N-methyl-N-[C18-(unsaturated)alkanoyl]glycine

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:

17 May - 14 Jun 2005

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)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Activated sludge was collected on 13 May 2005 from the municipal waste water treatment plant Neustadt/Weinstrasse, Lachen-Speyerdorf
- Method of cultivation: The sludge was continuously aerated and washed with tap water and OECD medium
- Concentration of suspended solids: 12.78 g/L

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

other: TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral medium as recommended by the guideline
- Test temperature: 21 ± 1 °C
- Aeration of dilution water: All vessels were aerated overnight with CO2-free air prior to test start and during the test
- Suspended solids concentration: 25 mg/L

TEST SYSTEM
- Culturing apparatus: 2 L Glass bottles, 1500 mL fill volume
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: Aeration with CO2-free air
- Details of trap for CO2: Outgoing air from the test vessels passed two serial bottles containing 0.25 M NaOH solution
- Other:

SAMPLING
- Sampling frequency: Measurement of evolved CO2 on days 2, 4, 6, 8, 10, 14, 21, 28 and 29
- Sampling method: 0.5 mL aliquots of the NaOH solution was sampled at each time point and analysed using a TOC 5050A (Shimadzu)

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 vessels
- Abiotic sterile control: 1 vessel
- Toxicity control: 1 vessel

Reference substance:

aniline

Parameter:

% degradation (CO2 evolution)

Value:

85.2

Sampling time:

28 d

Details on results:

- The toxicity control attained 98.3% degradation.
- Abiotic degradation was 26.6%.

Results with reference substance:

The reference substance attained 79.9% degradation after 28 days.

Table 1: Percentage of Degradation

Day	% Degradation
	Reference	Test Item (mean of duplicates)	Abiotic Control	Toxicity Control
2	2.6	1.7	3.4	3.2
4	26.5	24.1	3.1	53.5
6	56.1	47.5	11.3	68.7
8	66.5	57.4	16.0	75.8
10	71.1	61.3	8.6	79.7
14	76.2	72.9	17.6	86.7
21	85.0	88.3	22.9	97.5
28	77.6	83.0	28.0	99.6
29	79.9	85.2	26.6	98.3

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Description of key information

Readily biodegradable: 85.2% in 28 d (OECD 301 B)

Additional information

There is one study available investigating the ready biodegradability of N-methyl-N-(C18-(unsaturated)alkanoyl)glycine (EC 701-177-3). This study was conducted according to the OECD guideline 301B using non-adapted activated sludge from a municipal waste water treatment plant. 20 mg/L test substance (based on TOC) was inoculated with 25 mg/L domestic, non-adapted activated sludge for 28 d under aeration with CO2-free air. Inoculum blanks, an abiotic sterile control and a toxicity control were run in parallel. CO2 was trapped in bottles containing 0.25 M NaOH solution and the evolution of CO2 concentration was followed by TOC analysis in regular intervals. After 28 d incubation, the test item was degraded by 85.2% in terms of CO2 evolution. Thus, it can be concluded that N-methyl-N-(C18-(unsaturated)alkanoyl)glycine (EC 701-177-3) is readily biodegradable according to the OECD guideline criteria.