An unbounded value of > 92.8 mg Sr/L (96h-LC50) was identified for the saltwater fish species Morone saxatilis

- An unbounded value of > 163.8 mg Sr/L (3 -h EC10) was derived for microorganisms (activated sludge)

Chronic aquatic toxicity is available for two trophic levels: algae and invertebrates.

- An ErC10 value of 24.3 mg Sr/L was identified for the growth rate of algae (Pseudokirchneriella subcapitata)

- A chronic value of 21 mg Sr/L is available for the invertebrate Daphnia magna.

2-ethylhexanoic acid

For the risk assessment the effect data for the neutralized test medium was used since the quantities of the substance that would be found in natural waters are not likely to affect the pH to a relevant extent.

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

- a 72-h ErC50 of 500 mg/L was identified for the algae Pseudokirchneriella subcapitata

- a 48-h EC50 of 913 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 130 mg/L was identified for the green algae Pseudokierchneriella subcapitata

- 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.