Lithium hydroxide

Endpoint summary

Additional information

Short-term toxicity to fish

The acute toxic effects of lithium hydroxide monohydrate to Zebrafish (Danio rerio) over a 96 hour static exposure period were assessed according to OECD guideline 203. For the range-finding test the test solutions were prepared in a dilution series from a stock solution of 100 mg/L of the test item in tap water. For the definitive test as limit test and the definitive test with five test concentrations the test solutions were prepared by direct transfer of weighted samples in various amounts of the test item into the tap water in the test vessels. AES-analysis confirmed that the test solutions were correctly dosed, i.e., the recoveries were within 92.6 to 96.2 % of the nominal concentrations at study start. At the end of the exposure, i.e., after 96 hours, the recoveries ranged from 98.8 to 101 % of the nominal concentrations demonstrating that the lithium concentrations were stable throughout the exposure period. Consequently, the results of the definitive test were based on nominal concentrations.

In this 96-h fish acute toxicity test with Zebrafish (Danio rerio) the 96h LC50 for lithium hydroxide monohydrate based on mortality was determined to be 109 mg/L. Based on these data the calculated LC50 for lithium hydroxide anhydrous is 62.2 mg/L.

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:

LOEC of 24.35 mg test item/L

NOEC of 17.35 mg test item/L

The following LOEC and NOEC values were calculated for lithium hydroxide anhydrous:

LOEC of 13.90 mg/L

NOEC of 9.90 mg/L

The NOEC result does not lead to classification and labelling of lithium hydroxide for long-term aquatic toxicity (fish) according to Regulation (EC) No. 1272/2008 (CLP) and Directive 67/548/EC (DSD).

Short-term toxicity to Daphnia magna

The acute toxicity of the test substance lithium hydroxide (55.2 %) to Daphnia magna was determined in a 48-hour static test according to the EU method Annex Part C.2 and the OECD Guideline No. 202. The nominal concentrations tested were 4.6, 10, 21, 46 and 100 mg test substance/L, and in parallel a control. At one series of test media the pH was adjusted to approximately pH 8 by HCl, at the other series not. This allowed to differentiate if a toxic effect is caused due to a pH-effect of the test substance with a strong basic pH, or if it is a real toxic effect of lithium(-hydroxide). The analytical determined test substance concentrations in the analysed test media varied in the range from 93.5 % to 103.2 % of the nominal values. In the test media the test substance concentrations were constant during the test period of 48 hours. Therefore, all reported biological results are related to the nominal concentrations of the test substance.

Without pH-adjustment the 48 hour EC50-value was 19.1 mg/L and with pH-adjustment the 48-hour EC50-value 34.3 mg/L for lithium hydroxide anhydrous. Based on these data, the calculated EC50 without pH-adjustment for lithium hydroxide monohydrate was 33.5 mg/L and with pH-adjustment 60.1 mg/L. Consequently the LC50 values of 34.3 mg/L and 60.1 mg/L represent the relevant figures for lithium hydroxide anhydrous and lithium hydroxide monohydrate, respectively.

Long-term toxicity to Daphnia magna

A semi-static Daphnia magna reproduction test was performed according to OECD Guideline 211. At this method Daphnia magna, aged lower or equal 24 h at the beginning of the test, are exposed to a range of lithium hydroxide monohydrate under defined conditions over a period of 21 days. The test solutions were prepared in a dilution series from a stock solution of 100 mg/L of the test item in culturing medium. In the definitive test the nominal concentrations were as follows: 0.25, 0.5, 1.0, 2.0, 4.0, 8.0 and 16.0 mg/L. Analysis of the test solutions for lithium confirmed that the test solutions were correctly dosed and stable during the exposure period (recoveries ranging from 95.5 to 102 % of nominal concentrations for the freshly prepared and aged test solutions). Therefore, the concentrations were reported as nominal concentrations. The test item lithium hydroxide monohydrate caused a statistically significant effect on live offspring of the Filial generation (F1) derived from the parent animals surviving at the end of the test at nominal test concentration of 8.0 mg lithium hydroxide monohydrate/L according to Dunnett`s test (p = 0.05).

The LOEC for lithium hydroxide monohydrate determined on reproduction was 8.0 mg/L and the calculated value for lithium hydroxide anhydrous 4.6 mg/L.

The respective NOEC for lithium hydroxide monohydrate determined on reproduction was 4.0 mg/L and the calculated value for lithium hydroxide anhydrous was 2.3 mg/L.

Toxicity to Algae

The influence of the test item lithium hydroxide monohydrate on the growth of Pseudokirchneriella subcapitata was investigated in a 72 h static test according to EU method C.3 and OECD Guideline No. 201 in 2010.

The test item had a statistically significant inhibitory effect on the growth based on the average specific growth rate, yield and areas under the curves of Pseudokirchneriella subcapitata after the exposure period of 72 hours in the concentration range of 20 - 160 mg/L test item/L (Bonferroni t-Test, alpha=0.05). The test concentration of 20 mg/L was determined as the 72-hour LOEC.

The results showed an EC50 value of 41.62 mg/L based on biomass and 153.44 mg/L based on growth rate (equivalent to 23.75 mg/L resp. 87.57 mg/L referred to lithium hydroxide anhydrous). The NOEC based on growth rate for lithium hydroxide monohydrate was 10 mg/L. The NOEC calculated for lithium hydroxide anhydrous was 5.71 mg/L.

Another study of 2004 performed with lithium hydroxide anhydrous was disregarded as lithium hydroxide monohydrate is more representative for lithium hydroxide in water due to strong hygroscopic character of the substance (i.e. lithium covered by hydrate mantle).

Toxicity to microorganisms

The influence of the test item lithium hydroxide on the activity of activated sludge by measuring the respiration rate was evaluated according to OECD Guideline 209 and EU method C.11. The respiration rate (oxygen consumption) of an aerobic activated sludge fed with a standard amount of synthetic sewage was measured in the presence of various concentrations of the test item after an incubation period of 3 hours. The inhibitory effect of the test item at the particular concentrations was expressed as percentage of the mean respiration rate of two controls. Following test concentrations were used: 10, 32, 100, 320 and 1000 mg lithium hydroxide/L; 3.2, 10 and 32 mg 3,5-Dichlorophenol/L and two inoculum controls. In comparison to the inoculum controls the respiration rate of the activated sludge was inhibited between –1.8% and 98.2 % up to the highest nominal test concentration of 1000 mg/L. Concentrations exceeding 1000 mg/L nominal were not tested. The 3-hour EC 50 for the positive control 3,5-Dichlorophenol, which was tested in the same way as the test item, was found to be 7.5 mg/L and is within the range of 5 – 30 mg/L recommended by the test guidelines; thus, confirming suitability of the activated sludge. The 3 hours 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 for lithium hydroxide anhydrous and 22.95 mg/L for lithium ion.