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Ecotoxicological information

Long-term toxicity to aquatic invertebrates

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Description of key information

Daphnia magna reproduction test (OECD 211): Immobilisation: EL50(21d): 0.75 mg/L, NOELR: 0.32 mg/L / Reproduction: EL50(21d): 0.50 mg/L, LOELR: 0.56 mg/L

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater invertebrates:
0.32 mg/L

Additional information

The long-term toxicity to invertebrates of the test substance to Daphnia magna was investigated according to OECD Guidelines for Testing of Chemicals No 211 (1998) "Daphnia magna, Reproduction Test" (Wetton, 2003). Based on the results of peliminary range-finding tests, the invertebrates were exposed (10 replicates of a single daphnid per group) to filtered Water Accommodated Fractions (WAFs) of the test material over a range of loading rates of 0.10, 0.18, 0.32, 0.56 and 1.0 mg/L for a period of 21 days. The test solutions were renewed 3 times per week. The numbers of live and dead adult Daphnia and young daphnids (live and dead) were determined daily. The Daphnia were fed daily with an algal suspension (Chlorella sp.), whereby the level was approximately 0.1 - 0.2 mg carbon/daphnid/day, dependent on the age and size of the animal. Adult Daphnia unable to swim for approximately 15 seconds after gentle agitation (ie. immobile), were considered to be dead. An immobilisation criterion for the young daphnids was considered to be inappropriate due to the large numbers of off-spring produced in the flasks.The 14 and 21-Day EL50 (immobilisation) value, based on nominal loading rates, for the parental Daphnia generation (P1) was calculated to be 0.75 mg/L loading rate WAF with 95 % confidence limits of 0.56 – 1.0 mg/L loading rate WAF. The 21-Day EL50 (reproduction) value based on nominal loading rates was calculated to be 0.50 mg/L loading rate WAF with 95 % confidence limits of 0.39 – 0.63 mg/L loading rate WAF. The "Lowest Observed Effect Loading Rate" was considered to be 0.56 mg/L on the basis that at this test concentration significantly fewer live young per adult (P < 0.05) were produced when compared to the control. The "No Observed Effect Loading Rate " was considered to be 0.32 mg/L on the basis that at this test concentration there were no mortalities (immobilisation) observed in the parental generation (P1) and that there were no significant differences (P 0.05) between the control and the 0.32 mg/L loading rate WAF test group in terms of numbers of live young produced per adult by Day 21.