Amines, N-(C16-18 and C18-unsatd. alkyl)trimethylenedi-, diacetates

Endpoint summary

Additional information

A fish toxicity test has been performed with Amines, N-(C16-18 and C18-unsatd. alkyl)trimethylenedi-, diacetates. For the other ecotoxicity tests, a read-across approach has been performed from diamines. Indeed, the physico-chemical properties of the diamines acetates and the fish toxicity test available reveal a comparable toxicity profile and indicates that the presence of acetates has no influence (see the read-across justification document).

It was decided to launch a both news GLP tests on the registered substance (CAS 1313206 -64 -2) according TG OECD 201 and 202 in order to improve the quality of the aquatic experimental data under REACH Annex VII. These data will be submited in the dossier for the next update.

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 long-term aquatic ecotoxicity 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.

For ecotoxicity tests performed using the bulk approach, however, adsorption to suspended matter and DOC is acceptable and only adsorption to glassware should be accounted for. For a valid bulk approach test, the concentration-effect relationship should be based on the sum of adsorbed and dissolved substance in the volume of the medium tested. One of the advantages of the bulk approach tests with these difficult substances is that in the presence of suspended matter, humic acids and/or algae, the residual sorption to glassware will be negligible. The results of these bulk approach tests are therefore much easier to interpret, more environmental realistic, and if compared to PEC_bulkclearly provide a more appropriate assessment of risks for the environment. All effect values given are therefore based on the nominal test item concentrations.