No terrestrial toxicity data are 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). The geometric mean of the most sensitive endpoint of the most sensitive test species was used for the PNEC derivation. The most sensitive endpoint was juvenile production from Folsomia candida with a reported value of 15.5 mg B/kg resulting in an endpoint of 48.2 mg NaBH4/kg.