Registration Dossier

Diss Factsheets

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
no hazard identified

Marine water

Hazard assessment conclusion:
no hazard identified

STP

Hazard assessment conclusion:
no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:
no hazard identified

Sediment (marine water)

Hazard assessment conclusion:
no hazard identified

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential to cause toxic effects if accumulated (in higher organisms) via the food chain

Additional information

A study investigating the acute aquatic toxicity of tantalum carbide to fish (OECD Guideline 203) demonstrates that the test substance is of no acute toxicity to Danio rerio (96h exposure, nominal concentration: 100 mg/L).

Further acute aquatic toxicity studies investigating the effects of tantalum carbide to aquatic invertebrates and algae where not conducted as there are mitigating factors indicating that aquatic toxicity is unlikely to occur.

Tantalum carbide is highly insoluble in water. The maximum water solubility of the substance analysed under the conditions of the T/D test (OECD Series on Testing and Assessment No. 29) was 0.333 µg/L after 7 days at 21.5 °C and a loading of 100 mg/L. The water solubility of tantalum carbide at environmentally relevant temperatures and reduced exposure time (48/72 h in test evaluating the acute toxicity to aquatic invertebrates/algae) is assumed to be even lower.

No adverse effects could be observed in available tests investigating the toxicity towards fish and soil invertebrates at 100 mg/L and 1000 mg/kg soil dw, respectively.

Conclusion: Based on the very low water solubility and very low bioavailability, toxic effects in aquatic organisms are not expected. Available results (fish, soil invertebrates) do not give rise to any concern. The non-toxicity of TaC is further supported by results available from read-across partners (Ta, TaCl5).

Conclusion on classification

Tantalum carbide is not toxic to fish as demonstrated by an available OECD 203 Guideline study.

Toxicity to aquatic invertebrates, algae and microorganisms is unlikely based on the mitigation factors elaborated above. Thus, TaC does not need to be classified for ecotoxicity.