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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report Date:
2019

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
a off-white powdery solid, without irritating odor

Test solutions

Vehicle:
yes
Details on test solutions:
99.84 %

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
Supplier: Hoseo Toxicological Research Center

Study design

Test type:
semi-static
Water media type:
other: OECD medium
Limit test:
yes
Total exposure duration:
72 h
Remarks on exposure duration:
24, 48 and 72 hrs

Test conditions

Test temperature:
22.4 ~ 22.6 °C
pH:
7.73 ~ 8.23
Nominal and measured concentrations:
5.0, 10.0 and 100.0 mg/L
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
other: EyC50
Effect conc.:
> 0.004 mg/L
Duration:
72 h
Dose descriptor:
other: ErC50
Effect conc.:
> 0.004 mg/L
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 0.004 mg/L
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
> 0.004 mg/L
Details on results:
Median Effective concentration(EC50), the No Observed Effect concentration(NOEC) and the Lowest Observed Effect concentration(LOEC)(Table 8, 9 and Appendix 1, 2) The 72 hours ErC50 and EyC50 value of TR-NPI-20400 to Pseudokirchneriella subcapitata was determined to be > 0.00375 mg/L, NOEC was ≥ 0.00375 mg/L and LOEC was > 0.00375 mg/L. The ErC50, EyC50, NOEC and LOEC were based on geometric means measured concentration.

Any other information on results incl. tables

This study was performed to assess the effect of the test substance, TR-NPI-20400, on the growth of the freshwater alga, Pseudokirchneriella subcapitata, when exposed to the test substance for 72 hrs under the shaking culture and to determine the median effective concentration(EC50) from the average specific growth rate and yield of each treatment group.

Based on the result of the range finding test, the limit test was conducted and the treatment levels were selected at 100.0 mg/L, and a control group was prepared for this study. The biomass in the control group was increased by 195 times or more during the exposure period, and each coefficient of variation was confirmed to be acceptable in this study.

As a result of the analytical report, the test substance in the test solution at the nominal concentration of 100.0 mg/L of this limit test was analyzed for 72 hrs. The average measured concentration of test solution was 0.00375 mg/L and the concentration was 0.00375 % compared to nominal concentration. Therefore, all test results were determined based on the geometric means measured concentration.

At 24, 48 and 72 hrs after exposure, no atypical cell morphology was evident in the 100.0 mg/L treatment group and control group.

During the exposure period, the water temperature and illuminance of the test solution were 22.4 ~ 22.6 °C and in the range of 5478 ~ 5926 Lux, respectively. These were within the permissible ranges. The measured pH values including 100.0 mg/L treatment group were in the range of 7.86 ~ 7.86 at initiation of the exposure and in the range of 7.73 ~ 8.23 at 72 hrs after exposure, respectively.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The 72 hours ErC50 and EyC50 value of TR-NPI-20400 to Pseudokirchneriella subcapitata was determined to be > 0.00375 mg/L, NOEC was ≥ 0.00375 mg/L and LOEC was > 0.00375 mg/L. The ErC50, EyC50, NOEC and LOEC were based on geometric means measured concentration.