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Toxicity to aquatic algae and cyanobacteria

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Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
16 May 2006 to 7 July 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
GLP according to German "Chemikaliengesetz", EC and OECD Guideline principles
Analytical monitoring:
yes
Details on sampling:
The saturated solution and control were analytically verified via analysis of organic carbon (DOC, according to DIN EN 1484) at test start and test end.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances): A dispersion of 10 mg/L, prepared in dilution water, was shaken with 20 rpm for 24 h at 23 ± 2 °C and centrifugated with 3000 rpm for 20 min.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Strain: Desmodesmus subspicatus CHODAT SAG 86.81
- Source (laboratory, culture collection): Sammlung von Algenkulturen (SAG), Pflanzenphysiologisches Institut der Universität Göttingen, Göttingen, Germany
- Age of inoculum (at test initiation): three day-old preculture
- Method of cultivation: Fresh stocks were prepared every month on Z-Agar. Light intensity amounted 35-70 ¿E·m-2·s-1 for 24 h per day.

ACCLIMATION
- Acclimation period: three days, see above
- Culturing media and conditions (same as test or not): preculture incubated at study conditions
- Any deformed or abnormal cells observed: no
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Post exposure observation period:
None. Observations were carried out during exposure at the beginning of the experiment and after 24, 48 and 72 hours.
Hardness:
0.24 mmol Ca+Mg/l for the dilution water
Test temperature:
22-24 (mean: 23) °C
pH:
Start: 7.91 (test solution), 7.81 (control)
End, 72 h: 8.33 (test solution), 8.31 (control)
Dissolved oxygen:
DOC (mg/l) (mean of two parallel determinations):
Start (without algae): 1.6 (test solution), 1.5 (control)
End, 72 h (without algae): 5.2 (test solution), 4.5 (control)
Nominal and measured concentrations:
A limit test with a saturated solution (dispersion of 10 mg/L, see above) was carried out.
Details on test conditions:
TEST SYSTEM
- Test vessel: Sterile erlenmeyer flasks, volume: 250 mL
- Initial cells density: nominally 1000 - 10000 cells/mL
- Control end cells density: 580011 (mean from 6 replicates) cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dilution water according to guidelines
- Intervals of water quality measurement: at the start and at the end (72 h)

OTHER TEST CONDITIONS
- Sterile test conditions: yes (sterile erlenmeyer flasks were used)
- Photoperiod: 24 h/d
- Light intensity and quality: 60.1 (start) and 67.7 (end, 72 h) (mean 64.4 ¿E·m-2·s-1)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Chlorophyll-impulsfluorometer
- Chlorophyll measurement: Chlorophyll-a-fluorescence, excitation at 435 nm, emission at 685 nm
- Other: measurements at the beginning of the test (after application) and every 24 h, dilution water was used as background signal

TEST CONCENTRATIONS
- Spacing factor for test concentrations: only one concentration (saturated solution), limit test
- Justification for using less concentrations than requested by guideline: limit test
Reference substance (positive control):
yes
Remarks:
Potassium dichromate p.a.
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Due to poor solubility of the test item, a limit test with a nominal concentration of 10 mg/L had been performed.
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: Due to poor solubility of the test item, a limit test with a nominal concentration of 10 mg/L had been performed.
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Due to poor solubility of the test item, a limit test with a nominal concentration of 10 mg/L had been performed.
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: Due to poor solubility of the test item, a limit test with a nominal concentration of 10 mg/L had been performed.
Details on results:
Biomass growth and rate-related inhibition:
- EC50: >saturated solution
- NOEC: saturated solution
- LOEC: >saturated solution

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no

Environmental conditions, pH-value, measured at 0 and 72 h, and room temperature, measured continuously, met the guideline requirements.
Results with reference substance (positive control):
- Results with reference substance valid? yes
- EC50 (biomass growth): 0.31 mg/l (0-72 h), 95 % confidence interval: 0.30-0.32 mg/l
- EC50 (rate-related inhibition): 0.65 mg/l (0-72 h), 95 % confidence interval: 0.57-0.73 mg/l
Reported statistics and error estimates:
The NOEC and LOEC were determined by calculation of statistical significance of biomass integrals and growth rates. One Way Analysis of Variance (ANOVA) and DUNNETT¿s test was carried out for the determination of statistically significant differences compared to control replicates. When running a One Way Analysis of Variance a Normality Test and an Equal Variance Test were done first. P-values for both Normality and Equal Variance Tests were 0.05. The ¿-value for ANOVA was ¿=0.05.
Validity criteria fulfilled:
yes
Conclusions:
No inhibiting effects on biomass growth and specific growth rate were found in the saturated solution. The EC50-values for inhibition of biomass growth (EbC50) and specific growth rate (ErC50) after 72 h were > saturated solution.
Executive summary:

The toxicity of the test item (Pigment Red 122) to the unicellular freshwater green alga Desmodesmus subspicatus was determined according to the principles of OECD-Guideline 201 (1984) and Directive 92/69/EC Method C.3 at DR.U.NOACK-LABORATORIEN in 31157 Sarstedt, Germany from May 22 to 25, 2006. The aim of the study was to assess the effects on growth rate and biomass production over a period of 72 h. The study was conducted under static conditions with an initial cell density of nominally 103 - 104 cells/mL. A limit test with a saturated solution was carried out. A dispersion of 10 mg/L was prepared in dilution water, shaken for 24 h at 23 ± 2°C and centrifugated with 3000 rpm for 20 min. Six replicates were tested for the saturated solution and control. Environmental conditions, pH-value and room temperature, were determined to be within the acceptable limits. DOC-analysis was carried out at test start and test end from the saturated solution and control. All effect values are based on the saturated solution of the test item.

In this study the test item did not cause any inhibiting effects to Desmodesmus subspicatus after 72 h when tested with a saturated solution.

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2008-04-11 - 2008-04-21
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The test had been conducted according to relevant guidelines with only a minor deviation (three treatment replicates instead of six for a limit test). It was performed compliant to GLP and all the validity criteria of the guideline are fulfilled. The results are plausible and well documented.
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
yes
Remarks:
OECD-Guideline 201 demands 6 treatment replicates for a limit test. Deviating from this, only 3 treatment replicates had been tested as demanded for standard testing of different test substance concentrations.
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
GLP compliance:
yes (incl. QA statement)
Remarks:
Swiss Ordinance on Good Laboratory Practice, adopted on 18th May 2005 [OGLP, SR 813.112.1) based on OECD-GLP 1997 (C(97)186/Final)
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
not applicable
Analytical monitoring:
no
Details on sampling:
not applicable
Vehicle:
no
Details on test solutions:
Due to the limited water solubility of the test substance, in a concentration of 100 mg/L was moderately stirred in algal medium for 96 h at room temperature. After this incubation time, the undissolved material was first removed by a glass fiber filter (MILLIPORE AP15) and subsequently by membrane filtration (0.1 µm, Supore-100) to obtain a water accommodated fraction for the algal growth test. The pH of the OECD medium was not adjusted before the test. Blanks of test medium without test substance served as controls. Three replicates of the test substance and five replicates for the blank control were prepared. An exponentially growing preculture of algae was used to inoculate sterile test flasks. Test flasks were placed on an orbital shaker at a nominal shaking speed of 160 revolutions per min.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
Axenic slope culture of Desmodesmus subspicatus (formerly known as Scenedesmus subspicatus) 86.81 SAG (Collection of Algal Cultures, Institute of Freshwater Ecology, University of Göttingen, D-37073 Göttingen, Germany.
Culture: 100 mL flask containing 50 mL of sterile OECD medium inoculated with cell material from axenic slope culture.
Continuous illumination (6000-10000 lux), from high pressure sodium lamp Eye Sunlux Ace (Eye, Tokio, Japan).
Temperature: 22 ± 2 °C, thermo-controlled room.
Sensitivity control: Periodically conducted reference test with potassium dichromate.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Post exposure observation period:
not applicable
Hardness:
according to OECD standard medium
Test temperature:
22°C +/- 2°C
pH:
8 +/- 0.2
Dissolved oxygen:
not applicable
Salinity:
not applicable
Nominal and measured concentrations:
Due to the poor water solubility of the test item, a ilmit test had been performed at 100 mg/L nominal concentration.
Details on test conditions:
According to OECD-guideline 201.
Reference substance (positive control):
no
Remarks:
Potassium dichromate as reference substance in periodically performed sensitivity tests - however, no data presented in the report.
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Limit test at 100 mg/L nominal concentration due to poor solubility of test item in water
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: Limit test at 100 mg/L nominal concentration due to poor solubility of test item in water
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Limit test at 100 mg/L nominal concentration due to poor solubility of test item in water
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: Limit test at 100 mg/L nominal concentration due to poor solubility of test item in water
Details on results:
Based an the results of the study it can be concluded that the EC50 (growth rate, 0-72 h) and the EC50 (yield, 0-72 h) of the test item to Desmodesmus subspicatus is >100 mg/L.
The STUDENT-t test for homogeneous variances revealed that the test item caused a significant growth stimulation (hormesis) in Desmodesmus subspicatus. Nevertheless, since no inhibition was observed, the no-observed-effect concentration (NOEC) for growth rates and yield with respect to the loading rate was equal to or larger as 100 mg/L.
Results with reference substance (positive control):
not applicable
Reported statistics and error estimates:
The no observed effect concentration (NOEC) is the highest concentration for which the observed effect is not significantly different from the controls. The statistical significance of differences between effects observed for control and test substance treatments was determined by STUDENT-t test for homogeneous variances using the ToxRat Standard Version 2.09 (ToxRat Solutions GmbH, Alsdorf, Germany).
Validity criteria fulfilled:
yes
Conclusions:
In a fresh water algal growth inhibition test with Desmodesmus subspicatus the toxicity of the submission substance to aquatic plants had been tested (reliability category 2, compliant to GLP). A static limit test had been performed at a nominal concentration of 100 mg/L due to the poor solubility of the test item. The submission substance prooved to be non-toxic to Desmodesmus subspicatus under the applied test conditions:
NOEC (growth rate / yield, 72h) equal to or larger as 100 mg/L;
EC50 (growth rate / yield, 72h) > 100 mg/L;
Executive summary:

The median growth inhibiting concentrations (EC50) based an the average specific growth rate and the yield (algal biomass production) within 3 days, of the test item to the green alga Desmodesmus subspicatus were investigated over a period of 72 h. The only applied nominal test concentration was 100 mg/L. Due to the limited water solubility of the test substance, only the water accommodated fraction of the test item was tested. This water accommodated fraction was prepared by moderately stirring the respective concentration per liter of algal medium for 96h. After this incubation time, the undissolved material was first removed by a glass fiber filter and subsequently by membrane filtration to obtain a water accommodated fraction for the algal growth test. 3 parallel test vessels were used for the tested concentration of the test substance. No chemical analysis of the test media was conducted.

At the loading rate of 100 mg/L no growth inhibition (<10%) with respect to algal growth rates and algal yield (biomas production) compared to the untreated controls were observed.

The no-observed-effect concentration (NOEC) for growth rates and yield with respect to the loading rate was ¿ 100 mg/L nominal concentration.

Based on the results of the study it can be concluded that the EC50 (growth rate / yield, 0 -72 h) of the test item to Desmodesmus subspicatus are >100 mg/L nominal concentration.

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
2008-04-11 - 2008-04-21
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The test had been conducted according to relevant guidelines with only a minor deviation (three treatment replicates instead of six for a limit test). It was performed compliant to GLP and all the validity criteria of the guideline are fulfilled. The results are plausible and well documented.
Justification for type of information:
see Rationale and Justification for the Analogue Read-Across Approach used for the Registration of Pigment Red 202 (Chapter 13)
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
yes
Remarks:
OECD-Guideline 201 demands 6 treatment replicates for a limit test. Deviating from this, only 3 treatment replicates had been tested as demanded for standard testing of different test substance concentrations.
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
GLP compliance:
yes (incl. QA statement)
Remarks:
Swiss Ordinance on Good Laboratory Practice, adopted on 18th May 2005 [OGLP, SR 813.112.1) based on OECD-GLP 1997 (C(97)186/Final)
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
not applicable
Analytical monitoring:
no
Details on sampling:
not applicable
Vehicle:
no
Details on test solutions:
Due to the limited water solubility of the test substance, in a concentration of 100 mg/L was moderately stirred in algal medium for 96 h at room temperature. After this incubation time, the undissolved material was first removed by a glass fiber filter (MILLIPORE AP15) and subsequently by membrane filtration (0.1 µm, Supore-100) to obtain a water accommodated fraction for the algal growth test. The pH of the OECD medium was not adjusted before the test. Blanks of test medium without test substance served as controls. Three replicates of the test substance and five replicates for the blank control were prepared. An exponentially growing preculture of algae was used to inoculate sterile test flasks. Test flasks were placed on an orbital shaker at a nominal shaking speed of 160 revolutions per min.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
Axenic slope culture of Desmodesmus subspicatus (formerly known as Scenedesmus subspicatus) 86.81 SAG (Collection of Algal Cultures, Institute of Freshwater Ecology, University of Göttingen, D-37073 Göttingen, Germany.
Culture: 100 mL flask containing 50 mL of sterile OECD medium inoculated with cell material from axenic slope culture.
Continuous illumination (6000-10000 lux), from high pressure sodium lamp Eye Sunlux Ace (Eye, Tokio, Japan).
Temperature: 22 ± 2 °C, thermo-controlled room.
Sensitivity control: Periodically conducted reference test with potassium dichromate.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Post exposure observation period:
not applicable
Hardness:
according to OECD standard medium
Test temperature:
22°C +/- 2°C
pH:
8 +/- 0.2
Dissolved oxygen:
not applicable
Salinity:
not applicable
Nominal and measured concentrations:
Due to the poor water solubility of the test item, a ilmit test had been performed at 100 mg/L nominal concentration.
Details on test conditions:
According to OECD-guideline 201.
Reference substance (positive control):
no
Remarks:
Potassium dichromate as reference substance in periodically performed sensitivity tests - however, no data presented in the report.
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Limit test at 100 mg/L nominal concentration due to poor solubility of test item in water
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: Limit test at 100 mg/L nominal concentration due to poor solubility of test item in water
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Limit test at 100 mg/L nominal concentration due to poor solubility of test item in water
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: Limit test at 100 mg/L nominal concentration due to poor solubility of test item in water
Details on results:
Based an the results of the study it can be concluded that the EC50 (growth rate, 0-72 h) and the EC50 (yield, 0-72 h) of the test item to Desmodesmus subspicatus is >100 mg/L.
The STUDENT-t test for homogeneous variances revealed that the test item caused a significant growth stimulation (hormesis) in Desmodesmus subspicatus. Nevertheless, since no inhibition was observed, the no-observed-effect concentration (NOEC) for growth rates and yield with respect to the loading rate was equal to or larger as 100 mg/L.
Results with reference substance (positive control):
not applicable
Reported statistics and error estimates:
The no observed effect concentration (NOEC) is the highest concentration for which the observed effect is not significantly different from the controls. The statistical significance of differences between effects observed for control and test substance treatments was determined by STUDENT-t test for homogeneous variances using the ToxRat Standard Version 2.09 (ToxRat Solutions GmbH, Alsdorf, Germany).
Validity criteria fulfilled:
yes
Conclusions:
In a fresh water algal growth inhibition test with Desmodesmus subspicatus the toxicity of the submission substance to aquatic plants had been tested (reliability category 2, compliant to GLP). A static limit test had been performed at a nominal concentration of 100 mg/L due to the poor solubility of the test item. The submission substance prooved to be non-toxic to Desmodesmus subspicatus under the applied test conditions:
NOEC (growth rate / yield, 72h) equal to or larger as 100 mg/L;
EC50 (growth rate / yield, 72h) > 100 mg/L;
Executive summary:

The median growth inhibiting concentrations (EC50) based an the average specific growth rate and the yield (algal biomass production) within 3 days, of the test item to the green alga Desmodesmus subspicatus were investigated over a period of 72 h. The only applied nominal test concentration was 100 mg/L. Due to the limited water solubility of the test substance, only the water accommodated fraction of the test item was tested. This water accommodated fraction was prepared by moderately stirring the respective concentration per liter of algal medium for 96h. After this incubation time, the undissolved material was first removed by a glass fiber filter and subsequently by membrane filtration to obtain a water accommodated fraction for the algal growth test. 3 parallel test vessels were used for the tested concentration of the test substance. No chemical analysis of the test media was conducted.

At the loading rate of 100 mg/L no growth inhibition (<10%) with respect to algal growth rates and algal yield (biomas production) compared to the untreated controls were observed.

The no-observed-effect concentration (NOEC) for growth rates and yield with respect to the loading rate was ¿ 100 mg/L nominal concentration.

Based on the results of the study it can be concluded that the EC50 (growth rate / yield, 0 -72 h) of the test item to Desmodesmus subspicatus are >100 mg/L nominal concentration.

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
16 May 2006 to 7 July 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
see Rationale and Justification for the Analogue Read-Across Approach used for the Registration of Pigment Red 202 (Chapter 13)
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
GLP according to German "Chemikaliengesetz", EC and OECD Guideline principles
Analytical monitoring:
yes
Details on sampling:
The saturated solution and control were analytically verified via analysis of organic carbon (DOC, according to DIN EN 1484) at test start and test end.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances): A dispersion of 10 mg/L, prepared in dilution water, was shaken with 20 rpm for 24 h at 23 ± 2 °C and centrifugated with 3000 rpm for 20 min.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Strain: Desmodesmus subspicatus CHODAT SAG 86.81
- Source (laboratory, culture collection): Sammlung von Algenkulturen (SAG), Pflanzenphysiologisches Institut der Universität Göttingen, Göttingen, Germany
- Age of inoculum (at test initiation): three day-old preculture
- Method of cultivation: Fresh stocks were prepared every month on Z-Agar. Light intensity amounted 35-70 ¿E·m-2·s-1 for 24 h per day.

ACCLIMATION
- Acclimation period: three days, see above
- Culturing media and conditions (same as test or not): preculture incubated at study conditions
- Any deformed or abnormal cells observed: no
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Post exposure observation period:
None. Observations were carried out during exposure at the beginning of the experiment and after 24, 48 and 72 hours.
Hardness:
0.24 mmol Ca+Mg/l for the dilution water
Test temperature:
22-24 (mean: 23) °C
pH:
Start: 7.91 (test solution), 7.81 (control)
End, 72 h: 8.33 (test solution), 8.31 (control)
Dissolved oxygen:
DOC (mg/l) (mean of two parallel determinations):
Start (without algae): 1.6 (test solution), 1.5 (control)
End, 72 h (without algae): 5.2 (test solution), 4.5 (control)
Nominal and measured concentrations:
A limit test with a saturated solution (dispersion of 10 mg/L, see above) was carried out.
Details on test conditions:
TEST SYSTEM
- Test vessel: Sterile erlenmeyer flasks, volume: 250 mL
- Initial cells density: nominally 1000 - 10000 cells/mL
- Control end cells density: 580011 (mean from 6 replicates) cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dilution water according to guidelines
- Intervals of water quality measurement: at the start and at the end (72 h)

OTHER TEST CONDITIONS
- Sterile test conditions: yes (sterile erlenmeyer flasks were used)
- Photoperiod: 24 h/d
- Light intensity and quality: 60.1 (start) and 67.7 (end, 72 h) (mean 64.4 ¿E·m-2·s-1)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Chlorophyll-impulsfluorometer
- Chlorophyll measurement: Chlorophyll-a-fluorescence, excitation at 435 nm, emission at 685 nm
- Other: measurements at the beginning of the test (after application) and every 24 h, dilution water was used as background signal

TEST CONCENTRATIONS
- Spacing factor for test concentrations: only one concentration (saturated solution), limit test
- Justification for using less concentrations than requested by guideline: limit test
Reference substance (positive control):
yes
Remarks:
Potassium dichromate p.a.
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Due to poor solubility of the test item, a limit test with a nominal concentration of 10 mg/L had been performed.
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: Due to poor solubility of the test item, a limit test with a nominal concentration of 10 mg/L had been performed.
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Due to poor solubility of the test item, a limit test with a nominal concentration of 10 mg/L had been performed.
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: Due to poor solubility of the test item, a limit test with a nominal concentration of 10 mg/L had been performed.
Details on results:
Biomass growth and rate-related inhibition:
- EC50: >saturated solution
- NOEC: saturated solution
- LOEC: >saturated solution

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no

Environmental conditions, pH-value, measured at 0 and 72 h, and room temperature, measured continuously, met the guideline requirements.
Results with reference substance (positive control):
- Results with reference substance valid? yes
- EC50 (biomass growth): 0.31 mg/l (0-72 h), 95 % confidence interval: 0.30-0.32 mg/l
- EC50 (rate-related inhibition): 0.65 mg/l (0-72 h), 95 % confidence interval: 0.57-0.73 mg/l
Reported statistics and error estimates:
The NOEC and LOEC were determined by calculation of statistical significance of biomass integrals and growth rates. One Way Analysis of Variance (ANOVA) and DUNNETT¿s test was carried out for the determination of statistically significant differences compared to control replicates. When running a One Way Analysis of Variance a Normality Test and an Equal Variance Test were done first. P-values for both Normality and Equal Variance Tests were 0.05. The ¿-value for ANOVA was ¿=0.05.
Validity criteria fulfilled:
yes
Conclusions:
No inhibiting effects on biomass growth and specific growth rate were found in the saturated solution. The EC50-values for inhibition of biomass growth (EbC50) and specific growth rate (ErC50) after 72 h were > saturated solution.
Executive summary:

The toxicity of the test item (Pigment Red 122) to the unicellular freshwater green alga Desmodesmus subspicatus was determined according to the principles of OECD-Guideline 201 (1984) and Directive 92/69/EC Method C.3 at DR.U.NOACK-LABORATORIEN in 31157 Sarstedt, Germany from May 22 to 25, 2006. The aim of the study was to assess the effects on growth rate and biomass production over a period of 72 h. The study was conducted under static conditions with an initial cell density of nominally 103 - 104 cells/mL. A limit test with a saturated solution was carried out. A dispersion of 10 mg/L was prepared in dilution water, shaken for 24 h at 23 ± 2°C and centrifugated with 3000 rpm for 20 min. Six replicates were tested for the saturated solution and control. Environmental conditions, pH-value and room temperature, were determined to be within the acceptable limits. DOC-analysis was carried out at test start and test end from the saturated solution and control. All effect values are based on the saturated solution of the test item.

In this study the test item did not cause any inhibiting effects to Desmodesmus subspicatus after 72 h when tested with a saturated solution.

Description of key information

Two key studies with a read across substance are available. In one test no inhibiting effects on biomass growth and specific growth rate were found in the saturated solution. The EC50-values for inhibition of biomass growth (EbC50) and specific growth rate (ErC50) after 72 h were > saturated solution.

In the study with the read across substance also no toxic effects were found.

In a fresh water algal growth inhibition test with Desmodesmus subspicatus the toxicity of the submission substance to aquatic plants had been tested (reliability category 2, compliant to GLP). A static limit test had been performed at a nominal concentration of 100 mg/L due to the poor solubility of the test item. The submission substance proved to be non-toxic to Desmodesmus subspicatus under the applied test conditions:

NOEC (growth rate / yield, 72h) equal to or larger as 100 mg/L;

EC50 (growth rate / yield, 72h) > 100 mg/L;

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:
100 mg/L

Additional information