1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine

Short-term toxicity to aquatic invertebrates

Description of key information

48-hour EC50 = 18 mg/L, NOEC = 10 mg/L, LOEC = 32 mg/L, OECD 202 and EU Method C.2

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

18 mg/L

Additional information

A study was performed to assess the acute toxicity of the test material to Daphnia magna. The study was conducted in accordance with the standardised guidelines OECD 202 and EU method C.2 under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

Following a preliminary range-finding test, twenty daphnids (4 replicates of 5 animals) were exposed to an aqueous solution of the test material at concentrations of 1.0, 3.2, 10, 32 and 100 mg/L for 48 hours at a temperature of approximately 20 °C under semi-static test conditions. The number of immobilised daphnia was recorded after 24 and 48 hours.

Analysis of the test preparations at 0, 24 (old and fresh media) and 48 hours showed measured test concentrations to range from 97 to 104 % of nominal value and so the results are based on nominal test concentrations only.

100 % immobilisation at 48 hours was observed in the 32 and 100 mg/L test concentrations. Microscopic observations were performed on the immobilised daphnia in the 32 mg/L test concentration due to the fact that precipitation was observed. However, no test material was observed to be adhered to the daphnia and as such it was considered that the immobilisation observed was due to a true toxic effect of the test material rather than due to any physical effects.

Under the conditions of this study, the 48 hour EC50 was 18 mg/L (95 % Confidence Limits 10 - 32 mg/L). The NOEC and LOEC were 10 and 32 mg/L, respectively.