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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:
2006

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Test material form:
liquid
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Purity : 96.70%

Sampling and analysis

Analytical monitoring:
yes

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
ACCLIMATION
- Acclimation period:12 days
- Acclimation conditions: same as test

Study design

Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
Algal cell density was measured every 24 h by microscope direct count in all the best concentration and in the control.

Test conditions

Test temperature:
in the range 23 °C /- 2°C
pH:
8.70-8.80
Nominal and measured concentrations:
Nominal concentration in a geometric series, namely 0.5, 0.9, 1.6, 2.8 and 5.0 mg/l.
Details on test conditions:
Three replicates for each concentration and six for control were prepared.
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
0.6 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
2.9 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
0.2 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
0.4 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Details on results:
The test item concentration was not stable during the test, the measured concentrations ranging from 34% to 92% of the nominal value already short after being prepared (time 0 h), while further decrease occurrred during the following day (to 29-43 % of the nominal after 72 h). Therefore the biological results are not referred to the nominal concentration but to the geometric mean of the measured concentration.

Any other information on results incl. tables

In the test medium concentration the algal biomass and the growth rate after 72 hours of exposure were inhibited respectively by 17% and 3% for lowest concentration to a maximum of 86% and 44% for the highest concentration, compared with control flash.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
For the test item d-trans Allethrin 75/25 the NOEC and LOEC values after 72 hours are the same for both endpoint, growth rate and biomass growth, respectively 0.20 and 0.41 mg/l.
EC50 growth rate: 2.87 mg/l (95% 2.31-3.50)
EC50 biomass: 0.57 mg/l (95% 0.15-0.97)

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