Lithium carbonate

Endpoint summary

Additional information

Abiotic degradation

Lithium carbonate is an inorganic substance soluble in water (8.4 – 13 g/L at 20 °C). Hydrolysis of lithium carbonate produces basic solutions of lithium hydroxide and lithium hydrogen carbonate. Further decay produces lithium ions, hydrogen carbonate and carbonate. The hydrolysis of carbonates is a well known chemical process. In water, CO2 is the predominant species at a pH lower than 6.33, HCO3- (hydrogen carbonate ion) at a pH in the range of 6.35 -10.33, and CO32- (carbonate ion) at a pH higher than 10.33. The carbonate will finally be incorporated into the inorganic and organic carbon cycle. Lithium ions do not undergo further degradation and are eventually incorporated into the soil minerals inventory.

 

Biotic degradation

Biodegradation in water: screening test, Biodegradation in water and sediment, Biodegradation in soil

In accordance with column 2 of REACH Regulation 1907/2006/EC Annex VII section 9.2.1.1, a biodegradation test does not need to be conducted as the test substance lithium carbonate is an inorganic substance. Furthermore according to REACH Annex X, Section 9.2, Column 2, further biotic degradation testing shall be proposed, if the chemical safety assessment according to Annex I indicates the need to investigate further degradation.

The CSA does not indicate any need to further assess degradation. Risk assessment was already performed assuming worst case conditions including “no biodegradation”. All risks are adequately controlled. Thus, any further information that would lead to the conclusion that the registered substance is not biodegradable would not influence the chemical safety assessment. Please refer to the attached CSR in IUCLID section 13 for further information.

Bioaccumulation in aquatic/ sediment

Lithium salts are not considered to bioaccumulate. The anionic part of the lithium salts is either natural or chemically indistinguishable from natural substances. Anionic parts like carbonate, chloride or nitrate can be found ubiquitous in nature. Thus, only data on the bioaccumulation potential of the lithium component are presented here. The highest BCF/BAF was determined by Antonkiewicz et al. (2017) for terrestrial plants under hydroponic conditions with values between 9 and 16 over the different dosing groups. Barber et al (2006) determined a BCF of around 8 L/kg in freshwater fish. Other publications indicate BCF/BAF values of 1 (Karlsson et al. 2002) or below 1 (Pokorska et al., 2012). Kastanek (2015) concluded in his study with three different algae species that the bioaccumulation potential of lithium is neglible.

Recalculation of the highest BAF/BCF values of the evaluated literature resulted in a BCF of 42 L/kg and a BAF of 84 for lithium carbonate. Thus, lithium carbonate is not considered as bioaccumulative.

Adsorption/ desorption

Lithium carbonate is inorganic and thus OECD guideline 121 and OECD guideline 106 cannot be used to determine the partition coefficient. Kd values were found for soil and marine sediment. Both values are below the threshold of 3 and thus the substance adsorption potential can be regarded as low.