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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:
2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline Study with detailed documentation

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report date:
2016

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
yes
Remarks:
The temperature in the experiment was in a range of 23.3 – 24.7 °C and therefore higher than stated in the guideline (21 – 24 °C). Because normal growth was observed, this can be stated as uncritical.
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
yes
Remarks:
The temperature in the experiment was in a range of 23.3 – 24.7 °C and therefore higher than stated in the guideline (21 – 24 °C). Because normal growth was observed, this can be stated as uncritical.
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Reference substance name:
MAEEBP
IUPAC Name:
MAEEBP
Details on test material:
- Name of test material (as cited in study report): MAEEBP- Physical state: colourless liquid- Composition of test material (percentage of components): 4-methacryloyl diethoxy benzophenone (85 area%) , impurities: 4-hydroxybenzophenone (<5%), 4-methacryloyl benzophenone (<5%), polymethacrylate (<5%)- Lot/batch No.: 150301- Expiration date of the lot/batch: 31.12.2015- Storage condition of test material: fridge: 2-8°C, keep away from light and humidity

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
The concentration of the test item in the test vessels was measured at the start and every 24 hours during the test.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION- Method: A saturated solution was prepared for the test. This was done by weighing the nominal load 100 mg/L (real load 101.4 mg/L), adding the corresponding amount of algal medium (demineralised water enriched with minerals but without algae) and shaking vigorously for 24 hours. The resulting solution was filtrated through 0.45 µm filters. This solution was used as highest concentrated treatment and for preparation of the lower concentrated treatments.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM- Strain: SAG 86.81- Source: obtained in February 2014 by MBM Sciencebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen). The algae are kept as stock culture on solid agar at 2 - 8 °C. From the stock culture, a permanent culture was prepared. From an aliquot of the stock culture, the pre-culture was prepared.

Study design

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

Test conditions

Test temperature:
23.3 – 24.7 °C
pH:
7.6 - 8.7
Nominal and measured concentrations:
4.6 / 10 / 22 / 46 / 100 mg/L nominal concentrationsThe recovery after 72 hours was in a range of 23 % - 74 % of the measured start concentrations in the test solutions with algae, and 65 % - 78 % in treatments (4.6 mg/L and 100 mg/L) without algae. In the lowest concentrated treatment, in the solution without algae, recovery at the end of the test was clearly higher than in the solution with algae. That means test item was adsorbed or ingested by the algae cells.The geometric mean of the measured concentration was used for the determination of the results. Because of erroneous HPLC measurements, the measured concentrations after 48 hours were partly not evaluable. Therefore the measured values after 48 hours were not used for calculation of the biological results.
Details on test conditions:
TEST SYSTEM- Test vessel: glass flasks total volume 65 mL- Initial cells density: 3.2*10exp3 cells/mL- No. of vessels per concentration (replicates): 3 vessels, each filled with 45 mL test solution and algae, 1 additional replicate without algae only for analytical measurement for the highest and the lowest concentrated treatment- No. of vessels per control (replicates): 6 vessels, each filled with 45 mL nutrient medium and algaeGROWTH MEDIUM- Standard medium used: yesTEST MEDIUM / WATER PARAMETERS- Intervals of water quality measurement: the pH values measured at the start and the end of the test- Photoperiod: continuous- Light intensity: 5300 Lux EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :At the end of the test, the treatments were examined microscopically in order to assess the appearance of the algae and detect abnormalities (e.g. caused by the exposure to the test item). Cell numbers were determined by photometric measurement of optical density after 0, 24, 48 and 72 h treatment.
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
0.38 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
0.38 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
0.98 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 95% CI: 0.81 – 1.2 mg/L
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
0.69 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: 95% CI: 0.55 – 0.87 mg/L
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
2.5 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 95% CI: 2.0 – 3.1 mg/L
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
1.3 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: 95% CI: 1.0 – 1.7 mg/L
Results with reference substance (positive control):
- Results with reference substance valid? yes-72h EC50: 1.1 mg/L (0.95 – 1.3 mg/L)- 72h NOEC: 0.39 mg/L (0.33 – 0.44 mg/L)
Reported statistics and error estimates:
Calculation was performed with Microsoft Excel® and ToxRat® Professional, version 3.2

Any other information on results incl. tables

Measured Concentrations:

Nominal
Concentration Test Item

Measured

Concentration
 t = 0 h

Measured Concentration
 t = 24 h

**Measured Concentration

 t = 48 h

Measured Concentration

 t = 72 h

mg/L

mg/L

mg/L

mg/L

mg/L

Blank control

n. d.

0.02

0.01

0.01

4.6

0.68

0.50

0.23

0.16

10

1.21

1.19

0.56

0.49

22

2.53

2.66

4.41

1.82

46

4.09

4.42

2.92

3.06

100

9.05

8.78

6.98

6.69

*4.6

0.87

0.71

0.45

0.57

*100

8.76

8.68

8.23

6.84

  * test solutions without algae

** Because of an erroneous HPLC measurement, the measured concentrations after 48 hours were partly not evaluable. Therefore the measured values after 48 hours were not used for calculation of the geometric mean.

n. d. = not detectable

 

Growth Rate µ, Yield:

Nominal Concentration in mg/L

Parameter

Growth Rate

(0-72h) [day-1]

Yield (0-72h)

[Cell Concentration/mL]

Blank control

Mean

1.56

348014

SD

0.04

41243

4.6

Mean

1.53

318369

SD

0.00

3465

10

Mean

1.47

266985

SD

0.02

18368

22

Mean

0.87

40605

SD

0.02

2244

46

Mean

0.39

7187

SD

0.02

622

100

Mean

0.19

2515

SD

0.04

622

SD = Standard Deviation

 

Inhibition Values:

Nominal concentration in mg/L

% Inhibition

Growth Rate (0-72h)

Yield (0-72h)

Blank control

0

0

4.6

1.8

8.5

10

5.5

23.3

22

44.3

88.3

46

75.0

97.9

100

87.8

99.3

 

Microscopical Observations:

Nominal Concentration in mg/L

Normal and Healthy Appearance of the Algae

Blank control

Yes

4.6

Yes

10

Yes

22

No cells visible

46

No cells visible

100

No cells visible

 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The toxicity of MAEEBP against Desmodesmus subspicatus was tested according to OECD 201 resp. EU C.3. The 72h-EC50 value (growth rate), based on the geometric mean of the measured concentrations, was determined to be 2.5 mg/L.
Executive summary:

The toxicity of MAEEBP against Desmodesmus subspicatus was tested according to OECD 201 resp. EU C.3. Five concentrations ranging from 4.6 to 100 mg/L (nominal) were tested. Incubation time of the test system (Desmodesmus subspicatus) was 72 hours. The cell concentration of each replicate was determined by measuring the absorption of the solutions at 440 nm every 24 hours with a spectral photometer. The cell density of the cultures was calculated based on the correlation curve between the absorption and the cell density of the cultures determined with a cell counter. Growth rate and the yield were determined from the cell number at the respective observation times.

Significant inhibition of algal growth was observed at all concentrations with the exception of the lowest concentrated treatment.

 The determination of the results was based on the geometric mean of the measured concentrations.

The 72h-EC50s of the reference substance potassium dichromate (K2Cr2O7, CAS No. 7778-50-9) were determined in a separate reference test. The values lay within the range of the validity criteria of the Guideline (growth rate 0.73 - 1.10 mg/L, yield 0.21 – 0.55 mg/L).

The following results for the test itemMAEEBP were determined: NOEC (growth rate 72 h) 0.38 mg/L, LOEC (growth rate 72 h) 0.89 mg/L, EC10 (growth rate 72 h) 0.98 mg/L, EC50 (growth rate 72 h) 2.5 mg/L, NOEC (yield 72 h) 0.38 mg/L, LOEC (yield 72 h) 0.89 mg/L, EC10 (yield 72 h) 0.69 mg/L, EC50 (yield 72 h) 1.3 mg/L.

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