Lithium neodecanoate

Endpoint summary

Description of key information

In the assessment of lithium neodecanoate, read-across to the assessment entities lithium cations and neodecanoate anions is applied since the ions of lithium neodecanoate determine its fate and toxicity in the environment.

 

Lithium:

Reliable acute data are available for three trophic levels: algae, invertebrates and fish

- a 96 -h LC50 of 5.70 mg lithium/L was determined in a GLP-conform OECD 203 test of lithium carbonate and O. mykiss

- a 48-h EC50 (mobility) of 6.24 mg lithium/L was derived in a GLP-conform OECD 202 test with lithium carbonate and Daphnia magna

- a 72-h EC50 (growth rate) of >75.19 mg Li/L was determined in a GLP-conform OECD 201 test with lithium carbonate and the green algae P. subcapitata

- 3-h EC10 and EC50 values for respiration inhibition of activated sewage sludge of 22.95 mg Li/L and 52.4 mg Li/L, respectively, were determined in a GLP-conform OECD 209 test with lithium hydroxide

 

Reliable chronic data are available from GLP-conform guideline studies for three trophic levels: algae, invertebrates and fish

- a 34-d NOEC (mortality) of 2.87 mg Li/L was determined for Danio rerio in a GLP-conform OECD 210 test with lithium hydroxide monohydrate

- a 21-d NOEC of 4.78 mg Li/L was determined in a study with lithium metal for the reproduction of Daphnia magna

- a 72-h EC10 (growth rate) of 16.92 mg Li/L was determined for the green algae P. subcapitata in a GLP-conform OECD 201 test with dilithium carbonate

 

Neodecanoate:

Reliable acute data are available from GLP-conform guideline studies for three trophic levels: algae, invertebrates and fish

- an unbounded value of > 100 mg/L (96h-LL50) was identified for rainbow trout

- an unbounded value of > 457 mg/L (48h-EL50) was identified for the invertebrate species Daphnia magna

- an unbounded value of > 100 mg/L (72h-LL50) was identified for the algae Pseudokirchneriella subcapitata  

 

Reliable chronic data are available from GLP-conform guideline studies for two trophic levels: invertebrates and fish

- 21-d NOEC of 4.78 mg/L neoheptanoic acid (structural analogue) for reproduction of D. magna; Chronic Value (ChV) of 1.7 mg/L (QSAR-based estimate) for daphnids

- 14-d NOEC of 2.22 mg/L neodecanoic acid for growth of Oncorrhynchus mykiss; Chronic Value (ChV) of 1.6 mg/L (QSAR-based estimate) for fish

- Regarding algae, an EC10 or NOEC is not available for neodecanoate. However, based on the fact that the EC50 for growth rate of algae is > 100 mg/L, we may assume that it is unlikely that the EC10/NOEC < 1 mg/L. According to the QSAR-based outcome of the model ECOSAR v.2.0, neodecanoic acid has a very low potential for chronic toxicity to green algae since the chronic value (ChV = 10^([log (LOEC x NOEC)]/2)) of 12.3 mg/L is >> 1 mg/L.

 

Regarding the toxicity to aquatic microorganisms, a 4-h NOEC of ≥ 200 mg/L for the inhibition of nitrification by microorganisms (Nitrosomonas sp.) is available.

 

In sum, neodecanoic acid has very low potential for acute aquatic toxicity and a low potential for chronic toxicity.

Lithium neodecanoate

According to aquatic toxicity data of the dissociation products of lithium neodecanoate, the aquatic hazard assessment is based on the most toxic moiety. Existing aquatic toxicity data of neodecanoic acid and lithium cations are recalculated for lithium neodecanoate based on the respective maximum content of 96.6 % (w/w) neodecanoate and 6.4 % (w/w) lithium of lithium neodecanoate.

Reliable data available for soluble lithium substances and neodecanoate indicate that the moiety of concern for short-term aquatic toxicity are lithium cations. Thus, acute effect concentrations of lithium are conservatively recalculated for lithium neodecanoate based on a maximum lithium content of 6.4% as follows for algae, invertebrates and fish:

- 96 -h LC50 of 89.06 mg/L lithium neodecanoate was calculated based on a GLP-conform OECD 203 test of lithium carbonate for O. mykiss.

- 48-h EC50 (mobility) of 97.5 mg/L lithium neodecanoate was calculated based on a GLP-conform OECD 202 test with lithium carbonate for Daphnia magna

- 72-h EC50 (growth rate) of >1174 mg/L lithium neodecanoate was calculated based on a GLP-conform OECD 201 test using dilithium carbonate and the green algae P. subcapitata

- 3-h EC10 and 3-h EC50 values for the respiration inhibition of activated sewage sludge of 358.6 mg/L and 818.8 mg/L lithium neodecanoate, respectively, were calculated based on a GLP-conform OECD 209 test with lithium hydroxide.  

Reliable data available for soluble lithium substances and neodecanoate indicate that the moiety of concern for long-term aquatic toxicity are neodecanoate anions. Thus, long-term effect concentrations of neodecanoate are conservatively recalculated for lithium neodecanoate based on a maximum neodecanoate content of 96.6 % as follows for invertebrates and fish:

- 14-d NOEC of 2.30 mg/L for growth of Oncorrhynchus mykiss; Chronic Value (ChV) of 1.66 mg/L (QSAR-based estimate) for fish

- 21-d NOEC of 4.95 mg/L for reproduction of D. magna; Chronic Value (ChV) of 1.76 mg/L (QSAR-based estimate) for daphnids

- Regarding algae, lithium neodecanoate has a low potential for toxicity (as described for the assessment entities above).