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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The toxicity of tert.-Butylamine, the hydrolysis product of tert-butly isocyanate, to activated sludge was investigated according to ISO 8192 (Test for Inhibition of Oxygen Consumption by Activated Sludge) yielding an EC50(3 h) of 9655 mg/L as well as an EC10(3 h) of 1577 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:
9 655 mg/L
EC10 or NOEC for microorganisms:
1 577 mg/L

Additional information

read-across to the corresponding amine

Read-Across-Justification:

Isocyanates are known to rapidly hydrolyse under the formation of the corresponding amine as well as solid polyurea compounds *. However, the insoluble inert polyurea is not assumed to cause environmental hazards due to the reduced uptake of high molecular mass compounds, whereas the amine is assumed to be the ecotoxicological relevant species. Concluding, tests per-formed using the corresponding amine can equally be used to assess the ecotoxicological hazards of isocyanates assuming the complete transfer of the isocyanate into the corresponding amine while neglecting the formation of a certain fraction ecotoxicological not active polyurea com-pounds. An underestimation of environmental hazards is thus avoided supporting a conservative and thus protective hazard assessment.

*

Test Lab

(2004). 4-chlorophenyl-isocyanate: Investigation on Stability in Aque-ous Test Solutions. Project No: 200300181.

Test Lab

(2003). Isopropylisocyante: Investigation on Stability in Aqueous Test Solutions. Project No: 200300095.