2-Oxepanone, polymer with 1,6-hexanediol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Remarks:

The study on a similar substance serves as data source for the endpoint study record "TARGET - Biodegradation in water: screening tests_Capa203" and the justification for read-across is provided there.

Adequacy of study:

key study

Study period:

Not reported

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study conducted to OECD 301B, GLP compliant

Justification for type of information:

Study serves as data source; read-across justification is found in corresponding Target record.

Reason / purpose for cross-reference:

read-across source

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:

Secondary (biological) activated sludge was obtained from the RWZI Horstermeer in Nederhorst den Berg, The Netherlands on January 13, 1993. The RWZI Horstermeer was an activated sludge plant treating predominantly domestic waste water. The dry weight of this inoculum appeared to be 4.0 mg/ml.

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

test mat.

Initial conc.:

10 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Reference substance:

acetic acid, sodium salt

Key result

Parameter:

% degradation (TOC removal)

Value:

ca. 60

Sampling time:

7 d

Remarks on result:

other: initial conc. 10 mg/L

Parameter:

% degradation (TOC removal)

Value:

ca. 84

Sampling time:

28 d

Remarks on result:

other: initial conc. 10 mg/L

Parameter:

% degradation (TOC removal)

Value:

ca. 42

Sampling time:

7 d

Remarks on result:

other: initial conc. 20 mg/L

Parameter:

% degradation (TOC removal)

Value:

ca. 56

Sampling time:

28 d

Remarks on result:

other: initial conc. 20 mg/L

Table 1: Results of the biodegradation test with CAPA 203 and sodium acetate. The results are expressed as CO₂ mg (cumulative) formed after 7, 14, 21, 28 and 29 days (n=2)

Concentration CAPA 203 (mg/L)	Concentration Sodium acetate (mg/L)	mg CO2 produced
		7 days	14 days	21 days	28 days	29 days
0	100	44.0	56.9	60.8	59.4	59.8
20	100	37.6	61.5	71.4	73.1	72.9
10	0	28.6	35.7	38.6	40.0	40.2
20	0	39.9	50.8	52.4	53.2	53.2

Table 2: Percentage degradation of 100 mg/L sodium acetate, 20 mg/L CAPA 203 in the presence of 100 mg/L sodium acetate and CAPA 203 at a concentration of 10 and 20 mg/L

	% biodegradation
	7 days	14 days	21 days	28 days	29 days
sodium acetate (100 mg/L)	44	57	61	60	60
CAPA 203 (20 mg/L) in the presence of sodium acetate (100 mg/L)	-7	5	11	14	14
CAPA 203 (10 mg/L)	60	75	81	84	84
CAPA 203 (20 mg/L)	42	53	55	56	56

Table 3: Results of the biodegradability test

Concentration CAPA 203 (mg/L)	Concentration Sodium acetate (mg/L)	mg CO2 of absorbed in the period
		0-7 days	7-14 days	14-21 days	21-28 days	28-29 days
0		15.3	8.6	4.9	1.3	1.1
0		15.8	10.7	8.2	7.4	1.1
average		15.6	9.7	6.6	4.4	1.1
	100	80.3	22.1	10.2	3.1	1.9
	100	38.8	23.0	10.8	2.8	1.1
	average	59.6	22.6	10.5	3.0	1.5
20	100	53.2	33.6	16.5	6.1	0.9
10		43.4	18.5	11.1	9.5	1.4
10		44.9	15.0	7.9	2.1	1.1
average		44.2	16.8	9.5	5.8	1.3
20		74.8	19.6	3.7	1.9	1.1
20		36.2	21.6	12.7	8.5	1.1
average		55.5	20.6	8.2	5.2	1.1

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test substance CAPA 203 was classified as readily biodegradable.

Executive summary:

A study was conducted to guideline OECD 301B using the substance CAPA 203. The reference compound (sodium acetate) degraded to 60% within 28 days. The total CO₂-evolution in the inoculum blank at the end of the test was 37 mg, which was below the maximum acceptable amount according to the guideline (40 mg CO₂L). The substance CAPA 203 was 60% degraded within 7 days when incubated at a concentration of 10 mg/L and 42% degraded when incubated at a concentration of 20 mg/L. On the basis of this result, CAPA 203 was classified as readily biodegradable.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

Not reported

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study conducted to OECD 301B, GLP compliant

Justification for type of information:

It is considered appropriate to address the ready biodegradability data requirement for 2-oxepanone, polymer with 1,6-hexanediol by applying read-across from available experimental study data on 2-oxepanone, polymer with 1,4-butanediol. The source and target substances are low molecular weight polyester diols terminated by primary hydroxyl groups and are structurally similar in that they both contain 6-hydroxyhexanoic acid repeating units. The linking unit is 1,4-butanediol in 2-oxepanone, polymer with 1,4-butanediol and 1,6-hexanediol in 2-oxepanone, polymer with 1,6-hexanediol. The diols differ by two carbons in the aliphatic chain and are therefore sufficiently structurally similar to support a read-across approach. The source and target substances share similar physico-chemical properties in that both are liquids at room temperature and have similar water solubility and log Pow values. The substances are therefore sufficiently similar in terms of basic physico-chemical properties to support a read-across approach. A read-across justification document is attached in section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (TOC removal)

Value:

ca. 60

Sampling time:

7 d

Remarks on result:

other: initial conc. 10 mg/L

Parameter:

% degradation (TOC removal)

Value:

ca. 84

Sampling time:

28 d

Remarks on result:

other: initial conc. 10 mg/L

Parameter:

% degradation (TOC removal)

Value:

ca. 42

Sampling time:

7 d

Remarks on result:

other: initial conc. 20 mg/L

Parameter:

% degradation (TOC removal)

Value:

ca. 56

Sampling time:

28 d

Remarks on result:

other: initial conc. 20 mg/L

Table 1: Results of the biodegradation test with CAPA 203 and sodium acetate. The results are expressed asCO₂mg (cumulative) formed after 7, 14, 21, 28 and 29 days (n=2)

Concentration CAPA 203 (mg/L)	Concentration Sodium acetate (mg/L)	mg CO2 produced
		7 days	14 days	21 days	28 days	29 days
0	100	44.0	56.9	60.8	59.4	59.8
20	100	37.6	61.5	71.4	73.1	72.9
10	0	28.6	35.7	38.6	40.0	40.2
20	0	39.9	50.8	52.4	53.2	53.2

Table 2: Percentage degradation of 100 mg/L sodium acetate, 20 mg/L CAPA 203 in the presence of 100 mg/L sodium acetate and CAPA 203 at a concentration of 10 and 20 mg/L

	% biodegradation
	7 days	14 days	21 days	28 days	29 days
sodium acetate (100 mg/L)	44	57	61	60	60
CAPA 203 (20 mg/L) in the presence of sodium acetate (100 mg/L)	-7	5	11	14	14
CAPA 203 (10 mg/L)	60	75	81	84	84
CAPA 203 (20 mg/L)	42	53	55	56	56

Table 3: Results of the biodegradability test

Concentration CAPA 203 (mg/L)	Concentration Sodium acetate (mg/L)	mg CO2 of absorbed in the period
		0-7 days	7-14 days	14-21 days	21-28 days	28-29 days
0		15.3	8.6	4.9	1.3	1.1
0		15.8	10.7	8.2	7.4	1.1
average		15.6	9.7	6.6	4.4	1.1
	100	80.3	22.1	10.2	3.1	1.9
	100	38.8	23.0	10.8	2.8	1.1
	average	59.6	22.6	10.5	3.0	1.5
20	100	53.2	33.6	16.5	6.1	0.9
10		43.4	18.5	11.1	9.5	1.4
10		44.9	15.0	7.9	2.1	1.1
average		44.2	16.8	9.5	5.8	1.3
20		74.8	19.6	3.7	1.9	1.1
20		36.2	21.6	12.7	8.5	1.1
average		55.5	20.6	8.2	5.2	1.1

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The target substance 2-oxepanone, polymer with 1,6-hexanediol (Capa-2047A) is estimated to be readily biodegradable, based on read-across from a reliable study testing Capa-203 (2-oxepanone, polymer with 1,4-butanediol).

Executive summary:

A study was conducted to guideline OECD 301B using the substance Capa-203 (2-oxepanone, polymer with 1,4-butanediol). The reference compound (sodium acetate) degraded to 60% within 28 days. The total CO2-evolution in the inoculum blank at the end of the test was 37 mg, which was below the maximum acceptable amount according to the guideline (40 mg CO2L). The substance Capa-203 was 60% degraded within 7 days when incubated at a concentration of 10 mg/L and 42% degraded when incubated at a concentration of 20 mg/L. On the basis of this result, Capa-203 was classified as readily biodegradable.

The basic physico-chemical properties and chemical structural of the source substance Capa-203 and the target substance Capa-2047A (2-oxepanone, polymer with 1,6-hexanediol) are considered to be sufficiently similar to support a read-across approach. Therefore, the target substance CAPA 2047A is also concluded to be readily biodegradable.     

Description of key information

One key study is presented, which shows that the read-across substance 2-oxepanone, polymer with 1,4-butanediol is readily biodegradable. The target substance 2-oxepanone, polymer with 1,6-hexanediol is therefore concluded to be readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The basic physico-chemical properties and chemical structural of the source substance 2-oxepanone, polymer with 1,4-butanediol and the target substance 2-oxepanone, polymer with 1,6-hexanediol are considered to be sufficiently similar to support a read-across approach. The read-across substance 2-oxepanone, polymer with 1,4-butanediol has been found to be readily biodegradable with 60% degradation within 7 days when incubated at a concentration of 10 mg/L and 42% degradation when incubated at a concentration of 20 mg/L. On the basis of this result the target substance was classified as readily biodegradable.