5-(methoxymethyl)-2-furaldehyde

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:

July 12, 2011 - August 4, 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study has been performed in accordance with OECD 201 (2006) and according to GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

(2006)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

(2009)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: ISO International Standard 8692: "Water quality - Freshwater algal growth inhibition test with unicellular green algae", Second edition, 01 October 2004

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

5-(methoxymethyl)furan-2-carbaldehyde

EC Number:

700-511-5

Cas Number:

1917-64-2

Molecular formula:

C7H8O3

IUPAC Name:

5-(methoxymethyl)furan-2-carbaldehyde

Details on test material:

- Name of test material (as cited in study report): MMF
- Description: Clear yellow liquid
- CAS Number: 1917-64-2

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Samples for possible analysis were taken from all test concentrations and the control according to the schedule below.
Frequency: at t=0 h, t=24 h and t=72 h
Volume: 2 ml
Storage: Samples were stored in a freezer until analysis.
- At the end of the exposure period, the replicates with algae were pooled at each concentration before sampling.
- Compliance with the Quality criteria regarding maintenance of actual concentrations was demonstrated by running a test vessel at the highest substance concentration but without algae and samples for analysis were taken at the start, after 24 hours of exposure and at the end of the test period.

Test solutions

Vehicle:

no

Details on test solutions:

- MMF was completely soluble in test medium at the concentrations tested.
- Weighing of test substance was performed under yellow light (combined limit/range-finding test) or under normal light (final test) and preparation of test solutions was performed under dimmed light.
- Preparation of test solutions started with a nominal concentration of 100 mg/l applying 15 minutes of magnetic stirring to accelerate the dissolving of the test substance in the test medium. The lower test concentrations were prepared by subsequent dilutions of the 100 mg/l concentration in test medium. The final test solutions were all clear and colourless.
- After preparation, volumes of 50 ml were added to each replicate of the respective test concentration. Subsequently, 1 ml of an algal suspension was added to each replicate providing a cell density of 10^4 cells/ml.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: NIVA CHL 1
- Source: In-house laboratory culture

FRESH WATER ALGAE CULTURE
- Stock culture: Algae stock cultures were started by inoculating growth medium with algal cells from a pure culture on agar. The suspensions were continuously aerated and exposed to light in a climate room at a temperature of 21-24°C
- Light intensity: 60 to 120 μE/m^2/s when measured in the photosynthetically effective wavelength range of 400 to 700 nm
- Stock culture medium: M1; according to the NPR 6505 (“Nederlandse Praktijk Richtlijn no. 6505”) formulated using Milli-RO water (tapwater purified by reverse osmosis; Millipore Corp., Bedford, Mass., USA)
- Pre-culture: 3-4 days before the start of the test, cells from the algal stock culture were inoculated in culture medium at a cell density of 1 x 10^4 cells/ml. The pre-culture was maintained under the same conditions as used in the test. The cell density was measured immediately before use
- Pre-culture mediu: M2; according to the OECD 201 Guideline, formulated using Milli-Q water (tap water purified by reverse osmosis (Milli-RO) and subsequently passed over activated carbon and ion-exchange cartridges: Milli-Q water; Millipore Corp., Bedford, Mass., USA) preventing precipitation

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

The temperature of the test medium was 22.5°C at the start of the test. During the exposure period the temperature measured in the incubator was maintained between 22.1 and 23.0°C.

pH:

- At the beginning of the test: 8.1-8.2
- At the end of the test: 7.6-8.1

Nominal and measured concentrations:

Combined limit/range-finding test:
- Nominal concentrations: 0.10, 1.0, 10 and 100 mg/L
Final test:
- Nominal concentrations: 10, 18, 32, 56 and 100 mg/L
- Average exposure concentrations (Time Weight Average (TWA) of the concentrations of MMF measured in the samples taken at the start (Ct=0), after 24 hours (Ct=24) and the end of the test (Ct=72)): 4.2, 8.5, 22, 42 and 90 mg/L

Reference substance (positive control):

yes

Remarks:

the report includes the results of the most recent reference test with potassium dichromate (June 2011)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

8.5 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

42 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95%-confidence interval: 24-73 mg/L

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 90 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- At the start of the test, the actual test concentrations were in agreement with nominal (97-101%). These concentrations remained stable during the first 24 hours of exposure (84-101% of nominal) but decreased to values ranging from 5 to 72% of nominal for 18-100 mg/l at the end of the test. The actual concentration at 10 mg/l decreased to a value below the calibration range at the end of the test. Given these results, the effect parameters were based on the average exposure concentrations.
- Growth rates were in the range of the control at the two lowest test concentrations during the 72-hour test period. Statistically significant reduction of growth rate was found at test concentrations of 22 mg/l and higher (Bonferroni t-Test, α = 0.05).
- Microscopic observations at the end of the test revealed a normal and healthy appearance of the exposed cells when compared to the control.

Results with reference substance (positive control):

- The EC50 for growth rate reduction (ERC50: 0-72h) was 1.9 mg/l with a 95% confidence interval ranging from 1.3 to 2.7 mg/l. The historical ranges for growth rate reduction lie between 0.82 and 2.3 mg/l.
- The EC50 for yield inhibition (EYC50: 0-72h) was 0.52 mg/l with a 95% confidence interval ranging from 0.33 to 0.82 mg/l. The historical ranges of the 72h EC50 for yield inhibition lie between 0.43 and 1.1 mg/l.

Any other information on results incl. tables

Combined limit/range-finding test

Based on the biological results, the expected EC50 for growth rate reduction was above a nominal concentration of 100 mg/l. The expected EC50 for yield inhibition was between nominal concentrations of 10 and 100 mg/l. Samples taken from nominal 10 and 100 mg/l were analysed. The initial concentrations were in agreement with nominal (111-117%). The nominal 10 mg/l concentration remained stable during the first 24 hours of exposure (103%) but decreased to a value below the calibration range at the end of the test. The actual concentration at nominal 100 mg/l seemed to have decreased after 24 hours of exposure (66% of nominal) but was in agreement with nominal after 72 hours of exposure (99% of nominal). This was an unexpected result and not consistent with the line of decrease shown at 10 mg/l.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In accordance with OECD 201 (2006) and according to GLP principles the toxicity of MMF in Pseudokirchneriella subcapitata was investigated. MMF reduced growth rate of this fresh water algae species significantly at 22 mg/l and higher. The EC50 for growth rate reduction (ERC50: 0-72h) was beyond the range tested, i.e. >90 mg/l. The NOEC for growth rate reduction was 8.5 mg/l. The EC10 for growth rate reduction was 42 mg/L (95%-confidence interval: 24-73 mg/L).

Executive summary:

In this study, the toxicity of MMF in Pseudokirchneriella subcapitata was investigated. The study procedures were based on OECD 201 (2006). A final test was performed based on the results of a preceding combined limit/range-finding test. Preparation of test solutions started with a nominal concentration of 100 mg/l applying 15 minutes of magnetic stirring to accelerate the dissolving of the test substance in the test medium. The lower test concentrations were prepared by subsequent dilutions of the 100 mg/l concentration in test medium. The final test solutions were all clear and colourless. Three replicates of exponentially growing algal cultures per concentration were exposed to nominal MMF concentrations of 10, 18, 32, 56 and 100 mg/l. Simultaneously, six replicates were exposed to a control. The initial cell density was 10^4 cells/ml and the total test period was 72 hours. Samples for analytical confirmation of actual exposure concentrations were taken at the start, after 24 hours of exposure and at the end of the test. At the start of the test, the actual test concentrations were in agreement with nominal (97-101%). These concentrations remained stable during the first 24 hours of exposure (84-101% of nominal) but decreased to values ranging from 5 to 72% of nominal for 18-100 mg/l at the end of the test. The actual concentration at 10 mg/l decreased to a value below the calibration range at the end of the test. Given these results, the effect parameters were based on the average exposure concentrations that were calculated to be: 4.2, 8.5, 22, 42 and 90 mg/l. All the validity criteria were fulfilled. MMF reduced growth rate of this fresh water algae species significantly at 22 mg/l and higher. The EC50 for growth rate reduction (ErC50: 0-72h) was beyond the range tested, i.e. >90 mg/l. The NOEC for growth rate reduction was 8.5 mg/l. The EC10 for growth rate reduction was 42 mg/L with a 95% confidence interval ranging from 24 to 73 mg/l.