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Classification & Labelling & PBT assessment

PBT assessment

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PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB
Justification:

The available studies provide sufficient evidence to conclude that tetradonium bromide is not persistent in the environment.

Experimental data show that tetradonium bromide is readily biodegradable, at conditions where the substance does not exert toxicity to the microorganisms.

Experimental data for biodegradability in seawater demonstrated 65% degradation in 31 days of cetrimonium chloride indicating that the T½ < 60 days in marine water (Spangsberg & Schäfer, 1993). Also experimental data for degradation of cetrimonium chloride in soil demonstrated 60% degradation in 58 days indicating that the T½ < 120 days in soil (Spangsberg et al, 1993). The experimental results are sufficient evidence for passing the criteria for no persistence. As the degradability is determined by the alkyl structure and not the counterion, and the biodegradability decreases with the length of the alkyl chain the degradability of cetrimonium chloride is considered to represent that of tetradonium bromide.

The available studies provide sufficient evidence by read across to conclude that tetradonium bromide does not have a potential for bioaccumulation.

Estimated Log Kow is below 4.5

The substance may bioaccumulate to some extent in aquatic organisms, but the experimental data provide evidence that the substance do not fulfill the B criterion (BCF > 2000 L/kg).

In a weight of evidence approach, datasets on structurally alike quaternary ammonium halides are included as supporting data. The datasets in the weight of evidence approach represent experimental data as well as general considerations on the bioaccumulation of surfactants. The available studies provide sufficient evidence to conclude that tetradonium bromide does not have a potential for bioaccumulation.

Bioconcentration factors have been reported for cetrimonium bromide by the Japanese National Institute of Technology and Evaluation with BCF of 407 -741 for cetrimonium bromide in concentrations of 0.05 mg/L and BCF of 444-677 for concentrations of 0.005 mg/L. As the bioconcentration of alkyltrimethylammonium halides has been shown to increase with increasing length of the alkyl chain, the bioconcentration factors of tetradonium bromide is expected to be lower than those for cetrimonium bromide.

The available studies provide sufficient evidence to conclude that tetradonium bromide is toxic in the environment.

Toxicity to algae has been reported with EC50 (72h) of 0.005 mg/L and NOEC (72h) of 0.001 mg/L.