3-[(2-acetamidoacetyl)amino]propanoic acid

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

October 2013 to January 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

July 17, 1992

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Sampling and culturing of activated sludge:
1 L of fresh sludge from the aeration tank of the sewage disposal plant was collected from Jiangxinxhou city sewage plant. Coarse particles in the sludge were removed by filtration through a 20 mesh sieve. After discarding the supernatant, the sludge was washed in the mineral medium. Suspend the concentrated sludge in the mineral medium.
Threafter aerated until required at 22 ºC +/- 2 ºC

Preparation of culture Medium
Prepare the following stock solution using analytical grade reagents:
a) weighed 8.50 g KH2PO4, 21.75 g K2HPO4, 66.80 g Na2HPO4·12H2O and 0.50 g NH4Cl, dissolved in water and made up to 1 L, adjusted the paH of the solution to be 7.40 with HCl.
b) weighed 3.6400 g CaCl2·2H2O, dissolved in water and made up to 100 mL.
c) Weighed 1.0969 g MgSO4, dissolved in water and made up to 100 mL.
d) Weighed 0.0252 g FeCl3·6H2O, dissolved in wter and made up to 100 mL.
Mix 10 mL of solution (a) with 800 mL water , then add 1 mL of solution (b), (c) and (d) and make up to 1 L with water.

Measurement of concentration of suspended solid
4 samples of 10 mL activated sludge were transferred in evaporating dish and dried at 120 ºC. The concentration of suspended solid was calculated to be 4.37 g SS/L.

Duration of test (contact time):

28 d

Initial conc.:

10 g/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

The measured date was deviated from 1,2,3,6,8,10,14,17,21,24,29 day in the study plan to 1,2,3,5,7,10,14,17,21,24,29 day in practice, which has no influence on the results. Small temperature deviation also has no influence on experiment validity.

Reference substance:

benzoic acid, sodium salt

Test performance:

Determinations of CO2 evolution were performed on the 1st, 2nd, 3rd, 5th, 7th, 10th, 14th, 17th, 21st, 24th and 29th.
On the day of CO2 measurement, disconnect the Ba(OH)2 absorber closest to the test bottle and titrate the hydroxide solution with 0.05 mol/L HCl using phenolphthalein as the indicator. Move the remaining absorbers one place closer to the test bottle and place a new absorber conaining 100 mL fresh 0.0125 mol/L Ba(OH)2 at the far end of the series.
Add 1 mL of concentrated hydrochloric acid to each test bottle and aerate them overnight to drive of the CO2 present in the test solution on day 28th. On thay 29th make the last determination of CO2 evolution.

Key result

Parameter:

% degradation (CO2 evolution)

Value:

2.25

Sampling time:

1 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

14.2

Sampling time:

2 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

25.8

Sampling time:

3 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

47

Sampling time:

5 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

64.7

Sampling time:

7 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

82.7

Sampling time:

10 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

93.2

Sampling time:

14 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

96.8

Sampling time:

17 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

93.7

Sampling time:

21 d

Parameter:

% degradation (CO2 evolution)

Value:

92.4

Sampling time:

24 d

Parameter:

% degradation (CO2 evolution)

Value:

93.7

Sampling time:

28 d

Details on results:

At the end of the test, the total CO2 evolution in the inoculum control was 19.8 mg/L.
The biodegradation reate for reference item, sodium benzoate, was beyond 60% in 14 days, and reached 66.9%. These results verified that the biodegradability test for the test itom was effective.
The biodegradation rate for the toxicity control group in forteenth day reached 53.6% beyond 25%, and thus the effect of the tested substance n microbial activity is thought as no inhibition under the experimental conditions.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The biodegradation rates of the tested substance were more that 60% in the 28 day test period, thus achiving the required level as ready biodegradable sustance.

Executive summary:

This sudy tested the ready biodegradability of the substance in the aerobnic aquatic environment.

The test item was added at about 15 mg C/L in average into the test culture medium. The test results showed that, for the smples in containing activated sludge culture medium, the average cumulative degradation rates (n=2) in 1, 2, 3, 5,7, 10, 14, 17, 21, 24 and 28 day were respectively 2.25%, 14.2%, 25.8%, 47.0%, 64.7%, 82.7%, 93,2%, 96.8%, 93.7%, 92.4% and 93.7% . For acetyl glycyl beta-alanine in the 28 day test perioud, its biodegradation rates wre more than 60%, which acheved with the level for ready biodegradability.

The biodegradation rate for the toxicity control group in fourteen days reached 53.6%, beyond 25%, and thus the effect of the test item on microbial activity is thought as no inhibition under the experimental conditions.

The biodegradation rate for reference item, sodium benzoate, was beyond 60% in 14 days, it reached 66.9% in 14 days. Therse results verified that the biodegradability test for the test item was effective.

Description of key information

Readily biodegradable: 93.71% (CO2 evolution) after 28 d (OECD 301B).

The biodegradation rates of the tested substance were more than 60% in the 28 day test period, thus achiving the required level as ready biodegradable sustance.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater