Cyclohexanamine, 4,4'-methylenebis[N-(1-methylpropyl)-

Short-term toxicity to fish

Description of key information

The 96-hour LC50 (mortality) to fish (Oncorhynchus mykiss), > 570 mg/l based on the nominal concentration of the limit test as per US-EPA guideline 40CFR 797.1400. 

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

570 mg/L

Additional information

There are two studies available for acute toxicity to fish, The 96 hour LC50 (mortality to fish (Oncorhynchus mykiss) based on the nominal concentration of the limit test as per US-EPA guideline 40CFR 797.1400,and the 96 hour LC50 (mortality) to fish ( Oryzias latipes) based on nominal concentrations performed as semi-static test according to Japanese standard 71 of JIS K 0102-1998.

The results of the limit test (40CFR 797.1400) were regarded as reliable with restrictions to be used as a key study for this endpoint since the test substance concentration was not measured. In this case, this study performed as a limit test at concentration of 570 mg/l was acceptable to be used for C&L as the endpoint hadn't yet been reached by the limit of water solubility since the toxicity test with Rainbow trout was conducted with pure material and had the pH adjusted to 7. This pH adjustment maximizes the solubility of Clearlink 1000. This conclusion is based on the general knowledge on Clearlink 1000, that it is a pH active material. At alkaline pH's, Clearlink 1000 has very low water solubility and in neutral or acidic pH's, it is very water soluble. Also, as Clearlink 1000 has amine functionalities, it will coordinate with metals in solution thereby increasing the solubility. The solubility of Clearlink 1000 was higher in this study than in a water solubility study (131 mg/l, see IUCLID section 4.8). However, that is expected due to the more acidic pH and the presence of metals. In a water solubility study (section 4.8), the pH was not fixed and when amines are added to pure water, the pH becomes more basic.

The main objective of the supporting study (Japanese standard 71 of JIS K 0102-1998) was to select test concentrations for the BCF study of this substance (IUCLID section 5.3.1). However, the results of this study was regarded as unreliable since the solubilizing agent (HCO-40) used to increase the solubility of the substance interfered with the results. In addition, the original study report is in Japanese and the translated version is of poor quality (e.g. the structure of the report, detailed description of method and the discussion of the result). The results of this study were considered unreliable and cannot be used alone in deriving C&L of the substance in accordance with the criteria set out in Directive 67/548/EC and Regulation (EC) 1272/2008.

As a conclusion, the results of the key study were considered as acceptable to show that the fish is not the most sensitive organism to trigger C&L, and classification can be based on the lowest available EC50-value for algae (0.24 mg/l).