2-methoxy-4-(methoxymethyl)phenol

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted between 1 and 8 October 2002.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

other: Information used for read across

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

For the analysis of the actual test item concentrations duplicate samples without algae were taken from each test concentration and the control just before test start and after 72 hours (end of the test). For the 72-hour stability samples additional flasks with adequate volumes of the freshly prepared test media of all test concentrations and the control were incubated under the same conditions as in the actual test but without algae. The samples were deep-frozen.

For the estimation of the algal growth, small-volume samples (1.0 ml) were taken from control and test flasks at 24, 48 and 72 hours (and were not replaced). In addition, after 72 hours exposure, a sample was taken from the control and from a test concentratino with reduced algal growth (nominal 100 mg/l). The shape of the algal cells was microscopically examined in these samples.

Vehicle:

no

Details on test solutions:

The test solution at the nominal concentration of 100 mg/l was prepared and was stirred intensely for 10 min at RT. Then the other test solutions were prepared by diluting this solution by the direct addition to culture medium. The test solutions were prepared at the concentrations of 4.6, 10, 22, 46 and 100 mg/l.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
The test was carried out using Pseudokirchnerella subcapitata CHODAT strain no. 86.81 SAG, supplied by the Sammlung von Algenkulturen Gottingen, Universitat Gottingen, Gottingen, Germany. Cultures were maintained in the laboratory under standardized conditions.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

24 mg/l as CaCO3

Test temperature:

Temperature was maintained at 22 - 23°C throughout the test.

pH:

The pH of each control and test flask was determined at initiation of the test and after 72 hours exposure. The pH was maintained within 7.9 - 9.0.

Nominal and measured concentrations:

Based on the results of the range-finding test, the following test concentrations were assigned to the definitive test:
Nominal test concentrations: 4.6, 10, 22, 46 and 100 mg/I.
Measured test concentrations at the start of the test (only two concentrations were measured: 46 and 100 mg/l): 45.6 and 99.6 mg/I, respectively.
Measured test concentrations at 72 h (only two concentrations were measured: 46 and 100 mg/l): 43.9 and 96.4 mg/I, respectively.

The samples from all lower test concentrations were not analyzed, since these concentrations were below the determined 72-hour NOEC.

Details on test conditions:

TEST SYSTEM
- Test vessel:
50 mL flasks were used.
The control group was maintained under identical conditions but not exposed to the test material.

- Initial cells density:
Pre-culture conditions gave an algal suspension in log phase growth.

- No. of vessels per concentration (replicates): 3

- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes
The culture medium was prepared using analytical grade salts dissolved in sterile purified water.

- Photoperiod:
The flasks were incubated at 22-23°C under continuous illumination at a measured light intensity of about 8600 Lux (mean value), range: 8000 to 9200 Lux. This illumination was achieved by fluorescent tubes installed above the test flasks.

- Light intensity and quality:
intensity approximately 8600 lux

- Determination of cell concentrations:
Samples were taken at 24, 48 and 72 hours and the cell densities determined using a Coulter Counter.

- The water temperature was recorded daily. The pH was recorded in each test concentration and the control at the start and at the end of the test. The appearance of the test media was recorded daily.

Reference substance (positive control):

yes

Remarks:

potassium dichromate, tested at least once a year

Key result

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: The nominal values are in line with the measured ones (>95%).

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: The nominal values are in line with the measured ones (>95%).

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: The nominal values are in line with the measured ones (>95%).

Details on results:

At the start of the test, the measured levels of the test substance ranged between 99 and 100% of their nominal values, and after 72 h they ranged between 95 and 96% of their initial values.

Reported statistics and error estimates:

The EC10 value was calculated by Probit Analysis.
For the determination of the LOEC and NOEC, the calculated mean biomass and the mean growth rate at the test concentrations were tested for significant differences compared to the control values by a Dunnett-test.

Validity criteria fulfilled:

yes

Conclusions:

Algae toxicity test (OECD TG 201): The ErC50, EC10 and NOEC were >100, >100 and 46 mg/l, respectively.

Executive summary:

A study was performed to assess the effect of the test material on the growth of the green alga Pseudokirchnerella subcapitata. The method followed that described in the OECD TG No 201. Following a preliminary range-finding test, Pseudokirchnerella subcapitata was exposed to solutions of the test material at nominal concentrations of 4.6, 10, 22, 46 and 100 mg/l (3 replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 22 -23°C. The test material solutions were prepared by stirring overnight.
At the start of the test, the measured levels of the test substance ranged between 99 and 100% of their nominal values, and after 72 h they ranged between 95 and 96% of their initial values. Because the solutions were stable during the experiment, the nominal values were used for the effect assessment. The ErC50, EC10 and NOEC were >100, >100 and 46 mg/l, respectively.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: read-across was applied

Justification for type of information:

Read across from Methyl diantilis was applied. The respective read-across document can be found in the endpoint summary. The read-across document is also attached in the endpoint summary.

Reason / purpose for cross-reference:

read-across source

Key result

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: The nominal values are in line with the measured ones (>95%).

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: The nominal values are in line with the measured ones (>95%).

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: The nominal values are in line with the measured ones (>95%).

Details on results:

The NOEC is based on the ca 6% decrease in growth rate at 100 mg/l.

Description of key information

A study was performed to assess the effect of the test material on the growth of the green alga Pseudokirchnerella subcapitata. The method followed that described in the OECD TG No 201. Following a preliminary range-finding test, Pseudokirchnerella subcapitata was exposed to solutions of the test material at nominal concentrations of 4.6, 10, 22, 46 and 100 mg/l (3 replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 22 -23°C. The test material solutions were prepared by stirring overnight.
At the start of the test, the measured levels of the test substance ranged between 99 and 100% of their nominal values, and after 72 h they ranged between 95 and 96% of their initial values. Because the solutions were stable during the experiment, the nominal values were used for the effect assessment. The ErC50 and NOEC were >100 and 46 mg/l, respectively.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

46 mg/L