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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Description of key information

The decreased pH caused by the formation of HCl during hydrolysis of BCl3 is decisive for the acute toxicity to Daphnia.

The "EC50" of pH = 4.9 is best described in pH-units and not by the concentration, in case of more or less buffered aquatic environments.

Key value for chemical safety assessment

Additional information

A degradation category approach is applied, based on the very rapid and complete degradation (hydrolysis) of boron trichloride in water to form hydrochloric acid and boric acid. The description and justification of the category is presented in Section 13.

The endpoint results of the degradation products are transcribed to boron trichloride.

 

Relevant information for the 2 degradation products:

Hydrogen chloride:

A Daphnia EC50,48h value from a key study was pH = 4.9 (NOEC: pH 5.5). Normalised, this corresponds to EC50,48h = 0.45 mg HCl/L in non-buffered water. An EC50,48h of ≥0.49 mg BCl3/L is calculated after converting to BCl3, if not only pure water is considered. NOEC ≥0.1 mg BCl3/L

Boric acid:

Daphnia magna, lowest value from an acute test of reliable quality: An EC50,48h = 760 mg B(OH)3/L. An EC50,48h = 1440 mg BCl3/L is obtained after converting to BCl3.

Endpoint conclusion:

The decreased pH caused by the formation of HCl during hydrolysis of BCl3 is decisive for the acute toxicity to Daphnia.

An EC50,48h of ≥0.49 mg BCl3/L is calculated after converting to BCl3, if not only pure water is considered. NOEC ≥0.1 mg BCl3/L.