Registration Dossier

Diss Factsheets

Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

EC50 (48h) >100 mg/L for Daphnia magna (OECD TG 202)

Key value for chemical safety assessment

Additional information

In accordance with Annex XI, section 1.5 of Regulation (EC) No 1907/2006 (REACH) a read across approach may be used when substances have similarities based on the likelihood of common breakdown products via physical and biological processes, which result in structurally similar chemicals. As mentioned in the hydrolysis summary, polyphosphoric acid is hydrolysed to orthophosphate in environmental conditions. Thus a read across from orthophosphoric acid to pyrophosphoric acid is justified. In addition, studies performed with pyrophosphate salts can also be used. Pyrophosphate salts are ionic in nature and therefore dissociate readily into cations and anions in water. Cations as potassium and sodium are essential micronutrients that are ubiquitous in the enviroment. As such, their uptake is tightly regulated and is therefore not considered to pose a risk for ecotoxicity. In environmental conditions, the pyrophosphate anion is unstable and a number of different processes result to an ultimate breakdown product of orthophosphate.

The acute toxicity of orthophosphoric acid to daphnia was studied according to OECD TG 202 and GLP requirements (Priestly, 2010). In the study, Daphnia magna were exposed to aqueous solutions of phosphoric acid under static test conditions. The pH was adjusted to 7 (pH from 7 to 7.8). The 48h-EC50 was determined to be higher than 100 mg/L (nominal concentration).

As a supporting study, a daphnia toxicity test performed with a pyrophosphate salt (tetrapotassium pyrophosphate) has been investigated and gave a 48h EC50 of greater than 100 mg/L (Vaishnav et al., 1991).

Categories Display