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Ecotoxicological information

Long-term toxicity to aquatic invertebrates

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Description of key information

The 21-day EC50 values for mortality and juvenile production of adult D. magna exposed to 'Chromosal B' under semi-static conditions were both greater than 0.0200 mg total Cr/L, based on nominal concentrations, or greater than 0.0144 mg Cr/L, based on mean, background-corrected, measured concentrations of dissolved chromium. 

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater invertebrates:
0.014 mg/L

Additional information

No studies with dichromium tris(chromate) are available. A read across is proposed to chromium (III) hydroxide sulphate, because the only source of significant environmental exposure will be to the trivalent form of chromium.

A study of the chronic toxicity of 'Chromosal B' (chromium hydroxide sulphate) to Daphnia magna was conducted with adult female test organisms exposed for 21 days to nominal concentrations of dissolved chromium ranging from 0.0020 to 0.0200 mg/L under semi-static conditions. Based on the absence of treatment-related adult mortality or adverse impact on numbers of juveniles per adult daphnid, the mortality and reproductive EC50 values were both greater than 0.0200 mg Cr/L, the highest nominal concentration tested. Samples of fresh and expired media were taken at intervals during the study and analysed by atomic absorption spectrometry. After subtraction of the mean background concentration of chromium in the untreated control, the mean measured concentrations of dissolved Cr were 0.0010, 0.0041 and 0.0144 mg Cr/L at nominal concentrations of 0.020, 0.0063 and 0.0200 mg/L, respectively. Based on mean, background-corrected concentrations, the mortality and reproductive EC50 values were both >0.0144 mg Cr/L (measured).