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

Toxicity to aquatic algae and cyanobacteria

Description of key information

Under the test conditions, the 72 h EbC50 and ErC50 values for the test substance were 83 and >109 μg a.i./L, respectively, and the 96 h EbC50 and ErC50 were 94 and >109 μg a.i./L, respectively. The 72 and 96 h NOEC values were determined to be 30 μg a.i./L.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

0.03 mg/L

Additional information

A study was conducted to determine the effect of the test substance on algal growth using the freshwater alga (Pseudokirchneriella subcapitata), over an exposure period of 96 h according to OECD Guideline 201, EU Method C.3., and OPPTS 850.5400.Three replicate per test concentration of P. subcapitata (initial cell density in each chamber was 1 x 10⁴cells/mL) were exposed to the test substance for 96 h at nominal concentrations of 63, 125, 250, 500 and 1,000 μg a.i./L under static condition. These values corresponded to measured concentrations of 24, 30, 38, 77 and 109 μg a.i./L. A solvent control group (0.1 mL N,N-dimethylformamide/L) with three replicate test chambers and a negative control group (culture medium) with six replicate chambers were held under the same environmental conditions concurrently. All samples were evaluated for effects on cell density, area under the growth curve, yield and growth rate. The 72 and 96 h NOEC values were determined to be 30 μg a.i./L. The 72 h EbC50 and ErC50 values were 83 and109 μg a.i./L, respectively. The 96 h EbC50 and ErC50 values were 94 and >109 μg a.i./L, respectively (Arnie JR, 2014).