N,N-bis(carboxymethyl)glycine, compound with 2-aminoethanol (1:3)

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:

02/02/2005 - 03/05/2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Dissolved in seawater
- Final preparation of a solid: Dissolved in seawater

FORM AS APPLIED IN THE TEST (if different from that of starting material) Aqueous, in solution

Analytical monitoring:

no

Details on sampling:

- Concentrations: Definitive test (nominal concentrations): 100, 320, 1000, 3200, 10 006 mg/L
- Sampling method: Growth rate of population

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test material dissolved in seawater
- Controls: 4 growth rate controls (1 replicate), 5 positive controls (Reference substance, 3,5-Dichlorophenol) at 5.6, 3.2, 1.8, 1.0 and 0.56 mg/L(2 replicates)
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): No, test was soluble in seawater

Test organisms (species):

Skeletonema costatum

Details on test organisms:

TEST ORGANISM
- Common name: Skeletonema costatum
- Strain: C5B1 A
- Source (laboratory, culture collection): Stock laboratory culture
- Method of cultivation: Inoculation of ISO culture medium

ACCLIMATION
- Any deformed or abnormal cells observed: No

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

Measurements were taken at 24, 48 and 72 hours

Test temperature:

18.6 - 21.6

pH:

Control and Definitive test (0 hours) pH 7.82 - 8.15
Definitive test (1 hour) pH 8.12 - 9.09

Conductivity:

52.1 - 53.4 mS/cm

Nominal and measured concentrations:

Nominal test substance concentrations- 100, 320, 1000, 3200, 10 006 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: conical flask
- Type: closed
- Material, size, headspace, fill volume: 100 ml
- Aeration: Flasks shaken (orbital shaker)
- Initial cells density: 10235 cells/ ml
- Control end cells density: 8.66 - 8.81
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): Growth rate control (1 replicate), positive control (2 replicates)

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: natural seawater, from Scapa Flow, Orkney.
- Alkalinity: pH 8 (+- 0.2)
- Particulate matter: 0.2 µm filtered seawater
- Culture medium different from test medium: No
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Sterile conditions: Yes
- Light intensity and quality: Cool white illumination
- Salinity (for marine algae): natural seawater

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : growth rate of population
- Determination of cell concentrations: microscope using either a haemocytometer or Sedgewick-Rafter chamber

TEST CONCENTRATIONS
- Range finding study: 1, 10, 100 and 1000 mg/ L test substance, no observed effect
- Test concentrations: Definitive test: 100, 320, 1000, 10 000 mg/ L
- Results used to determine the conditions for the definitive study: Results from Rangefinding test used

Reference substance (positive control):

yes

Remarks:

3,5 Dichlorophenol

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

1 842.82 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2 104.86 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

1 935.67 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

2 956.24 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): no
- Observation of abnormalities (for algal test): no
- Any stimulation of growth found in any treatment: No
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: No

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: 2.86 mg L

Validity criteria fulfilled:

yes

Conclusions:

The test substance has an EC50 of 1842.82 mg /L for 24 hours, 2104.86 mg/L for 48 hours and 1935.67 mg/L for 72 hours. The EC90 for 72 hours is 2956.24 mg/L and the NOEC for 72 hours is 320 mg/L.

Executive summary:

The study assesses Monoethanolamine Salt of Nitrilotriacetic Acid's toxicity to aquatic algae. The study is GLP compliant and was performed according to the ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum). The test organism was Skeletonema costatum and all the validity criteria were met. A rangefinding test was performed for the test substance (nominal concentrations, 1, 10, 100, 1000 mg/L) however, there was no observed effect on the test organism growth rate over these concentrations. Monoethanolamine Salt of Nitrilotriacetic Acid exhibited a 72h EC50 value of 1935.67 mg/L (dilution series) to the marine phytoplankton Skeletonema costatum in the aqueous phase.

Description of key information

The study assesses Monoethanolamine Salt of Nitrilotriacetic Acid's toxicity to aquatic algae. The study is GLP compliant and was performed according to the ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum). The test organism was Skeletonema costatum and all the validity criteria were met. A rangefinding test was performed for the test substance (nominal concentrations, 1, 10, 100, 1000 mg/L) however, there was no observed effect on the test organism growth rate over these concentrations. Monoethanolamine Salt of Nitrilotriacetic Acid exhibited a 72h EC50 value of 1935.67 mg/L (dilution series) to the marine phytoplankton Skeletonema costatum in the aqueous phase.

Key value for chemical safety assessment

EC50 for marine water algae:

1 935.67 mg/L

EC10 or NOEC for marine water algae:

320 mg/L