Sodium 2-biphenylate

Endpoint summary

Additional information

According to Annex VII of Regulation (EC) No 1907/2006 the generation of soil data is not required. Data on the soil toxicity was assessed to allow a realistic PNEC soil derivation based on experimental data. Data on the toxicity of

 According to Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 substances can be considered similar if their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity. The source substance 2-phenylphenol (CAS 90-43-7) is the conjugate acid of sodium 2-biphenylate. Under environmentally relevant conditions sodium 2-biphenylate will dissociate on contact with water forming NaOH and 2-phenylphenol. The target and the source substance are expected to have a similar environmental fate and ecotoxicity profile due to the comparable physico-chemical properties of both substances. The target and the source substance are characterised by a low vapour pressure (1.2 and0.474 Pa at 20 °C respectively)and low adsorption potential (log Koc <3). The water solubility of the source substance Sodium 2-biphenylate is > 1000 g/L at pH 13.6 and 20 °C. However, as indicated by the measured dissociation constant for the substance (pKa(2-phenylphenol) = 9.5) Sodium 2-biphenylate will dissociate forming 2-phenylphenol under environmental relevant pH (pH 5 - 9). The measured water solubility of 2-phenylphenol ranged from 0.53 – 0.64 mg/L (pH 5-9 at 20°C). Further justification is given within in the analogue justification in IUCLID section 13.

Data are available for three trophic levels. In an earthworm test the effects of the source substance 2-phenylphenol (CAS 90-43-7) onEisenia fetidawere investigated. The LC50 (14 d) value was 198.2 mg test item/kg dw. The NOEC (14 d) for mortality as well as the NOEC for biomass was determined to be 125 mg test item/kg dw.

Reliable tests on the toxicity of sodium 2-biphenylate (CAS 132-27-4) and the read across substance 2-phenylphenol (CAS 90-43-7) to terrestrial plants are available. The key information for evaluation of the toxicity to plants was obtained from the read across study on 2-phenylphenol (CAS 90-43-7). The effects of the source substance 2-phenylphenol (CAS 90-43-7) on terrestrial plants were studied in three plant species of three different families:Brassica napus, Glycine maxandAvena sativa. Test parameters were germination rate, mortality and phytotoxicity. Phytotoxic effects observed were growth reduction (all species), slight chlorosis (Brassica napusandGlycine max) and slight necrosis (all species). Additionally,Brassica napusshowed abnormal growth of the leaves, andGlycine maxshowed abnormal growth of the leaves and the stems.

The most sensitive species in terms of fresh weight was Avena sativa with an EC50 value of 53.9 mg/kg soil dry weight and NOEC 12.5 mg/kg soil dry weight. It was followed byBrassica napus(EC50 62.9 and NOEC 25 mg/kg soil dry weight). The least sensitive species wasGlycine maxwhich showed an EC50 value of 89.7 and NOEC 25 mg/kg soil dry weight.

Furthermore, the effects the source substance 2-phenylphenol on soil nitrification of soil micro-organisms were tested over an exposure period of 100 days. The NOEC of 2-phenylphenol (CAS 90-43-7) was calculated to be 300 mg/kg soil dry weight 28 days and 100 days after application. The EC50 was calculated to be 633.5 mg/kg and 829.1 mg/kg soil dry weight 28 days and 100 days after application, respectively. In an additional test on soil respiration and nitrification, 2-phenylphenol (CAS 90-43-7) had no impact on respiration and nitrogen transformation of soil microflora when applied up to 1.0 mg a.i./kg soil.