Hexaphenoxycyclotriphosphazene

Toxicity to aquatic algae and cyanobacteria

Description of key information

Algal growth inhibition test of FP-100 with Pseudcikirchneriella subcapitata was conducted. The time-weighted mean values obtained at 1.00, 0.316 and 0.100 mg/L were 0.643, 0.215 and 0.0727 mg/L, respectively, and test results were evaluated based on these values.
EbC50 (0-72h) and ErC50 (0-3d) of FP-100 calculated from the data on the area under the growth curve and growth rate were both >0.643 mg/L. No observed effect concentration (NOEC) based on each parameter was also 0.643 mg/L.
The measured concentrations was 0.402 mg/L in 1.00 mg/L of the highest concentration at the end of the exposure although each measured concentration during the exposure was not kept within ±20 per cent of the nominal concentration. This concentration was estimated to be higher than the expected solubility to test medium. Therefore, It is concluded that there is no potential for adverse effect of the test item on the test organisms near the solubility to the test medium.

Key value for chemical safety assessment

EC50 for freshwater algae:

0.643 mg/L

EC10 or NOEC for freshwater algae:

0.643 mg/L

Additional information

Algal growth inhibition test of FP-100 withPseudcikirchneriella subcapitatawas conducted. The test was performed under the following conditions: three concentrations of test item at 1.00, 0.316 and 0.100 mg/L, and a vehicle control and a control, temperature at 21-24°C (deviation of ±2°C), continuous fluorescent lamp illumination of 60-120 µE/m2s (deviation of ±20%) at surface of the test solutions. The airtight test vessels were used and continuously shaken with gyration at about 100 rpm. Algal growth was determined by the measurement of cell concentration.   The measured concentrations of the test item in the test solution at the start and end of the exposure were 96.6 to 109% and 26.0 to 40.2% of the nominal concentration, respectively. The time-weighted mean values obtained at 1.00, 0.316 and 0.100 mg/L were 0.643, 0.215 and 0.0727 mg/L, respectively, and test results were evaluated based on these values.   EbC50 (0-72h) and ErC50 (0-3d) of FP-100 calculated from the data on the area under the growth curve and growth rate were both >0.643 mg/L. No observed effect concentration (NOEC) based on each parameter was also 0.643 mg/L.   The measured concentrations was 0.402 mg/L in 1.00 mg/L of the highest concentration at the end of the exposure although each measured concentration during the exposure was not kept within ±20 per cent of the nominal concentration. This concentration was estimated to be higher than the expected solubility to test medium. Therefore, It is concluded that there is no potential for adverse effect of the test item on the test organisms near the solubility to the test medium.