Propionaldehyde, reaction product with formaldehyde

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

Study period:

from 9 March 2010 to 3 August 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: All nominal concentrations (0.0, 0.4, 1.0, 3.0, 7.0, 20.0, 60.0, 170.0, 500.0 mg/L) were tested.
- Sampling method: At the start and at the end of the incubation period, samples of the test media were drawn and the concentrations of the test substance were determined in aliquots of the blank containing test substance, but no algae; of one replicate of each of the test and control cultures (after filtering through a 0.2 µm filter).
- Sample storage conditions before analysis: samples were immediately analysed by HPLC.

Vehicle:

no

Details on test solutions:

- Method: A stock solution with a nominal test substance concentration of 555 mg/L (dry weight) was prepared by addition of 603 mg test substance (6 % water content) in 1 L of nutrient medium and stirring for 20 minutes.
- Controls: For the negative control group only nutrient medium was used.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): no vehicle was used.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): No.

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum)
- Strain: ATCC (American Type Culture Collection) 22662.
- Source (laboratory, culture collection): LGC Promochem GmbH, Germany
- Method of cultivation: Stock cultures, initially cultivated from deep frozen algae, are continuously maintained in
250 mL conical flasks (Erlenmeyer), each containing 100 mL nutrient medium, at a temperature in the range of 21 to 24 (± 2) °C under permanent light with an intensity between 4400 and 8800 lux. In about weekly intervals 1 mL of the stock culture is
diluted 100-fold with nutrient medium for precultivation and incubation is continued.

ACCLIMATION
- Acclimation period: Precultures were prepared by incubating a new stock culture for four days.
- Culturing media and conditions (same as test or not): same as test.
- Any deformed or abnormal cells observed: no.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

None.

Hardness:

not reported.

Test temperature:

22 °C

pH:

The pH was between 7.5 and 7.6 at the start of the incubation in the test cultures and it was 7.3 in the control cultures.
After 72 hours of incubation the pH was between 7.0 and 8.6 in the test cultures and it was 8.3 in the control cultures.

Dissolved oxygen:

Not reported.

Nominal and measured concentrations:

Nominal concentrations: 0.0, 0.4, 1.0, 3.0, 7.0, 20.0, 60.0, 170.0, 500.0 mg/L
Geometric mean of actual/calculated concentrations: 0.10 (calculated), 0.31 (calculated), 1.00 (calculated), 3.21 (calculated), 10.36 (calculated), 33.39, 118.86, 343.14 mg/L. For details see attached background material.

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL closed Erlenmeyer flasks filled with 100 mL medium .
- Initial cells density: 10 000 cells/mL
- Control end cells density: the cell density in the control cultures increased by a factor of about 123.
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes.
- Sterile deionised water and sterile concentrated nutrient medium 9 + 1 was used.
- Conductivity of the deionised water: <5 µS/cm

OTHER TEST CONDITIONS
- Sterile test conditions: The test cultures are prepared under steril conditions.
- Adjustment of pH: no.
- Photoperiod: 24 h.
- Light intensity and quality: at least 4710 lux. Wavelength of 400 to 700 nm.


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic cell counter with Casy Cell Counter after 24, 48, and 72 hours of incubation
- Chlorophyll measurement: no.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: < 3.2
- Justification for using less concentrations than requested by guideline: not applicable.
- Range finding study: yes .
- Test concentrations: . A preliminary range finding study not according to GLP using nominal concentrations of 10, 100, 1 000, and 10 000 mg/L (including 6 % water content) was conducted
- Results used to determine the conditions for the definitive study: The range finding study revealed EC50 values below 10 mg/L (based on the yield) and between 10 and 100 mg/L (based on the growth rates).

Reference substance (positive control):

yes

Remarks:

72h EC50 (K2Cr2O7): for growth rate 1.32 mg/L and yield 0.62 mg/L

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

10.4 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.:

10.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

67.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

16.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Details on results:

- Exponential growth in the control (for algal test): During the 72 hours incubation period the cell density in the control cultures increased by
a factor of about 123, corresponding to about 7.0 generations.
- Observation of abnormalities (for algal test): None
- Colour differences: No
- Any stimulation of growth found in any treatment: Yes.
- Effect concentrations exceeding solubility of substance in test medium: No.

Growth Inhibition:
• Based on the yield and compared to the negative controls: In all concentrations tested, the influence on algal growth ranged from 98.2 % inhibition to 6.9 % enhancement.
• Based on the average growth rates and compared to the negative controls: In all concentrations tested, the influence on algal growth ranged from 76.9 % inhibition to 1.5 % enhancement.

Results with reference substance (positive control):

The last reference test with K2Cr2O7 was conducted from the 21st to the 24th of June 2010 with Pseudokirchneriella subcapitata to evaluate the reliability of the test conditions. The 72 hour EC50 for growth rate and yield were 1.32 and 0.62 mg K2Cr2O7/L, respectively. These results establish the reliability of the test procedures for this kind of study type.

Reported statistics and error estimates:

Based on the yield as well as on the average growth rates two "lowest observed effective
concentrations" (LOECs) are calculated by comparison of the data of the three replicates of
each test substance culture with the negative control (analysis of variance, followed by the
Scheffé-test, P = 0.05). The "no observed effect concentrations" (NOECs) are then derived
from these results (highest concentration with no statistically significant difference to the
control).

Validity criteria:

All acceptance criteria for controls given in the EC Regulation were met:

·      During the 72 hours incubation period the cell density in the control cultures increased by a factor of about 123, corresponding to about 7.0 generations.

·      The mean coefficient of variation for section-by-section specific growth rates was 10.4 %.

·      The coefficient of variation of average specific growth rates during the whole test period in replicate control cultures was 2.7 %.

Validity criteria fulfilled:

yes

Conclusions:

based on the yield NOEC = 10.4 mg/L
based on the average growth rates NOEC = 10.4 mg/L
based on the yield EC50 = 16.8 mg/L
based on the average growth rates EC50 = 67.6 mg/L

Executive summary:

A Pseudokirchneriella subcapitata growth inhibition test according to the EC regulation 761/2009 Part C.3 and theOECD-Guideline 201 (adopted by the Council on 23^rdMarch 2006) was performed to determine the possible effects of the test substance on the growth of a unicellular green algal species.Eight different concentrations ofbetween nominal 0.4 and 500.0 mg per L nutrient medium, spaced by a factor of about 3, were tested against one concurrent negative control (nutrient medium only). Three replicates were used for each test culture and six replicates for the control culture. The cell count of the algae was about 10 000 cells/mL at the start of the exposure in each vessel.

In each vessel the cell density of the algae was determined 24, 48 and 72 hours after the onset of incubation and the pH was measured at the begin and at the end of the incubation period. Visual observations on the appearance of the algal cultures were made each time when the cell densities were determined. Possible test substance effects were determined by comparison of the yield and of the growth rates.

At the start and at the end of the experiment, filtered samples of the cultures exposed to the test substance, of the control cultures and also of the blank with the highest concentration of the test substance, but no algae, were taken and immediately analysed in duplicate by HPLC.

After 72 hours the ErC50 was determined to be 67.4 mg/L and the NOEC was determined to be 10.4 mg/L.

Following results were determined:

- based on the yield NOEC = 10.4 mg/L

- based on the average growth rates NOEC = 10.4 mg/L

- based on the yield EC50 = 16.8 mg/L

- based on the average growth rates EC50 = 67.6 mg/L

Description of key information

A Pseudokirchneriella subcapitata growth inhibition test was performed according to the EC regulation 761/2009 Part C.3 and the OECD-Guideline 201 (2006) to determine the possible effects of the test substance on the growth of a unicellular green algal species. After 72 hours the ErC50 was determined to be 67.4 mg/L and the NOEC was determined to be 10.4 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

67.6 mg/L

EC10 or NOEC for freshwater algae:

10.4 mg/L

Additional information

A Pseudokirchneriella subcapitata growth inhibition test according to the EC regulation 761/2009 Part C.3 and the OECD-Guideline 201 (adopted by the Council on 23^rd March 2006) was performed to determine the possible effects of the test substance on the growth of a unicellular green algal species. Eight different concentrations of between nominal 0.4 and 500.0 mg per L nutrient medium, spaced by a factor of about 3, were tested against one concurrent negative control (nutrient medium only). Three replicates were used for each test culture and six replicates for the control culture. The cell count of the algae was about 10 000 cells/mL at the start of the exposure in each vessel.

In each vessel the cell density of the algae was determined 24, 48 and 72 hours after the onset of incubation and the pH was measured at the begin and at the end of the incubation period. Visual observations on the appearance of the algal cultures were made each time when the cell densities were determined. Possible test substance effects were determined by comparison of the yield and of the growth rates.

At the start and at the end of the experiment, filtered samples of the cultures exposed to the test substance, of the control cultures and also of the blank with the highest concentration of the test substance, but no algae, were taken and immediately analysed in duplicate by HPLC.

After 72 hours the ErC50 was determined to be 67.4 mg/L and the NOEC was determined to be 10.4 mg/L.

Following results were determined:

- based on the yield NOEC = 10.4 mg/L

- based on the average growth rates NOEC = 10.4 mg/L

- based on the yield EC50 = 16.8 mg/L

- based on the average growth rates EC50 = 67.6 mg/L