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Ecotoxicological information

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Description of key information

Chromium is highly insoluble as demonstrate in the T/D test as a consequence: chromium (III) produces soluble (bio)available ionic and other chromium-bearing species in environmental media is limited. The insolubility of chromium (III) is expected to determine its behavior, its fate in the environment, and subsequently its ecotoxicity potency.


In accordance with ECHA’s Guidance on IR & CSA, Appendix R.7.13-2 (2008), the substance can be evaluated by comparing the dissolved chromium (III) ion level resulting from the T/D at a loading rate of 1 mg/L after 7-days with the lowest chronic effect concentration as determined for the (soluble) chromium (III) ion.

For the (soluble) chromium (III) ion, no inhibition of respiration of activated sludge was observed in a GLP guideline study with potassium chromium sulphate dodecahydrate and a 3 h ≥ NOEC > 1000 mg Cr/L was derived (Caspers, 1988). Dissolved chromium concentrations of <0.01 µg/L in the T/D after 7-Days at pH 6 (i.e. the pH that maximizes the dissolution) are significantly lower than the lowest effect concentration derived in activated sludge respiration inhibition tests (i.e. NOEC ≥ 1000 mg Cr(III)/L) as well as the lowest effect concentration derived in single species tests (NOEC of 0.26 mg Cr/L).

Hence, chromium (III) is not sufficiently soluble in environmental media to cause chronic toxicity to micro-organisms at the level of the lowest chronic effect concentration (expressed as the NOEC).


According to this data, no toxicity for micro-organisms is expected.

Key value for chemical safety assessment

Additional information