Registration Dossier

Diss Factsheets

Ecotoxicological information

Long-term toxicity to fish

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

A waiver is proposed to cover this endpoint, and supporting evidence with a study on sodium nitrate (Adelman, 2009) is provided. The read-across rationale can be found in the category approach document attached in Section 13 of IUCLID and is fully incorporated in the CSR. 

Key value for chemical safety assessment

Additional information

The endpoint 'long-term toxicity to fish' can be covered by a waiver which is based on two arguments:

1) according to REACH Annex IX column 2, the study does not need to be performed when the chemical safety assessment indicates no need to further investigate the effects on aquatic organisms. The CSA indicated no risks for the aquatic environment, so the aforementioned waiving argument is valid.

2) according to REACH Annex XI section 1.5, the study can be waived when it can be covered by a structural analogue. Nitric acid will dissociate in the environment into its ions: H+ ions and nitrate ions. The H+ ions will cause a pH decrease, but in the aquatic environment the net pH decrease will be limited due to buffering. Regulatory aquatic ecotoxicity studies should be conducted at relevant environmental pH (i.e. pH 6 -9). At this pH, exposure to nitric acid comes down to exposure to nitrate ions. Studies done on sodium nitrate, which also dissociates into nitrate ions, can be used to support the low long-term aquatic toxicity of nitrate:

There are reliable 30d growth rate and 32d embryo-larval tests available for sodium nitrate from Adelman (2009).

In the 30d growth rate test the NOEC for juvenile Topeka shiner was 268 mg/L (growth rate) and the NOEC for Fathead minnow was 58 mg/L (mortality).

In the 32d embryo-larval test, the NOEC to Fathead minnow was 157 mg/L based on growth rate (no effect on embryo survival).

These tests confirm the low long-term toxicity of sodium nitrate.