Amines, N-C16-22-alkyltrimethylenedi-

Endpoint summary

Additional information

Alkyl-1,3-diaminopropanes are poorly soluble in water and also have a strong tendency to adsorb to negatively charged surfaces such as suspended matter and test vessels or organic material (including dissolved organic matter such as humic acids). Many cationic substances in general but long chain alkyl polyamines in particular rank among the most difficult substances to test in environmental toxicology. Standard guideline studies are inappropriate to test substances with such properties and the current REACH Guidance Documents do not provide sufficient guidance concerning bioavailability and exposure assessment for cationic surface-active substances like the alkyl-1,3-diaminopropanes as these were written with normal hydrophobic chemicals in mind, failing to take into account the lack of bioavailability that occurs in the environment with these substances.

 

The chronic daphnia test and algae toxicity tests with alkyl-1,3 -diaminopropanes were therefore performed in river water to allow a PEC_aquatic,bulk/PNEC_aquatic,bulkapproach and is considered to be conservative but more environmentally realistic than the standard method. This approach is based on PEC estimations representing ‘total aquatic concentrations’. To characterize the risk to the aquatic compartment the PEC_aquatic,bulkis compared with the PNEC_aquatic,bulkderived from river water ecotoxicity studies (ECETOC, 2001).

 

In order to class standard laboratory toxicity study valid, it is of particular importance that - besides information on test substance, test method / conditions and test organism used - suitable precautions are taken to prevent the loss of test substance by adsorption and that exposure concentrations are based upon measured levels.

 

Data of other diamines have been used for the evaluation of the aquatic toxicity of Amines, N-C16 -22 -alkyltrimethylenedi.

All alkyl-1,3 -diamines under consideration consist of carbon, hydrogen and nitrogen only. The basic structure includes a hydrocarbon chain with a 1,3 -propanediamine group at the end of the chain. The main difference consists of differing chain lengths and slight variations in the degree of saturation in the alkyl chain. The available ecotoxicity data reveal a comparable toxicity independent of the alkyl chain length. Therefore a read-across approach is considered justified. 

 

An overview of the key values used are presented in the following table:

 

	CAS number	Result	Reference
Daphnia OECD 211 KEY Study	90640-43-0	21d-EC50 = 179 ug/L parental mortality, river water	Noack, 2008
Danio rerio OECD 203 KEY Study	133991 -07 -0	96h-LC50 = 148 ug/L, reconst lab water	Clariant, 1990
Pseudokircherniella subcapitata OECD 201 KEY Study	90640 -45 -2	72h-ErC50 = 0.15 mg/L, river water 72h-ErC10 = 0.08 mg/L, river water	Charles River, 2013
Daphnia OECD 211 KEY Study	90640-43-0	21d-NOEC = 32 ug/L Reproduction, river water	Noack, 2008
Microorganisms OECD 209 Key Study	90640 -43 -0	3h-EC50 = 20.5 mg/L	Noack, 2008

 

It should be noted that the fish study is the only study performed with reconstituted lab water, while the studies with Daphnia and algae were performed with river water. However, it was decided not to repeat the fish study in natural river water for ethical reasons.