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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:
July 20, 2007 - August 01, 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: study conform with Directive 92/69/EEC, C.3, OECD Guideline No. 201

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

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

Test material

Constituent 1
Details on test material:
Identity: AES
Batch No.: LSF7
Purity: 80.3%
Expiration date: February 15, 2008
Solubility in water: Very soluble
Stability in water: 30 days
Aggregate state / physical
form at room temperature: Solid
Specific information: Slightly hygroscopic
Storage conditions: In a refrigerator at about 4 °C.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Treatment samples and control samples were thawed at 30 °C (water bath) for 0.5 hours and shaken manually to obtain homogeneous sample solutions. 1 mL solution A was added to 0.167 mL of each standard and sample. The mixtures were left in the dark for 30 minutes and shaken manually.
A15/25/26/27/28 and AZ2/4 were filtered through a 0.45 µm PTFE filter (13 mm, P/N: F1304-2, Lot: 00064395) because of a turbidity due to algae growth.
Aliquots of the final solutions were analyzed by HPLC with UV/VIS-detection.

Test solutions

Vehicle:
no
Details on test solutions:
The following nominal concentrations of AES were tested: 2.2, 4.6, 10, 22, 46 and 100 mg/L. Additionally, a control was tested in parallel (test water without test item).
The test medium of the highest nominal test item concentration of 100 mg/L was prepared by dissolving 50.3 mg of the test item completely in 500 mL of test water using intense stirring (15 minutes at room temperature). Adequate volumes of this test medium were diluted with test water to prepare the test media with the lower test item concentrations. The test media were prepared just before the start of the test (= addition of algae).

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
Strain No. 61.81 SAG
Supplied by the Collection of Algal Cultures (SAG, Institute for Plant Physiology, Universität of Göttingen / Germany)
The algae are cultivated in RCC's laboratories under standardized conditions according to the test guidelines.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

Hardness:
24 mg/L as CaCO3
Test temperature:
23°C
pH:
pH value of 8.7 to 9.8 were measured.
Nominal and measured concentrations:
LOEC: Mean measured concentration of 95 mg/L (nominal concentration of 100 mg/L)
NOEC: Mean measured concentration of 36 mg/L (nominal concentration of 46 mg/L)
Details on test conditions:
The algae were cultivated and tested in synthetic test water, prepared according to the test guidelines. Analytical grade salts were dissolved in sterile purified water to obtain the Calculated water hardness of the test water: 0.24 mmol/L (= 24 mg/L as CaCO3).
-The test design: Three replicates per test concentration and six replicates for the control.
-Volumes : 15 mL algal suspension for each replicate
-Temperature: Controlled water bath at a temperature of 23 °C
-Measured light intensity: 6900 Lux (mean value), range: 6200 to 7500 Lux
-Fluorescent tubes: (Philips TLD 36W/840), installed about 35 cm above the test flasks.
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 95 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: could not be determined
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
88 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: could not be determined
Duration:
72 h
Dose descriptor:
EC90
Effect conc.:
> 95 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: could not be determined
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
36 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
95 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
The microscopic examination of the algal cells after 72 hours exposure showed no difference between the algae growing at the nominal test concentration of 100 mg/L and the algal cells in the control. The shape and size of the algal cells growing in test media containing the test item at and up to this test concentration were obviously not affected.
No remarkable observations were made concerning the appearance of the test media. All test media were clear solutions throughout the test period.
Results with reference substance (positive control):
The algal cells after 72 hours exposure showed no difference between the algae growing at the nominal test concentration of 100 mg/L and the algal cells in the control.
Reported statistics and error estimates:
The growth rate and yield of the algae were not statistically significantly lower than in the control.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
No remarkable observations were made concerning the appearance of the test media.
Executive summary:

The 72‑hour NOEC (highest concentration tested without toxic effects) was determined to be 36 mg/L (nominal 46 mg/L), since up to and including this test concentration the growth rate and yield of the algae were not statistically significantly lower than in the control. The EC values as well as the NOEC and LOEC were calculated for both parameters, the growth rate and the yield after 72 hours test duration on the basis of mean measured concentrations of the test item.