Strontium chromate

Endpoint summary

Additional information

A study of the acute toxicity of 'Chromoxid-gruen GN' (chromium (III) oxide) to fish was conducted with zebra fish (B. danio) exposed to a nominal limit concentration of 10000 mg 'Chromoxid-gruen GN'/L for 96 hours under static conditions (Caspers, 1992). The 96 hour LC50 of 'Chromoxid-gruen GN' was >10000 mg/L, based on the nominal limit concentration applied in the test. Based on the absence of abnormal swimming behaviour, the 96 h NOEC was 10000 mg/L (nominal). The solubility of 'Chromoxid-gruen GN' was low under the conditions of the test. Based on the mean measured concentration of dissolved chromium at the nominal limit concentration of 'Chromoxid-Gruen GN', the 96 hour LC50 was >1.0 microgram Cr/L (equivalent to 2.9 microgram dissolved 'Chromoxid-gruen GN'/L).

A study of the long-term toxicity of 'basisches Chromsulfat' (chromium hydroxide sulphate) to fish was conducted in a 30-day early life-stage test with embryonic and hatched juvenile zebra fish (B. danio) exposed to nominal concentrations of 'basisches Chromsulfat' ranging from 3.2 to 1000 mg/L under semi-static conditions, with renewal of pH-adjusted media at 48 -72-h intervals (Adema & de Ruiter, 1990). The 30 -day NOEC of 'basisches Chromsulfat' was 1000 mg/L, based on the highest nominal concentration applied in the test and the absence of adverse effects on hatch, survival, growth and behaviour of the test organisms. The solubility of 'basisches Chromsulfat' was low under the conditions of the test. Based on the maximum mean measured concentration of dissolved chromium recorded in any of the 'basisches Chromsulfat' treatments, the 30 day NOEC was 0.018 mg Cr/L.

A waiver is proposed for the short-term toxicity to aquatic invertebrates, based on the presence of a chronic toxicity study.

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 (Caspers, 1989). Chromium hydroxide sulphate is considered a suitable substance to represent chromium (III)oxide (see point made below regarding the suitability of potassium chromium sulphate dodecahydrate). 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 absorbtion 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).

The respiration of activated sludge was unaffected by 3-h exposure to 'Kaliumchromalaun' (potassium chromium sulphate dodecahydrate) at nominal concentrations of between 100 and 10000 mg/L (Caspers, 1988).  Based on nominal concentrations, the 3-hour EC50 was >10000 mg 'Kaliumchromalaun'/L.  'Kaliumchromalaun' (potassium chromium sulphate dodecahydrate) is a suitable substance to represent the toxicity of chromium (III)oxide under aquatic test conditions. The water solubility of potassium chromium sulphate is generally known to be high (11.1% at 25 °C; 'Chromium compounds', Ullman (2005), Wiley-VCH Verlag GbmH & Co KGaA) compared to the relatively insoluble chromium (III)oxide (Section 4.8 orf this IUCLID dossier). Therefore, in aqueous media the liberation of the Cr(III) ion will be high if potassium chromium sulphate dodecahydrate is tested and thus will represent a worst-case with respect to the toxicity of organisms in aquatic media.

Sediment toxicity data with Cr(III) is lacking. However, the equilibrium approach has been adopted and presented in the EU RAR (2005) to provide a PNECsediment.

Cr(VI) data are also retrieved from the EU RAR(2005) and reported in the CSR.