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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
Study period:
from 12 December 1988 to 20 April 1989
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report Date:
1989

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Batch n. Lot 210200
Purity: 98.2%
Appaerance: white powder
Solubility in water: 30 mg/L
Storage: room temperature

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Duplicate samples (ca. 50 ml) were taken at 0h and 72 h.
Samples for analysis were taken at the start and at the end of the exposure.

Test solutions

Vehicle:
yes
Details on test solutions:
The nominal test concentrations (mg/L): 0.0037, 0.011, 0.033, 0.10, 0.30.
Calculated amounts of stock solution to produce the desired test concentrations were given into the water and were homogeneously distributed.
The stock solution has been prepared mixing 10 mg of atrazine with 4 mg of alkylphenol-polyglykol-ether and made up to 1000 ml with water. This solution was diluted to 0.303 mg/L with water.
Controls:
The blank was water
The vehicle: 0.12 mg alkylphenol-polyglykol-ether per liter water in the concentration used for the highest test concentration.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
Test system: Scenedesmus subspicatus
Strain / Origin:276/20
Initial cell density: 1.2 * 10000 cells/ml
Culture: According to OECD-Guideline No. 201,1984
Preculture: 3 days under test conditions

Study design

Test type:
not specified
Water media type:
not specified
Limit test:
no
Total exposure duration:
72 h

Test conditions

Hardness:
see salinity
Test temperature:
23 ± 2°C, The temperature has been measured in continuous.
pH:
pH
Conc. Nominal mg/L 0 h 72 h
Blank 7.4 10.2
Vehicle 7.4 10.0
0.0037 7.4 10.1
0.011 7.4 10.1
0.033 7.4 9.5
0.10 7.4 7.9
0.30 7.4 7.8
The pH has been measured at the start and at the and of the exposure.
Dissolved oxygen:
no data
Salinity:
Composition of water according to OECD-Guideline No. 201, Paris 1984
Nominal and measured concentrations:
The content of atrazine was found to vary between 91 and 102% of the nominal concentrations in the day 0 samples and between 78 and 93 % of the nominal concentrations in the day 3 samples.
Details on test conditions:
Exposure : 100 ml Erlenmeyer flasks. stoppered with aluminium caps, on lab-shaker, 50 ml test solution
Water : Composition according to: OECD-Guideline No. 201,1984
Temperature : 23 ± 2°C
Aeration : None
Light : Continuous illumination, cold white fluorescent light, 120 sE/m2sec ± 20% (approx. 8000 lux)
Duration : 72 hours
Each test concentration was tested in 3 replicates, the blank control in 6.
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
0.043 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
cell number
Remarks on result:
other: none
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
0.011 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
cell number
Details on results:
EC50 (0 - 72h) calculated: 0.043 mg/L
EC50 (0 - 72h) graphically determined: 0.045 mg/L
NOEC (0 - 72h): 0.011 mg/L

Comparison of areas under the growth curve according to OECD-Guideline No. 201,1984.
The EC-50 values were calculated according to BERKSON, JASA 48 (1953), 569-599.
EC-values were graphically determined on gausso-logarithmic probabilitypaper.
The NOEC was calculated according to DUNNETT, C.W., JASA 50 (1955), 1096-1121, Biometrics 20 (1964), 482-491, and modified by MARCUS et al.,Biometrika 63 (1976), 655-660.
Results with reference substance (positive control):
Not applicable

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified