Amitrole

Short-term toxicity to aquatic invertebrates

Description of key information

Key study, US EPA-similar to OECD 202- GLP:

48h-LC50 (Daphnia magna)= 18 mg/L

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

18 mg/L

Additional information

In an acute aquatic toxicity study, performed similarly to OECD Guideline 202 and in compliance with GLP, groups (20/dose, 2 replicates of 10 daphnids/vessel) of Daphnia magna were exposed to the test item at nominal concentrations of 0 (control), 10, 18, 32, 56 and 100 mg/L for 48 h under static conditions. All vessels were observed at 24 and 48 h for mortality and abnormal effects such as surfacing, clumping of the daphnids together and daphnids lying on the bottom of test chambers. A preliminary range-finding test was also conducted on daphnids (10/concentration) at 1, 10 and 100 mg/L (nominal) and mortality and behavioural observations were observed for 48 h. In this previous test, mortalities at 1.0, 10 and 100 mg/L were 0, 0, and 0 at 24 h, and 0, 0 and 10 at 48 h, respectively.

In the main test, mortalities at 0, 10, 18, 32, 56 and 100 mg/L were 0, 0, 0, 0, 80 and 100% at 24 h; and 0, 0, 55, 95, 100 and 100% at 48 h, respectively. The 24 and 48 h LC50 values for the test item in Daphnia magna was considered to be 47 (32-56) and 18 (16-21) mg/L (nominal concentrations), respectively. The highest tested concentration without observed effect (48 h) was 10 mg/L, based on the lack of mortality and abnormal effects.

Under the test conditions, the 48 h LC50 for the test item was 18 (16-21) mg/L on Daphnia magna.