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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Klimisch 1 study (Egeler P, Kiefer R (2010): study on the acute toxicity of GaAs to algae (Pseudokirchneriella subcapitata), conducted according to OECD 201. No acute effect was noted at WAF of 100 mg GaAs/L;  NOEC (72h)≥ 100 mg GaAs/L or ( ≥0.465 mg Ga/L + ≥1.33 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 . 

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Additional information

The results of the study with GaAs in powder form demonstrate that the no-observed effect concentration for Pseudokirchneriella subcapitata for the parameters yield and growth rate is ≥ the water accommodated fraction (WAF) at a loading rate of 100 mg test item/L (nominal concentration).

- 72h-NOEC: ≥ 0.465 mg Ga/L + ≥ 1.33 mg As/L

- 72h-NOEC- % of WAF: ≥100 % of 100 mg GaAs/L

Data were evaluated for homogeneity of variances by Levene's Test and by Williams' test to calculate differences between the growth of algae of the controls and exposed to test item concentrations.