[ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid, calcium sodium salt

Toxicity to aquatic plants other than algae

Administrative data

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to the appropriate OECD guideline, 201, however it was conducted according to GLP and no analytical monitoring was carried out.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 221 (Lemna sp. Growth Inhibition Test)

Version / remarks:

(year 1984)

Deviations:

yes

Remarks:

no analytical monitoring

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

[ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid, calcium sodium salt

EC Number:

287-370-9

EC Name:

[ethylenebis[nitrilobis(methylene)]]tetrakisphosphonic acid, calcium sodium salt

Cas Number:

85480-89-3

Molecular formula:

C6H20-2x-yN2O12P4.xCa.yNa

IUPAC Name:

x calcium y sodium {ethane-1,2-diylbis[nitrilobis(methylene)]}tetrakis(phosphonate)

Details on test material:

- Name of test material (as cited in study report): Dequest 2047
- Physical state: powder
- Analytical purity: not reported
- Impurities (identity and concentrations): not reported

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

other: Phaeodactylum tricornutum

Study design

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

72 h

Results and discussion

Effect concentrations

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

86 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL 11 to >96 mg/l

Any other information on results incl. tables

It was not possible to determine an EC100 during the study. The data report the same level of toxicity between the exposure concentration of 6 and 96 mg/l, hence the large confidence intervals around the EC50. The observed effects are thought to be consistent with the idea that nutrient chelation is responsible for the observed effects, rather than true toxicity.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

A 72 h EC50 value of 86 mg/l has been reported for the effects of the test substance on the cell growth rate of the marine diatom Phaeodactylum tricornutum. A similar rate of effects was observed between 6 and 96 mg/l exposure concentrations, which is consistent with the concept that nutrient chelation and not instrinsic toxicity is responsible for the observed effects.