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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:
08/05/1989 - 12/05/1989
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study was performed to guidelines however no GLP compliance statement was included with the report although is believed that it complies with the 'principles of GLP'.

Data source

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

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: DIN38412 L9
GLP compliance:
not specified
Remarks:
Believed to be in accordance with the principles of GLP.

Test material

Constituent 1
Chemical structure
Reference substance name:
4-chloro-o-cresol
EC Number:
216-381-3
EC Name:
4-chloro-o-cresol
Cas Number:
1570-64-5
Molecular formula:
C7H7ClO
IUPAC Name:
4-chloro-2-methylphenol

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Strain: Chodat
- Source (laboratory, culture collection): Gottingen Algal Collection SAG 86.81

Study design

Test type:
not specified
Water media type:
not specified
Total exposure duration:
96 h

Test conditions

Nominal and measured concentrations:
The test solutions were prepared at the following concentrations:
1.0, 2.5, 5.0, 10.0 25.0 and 50.0 mg/L
Details on test conditions:
TEST SYSTEM
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

OTHER TEST CONDITIONS
- Adjustment of pH: initial and end point measurements in all test batches
-Temperature: incubation of test and control batches at 21 -25°C , temperature must remain within 2 degrees for the duration of the test.


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: fluorimeter

Reference substance (positive control):
yes
Remarks:
Potassium Dichromate

Results and discussion

Effect concentrations
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
ca. 14.81 mg/L
Nominal / measured:
not specified
Conc. based on:
other: Not specified but assumed to be nominal.
Basis for effect:
other: Cell density, growth rate and Inhibition of biomass.
Details on results:
The results were measured using a pulse fluorimeter. The mean results for the 4 replicates at each concentration after 72 hours are summarised below .
Cell Density
0h 24h 48h 72h 96h
Concentration
mg/L (N/ml x 103) (N/ml x 103) (N/ml x 103) (N/ml x 103) (N/ml x 103)
Control 12 29 67 206 564
1.0 13 29 57 158 434
2.5 13 29 57 160 424
5.0 13 29 58 157 438
10.0 13 30 56 128 330
25.0 13 24 35 58 136
50.0 13 17 21 26 23

Evaluation after 72 hours
Concentration
mg/L Growth Rate Inhibition of biomass [%] Rate-Related Inhibition [%]
Control 0.95 - -
1.0 0.83 19.7 12.1
2.5 0.84 19.3 11.7
5.0 0.83 19.1 12.4
10.0 0.76 26.5 19.6
25.0 0.50 61.7 47.4
50.0 0.23 83.3 75.6

EC 10: 1.856 mg/L EbC 10: 0.971 mg/L
EC 50: 26.904 mg/L EbC 50: 14.809 mg/L


Evaluation after 96hours
Concentration
mg/L Growth Rate Inhibition of biomass [%] Rate-Related Inhibition [%]
Control 0.95 - -
1.0 0.88 23.3 8.9
2.5 0.87 23.5 9.5
5.0 0.88 23.2 8.6
10.0 0.81 38.3 16.0
25.0 0.59 73.6 39.0
50.0 0.14 92.5 85.2

EC 10: 2.670 mg/L EbC 10: 0.890 mg/L
EC 50: 25.766 mg/L EbC 50: 8.247 mg/L


The EC50 after 72 hours was calculated to be 14.81 mg/L

Applicant's summary and conclusion

Conclusions:
The EC50 calculated from the study was 14.81 mg/L .
Executive summary:

A guideline study was performed to determine the effect of PCOC on algal cell multiplication.

The test was performed using the test system Scenedesmus subspicatus Chodat, at PCOC concentrations of 1.0, 2.5, 5.0, 10.0, 25.0 and 50.0 mg/L. The cell densities were measured every 24 hours using a fluorimeter..

The test solutions and control were incubated at 21 -25°C with a 2 degree maximum variation over the duration of the test.

The cell density, growth rate and inhibition of biomass were used to calculate the EC 50 value.

The EC50 (72 hours) was 14.81 mg/L PCOC.

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