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Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study was performed according to OECD Guideline and with GLP compliance

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

yes

Remarks:

Deviation of the temperature was stated as uncritical

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

yes

Remarks:

Deviation of the temperature was stated as uncritical

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

For each treatment, 160 mL of the respective test solution (1.25-fold concentrated) was prepared and mixed with 40 mL of the test culture. In this mixture, the pH-value was measured. A sample for the analytical determination was taken.
The test vessels were filled with 45 ± 5 mL of the mixture and were incubated open for 72 hours shaken on an orbital shaker. Before the start of incubation and every 24 hours, the cell number was detected using a cell counter. After the test, the pH value in treatments and control was measured.
At the end of the test, the treatments were examined microscopically in order to assess the appearance of the alga and detect abnormalities (e.g. caused by the exposure to the test item).
The content of the test item in the test vessels was measured at the start and at the end of the test.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Desmodesmus subspicatus (Unicellular freshwater green alga)
- Strain: Chodat
- Source (laboratory, culture collection): MBM Sciencebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen).
- Age of inoculum: no data
- Method of cultivation: stock culture on solid guar at 8°C

ACCLIMATION
- Acclimation period: no data
- Culturing media and conditions (same as test or not): no data
- Any deformed or abnormal cells observed: not observed (normal cells)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

Range 24.0 to 25.0°C (deviation observed but was stated as uncritical).

pH:

Range 7.6 to 7.8

Dissolved oxygen:

No data

Nominal and measured concentrations:

Nominal concentrations: Control - 4.6 - 10 - 22 - 46 and 100 mg/L
At the start and at the end of the test, the content of the test item in the test solutions was determined using HPLC. The recovery after 72 hours was in a range of 99.98 %and 101.51 % of the start concentration. The measured concentrations lay between 106.11 % and 131.40 % of the nominal concentration at the beginning of the test and between 107.32 % and 132.36 % of the nominal concentration at the end of the test. Therefore, the determination of the results was based on the mean of the measured concentrations.
Mean of measured concentrations: 0 - 6.1 - 11 - 24 - 49 and 107 mg/L

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

87 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: CI (95%) = 73 - 107 mg/L

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

11 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

24 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

14 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CI = [11 - 17] mg/L

Details on results:

No abnormalities are observed during the study.

Biological results of the positive control:

Parameter	Value	95%-confidence-interval
NOEC 72 h	0.25 mg/L	not determinable
LOEC 72 h	0.4 mg/L	not determinable
72h ErC50	1.40 mg/L	> 1.1 mg/L
72h EbC50	0.61 mg/L	0.51 – 0.74 mg/L
72h EyC50	0.38 mg/L	0.30 – 0.47 mg/L

Biological result of the test item:

Parameter	Value	95%-confidence-interval
NOEC (Growth Rate) 72 h	11 mg/L	not determinable
NOEC (AUC) 72 h	6.1 mg/L	not determinable
NOEC (Yield) 72 h	6.1 mg/L	not determinable
LOEC (Growth Rate) 72 h	24 mg/L	not determinable
LOEC (AUC) 72 h	11 mg/L	not determinable
LOEC (Yield) 72 h	11 mg/L	not determinable
72h ErC50	87 mg/L	73 – 107 mg/L
72h EbC50	25 mg/L	21 – 30 mg/L
72h EyC50	24 mg/L	20 – 27 mg/L
72h-ErC100	> 107 mg/L	not determinable
72h-EbC100	> 107 mg/L	not determinable
72h-EyC100	> 107 mg/L	not determinable
72h-ErC10	14 mg/L	11 - 17 mg/L

Validity criteria fulfilled:

yes

Conclusions:

Reaction mass of N-[2-(2-Oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid was tested on Desmodesmus subspicatus for evaluate toxicity on Alga during 72 hours, in accordance to european guidelines C3, Algal inhibition test, Directive n° 92/69/EEC (OECD 201).
The ECr50 for the test item was found to be 87 mg/L with a confidentce interval at 73 - 107 mg/L and the ECr10 was found to be 14 mg/L (95% CI =[11 - 17 mg/L]).

Executive summary:

The effect of Reaction mass of N-[2-(2-Oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid on the growth of the unicellular green alga Desmodesmus subspicatus was assessed. The study was conducted in accordance with EC Methods for Determination of Ecotoxicity Annex to Directive 92/69/EEC (O.J. No. L383A, 1992) Part C, Method 3 "Algal Inhibition Test" and the OECD Guideline for Testing of Chemicals No. 201 "Alga, Growth Inhibition Test" (1984).

Triplicate algal cultures, were exposed to aqueous solutions of test item

prepared at five nominal concentrations : 4.6 - 10 - 22 - 46 and 100 mg/L.

Under the conditions of this test, measured concentrations of test item in samples of the test cultures ranged between 99.98 and 101.5% of their nominal values at the beginning of the test. After 72 hours, the measured levels were between 107.32 and 132.36% of their initial values. The overall mean measured levels of Reaction mass of N-[2-(2-Oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid were 6.1 - 11 - 24 - 49 and 107 mg/L.

Cell numbers were counted daily to monitor growth.The following values were derived from the data:

Average specific growth rate: ErC50 (0 - 72 h): 87 mg/L [73 - 107 mg/L]

Average specific growth rate: ErC10 (0 - 72h): 14 mg/L [11 - 17 mg/L]

No Observed Effect Concentration (NOECr): 11 mg/L

Low Observed Effect Concentration (LOECr): 24 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:

87 mg/L

EC10 or NOEC for freshwater algae:

14 mg/L

Additional information

Reaction mass of N-[2-(2-Oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid was tested on Desmodesmus subspicatus for evaluate toxicity on Alga during 72hours, in accordance to european guidelines C3, Algal inhibition test, Directive n° 92/69/EEC (OECD 201). The ECr50 for the test item was found to be 87 mg/L with a confidentce interval at 73 - 107 mg/L and an ECr10 at 14 mg/L with a confidence interval at 11 - 17 mg/L.