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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Toxicity to microorganisms

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Administrative data

Link to relevant study record(s)

Description of key information

The lowest reliable observed EC10 value for respiration (inhibition of respiration after a 3h incubation period) using activated sludge was 3.73 mg dissolved Co/L (Lee 2010).  The test was conducted with cobalt dichloride.

Key value for chemical safety assessment

EC50 for microorganisms:
120 mg/L
EC10 or NOEC for microorganisms:
3.73 mg/L

Additional information

According to REACH Guidance (Guidance on information requirements and chemical safety assessment: Chapter R10 Characterisation of dose [concentration]-response for environment) the PNECmicroorganisms should be derived from respiration inhibition test (OECD 209) data by applying an Assessment Factor of 10 to available EC10 value (Table R10 in ECHA R10 Guidance). 


The extant data for aquatic microorganisms are insufficient to perform a statistical extrapolation analysis (i.e. Species Sensitivity Distribution) for deriving a PNECmicroorganisms. The only available Klimisch 1 or 2 data identified were that of Lee (2010); an Activated Sludge Respiration Inhibition Test following OECD Method 209 that was conducted with cobalt dichloride. The results of this test showed that the respiration rates of the two control flasks were within 15% of each other, which satisfies the criterion for acceptability outlined in the test guideline concerning data from the control flasks. The test substance (cobalt dichloride) showed 2.3, 24.4, 36.0, 61.7, and 64.4% inhibition vs. the pooled control at analytically verified concentrations of 4.34, 15.8, 48.2, 156, and 538 mg dissolved Co/L, respectively. The estimated 30-minute EC10 and EC50values for cobalt were 3.73 and 120 mg dissolved Co/L, respectively.