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

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

08 Mar 1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

adopted in 1984

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test item was directly added to the test medium.

Test organisms (species):

activated sludge

Details on inoculum:

- Source of inoculum: Activated sludge was collected from the sewage treatment plant of Therwil, Switzerland on 06 Mar 1989.
- Preparation of inoculum for exposure: The sludge was separated from the aqueous layer by settling.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

18 - 20 °C

Nominal and measured concentrations:

Nominal: 0, 1.1, 3.3, 10.7, 32.0, 100.2 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: BOD flasks with gas inlet
- Size, fill volume: 250 mL, 200 mL
- Aeration: Yes
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- Concentration of sludge: 1.6 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dechlorinated drinking water

EFFECT PARAMETERS MEASURED (with observation intervals if applicable)
- Microbial respiration was measured after 3 h of incubation.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: approx. 3.2

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Duration:

3 h

Dose descriptor:

other: IC20

Effect conc.:

75 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

- Validity criteria are fulfilled.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: IC50 = 13 mg/L

Table 1: Inhibition of microbial respiration

Concentration (mg/L)	Consumption Rate (mg/L*h)	Inhibition (%)
Blank 1	40.62	2
Blank 2	42.21	-2
1.1	41.62	0
3.3	43.97	-6
10.7	41.79	-1
32.0	35.70	14
100.2	30.00	28

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

09 Sep 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

adopted in 1984

Deviations:

yes

Remarks:

Higher temperature during the test (Guideline: 18 - 20 °C, Test: 23.3 - 24.4 °C)

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Version / remarks:

adopted in 2008

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Mainz, Germany

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution containing 10 g/L was prepared using the following procedure: 10 g test item was mixed with 1.1 g NaOH (45%). 40 mL deionised water (80 – 100 °C) was added. After homogenisation with a glass stirrer, 85 mL deionised water (room temperature) was added. Then, the vessel was stirred on a magnetic stirrer. 0.5 M NaOH was added until the resulting solution was clear. The pH of the solution was adjusted to 7.8 ± 0.2 with 1 M HCl. the solution was transferred into a volumetric flask and filled up to 1000 mL with deionised water.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source of the inoculum: The sludge was taken from the activation basin of the sewage plant in Edenkoben, Germany
- Laboratory culture: Upon arrival, the sludge was washed with tap water three times, centrifuged and resuspended in tap water.
- Suspended solids: 4.2 g/L

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

pH:

7.7 - 8.1

Nominal and measured concentrations:

Nominal: 0, 1.0, 3.2, 10, 32, 100, 320, 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Beakers
- Material, fill volume: Glass, 500 mL
- Aeration: Purified air at 0.75 L/min
- No. of vessels per concentration (replicates): 2 for treatment 1000 mg/L, 1 for all other treatments and positive control
- Concentration of suspended solids: 1.7 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water
- Total organic carbon: < 1.0 mg/L
- Metals (mg/L): Na 4.7, K 2.6, Ca 33.1, Mg 2.1, other metals < 0.0005 to < 0.01
- Pesticides: < LOD
- Chloride: 9.0 mg/L
- Conductivity: 189 µS/cm
- Intervals of water quality measurement: pH was measured at test end.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable)
- Respiration rate was measured after 3 h of incubation

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

130 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 95% CL = 62 - 310 mg/L

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

1 300 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 95% CL = 480 - 7200 mg/L; extrapolated

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

- The inhibition caused by the test item did not rise above 45%. Therefore the EC50(3h) was determined by extrapolation.
- All validity criteria are fulfilled.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: 9.1 mg/L, 95% CL = 7.2 - 11.0 mg/L

Table 1: Inhibition (%) of microbial respiration after 3 h of incubation

Concentration	% Inhibition
Control	-
1.0	-3.2
3.2	1.2
10	1.7
32	16.9
100	25.5
320	24.0
1000 (1)	43.8
1000 (2)	45.3

Description of key information

NOEC (3h) = 10 mg/L (OECD 209)

Additional information

Two studies investigating the toxicity to microorganism of N-methyl-N-(C18-(unsaturated)alkanoyl)glycine (EC 701-177-3) are available.

The key study was carried out according to OECD 209 under GLP-conditions with domestic activated sludge as inoculum. In this static test seven test concentrations were used (1.0, 3.2, 10, 32, 100, 320 and 1000 mg/L). The dry matter was determined as 4.2 g suspended solids/L, giving a concentration of 1.7 g suspended solids/L in the test. The highest inhibition of respiration rate was determined for the highest tested concentration (1000 mg/L nominal) with 45.3% and 43.8% inhibition. Thus, the inhibition of respiration rate is < 50%. In the study report the EC50 was extrapolated with an EC50 (3h) of 1300 mg/L. But as an extrapolation is imprecise, the EC50 (3h) > 1000 mg/L (nominal) could be stated. The NOEC (3h) was reported as 10 mg/L.

The supporting study was conducted according to OECD 209 under non-GLP conditions. Five test concentrations (1.1, 3.3, 10.7, 32.0, 100.2 mg/L) were inoculated to activated sludge. In this study, the IC50 (3h) for respiration inhibition was above the highest test concentration of 100 mg/L. A NOEC of 10 mg/L is reported.