4-hydroxy-4-methylpentan-2-one

Short-term toxicity to aquatic invertebrates

Description of key information

DAA was reported to have a 48 hour EC50 of greater than 1000 mg/L and a 48-hr NOEC of 1000 mg/L for Daphnia magna (Mitsubishi Chemical Safety Institute Ltd., 1997). The study was conducted under GLP and according to OECD Guideline 202 with no exceptions. The study was performed in a semi-static system and one nominal concentration, 1000 mg/L was tested. Purity of the test substance was 99.6%, pH varied between 7.9 and 8.1, dissolved oxygen concentration was between 7.6 and 8.2 mg/L and the temperature was 20±1 °C. Although Immobilization (5 %) was observed in 1000 mg/L group at 48 hours exposure, it was regarded as incidental. Therefore the 48-hr EC50 was greater than 1000 mg/L and the 48-hr NOEC was 1000 mg/L under the conditions of the study.

Three acute toxicity studies were conducted to assess the acute toxicity of DAA in Daphnia magna; however, these studies deviated from guidelines and therefore are considered to be reliable with restrictions (Bringmann and Kühn, 1977, 1982; Boutonnet, 1988). Bringmann and Kühn (1977) reported an EC50(24 h) value of 9000 mg/L for DAA in the Daphnia sp. acute immobilization test. This study was conducted in a manner similar to OECD Guideline 202, with the following restrictions: 10 animals were used per concentration, the test period was 24 hours, no controls were used, and the oxygen concentration was not measured. In a subsequent study, Bringmann and Kühn (1982) reported an EC50(24 h) value of 8750 mg/L for DAA in the Daphnia sp. acute immobilisation test. This study was conducted in a manner similar to OECD Guideline 202, with the following deviations: 10 animals were used per concentration, the test period was 24 hours, of which only 9 hours were conducted in the light, no acclimation period was used, and the culture medium was different in composition from the test medium. The oxygen concentration was 2 mg/L at the end of the assay. This study was rated ‘2’ for reliability (reliable with restrictions).

An acute toxicity study was conducted to assess the toxicity of DAA in Daphnia magna (Boutonnet, 1988). The study was conducted according to the guideline ISO 6341 (1982) to determine the effect of the substance on the mobility of Daphnia magna after 24 h treatment. DAA was dissolved in water at a final concentration of 81.97 g/L. Daphnia was bred in reconstituted water and fed algae (Scenedesmus subspicatus) plus Tetramin. Immobilization in the controls was 0%. The EC50(24 h) of the reference substance (potassium dichromate) was 0.9 mg/L. The author reported that the EC50(24 h) of DAA in the Daphnia magna acute immobilization test after 24 hours was: 9016 mg/L.