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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Description of key information

Klimisch 1 study (Egeler P, Goth A, Kiefer R (2010): study on the acute toxicity of GaAs to Daphnia magna, conducted according to OECD 202: EC50(48h) = 47.9 mg/L GaAs  based on a WAF-test (corresponding values based on measured concentrations: 4.03 mg Ga/L + 5.28 mg As/L). Test was conducted with the water-accommodated fraction of GaAs-powder; this physical form, however, is not relevant for the industrial production/use of GaAs where this substance is only present as a massive or as wafers. No toxicity data based on massive/wafer GaAs are available. Reported effects based on GaAs powder should therefore be considered as a worst case, predominantly reflecting the powder GaAs toxicity . 

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
47.9 mg/L

Additional information

A clear concentration-response relationship was observed and the following 48h-EC50 value for immobility of daphnids was determined (from WAF tests with GaAs powder):

- 48h-EC50= 4.03 mg Ga/L + 5.28 mg As/L (total measured As and Ga present in the WAF-fraction causing 50% effect)

- 48h-EC50= 47.91 % WAF of 100 mg GaAs/L, corresponding to 47.9 mg GaAs/L

The EC50 values reported refer to the immobilization of daphnids and are based on statistical evaluation of biological results and nominal concentrations in % of WAF at loading rate of 100 mg test item/L, and measured concentrations in mg/L.