Oxacycloheptadec-10-en-2-one

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

according to guideline

Guideline:

other: "Microbial degradation test of chemical substances," specified in the notification concerning "Test Methods of New Chemical Substances etc."

Version / remarks:

(Notification No. 1121002 of Pharmaceutical and Food Safety Bureau, MHLW, dated on Nov. 21, 2003, Notification No. 2 of Manufacturing Industries Bureau, METI, dated on Nov. 13, 2003, and Notification No. 031121002 of Policy Planning Division, Environmental Health Department, Environmental Policy Bureau, MOE, finally revised on Nov. 20, 2006)

Principles of method if other than guideline:

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test chemical.

GLP compliance:

yes

Oxygen conditions:

not specified

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 (surface water containing surface soils from rivers, lakes and marshes and inland seas and returned sludge from sewage treatment plants) was collected at 10 sites in Japan.
- Preparation of inoculum for exposure: The activated sludge was incubated in synthetic sewage (purified water containing glucose, peptone and potassium dihydrogen phosphate at a pH adjusted to 7.0±1.0) for 19 hrs.
- Concentration of sludge: 30 mg/l (as suspended solid concentration)

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation:

other: GC

Details on study design:

TEST CONDITIONS
- Composition of medium: Three millilters of the solution in the composition A, B, C, or D specified in JIS K0102-2010 21 was added to purified water to make a solution of 1 L.
- Test temperature: 25±1°C
- pH: 7.0
- pH adjusted: yes, pH was adjusted to 7.0
- Suspended solids concentration: 30 mg/l
- Continuous darkness: Yes, test was performed under shaded condition.
- Other: Agitation method: revolutional agitation with stirrer.

TEST SYSTEM
- Culturing apparatus: culture bottle (300 ml) (improved culture bottle).
- Number of culture flasks/concentration: 6
- Measuring equipment: Closed-system oxygen consumption measuring apparatus.
- Details of trap for CO2 and volatile organics if used: Soda lime No.1 (Wako Pure Chemical Industries, Ltd. for absorption of carbon dioxide).
- Other: Tubes with stopcock were used for connection of the test containers and the measurement unit.

Constant temperature bath (equipped with measurement unit): AI-0001

CONTROL AND BLANK SYSTEM
- Inoculum blank: sludge blank system was used.

Reference substance:

aniline

Preliminary study:

Yes, preliminary test was performed.

Key result

Parameter:

% degradation (O2 consumption)

Value:

94

Sampling time:

28 d

Remarks on result:

other: Other details not known

Key result

Parameter:

other: GC

Value:

100

Sampling time:

28 d

Remarks on result:

other: Other details not known

Details on results:

Test chemical undergoes 94 and 100% degradation by oxygen consumption and GC parameter in 28 days.

Results with reference substance:

Reference substance aniline undergoes 77% degradation after 28 days.

Table: Calculation table for percentage biodegradation by BOD.

Study No.15581

Duration of cultivation:28 days

Vessel no.	28^thday		Mean
	BOD (mg)	Deg. (%)	Deg. (%)
6	77.1	77	-
5	7.8	-	-
2	86.5	94	94
3	85.3	93
4	88.0	96
1	0.7	-	-

Deg.:Percentage biodegradation

Vessel no. 6       : Sludge + aniline

Vessel no. 5       : Control blank (B)

Vessel no. 2, 3, 4: Sludge + test item

Vessel no. 1       : Water + test item

 

Formula:

Deg. (%) = [BOD-B]/ [TOD] × 100%

Where,

TOD of test item = 83.7 mg

TOD of aniline = 90.3 gm

Table: Analytical results of test solutions.

		(Water + test substance) system	(Sludge + test substance) system			Theoretical amount
		1	2	3	4
BOD^*1	mg	0.7	78.7	77.5	80.2	83.7
Amount of DOC detected and detection rate^*1*2	mgC	-	0.4	0.5	0.8	22.8
	%	-	2	2	4	-
Test substance residual amount and residual rate (GC)	mg	29.1	0	0	0	30.0
	%	97	0	0	0	-

Note: *1 The value of the (sludge + test substance) system was shown, as it is subtracted by the value of the sludge blank system.

*2 The (sludge + test substance) systems and the sludge blank system were analyzed to examine whether there was water-soluble products generated.

Table: Percentage degradability by BOD and GC.

		(Sludge + test substance) system
		2	3	4	Average
BOD degradability	%	94	93	96	94
Test substance degradability (GC)	%	100	100	100	100

Table: Calculation table for percentage biodegradation by BOD

Study No. 15581

Duration of cultivation: 28 days

 

Vessel no.	7^thday		14^thday		21^stday		28^thday		Mean
	BOD (mg)	Deg. (%)	BOD (mg)	Deg. (%)	BOD (mg)	Deg. (%)	BOD (mg)	Deg. (%)	Deg. (%)
6	60.9	65	72.5	75	75.1	76	77.1	77	-
5	2.3	-	5.1	-	6.5	-	7.8	-	-
2	40.8	46	64.4	71	80.8	89	86.5	94	94
3	22.4	24	48.5	52	73.2	80	85.3	93
4	43.2	49	63.2	69	79.7	87	88.0	96
1	0.0	-	0.0	-	0.0	-	0.7	-	-

 

Deg.: Percentage biodegradation

Vessel no. 6                       : Sludge + aniline

Vessel no. 5                       : Control blank (B)

Vessel no. 2, 3, 4             : Sludge + test item

Vessel no. 1                       : Water + test item

 

Test item of 30 mg was added

Deg. = [BOD-B]/ [TOD] × 100%

 

TOD of test item: 83.7 (mg)

C₁₆H₂₈O₂+ 22O₂  → 16O₂+ 14H₂O

22O₂/ C₁₆H₂₈O₂= 703.97/252.39 = 2.79

TOD = 30 × 2.79 = 83.7 (mg)

 

TOD of aniline: 90.3 (mg)

C₆H₇N + 8.75O₂→ 6CO₂+ 3.5H₂O + NO₂

8.75O₂/ C₆H₇N = 279.99/93.13 = 3.01

TOD = 30 × 3.01 = 90.3 (mg)

 

Table: Calculation table for percentage detection of DOC

Study No. 15581

Sample description	A	D	E	F
Water blank	n.d
(2) Sludge + test item	2.6	0.4	2
(3) Sludge + test item	3.0	0.5	2	2
(4) Sludge + test item	4.1	0.8	4
(5) Control blank	1.4

 

Amount of test item added: 30 mg

Theoretical amount of carbon: 22.8 mgC              30 × 16C/ C₁₆H₂₈O₂

A: Measured value (mgC/L)

B: Final volume: 40 mL

C: Ratio of portion used for analysis: 40/300

D: Detection amount of DOC

               Ds= ( A(Sludge + test item) – A(Control blank) ) × (B/C) / 1000 (mgC)

E: Percentage detection (%)

               E= D/ (Theoretical amount of carbon) × 100

F: Average percentage detection (%)

 

 

Table: Calculation table for percentage biodegradation of test item

Study No. 15581

Sample description	A	E	F	G	H
Standard solution 300 mg/l	403027
(1)Water + test item	380751	29.1	97
(2)Sludge + test item	n.d.	0	0	100
(3)Sludge + test item	n.d.	0	0	100	100
(4)Sludge + test item	n.d.	0	0	100
(5)Control blank	n.d.

 

Amount of test item added: 30 mg

A: Peak area (fA sec)

B: Final volume: 100 ml

C: Ratio of portion used for anaylsis: 300/300

D: Recovery rate: 97.4 % (water + test item)

                                 96.7 % (sludge + test item)

E: Residual amount of test item (mg)

               Ew= I × ( A(water + test item) / A(standard) × (B/C) / (D /100) / 1000

               Es= I ×  [ A(sludge + test item) – A(Control blank) / A(Standard)] × (B/C) / (D /100) / 1000

F: Percentage residue (%)

               F= E / 30 mg × 100

G: Percentage biodegradation (%),

               G= [ (E(water + test item) - E(sludge + test item) ) / E(water + test item) ] × 100

H: Average percentage biodegradation (%)

I: Concentration of standard solution: 300 mg/l

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

The average percentage degradation of test chemical was determined to be 94 and 100% by oxygen consumption and GC parameter in 28 days. The amount of DOC detected was less than 1 mgC, indicating that no water-soluble products were formed. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in water.

Executive summary:

Biodegradation study of the test chemical was carried out with a total duration period of 28 days.The test chemical was considered to be 100% pure.Specific density of the test substance is 0.9520 (20/4ᵒC). Identity of test substance was confirmed by comparing the infrared absorption spectrum of the sample provided by the sponsor with that of the sample tested in the test facility. Activated sludge was used as a test inoculum obtained fromsludge (surface water containing surface soils from rivers, lakes and marshes and inland seas and returned sludge from sewage treatment plants) was collected at 10 sites in Japan. The activated sludge was incubated insynthetic sewage (purified water containing glucose, peptone and potassium dihydrogen phosphate at a pH adjusted to7.0±1.0) for 19 hrs. Conc. of inoculum used for the study is 30 mg/l and initial test substance conc. used for the study was 100 mg/l. The test substance was stored at room temperature in dark place. Aniline was used as a reference substance for the study.The suspended solid conc. was measured for determination of the activated sludge added. Measurement method used was according to JIS K0102-2010 14. After measurement, the suspended solid concentration of the activated sludge was determined to be 2660 mg/L.Sufficiently high activity of the activated sludge was confirmed by using aniline.Change in the BOD of the test solution was monitored continuously with a closed-system oxygen consumption measuring apparatus during the culture period. The temperature of the closed-system oxygen consumption measuring apparatus in the constant temperature bath was recorded every day. After the culture period, the test substance in the test solution was analyzed. From the preliminary test, it was found that the test substance is not soluble in the test solution. The dissolved organic carbon (DOC) in the test solutions of the (sludge + test substance) systems and the sludge blank system was analyzed for confirmation of whether there are water-soluble products generated. Analytical methods involve the pretreatment of the test solution of the (water + test substance) system was done to prepare a gas chromatography sample (GC) sample for analysis of the test substance. Pretreatment was also done of test solution of the (sludge + test substance) system and a sludge blank system to prepare total organic carbon analysis (TOC) samples for analysis of DOC (Dissolved Organic Carbon) and gas chromatography (GC) samples for analysis of the test substance. Quantification of the test substance was done by gas chromatography (GC).The average recovery rate of each test solution was 90% or more and the variability was within 5%.The test is carried at a temperature of 25±1°C with a duration period of 28 days. Reference substance aniline undergoes 77% degradation after 28 days. The average percentage degradation of test chemical was determined to be 94 and 100% by oxygen consumption and GC parameter in 28 days. The amount of DOC detected was less than 1 mgC, indicating that no water-soluble products were formed. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

Description of key information

Biodegradation study of the test chemical was carried out with a total duration period of 28 days (Experimental study report, 2011).The test chemical was considered to be 100% pure.Specific density of the test substance is 0.9520 (20/4ᵒC). Identity of test substance was confirmed by comparing the infrared absorption spectrum of the sample provided by the sponsor with that of the sample tested in the test facility. Activated sludge was used as a test inoculum obtained fromsludge (surface water containing surface soils from rivers, lakes and marshes and inland seas and returned sludge from sewage treatment plants) was collected at 10 sites in Japan. The activated sludge was incubated insynthetic sewage (purified water containing glucose, peptone and potassium dihydrogen phosphate at a pH adjusted to7.0±1.0) for 19 hrs. Conc. of inoculum used for the study is 30 mg/l and initial test substance conc. used for the study was 100 mg/l. The test substance wasstored at room temperature in dark place.Aniline was used as a reference substance for the study.The suspended solid conc. was measured for determination of the activated sludge added. Measurement method used was according to JIS K0102-2010 14. After measurement, the suspended solid concentration of the activated sludge was determined to be 2660 mg/L.Sufficiently high activity of the activated sludge was confirmed by using aniline.Change in the BOD of the test solution was monitored continuously with a closed-system oxygen consumption measuring apparatus during the culture period. The temperature of the closed-system oxygen consumption measuring apparatus in the constant temperature bath was recorded every day.After the culture period, the test substance in the test solution was analyzed. From the preliminary test, it was found that the test substance is not soluble in the test solution. The dissolved organic carbon (DOC) in the test solutions of the (sludge + test substance) systems and the sludge blank system was analyzed for confirmation of whether there are water-soluble products generated. Analytical methods involve thepretreatment of the test solution of the (water + test substance) system was done to prepare a gas chromatography sample (GC) sample for analysis of the test substance. Pretreatment was also done of test solution of the (sludge + test substance) system and a sludge blank system to prepare total organic carbon analysis (TOC) samples for analysis of DOC (Dissolved Organic Carbon) and gas chromatography (GC) samples for analysis of the test substance. Quantification of the test substance was done by gas chromatography (GC).The average recovery rate of each test solution was 90% or more and the variability was within 5%.The test is carried at a temperature of25±1°C with a duration period of 28 days.Reference substance aniline undergoes 77% degradation after 28 days. The average percentage degradation of test chemical was determined to be 94 and 100% by oxygen consumption and GC parameter in 28 days. The amount of DOC detected was less than 1 mgC, indicating that no water-soluble products were formed. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Various experimental key and supporting studies of the test chemical were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from study report (2011),biodegradation study of the test chemical was carried out with a total duration period of 28 days. The test chemical was considered to be 100% pure. Specific density of the test substance is 0.9520 (20/4ᵒC). Identity of test substance was confirmed by comparing the infrared absorption spectrum of the sample provided by the sponsor with that of the sample tested in the test facility. Activated sludge was used as a test inoculum obtained from sludge (surface water containing surface soils from rivers, lakes and marshes and inland seas and returned sludge from sewage treatment plants) was collected at 10 sites in Japan. The activated sludge was incubated in synthetic sewage (purified water containing glucose, peptone and potassium dihydrogen phosphate at a pH adjusted to7.0±1.0) for 19 hrs. Conc. of inoculum used for the study is 30 mg/l and initial test substance conc. used for the study was 100 mg/l. The test substance was stored at room temperature in dark place. Aniline was used as a reference substance for the study. The suspended solid conc. was measured for determination of the activated sludge added. Measurement method used was according to JIS K0102-2010 14. After measurement, the suspended solid concentration of the activated sludge was determined to be 2660 mg/L. Sufficiently high activity of the activated sludge was confirmed by using aniline. Change in the BOD of the test solution was monitored continuously with a closed-system oxygen consumption measuring apparatus during the culture period. The temperature of the closed-system oxygen consumption measuring apparatus in the constant temperature bath was recorded every day. After the culture period, the test substance in the test solution was analyzed. From the preliminary test, it was found that the test substance is not soluble in the test solution. The dissolved organic carbon (DOC) in the test solutions of the (sludge + test substance) systems and the sludge blank system was analyzed for confirmation of whether there are water-soluble products generated. Analytical methods involve the pretreatment of the test solution of the (water + test substance) system was done to prepare a gas chromatography sample (GC) sample for analysis of the test substance. Pretreatment was also done of test solution of the (sludge + test substance) system and a sludge blank system to prepare total organic carbon analysis (TOC) samples for analysis of DOC (Dissolved Organic Carbon) and gas chromatography (GC) samples for analysis of the test substance. Quantification of the test substance was done by gas chromatography (GC).The average recovery rate of each test solution was 90% or more and the variability was within 5%.The test is carried at a temperature of 25±1°C with a duration period of 28 days. Reference substance aniline undergoes 77% degradation after 28 days. The average percentage degradation of test chemical was determined to be 94 and 100% by oxygen consumption and GC parameter in 28 days. The amount of DOC detected was less than 1 mgC, indicating that no water-soluble products were formed. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

 

For the test chemical, 28-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical (Experimental study report, 2017). The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used for this study. 1 polyseed capsule were added in 500 ml D.I water and then stirred for 1 hour for proper mixing and functioning of inoculum. This gave the bacterial count as 10E7 to 10E8 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. The concentration of test and reference chemical (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test chemical and reference chemical. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 73.49% at 20 ± 1°C. Degradation of Sodium Benzoate exceeds 43.37% on 7th days & 58.43% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid.The BOD28 value of test chemical was observed to be 1.17 mgO2/mg. ThOD was calculated as 2.78 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 42.08%. Based on the results, the test item, under the test conditions, was considered to be ultimate inherently biodegradable in nature.

 

In a supporting study from peer reviewed journal (Daniel Salvito et. al., 2011),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of test chemical. The study was performed according to OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test).The percentage degradation of test chemical was determined to be 84% by O2 consumption parameter in 28 days. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

 

On the basis of above overall results for test chemical, it can be concluded that the test chemical is considered to be readily biodegradable in water.