Potassium; 2-[bis[2-[bis(carboxylatomethyl)amino]ethyl]amino]acetate; iron(3+)

Biodegradation in water: screening tests

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Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

1987

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test performed under GLP, according to guidelines, no CoA available.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Details on test material:

- Name of test material (as cited in study report): glycine N-N bis [2-[bis(carboxymethyl) amine] ethyl] - pentapotasium salt
- Physical state: white powder
- Analytical purity: 97.0%
- Impurities (identity and concentrations): water
- Lot/batch No.: ???
- Storage condition of test material: In original container at room temperature and protected from strong light and moisture

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge from the aeration stage of the HRC Limited sewage treatment plant treating predominantly domestic sewage
- Preparation of inoculum for exposure: the sample was allowed to settle and the supernatant filtered through Whatman GFA filter paper (first 250 ml discarded)

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: The nutrient medium of the closed bottle test contained per litre of deionized water: 8.5 mg KH2PO4, 21.75 mg K2HPO4, 33.4 mg Na2HPO4.2H2O, 1.7 mg/l NH4Cl, 22.5 mg MgSO4.7H2O, 27.5 mg CaCl2, 0.25 mg FeCl3.6H2O.
- Test temperature: 23 +/- 1 °C
- pH adjusted: no
- Aeration of mineral medium: yes
- Inoculum concentration: 1 drop of inoculum per litre
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: water bath
- Number of culture flasks/concentration:
8 bottles containing only mineral medium (without inoculum, without test or reference substance)
8 bottles containing only inoculum = inoculum blank
8 bottles containing test substance and inoculum =test
8 bottles containing sodium benzoate and inoculum = reference control
- Method used to create aerobic conditions: aeration by agitation
- Measuring equipment: oxygen meter


SAMPLING
- Sampling frequency: day 0, 5, 21 ,28
- Sampling method: the bottles were discarded after the oxygen measurement.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: no
- Reference control: yes


CALCULATIONS:
THOD = 1.0 mg/mg
THOD sodium benzoate = 1.67 mg/mg

Oxygen consumption (mg/l) (BOD) = mean oxygen concentration (mg/l) inoculum blank - mean oxygen concentration (mg/l) test (or reference)
Biodegradation (%) = BOD/THOD *100

Results and discussion

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Details on results:

Of the reference substance 67% biodegraded at day 5 and 89% at day 28

Any other information on results incl. tables

Mean oxygen depletion and percentages biodegradation values

	O2 depleation (mg/l)			Degradation (%)
	day 5	day 21	day 28	day 5	day 21	day 28
Dilution water without inoculum	0.25	0.3	0.35	-	-	-
Dilution water with inoculum	0.35	0.325	0.550	-	-	-
Test substance	0.5	0.125	-0.025	10	2	0
Standard substance	3.325	4.75	4.425	67	95	89

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

endogenous respiration of <0.6 mg/l; biodegradation of reference substance; >0.5 mg/l of oxygen in bottles during the test and <20% differences between replicates at day 28.

Conclusions:

Glycine N-N bis[2-[bis (carboxymethyl) amine] ethyl] -pentapotasium was biodegraded 0% at day 28 in the closed bottle test and can therefore not be classified as readily biodegradable. No biodegradation in this test does not necessarily mean that the test substance is not biodegradable under environmental conditions, but that more work will be necessary to establish this.

Executive summary:

Glycine N-N bis [2- [bis (carboxymethyl) amine] ethyl]-pentapotassium salt attained insignificant degradation within 28 days and, cannot, therefore be considered as readily biodegradable.