Tantalum

Toxicity to soil microorganisms

Description of key information

Toxicity to terrestrial organisms is considered not to be relevant for assessment since tantalum is not exposed to this compartment. Additionally, Tantalum metal is practically insoluble in water and as it is an inorganic substance it cannot be dissolved in organic solvents. As a result, testing of the effect of tantalum metal to soil organisms (especially via soil pore-water exposure) is technically not feasible.

Additional information

According to column 2 of Annex IXsection 9.4 of the REACH regulation, studies on terrestrial organisms do not need to be conducted if direct and indirect exposure of the soil compartment is unlikely. For tantalum metal, an entry into the environment is very unlikely to occur. Furthermore, no negative environmental effects have been reported.  An indirect exposure to soil via sewage sludge transfer is also unlikely since there is no entry into the aquatic environment and tantalum metal is not water soluble. For a substance being considered as “insoluble”, it can be assumed that it will be adsorbed and removed by within the STP process and as a consequence a transfer to the soil compartment is not expected. Therefore, no tests on terrestrial organisms are provided.  Moreover, long-term toxicity testing shall be proposed by the registrant only if the results of the chemical safety assessment according to Annex I indicate the need to investigate further the effects of the substance and/or degradation products on terrestrial organisms. This is not the case. As the test material is not environmentally toxic or harmful, there is no need for long-term testing. Elemental tantalum is considered to be physiologically inert and harmless.