[iminobis(ethyleneiminomethylene)]bis(phosphonic) acid, N,N-bis(phosphonomethyl) derivative, sodium salt

Biodegradation in water and sediment: simulation tests

Administrative data

Endpoint:

biodegradation in water: simulation testing on ultimate degradation in surface water

Type of information:

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

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to an appropriate OECD test guideline, and in compliance with GLP. The test substance in this study is the penta-phosphonate form and is one of the components in the substance to be registered.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 306 (Biodegradability in Seawater)

Deviations:

yes

Remarks:

The nutrient stock solution contained 50.2g (not 48.77g) of Na2HPO4.7H2O

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

[[(phosphonomethyl)imino]bis[(ethylenenitrilo)bis(methylene)]]tetrakisphosphonic acid, sodium salt

EC Number:

244-751-4

EC Name:

[[(phosphonomethyl)imino]bis[(ethylenenitrilo)bis(methylene)]]tetrakisphosphonic acid, sodium salt

Cas Number:

22042-96-2

Molecular formula:

C9H28N3O15P5.xNa

IUPAC Name:

[[(phosphonomethyl)imino]bis[(ethylenenitrilo)bis(methylene)]]tetrakisphosphonic acid, sodium salt

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

natural water

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): A sample of natural seawater was collected from the Eatern Scheldt in the Netherlands (Jacobahaven) about 2.5 meters above the sea bed. After sedimentation of the coarse particle the seawater was decanted over a sieve and aerated until start of test.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

13.5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS

- Test temperature: 20.0-20.6°C

- pH: 7.9-8.0

- pH adjusted: no

- Continuous darkness: yes

TEST SYSTEM

- Culturing apparatus: BOD bottles with a volume of about 293ml

- Number of culture flasks/concentration: 5 inoculum blank, 5 test material, 3 reference substance, 3 toxicity control

SAMPLING

- Sampling frequency: 0, 5, 15, 28 days

- Sampling method: a separate set (3 to 5 bottles) of each treatment was sacrificed for each measurement.

CONTROL AND BLANK SYSTEM

- Inoculum blank: yes

- Toxicity control: yes

Results and discussion

% Degradation

% Degr.:

< 0

Parameter:

O2 consumption

Remarks:

Relative to theoretical oxygen demand

Sampling time:

28 d

Details on results:

The oxygen depletion in the inoculum blank was 2.63 mg O2/l at the end of the test (28 days). This is more than the maximum value of 2mg O2/l prescribed by the guideline but is characteristic of the natural seawater used and is not expected to influence the ready biodegradability.
The oxygen depletion in the toxicity control was lower than that in the reference substance. This indicated that the test material inhibited the degradation of the reference substance.
Oxygen depletion was inhibited by the test substance after 28 days of incubation in natural seawater medium. The test material is therefore considered to be not ready biodegradable in this test.

Results with reference substance:

Rapid degradation (almost complete within five days).

Any other information on results incl. tables

Table 1: Oxygen concentrations in the individual bottles determined after 0, 5, 15, and 28 days incubation with Dequest 2066.

Addition to flask	O2(mg/l) concentration after n days
	0	5	15	28
Inoculum blank	7.47	6.90	5.64	4.79
Inoculum blank		6.89	5.55	4.78
Inoculum blank		6.87	5.60	4.82
Inoculum blank				4.84
Inoculum blank				4.67
Test substance	7.41	6.93	6.64	6.18
Test substance		6.89	6.55	6.15
Test substance		6.85	6.62	6.17
Test substance				6.15
Test substance				6.27
Reference substance	7.37	4.44	2.97
Reference substance		4.42	3.11
Reference substance		4.41	3.20
Toxicity control	7.40	4.47	3.90
Toxicity control		4.47	3.94
Toxicity control		4.49	3.96

Applicant's summary and conclusion

Conclusions:

A degradation rate <0% in 28 days was determined in a reliable study conducted according to an appropriate test protocol, and in compliance with GLP.