Lithium

Endpoint summary

Additional information

Lithium reacts intensely with water forming lithium hydroxide and highly flammable hydrogen (classified and labelled as water react. 1 (category 1), H260). Results of aquatic toxicity studies with lithium hydroxide which is formed when lithium reacts with water were available. Therefore, results of acute and long-term aquatic toxicity studies with lithium hydroxide were used in a read-across approach when required.

Short-term toxicity to fish

In this 96-h fish acute toxicity test with Zebrafish (Danio rerio) the 96-h LC50 for lithium hydroxide monohydrate based on mortality was determined to be 109 mg/L. Based on a read-across approach, the calculated 96-h LC50 value for lithium metal was 18 mg/L. Thus, this result does not lead to classification and labelling.

Long-term toxicity to fish

The purpose of the performed study was to evaluate the chronic toxicity of the test item lithium hydroxide monohydrate to early life stages (embryo, larvae and juveniles) of fish (Danio rerio) according to the OECD 210 Guideline. Around 40 eggs per treatment / concentration level (2 replicates per treatment) were exposed in a semi static test to aqueous test media containing the test item for 34 days at a range of concentrations (based on a preliminary study) under defined conditions. Results showed that lithium hydroxide monohydrate had significant lethal effect on early life stages of Zebrafish (Danio rerio) at a concentration level of 24.35 mg/L (measured concentration). The observed effect was associated with larval/juvenile stages, but no significant effect was observed during the embryonic stage.

No significant sub lethal effects (hatching of the larvae, body weight, body length, deformities and abnormal behaviour) were observed in any concentration tested.

The following endpoints (34 days LOEC and NOEC) were calculated in the study:

The 34 d LOEC 24.35 mg test item/L

The 34 d NOEC 17.35 mg test item/L

Based on read-across approach, the calculated 34 d LOEC and NOEC values for lithium metal were 4.03 and 2.87 mg/L respectively.

The NOEC result does not lead to classification and labelling of lithium for long-term aquatic toxicity (fish) according to Regulation (EC) 1272/2008 (CLP) and Directive 67/548/EC (DSD).

Short-term toxicity to aquatic invertebrates

Lithium hydroxide (purity 55.2 %) was tested for short term aquatic toxicity in daphnia in an 48-hour static test according to EU Method C.2 and OECD Guideline 202. Without pH-adjustment the 48-hour EC 50-value was 19.1 mg/L. With pH-adjustment the 48-hour EC 50-value 34.3 mg/L. Based on a read-across approach the calculated EC50 value (with pH-adjustment) for lithium metal was 10 mg/L.

Long-term to aquatic invertebrates

The purpose of the study was to evaluate the influence of the test item lithium on the reproductive output of Daphnia magna in a semi-static test system according to OECD Guideline 211. Young female Daphnia (the parent animals) aged less than 24 hours at the start of the test were exposed to aqueous test media containing the test item for 21 days at a range of concentrations. The nominal test item concentrations were 0.50, 0.75, 1.13, 1.70, 2.53, 3.80 and 5.70 mg lithium/L. The parallel running analytical determinations confirmed that the test item concentrations examined (lowest and highest test concentrations) remained within the range of ± 20 % of the nominal and of the initial concentrations (varied between 98 and 117 per cent of the nominal concentration); thus, all results were based on the nominal test item concentrations.
 
In the three highest tested concentrations (2.53, 3.80 and 5.70 mg/L) all parent animals died by the 13th day of the test without producing any offspring. Therefore the results of these concentrations were excluded from the data analysis related to the reproductive output. In the control group two parent animals (20 %) died during the test which was within the acceptable validity criteria. In the concentration range of 0.50 – 1.70 mg/L mortality of parent animals was not observed during the experiment. The reproduction was not reduced statistically significantly in the concentration range of 0.50 – 1.70 mg/L compared to the untreated control group. During the evaluation of the body length of parent animals at the end of the test, statistically significant difference was not observed in the remained living parent daphnids (in the concentration range of 0.50 – 1.70 mg/L) compared to the control group. Aborted broods, presence of male neonates or ephippia were not noticed during the test.
Accordingly, the 21-day NOEC value related to reproduction was determined to be 1.70 mg/L and the LOEC value as 2.53 mg/L. The obtained results were not sufficient for an exact EC50 value estimation. The 21-day EC50 was determined to be higher than 1.70 mg/L.

Toxicity to aquatic algae and cyanobacteria

Lithium hydroxide monohydrate was tested for toxicity to algae in a 72-h static test. The results, based on growth rate showed an EC50 value of 153.44 mg/L and a NOEC of 10 mg/L. Based on a read-across approach an EC50 (growth rate) value of 25.6 mg/L and NOEC value of 1.65 mg/L were calculated for lithium metal.

Thus, lithium has not to be classified according to (EC) No 1272/2008 (CLP) and directive 67/548/EC (DSD) critera for long-term aquatic toxicity (algae).

Toxicity to microorganisms

The 3-hour EC20, EC50, and EC80 values for the test substance lithium hydroxide in the activated sludge respiration inhibition test were 114.3, 180.8, and 286.1 mg/L (based on measured inhibition rates), respectively. The EC10 value was calculated by linear regression to be 79.2 mg/L.

Based on a read-across approach an EC50 value of 52.39 mg/L and an EC10 of 22.95 mg/L were calculated for lithium metal.