1,2,4-Oxadiazole, 3-phenyl-5-(2-thienyl)-

Short-term toxicity to fish

Description of key information

The 96 h LC50 value for the test substance was determined  as 76 μg a.i./L, with a 95% confidence interval of 59 to 108 μg a.i./L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.076 mg/L

Additional information

A study was conducted to assess the effects of the test substance on rainbow trout (Oncorhyncus mykiss) according to OECD Guideline 203 and US EPA OPPTS 850.1075, in compliance with GLP. In the study, the fish were tested at nominal concentrations of 0.0 (negative control), 0.0 (solvent control), 9.4, 19, 38, 75, and 150 μg a.i./L in a static-renewal system for 96 h, with renewals being performed every 24 h. Two replicate test chambers were maintained in each treatment and control group, with 10 fish in each test chamber, for a total of 20 fish per concentration. Mortality and signs of toxicity or abnormal behavior were monitored at approximately 6, 24, 48, 72 and 96 h after test initiation. The mean measured test concentrations were 7.2, 14, 30, 61 and 126 μg a.i /L, representing 77, 74, 79, 81 and 84% of nominal values, respectively. The results of the study were calculated based on mean measured concentrations. All water quality measurements remained within acceptable limits. The concentrations of the test substance remained stable over time under the conditions of administration, ranging from 60 to 99% of nominal values during the study. All fish in the negative control, solvent control, 7.2 and 14 μg a.i./L treatment groups appeared normal and healthy throughout the test. Mortality in the 30, 61 and 126 μg a.i./L treatment groups was equivalent to 10, 45 and 70%, respectively. Signs of toxicity observed in the 61 and 126 μg a.i./L treatment groups included lethargy and loss of equilibrium. The 96 h LC₅₀value was determined as 76 μg a.i./L, with a 95% confidence interval of 59 to 108 μg a.i./L (Thomas ST, 2012).