Reaction mass of 1,5-naphthylene diisocyanate and Amines, hydrogenated tallow alkyl

Long-term toxicity to aquatic invertebrates

Description of key information

The long-term toxicity to Daphnia magna has been assessed for one substance within the NDI category definition. The study was conducted using a water accommodated fraction as the test item is poorly soluble. The determined EL50 values, based on parental mortality and reproduction, were >100 mg/L, with a NOELR value of 100 mg/L, the only concentration tested. Based on these results, members of the NDI category are not expected to be toxic to aquatic invertebrates at the limit of solubility.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

A study was performed to assess the long-term toxicity of the Reaction product of 1,5-naphthylene diisocyanate and cyclohexylamine to Daphnia magna (Ablitt 2018). The results from this study are read across to other members of the polyurea NDI category.

 

The method followed was designed to be compatible with the OECD guideline 211, "Daphnia magna, Reproduction Test". Following preliminary range-finding tests, ten daphnids (ten replicates of one animal) were exposed to a Water Accommodated Fraction (WAF), at a single nominal loading rate of 100 mg/L, with test media renewal three times per week. The stirring period for the WAF preparation was validated in a preliminary study before the main test. The study was conducted with 21 days exposure at a temperature of 19°C to 21°C. As a test item specific analytical method could not be developed, TOC analysis of the freshly prepared test preparations on Days 0, 4, 11 and 20, and of the old or expired media on Days 6, 13 and 21 was conducted and showed measured test concentrations of less than the LOQ which was determined to be 1.0 mg C/L. On a daily basis the numbers of live and dead of the "Parental" (P1) generation, the numbers of live and dead "Filial" (F1) Daphnia and the number of discarded unhatched eggs were counted. An assessment was also made of the general condition and size of the parental Daphnia as compared with the controls. At the end of the test, the length of each surviving parent animal was determined.

 

The 21-Day EL50 (immobilization) value for the parental daphnia generation (P1) and the 21-Day EL50 (reproduction) were > 100 mg/L, based on nominal loading rates. The No Observed Effect Loading Rate based on nominal loading rates was 100 mg/L, the only concentration tested. Given that the toxicity cannot be attributed to a single component or a mixture of components, but to the test substance as a whole, and the dissolved concentrations were below the quantifiable limit of the analytical method, the results were based on nominal loading rates only.