Sodium [[α,α'-(ethylenediimino)bis[2-hydroxybenzene-1-acetato]](4-)]ferrate(1-)

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Reason / purpose for cross-reference:

read-across source

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
- Name of test material (as cited in study report): Acetic acid,oxo-,sodium salt (Fe(Na)EDDHA)
-Synonym: Acetic acid,oxo-,sodium salt, reaction products with ethylenediamine and phenol,iron sodium salts
- Physical state: Solid/ red, dark
- Analytical purity: 100 % (UVCB)
- Storage condition of test material: At ambient temperature under exclusion of light

Analytical monitoring:

yes

Details on sampling:

Sampling was performed at the start of the exposure (0 h) from the inoculated replicate
7 of each concentration and the control. At the end of the exposure (72 h) samples of the inoculated replicates 1 - 3 of the test concentrations and of the inoculated replicates 1 - 6 of the control group were taken. The replicates were combined before sampling. All samples were placed into glass sample vials and covered with aluminium foil for light protection.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
The test solutions were prepared separately for each test concentration (differential loading). The solutions were stirred for approx. 10 min under light exclusion.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Test species and strain: Desmodesmus subspicatus CHODAT (SAG 86.81)
- Source (laboratory, culture collection): Collection of algal cultures in University of Göttingen/Germany
- Age of inoculum (at test initiation): A stock algal culture is maintained continuously at the test facility. Before the exposure an inoculum culture is prepared from the stock culture and incubated for 4 days at 21 – 24 °C (max. temperature difference 2 °C). After this time, the inoculum culture is in exponential growth phase and can be used to initiate the test (study day 0).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

No post exposure observation period reported.

Hardness:

No details available.

Test temperature:

23.1 – 23.5 °C

pH:

7.9 - 8.2 (measured at start and end of the test)

Dissolved oxygen:

No details available.

Salinity:

Not applicable.

Nominal and measured concentrations:

3.2, 10, 32, 100 and 320 mg/L as nominal concentrations based on test substance mass without correction for purity.

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks (nominal volume 250 mL) plugged with gas permeable silicone sponge caps
- Type: closed
- Test volume: 50 mL (volume reduced for algal test - according to guidance in OECD 23, since the test substance is strongly colored)
- Test chamber: Vötsch Industrietechnik GmbH Bioline (VB1014) controlled climate cabinet
- Initial cells density: 0.3 x 10E4 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- Additional replicate per test group for initial concentration control analysis only: 1
- Additional uninoculated (without algae) replicate per test group for background fluorescence correction and to determine the influence of the test design on test substance stability: 1

GROWTH MEDIUM
- Standard medium used: yes (according to OECD Guideline 201)

TEST MEDIUM / WATER PARAMETERS
The test medium was prepared according to OECD Guideline 201, March 2006. The pH value was 8.1.

OTHER TEST CONDITIONS
- Illumination: Artificial light, type universal white (OSRAM L 25), permanent illumination. The minimize the potential effect of slight variations in illumination, the test vessels are rearranged daily
- Light intensity: Average 8144 lux (within +/- 15 % variability) at a wave length of 400 - 700 nm. Light intensity was adjusted to the higher end of the acceptable range, according to guidance in OECD 23 for algal testing of colored substances.
- Shaking rate: Continuous (approx. 85 rpm)

RANGE FINDING STUDY
The test concentrations in the definitive test were selected on the basis of a range finding test (experimental conduct in accordance with GLP but without a GLP status.
- Results used to determine the concentrations in the definitive test: EC50 (fluorescence): 46.1 mg/L; ErC50 > 100 mg/L (nominal)

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7)

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 294 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.:

8.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

29.3 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.:

27.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

2.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

8.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

After 72 h exposure, in test groups up to 32 mg/L no remarkable observations were reported. Concerning the test groups with 100 and 320 mg/L, a low cell density was recorded.

Results with reference substance (positive control):

According to the test ISO guideline 8692 the EC50 values of the reference substance potassium dichromate should be in the range: ErC50 = 0.71 – 0.97 mg/L after 72 hours for Desmodesmus subspicatus. The ErC50(72 h) of the control substance potassium dichromate was 0.82 mg/L.
These results indicate that the algae are responding normally to toxicant stress.

Reported statistics and error estimates:

No statistics and error estimates reported.

Validity criteria fulfilled:

yes

Remarks:

The test conformed to all validity criteria of the OECD Guideline used and is valid.

Conclusions:

In conclusion the 72 hour EC50 value for FeNaEDDHA with Desmodesmus subspicatus CHODAT (SAG 86.81) was > 294 mg/L and the NOEC was 8.2 mg/L based on algal growth rate. The 72 hour EC50 based on yield was 27.3 mg/L and the NOEC 2.4 mg/L.The same results are expected for the target substance since it has the same constituents that act via the same mechanism as the source substance. No differences in the magnitude of the effects are expected. Therefore the same EC50 and NOEC values are also applicable for the target substance.

Executive summary:

The toxic effects of Fe(Na)EDDHA on the growth of single-cell green algae as representatives of primary producers in freshwater plankton over a 72 hour static exposure period were determined according to the principles of OECD Guideline 201 and EU Method C.3 (Salinas, 2010).

The following nominal concentrations based on test substance mass without a correction for purity were used: 3.2, 10, 32, 100, 320 mg/L. The analytically determined concentrations of the test substance in the test water were in a range of 89 - 102 % of the nominal concentration at start of exposure and decreased to 63 - 86 % of the nominal concentration at the end of exposure. Therefore mean measured concentrations were considered to be an accurate representation of exposure levels throughout the exposure period.

The 72-hour EC50 value for Desmodesmus subspicatus CHODAT (SAG 86.81) was greater than 294 mg/L and the NOEC was 8.2 mg/L based on mean measured concentrations and growth rate. The 72 hour EC50 based on yield and mean measured concentrations was 27.3 mg/L and the NOEC was 2.4 mg/L.

Description of key information

EC50 (72h) > 294 mg/L (growth rate), NOEC (72h): 8.2 mg/L (growth rate), EC50 (72h): 27.3 mg/L (biomass), NOEC (72h): 2.4 mg/L (biomass) [OECD 201; Desmodesmus subspicatus; read-across substance Fe(Na)EDDHA]

Key value for chemical safety assessment

EC50 for freshwater algae:

27.3 mg/L

Additional information

Ecotoxicological effects towards aquatic algae and cyanobacteria of o-o-EDDHA (CAS16455-61-1) was not investigated experimentally. Read across from the structurally similar substance Fe(Na)EDDHA (CAS 84539-55-9) was performed to fulfil this relevant endpoint under REACH (for further details, please refer to the separate read-across statement).

The toxic effects of Fe(Na)EDDHA on the growth of single-cell green algae as representatives of primary producers in freshwater plankton over a 72 hour static exposure period were determined according to the principles of OECD Guideline 201 and EU Method C.3 (Salinas, 2010). The following nominal concentrations based on test substance mass without a correction for purity were used: 3.2, 10, 32, 100, 320 mg/L. The analytically determined concentrations of the test substance in the test water were in a range of 89 - 102 % of the nominal concentration at start of exposure and decreased to 63 - 86 % of the nominal concentration at the end of exposure. Therefore mean measured concentrations were considered to be an accurate representation of exposure levels throughout the exposure period. The 72 hour EC50 value for Desmodesmus subspicatus CHODAT (SAG 86.81) was greater than 294 mg/L and the NOEC was 8.2 mg/L based on mean measured concentrations and growth rate. The 72 hour EC50 based on yield and mean measured concentrations was 27.3 mg/L and the NOEC was 2.4 mg/L.