Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

No data on the behavior of fused tungsten carbide in the environment are available.

Abiotic degradation

Tungsten is a stable element and cannot degrade chemically. It can however, sometimes reversibly, participate in numerous chemical reactions that can proceed under a wide range of common environmental conditions. Thereby, different chemical compounds containing tungsten can be formed and also cease to exist, but the process of degradation is not a relevant fate pathway for such compounds (ATSDR, 2005). Although no data were available for the fused tungsten carbide, degradation is not relevant for this substance as an inorganic metal compound.

Biotic degradation

In accordance with column 2 of REACH Annex VII, a test for ready biodegradability does not need to be conducted, as the substance is inorganic. The process of biodegradation is not a relevant fate pathway for inorganic tungsten compounds such as this substance.

Additional information

Due to the formation of a common, soluble tungsten ion (tungstate) at a similar rate between fused tungsten carbide (target substance) and tungsten metal (source substance), these substances are expected to have a similar bioaccumulation potential. In addition, due to a much lower solubility of fused tungsten carbide (target substance) compared to sodium tungstate (source substance), the resulting bioaccumulation potential of fused tungsten carbide compared to sodium tungstate is expected to be significantly lower, so the usage of sodium tungstate is appropriate to adequately capture the worst-case bioaccumulation potential of fused tungsten carbide (target substance) in the environment. For more details refer to the attached description of the read-across approach.