Registration Dossier

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

No toxicity studies with microorganisms are available for sodium borohydrid since it rapidly hydrolyzes in water to form sodium borate/boric acid and hydrogen gas with half-lives ranging from seconds to minutes at environmentally relevant pHs. Therefore, aquatic toxicity data for boric acid was used.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
54.77 mg/L

Additional information

No aquatic toxicity data is available for sodium borohydride since the compound rapidly hydrolyzes in water to form sodium borate/boric acid and hydrogen gas with half-lives ranging from seconds to minutes at environmentally relevant pHs.

Therefore, toxicity data for the toxicologically relevant hydrolysis product boric acid is applied for the safety assessment.

The endpoints included in the dossier under environmental hazard assessment were reported from studies on the ecotoxicity of boron and various compounds, such as boric acid (H3BO3), anhydrous sodium tetraborate (Na2B4O7), and hydrated sodium tetraborates (Na2B4O7.xH2O). All endpoints were converted to concentrations of elemental boron (B) using the relative molar mass and then converted to NaBH4 for this IUCLID. A GLP study following OECD 209 respiration inhibition test guidelines was identified as the key study (Hanstveit and Schoonmade, 2000). The reported endpoint used to derive the PNECstp was an NOEC of 17.5 mg B/L or 54.77 mg NaBH4/L.