2-pyrrolidone

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparative testing and validation programme based on scientific principles and comparable to (later) established guidelines.

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: sewage treatment plant effluent

Details on inoculum:

In the ring test effluents of different industral waste water treatment plants was used:
Bayer AG: Bürrig sewage treatment plant effluent,
Hüls AG: CWH activated sludge test plant effluent,
BASF AG: industrial sewage treatment plant effluent,
Merck: Industrial sewage treatment plant effluent,
Henkel & Cie GmbH: Hochdahl sewage treatment plant effluent,
Solvay: effluent (source not reported).

Duration of test (contact time):

30 d

Initial conc.:

2

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Parameter:

other: BOD5

Remarks:

% BOD

Value:

ca. 44.9

Sampling time:

5 d

Remarks on result:

other: average of the three results depicted below

Parameter:

BOD5

Value:

39.5 other: % BOD (5 d)

Remarks on result:

other: result a

Parameter:

BOD5

Value:

42.1 other: % BOD (5 d)

Remarks on result:

other: result b

Parameter:

BOD5

Value:

53.2 other: % BOD (5 d)

Remarks on result:

other: result c

- Kinetic of degradation (mean values in % BOD)
Time [d]	BASF AG			Bayer	Huels	Henkel	Merck	Solvay
	a	b	c
5	39.5	42.1	53.2		0	0.7	16.2	25
15	85.1	101	116	85.4	2.1	0	86.9	68.0
30	85.1	122	98.8	94.9	4.7	0	95.4	85.0

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Rapid biodegradation was observed.

Executive summary:

In a ring test effluents of different industral waste water treatment plants was used to investigate biodegradability of the test substance N-methylpyrrolidone according to OECD guideline 301 D (Closed-Bottle Test): Bayer AG: Bürrig sewage treatment plant effluent, Hüls AG: CWH activated sludge test plant effluent, BASF AG: industrial sewage treatment plant effluent, Merck: Industrial sewage treatment plant effluent, Henkel & Cie GmbH: Hochdahl sewage treatment plant effluent, Solvay: effluent (source not reported).

The test substance N-methylpyrrolidone showed rapid biodegradation.

Reference 2

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial (adaptation not specified)

Duration of test (contact time):

9 d

Initial conc.:

1 298 mg/L

Based on:

other: TOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

preparation of the test assay:
- inoculum: 1 g/L dry weight
- incubation: at room temperature (20-25 °C) on a magnetic stirrer, aerated with air (sparging)

Reference substance:

not specified

Parameter:

% degradation (DOC removal)

Value:

ca. 98

Sampling time:

9 d

Details on results:

Kinetic of test substance (in %):
< 0 after 3 hour(s)
ca. 82 after 5 day(s)
ca. 85 after 7 day(s)

TOC disapearance

Time	3 h	1 d	5 d	7 d	9 d
Replicate 1
TOC measured [mg/L]	428	403	66	65	42
Theoretical TOC [mg/L]	400	393	387	386	386
Blank [mg/L]	12	18	25	19	32
TOC - Blank [mg/L]	416	385	41	46	10
TOC elimination [%]	0	2	89	88	97
Replicate 2
TOC measured [mg/L]	422	333	63	61	37
Theoretical TOC [mg/L]	400	395	390	389	389
Blank [mg/L]	12	18	25	19	32
TOC - Blank [mg/L]	410	375	38	42	5
TOC elimination [%]	0	5	90	89	99

Comment on the calculation of the elimination (%): samples were taken at regular intervals and the sample volume was always replaced with tap water. Thus, the starting liquid volume remained constant whereas the TOC-reference point was reduced according to the sample volume.

Validity criteria fulfilled:

yes

Interpretation of results:

other: easily eliminated from water

Conclusions:

The test substance was easily eliminated from water.

Executive summary:

An inherent biodegradation test was performed in accordance with OECD guideline 302 -B (Zahn-Wellens Test). Test was completed after exposure time of 9 days, since a complete degradation (98% DOC removal) was achieved in this time period.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Guideline study, basic data given but no detailed test protocol available as the tests from the Japanese authorities are only published as short result summary including deviations (if oocured). Nevertheless, test details are given by MITI guideline and an overall test description of CITI Japan.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Sludge was taken from 10 different sites in Japan (municipal STPs, industrial STPs, lakes, rivers and bays)
- Concentration of sludge: 30 mg/L dry substance

Duration of test (contact time):

28 d

Initial conc.:

100

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Solubilising agent (type and concentration if used): no data
- Test temperature: 25 °C +/- 1 °C
- pH: 7.0
- pH adjusted: yes
- other: Improved type for a volatile substance used (no further details given)

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes (Aniline)

TEST SYSTEM
- Measuring equipment: Closed system oxygen consumption measuring apparatus (Coulometer: Ohkura Electric Co Ltd.)
- Details of trap for CO2 and volatile organics if used: Soda lime No.1 (extra pure reagent, Wako Pure Chemicals Ind. Ltd.)

Reference substance:

not specified

Parameter:

% degradation (O2 consumption)

Value:

73

Sampling time:

28 d

Details on results:

RS-Freetext:
- Based on BOD measurements:
% BOD/ThBOD (28 d): #1: 73, #2: 73, #3: 73, mean: 73

- Based on TOC measurements:
% TOC removal (28 d): #1: 96, #2: 95, #3: 98, mean: 96

- Based on GC measurements:
% NMP removal (28 d): #1: 100, #2: 100, #3: 100, mean: 100

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Test substance N-methylpyrrolidone (NMP) can be classified as ready biodegradable

Executive summary:

A biodegradation test according to OECD guideline 301 C (MITI test) was performed with N-methylpyrrolidone. test period was 28 days, sludge of 10 different japanese municipal sewage treatment plants was used as inoculum. Based on the observed results, the test substance N-methylpyrrolidone (NMP) can be classified as ready biodegradable.

Reference 4

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions (eg. inoculum: industrial activated sludge instead of sludge of a wwtp treating domestic sewage).

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial (adaptation not specified)

Duration of test (contact time):

13 d

Initial conc.:

400 mg/L

Based on:

DOC

Parameter:

% degradation (DOC removal)

Value:

98

Sampling time:

13 d

Details on results:

- Kinetic of elimination:

Time DOC Blank Test substance [mg/L DOC] DOC elimination [%]
[d] [mg/L] #1 #2 #1 #2 mean
0 400
3 hours 395 21 405 402 3 4 4
1 390 21 387 402 6 2 4
2 386 18 344 357 16 12 14
5 386 40 60 62 95 94 95
7 386 30 51 50 95 95 95
9 386 31 51 43 95 97 96
13 386 27 34 34 98 98 98

- The sigmoidal shape of the elimination curve is a strong indication of biodegradation
- Comment on the calculation of the elimination (%) after 3 h, on day 1 and day 2: samples were taken and the sample volume (approx. 50 mL) was replaced with tap water. Thus, the starting volume remained constant (approx. 2000 mL), but the reference value to calculate the elimination degree had to be corrected after each sampling.

Validity criteria fulfilled:

yes

Interpretation of results:

other: easily eliminated from water (mainly by biodegradation)

Executive summary:

An inherent biodegradation test was also performed with N-methylpyrrolidone - a close analogue of 2 -pyrrolidone - in accordance with OECD guideline 302-B (Zahn-Wellens Test). The test was completed after exposure time of 13 days, since a complete degradation (98% DOC removal) was achieved in this time period.

Description of key information

Test substance and a close analogue - N-methylpyrrolidone - have been shown to be readily biodegradable according to OECD criteria.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

Ready biodegradability of 2 -pyrrolidone was demonstrated in an inherent biodegradation test, which was performed in accordance with OECD guideline 302-B (Zahn-Wellens Test). The test was completed after exposure time of 9 days, since a complete degradation (98% DOC removal) was achieved in this time period.

In a ring test effluents of different industral waste water treatment plants was used to investigate biodegradability of the close analogue of the test substance - N-methylpyrrolidone - according to OECD guideline 301 D (Closed-Bottle Test): Bayer AG: Bürrig sewage treatment plant effluent, Hüls AG: CWH activated sludge test plant effluent, BASF AG: industrial sewage treatment plant effluent, Merck: Industrial sewage treatment plant effluent, Henkel & Cie GmbH: Hochdahl sewage treatment plant effluent, Solvay: effluent (source not reported). The test substance N-methylpyrrolidone showed rapid biodegradation.

Moreover, a MITI-test according to OECD guideline 301 C by CITI (1992) is available, which prouve a close analogue of 2 -pyrrolidone - N-methylpyrrolidone - to be readiliy biodegradable as well. Test period was 28 days, sludge of 10 different japanese municipal sewage treatment plants was used as inoculum. Based on the observed results, the test substance can be classified as ready biodegradable.

In addtion, an inherent biodegradation test was also performed with N-methylpyrrolidone - a close analogue of 2 -pyrrolidone - in accordance with OECD guideline 302-B (Zahn-Wellens Test). The test was completed after exposure time of 13 days, since a complete degradation (98% DOC removal) was achieved in this time period.

All these results are confirmed by further available study reports.