Registration Dossier
Registration Dossier
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EC number: 210-743-4 | CAS number: 622-58-2
Toxicity to aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
Description of key information
According to OECD Guideline 201 a 72h-NOEC of 3.1 mg/l, and a 72h-EC50 of 24 mg/l was obtained for p-toluidine on Pseudokirchnerella subcapitata (MITI 1995). The hydrolysis product of p-tolyl isocyanate is harmful for aquatic plants.
Key value for chemical safety assessment
- EC50 for freshwater algae:
- 24 mg/L
- EC10 or NOEC for freshwater algae:
- 3.1 mg/L
Additional information
The hydrolysis product of p-tolyl isocyanate was considered for assessment.
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 performed 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 compounds. An underestimation of environmental hazards is thus avoided supporting a conservative and thus protective hazard assessment. * Bayer Industry Services (2004). 4-chlorophenyl-isocyanate: Investigation on Stability in Aqueous Test Solutions. Project No: 200300181. Leverkusen, Germany. Bayer Industry Services (2003). Isopropylisocyante: Investigation on Stability in Aqueous Test Solutions. Project No: 200300095. Leverkusen, Germany.
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