Sodium p-chloro-m-cresolate

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

Study period:

31 Oct 1996 to 28 Nov 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EU Method C.4-B (Determination of the "Ready" Biodegradability - Modified OECD Screening Test)

Deviations:

yes

Remarks:

intial test substance concentration lower than proposed in guideline

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Remarks:

Aquatic mixed population of microorganisms (activated sludge)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Effluent of a laboratory living sludge plant that is operated with wastewater from the southern Wupper Association.
- Date of sampling: 31.10.1996
- Pretreatment: None
- Concentration of sludge: 0.5 mL/L
- Water filtered: yes
- Type and size of filter used, if any: Coarse filter paper

Duration of test (contact time):

28 d

Initial conc.:

9.03 mg/L

Based on:

DOC

Initial conc.:

4.1 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Test temperature: 22 ± 2 °C
- Continuous darkness: yes

SAMPLING
- Sampling frequency: after 0, 7, 14, 21, 27 and 28 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes

Reference substance:

aniline

Parameter:

% degradation (DOC removal)

Value:

83

Sampling time:

28 d

Remarks on result:

other:

Remarks:

% Degradation at an initial concentration of 9.03 mg DOC/L

Parameter:

% degradation (DOC removal)

Value:

79

Sampling time:

28 d

Remarks on result:

other:

Remarks:

% Degradation at an initial concentration of 4.1 mg DOC/L

Details on results:

Please refer to "any other information on results incl. tables".

Results with reference substance:

92 % degradation after 14 days.

Table 1: DOC values of test item

9.03 mg/L DOC		DOC
Vessel no.
		0 h	7 d	14 d	21d	27 d	28 d
13	a1	9.70	9.80	7.90	4.40	2.80	3.30
	a2	10.10	9.60	6.70	4.40	2.70	3.50
	a, mean value	9.90	9.70	7.30	4.40	2.75	3.40
14	b1	9.10	10.50	5.80	2.40	3.80	1.90
	b2	10.20	10.90	5.90	2.20	3.30	2.40
	b, mean value	9.65	10.70	5.85	2.30	3.55	2.15
4.10 mg/L DOC		DOC
Vessel no.
		0 h	7 d	14 d	21d	27 d	28 d
15	a1	5.20	4.50	1.80	1.90	2.60	2.00
	a2	4.40	4.60	1.80	1.80	2.90	2.20
	a, mean value	4.80	4.55	1.80	1.85	2.75	2.10
16	b1	5.00	5.00	1.20	0.90	2.20	2.60
	b2	4.80	5.60	1.30	1.30	1.70	1.80
	b, mean value	4.90	5.30	1.25	1.10	1.95	2.20
2.20 mg/L DOC		DOC
Vessel no.
		0 h	7 d	14 d	21d	27 d	28 d
17	a1	3.20	3.50	0.40	1.00	1.80	0.80
	a2	2.60	3.20	1.20	1.00	1.80	0.60
	a, mean value	2.90	3.35	0.80	1.00	1.80	0.70
18	b1	3.20	3.30	1.20	2.30	1.70	1.30
	b2	2.80	4.00	2.20	3.10	1.00	1.20
	b, mean value	3.00	3.65	1.70	2.70	1.35	1.25
1.10 mg/L DOC		DOC
Vessel no.
		0 h	7 d	14 d	21d	27 d	28 d
19	a1	2.20	2.20	1.70	1.30	1.20	1.20
	a2	1.40	1.90	2.00	1.40	1.90	1.10
	a, mean value	1.80	2.05	1.85	1.35	1.55	1.15
20	b1	2.30	2.00	2.30	1.50	1.80	1.60
	b2	1.50	1.90	1.10	1.40	1.50	1.80
	b, mean value	1.90	1.95	1.70	1.45	1.65	1.70

Table 2: Degradation of test item (for the test concentrations 2.2 mg/L and 1.1 mg/L degradation clould not be determined as DOC values were close to the limit of detection)

9.03 mg/ DOC	% degradation
Vessel no.
	0 h	7 d	14 d	21d	27 d	28 d
13	0	2	23	60	84	77
14	0	0	37	82	74	90
mean value	0	1	30	71	79	83
4.10 mg/ DOC	% degradation
Vessel no.
	0 h	7 d	14 d	21d	27 d	28 d
15	0	6	62	72	63	80
16	0	0	77	90	83	78
mean value	0	3	69	81	73	79

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

After 28 days a degradation of 83 % was observed at concentrations of 9.03 and 4.10 mg/L DOC, respectively. Therefore the test item can be considered as ready biodegradable.

Executive summary:

The ready biodegradability of sodium p-chloro-m-cresol was investigated according to EU C. 4-B method (Modified OECD Screening Test (Müller 1996)). The effluent of a laboratory scale was treated with the test item at a concentration of 9 mg/L DOC and incubated in the dark for 28 days. As test parameter the removal of dissolved organic carbon was measured. After 28 days a degradation of 79 - 83 % was observed. Therefore, the test item can be considered as ready biodegradable.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

23 Aug 1995 - 18 Oct 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Remarks:

Aquatic mixed population of microorganisms (activated sludge)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Effluent of a laboratory living sludge plant that is operated with wastewater from the southern Wupper Association.
- Date of sampling: 18.08.1995
- Pretreatment: 5 days aeration
- Concentration of sludge: 5 mL/L
- Water filtered: yes
- Type and size of filter used, if any: Coarse filter paper

Duration of test (contact time):

56 d

Initial conc.:

5.13 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Test temperature: 20 - 21 °C
- Continuous darkness: yes

SAMPLING
- Sampling frequency: after 0, 7, 14, 21, 28, 35, 42, 49 and 56 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes, 5.13 mg/L test item with 2.0 mg/L reference item

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

18

Sampling time:

56 d

Details on results:

For results on the test substance section "Any other information on results incl. tables".
A pre-test was conducted (closed bottle) a degradation of 42% was reached after 28 days.

Results with reference substance:

62 % degradation after 14 days.

Table 1: O2 concentration of test item (mg O2/L after x days)

no flasks	0 d	no flasks	7 d	no flasks	14 d	no flasks	21 d	no flasks	28 d
37	7.87	39	7.89	41	7.95	43	7.33	45	7.46
38	7.82	40	7.88	42	7.84	44	7.37	46	7.47
Mean value	7.85		7.89		7.90		7.35		7.47
no flasks	0 d	no flasks	35 d	no flasks	42 d	no flasks	49 d	no flasks	56 d
37	7.87	47	7.52	49	7.24	51	7.37	53	6.48
38	7.82	48	7.24	50	6.76	52	6.28	54	6.46
Mean value	7.85		7.38		7.00		6.83		6.47

Table 2: O2 consumption: % degradation

Test item conc.:5.13 mg/L (ThOD: 1556 mg/L)	O2 consumption
	7 d	14 d	21 d	28 d	35 d	42 d	49 d	56 d
No 1: (mt0 - mtx) – (mb0 - mbx)	0.00	0.00	0.16	0.08	0.17	0.51	0.25	1.47
No 2: (mt0 - mtx) – (mb0 - mbx)	0.00	0.00	0.07	0.02	0.40	0.94	1.29	1.44
D1: % degradation	0	0	2	1	2	6	3	18
D2: % degradation	0	0	1	0	5	12	16	18
D: mean value	0	0	2	1	4	9	10	18

 Table 3: Results of pre-test

	7 d	14 d	21 d	28 d
% degradation	0	1	0	42

 

Validity criteria fulfilled:

not specified

Interpretation of results:

not readily biodegradable

Conclusions:

Under test conditions 18 % biodegradation was observed after 56 days.

Executive summary:

The ready biodegradability of sodium p-chloro-m-cresol was investigated according to EU C. 4-E method (closed bottle test (Caspers & Müller 1996). The effluent of a laboratory scale was treated with the test item at a concentration of 5.13 mg/L and incubated in the dark for 56 days. As test parameter the oxygen consumption was measured. After 56 days a degradation of 18 % was observed, therefore the test item cannot be considered as ready biodegradable. The results of the pre-test showed a degradation of 42 %.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

13 Jun 1996 - 11 Jul 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

EU Method C.4-B (Determination of the "Ready" Biodegradability - Modified OECD Screening Test)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

other: effluent of a laboratory scale

Details on inoculum:

- Source of sewage: south of Wupperverband
- Concentration of sludge: 0.5 mL/L
- Water filtered: yes

Duration of test (contact time):

28 d

Initial conc.:

18 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Test temperature: 22 ± 2 °C
- Continuous darkness: yes

SAMPLING
- Sampling frequency: after 0, 7, 14, 21, 27 and 28 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes

Reference substance:

aniline

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

28 d

Details on results:

Please refer to "any other information on results incl. tables".

Results with reference substance:

96 % degradation after 14 days.

Table 1: DOC values of test item

Vessel no.		DOC
		0 h	7 d	14 d	21d	27 d	28 d
5	a1	20.4	18.6	18.9	19.2	20.8	20.4
	a2	19.2	18.9	18.3	18.1	18.9	18.9
	a, mean value	19.8	18.8	18.6	18.7	19.9	19.7
6	b1	21.4	19.1	18.8	18.8	20.6	20.5
	b2	20.6	18.6	18.3	18.1	20.8	20.0
	b, mean value	21.0	18.9	18.6	18.5	20.7	20.3

Table 2: Degradation of test item

Vessel no.	% degradation
	0 h	7 d	14 d	21d	27 d	28 d
5	0	0	0	0	0	0
6	0	1	1	6	0	0
mean value	0	1	1	3	0	0

Interpretation of results:

not readily biodegradable

Conclusions:

Under test conditions no biodegradation was observed (0 % after 28 d).

Executive summary:

The ready biodegradability of sodium p-chloro-m-cresol was also investigated according to EU C. 4 –B method (Modified OECD Screening Test (Caspers & Müller 1996)). The effluent of laboratory scale was treated with the test item at a concentration of 18 mg/L and incubated in the dark for 28 days. As test parameter the removal of dissolved organic carbon was measured. After 28 days no degradation was observed, therefore the test item cannot be considered as ready biodegradable.

Description of key information

83 % degradation (EU-method C.4-B) after 28 days.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The biodegradability of sodium p-chloro-m-cresolate (CAS 15733-22-9) was investigated in three biodegradation studies.

 

The key study investigated the ready biodegradability of sodium p-chloro-m-cresolate according to EU C. 4-B method (Modified OECD Screening Test). Activated sludge of a wastewater treatment plant was treated with the test item at a concentration of 9 mg/L DOC and incubated in the dark for 28 days. As test parameter the removal of dissolved organic carbon was measured. After 28 days a degradation of 83% was observed. Therefore, the test item can be considered as ready biodegradable.

 

In a supporting study the ready biodegradability of sodium p-chloro-m-cresolate was investigated according to EU C. 4-E method (closed bottle test. Activated sludge of a wastewater treatment plant was treated with the test item at a concentration of 5.13 mg/L and incubated in the dark. As test parameter the oxygen consumption was measured. Due to a degradation of 42% after 28 days in a pre-test the duration of the main test was conducted with an expanded test duration time of 56 days. At the end of the 56 days test duration a degradation of 18 % was observed.

 

Furthermore ready biodegradability of sodium p-chloro-m-cresolate was investigated according to EU C. 4 –B method (Modified OECD Screening Test. Activated sludge of a wastewater treatment plant was treated with the test item at a concentration of 18 mg/L and incubated in the dark for 28 days. As test parameter the removal of dissolved organic carbon was measured. After 28 days no degradation was observed.

 

It can be concluded that sodium p-chloro-m-cresolate is readily biodegradable under stringent test conditions, i.e., a high inoculum activity and/or the presence of appropriate inoculum species being able to degrade the substance. Hence, sodium p-chloro-m-cresolate can be considered to be ready biodegradable.