Butanamide, N-(3-ethoxypropyl)-2,4-dihydroxy-3,3-dimethyl-

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 1994-09-20 to 1994-10-15

Reliability:

1 (reliable without restriction)

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Report date:

1994

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

directive 92/69/EEC

Deviations:

no

Principles of method if other than guideline:

NA

GLP compliance:

yes

Test material

Test material information

Constituent 1

Test material form:

liquid: viscous

Details on test material:

NA

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
NA

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Frequency: at t=0 h and t= 96h
Volume: 10 mL

Test solutions

Vehicle:

yes

Details on test solutions:

The test solutions were prepared using a stock solution in ISO-medium. For this purpose the test substance was added quantitatively to obtain a nominal concentration of 100 mg/L. From this stock solution the required volumes for preparation of the test concentrations were added to ISO-medium. The final volume of the test solutions was 50 mL per vessel. Subsequently, a volume of 0.59 mL of the algal suspension was added to each Vessel providing a concentration of 1 x 10000 algal cells/mL. At the start of the test all test solutions were clear.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

strain 86.81 SAG.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

NA

Test conditions

Hardness:

24 mg CaCO3/L

Test temperature:

The temperature ranged from 21 to 22 °C.

pH:

The pH-values ranged from 8.0 to 8.4 at 0h and 96h.

Dissolved oxygen:

NA

Salinity:

NA

Nominal and measured concentrations:

At the start of the test, the actual test concentrations were in agreement with nominal at 32 and 100 mg/L. The actual concentrantions measured in the sample taken 10 mg/L was ca. 30 % higher than nominal due to an interfering response recorded in the test medium. At the end of the 96-hour period the measured concentrations had not decreased by more than 20 % in any of the samples.

Details on test conditions:

NA

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

NA

Results with reference substance (positive control):

Concentrations: 0.18, 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L
The nominal 72-hour EC50 for growth inhibition (EBC50:0-72h) was 0.32 mg/L with 95 % fiducial limits: 0.20 - 0.44 mg/L.
The nominal 72-hour EC50 for growth rate reduction (ErC50: 0-72h) was 0.88 mg/L with 95 % fiducial limits: 0.65 - 1.42 mg/L.

Reported statistics and error estimates:

NA

Any other information on results incl. tables

no remarks

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

EC50 > 100 mg/L

Executive summary:

No inhibition of cell growth or reduction of growth rate was recorded at any of the concentrations of the test item tested. Hence, the EC50 values for both, cell growth inhibition (EBC50: 0 -96h) and growth rate reduction (ERC50: 24 -96 h) were beyond the range tested, i.e. > 100 mg/L.