Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Hydrogen bromide (HBr) is an inorganic substance so does not undergo biotic degradation. HBr forms hydrobromic acid in water. The toxic effect seen to aquatic organisms is from the acidity of the resulting solution, which is a function of the HBr concentration. Evaluation of the analogous substance hydrogen chloride under the OECD ICCA HPV Programme (2003) stated that it was not considered useful to calculate a PNEC for hydrochloric acid because factors such as the buffer capacity, the natural pH and the fluctuation of the pH are very specific for a certain ecosystem. There is a possibility that the emission of hydrochloric acid could locally decrease the pH in the aquatic environment. Normally, the pH of effluents is measured very frequently to maintain the water quality. In addition to that, water quality including the range of pH could be managed properly to prevent adverse effects on the aquatic environment based on the criteria of the pH in rivers and lakes. Therefore, a significant decrease of the pH of the receiving water is not expected. Generally the changes in pH of the receiving water should stay within the natural range of the pH, and for this reason, adverse effects on the aquatic environment are not expected due to anthropogenic or naturally occurring hydrochloric acid. Hydrobromic acid will react in the same manner as hydrochloric acid, so the evaluation is equally valid for hydrobromic acid. HBr in water forms hydrobromic acid which dissociates to ions (H+and Br-). Toxicity data for the bromide ion is available in other submissions so adequate information for environmental classification and labelling of the dissociation products of hydrobromic acid is available. As adequate information on HBr degradation is available and it is not technically feasible and scientifically unjustified biodegradation simulation studies would not be performed.