5-hept-6-enyloxolan-2-one

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:

supporting study

Study period:

Test dates: Nov. 02, 2012 to Jun. 19, 2013

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

It was reported in the study report that the maximum value of relative deviation between the two replicates was 14,8% (less than the validity criteria of 20%) but this relative deviation was calculated with the mean of replicates. If we consider the difference of extremes of replicate values (like mentioned in the OECD Guideline), and not the mean value, the deviation is >20% (21,5% at d14 and 24,5% at d28). But as the substance is well readily biodegradable and that we have another study showing the same conclusion, this study is reliable with restrictions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Qualifier:

according to guideline

Guideline:

other: Dangerous Chemicals Administration. GB/T 21801 "- 2008 Chemicals - Ready Biodegradability: Manometric Respirometry Test [S].

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

Issued on November 24, 2010.

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, adapted

Details on inoculum:

- Source of inoculum/activated sludge: The secondary of Liede Sewage Treatment Plant of Guangzhou

The sludge was washed by centrifugation, the supernatant liquid phase was decanted and the solid material resuspended in a mineral medium. A homogenized aliquot of the final sludge suspension was weighted. Based on this ration, calculated amount of wet sludge was suspended in mineral medium to obtain a concentration equivalent to 2.4g dry material per liter. Appropriate volume of inoculum“ was inoculated in each bottle to give a final concentration of 28 mg dry material per liter.

Duration of test (contact time):

28 d

Initial conc.:

22 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium:
Stock solution (a)
Potassium dihydrogen phosphate KH2PO4: 8.50 g/L
Dipotassium hydrogen phosphate K2HPO4: 28.5 g/L
Twelve hydration disodium hydrogen phosphate, Na2HPO4: 67.15 g/L
Ammonium chloride NH4Cl: 0.50 g/L
Dissolve in Water and made up to 1L.
Stock solution (b)
Anhydrous calcium chloride CaCl2: 13.75 g/L
Dissolve in water and made up to 0.5L.
Stock solution (c)
Magnesium sulfate heptahydrate MgSO4 7H2O: 11.25 g/L
Stock solution (d)
Iron (Ill) chloride hexahydrate FeCl3 6H2O: 0.125 g/L
Dissolve in water and make up to 0.5L.

80mL of solution (a) was mixed with 6000mL deionized Water, then 8 mL of solutions (b), (c) and (d) were added and made up to 8L with water.

- Test temperature: 22 °C ± 1°C
- pH: 7.4 ± 0.2

Reference substance:

benzoic acid, sodium salt

Remarks:

Guangzhou Chemical Reagent Factory (≥99.5%)

Test performance:

(1) The oxygen uptake of the inoculum blanks was 16.8 mg/L and 17.7 mg/L, less than 60 mg/L in 28 days.
(2) At the end of the test, pH values of each test bottle was in the range of 6.0-8.5.
(3) At the stable in the test, at end of the test and the end of 10d-window, the maximum relative deviation between two replicate was 14.8%, less than 20%.
(4) The percentage degradation (based on ThOD) of reference substance was 80.2%, which had reached the pass levels of 60% by day 14.

Key result

Parameter:

% degradation (O2 consumption)

Value:

83.3

Sampling time:

14 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

82.4

Sampling time:

28 d

Results with reference substance:

At 14 d, 80.2 % biodegradation is observed.

Table 5.2.1.1: The percentage biodegradadation calculated by BOD

 

Time (days)	Test Suspension-1	Test Suspension-2	Average	Relative differences	Procedure control
3	54.4	43.5	48.9	11.1	58.1
7	80.8	64.3	72.6	11.4	77.0
10	89.0	71.6	80.3	10.8	81.2
14	94.1	72.6	83.3	12.9	80.2
17	96.1	74.6	85.3	12.6	-
21	96.1	75.6	85.9	11.9	-
25	98.4	74.8	86.6	13.6	-
28	94.7	70.2	82.4	14.8	-

 

Validity criteria fulfilled:

yes

Remarks:

with one deviation: difference of extremes is >20% (21,5% at d14 and 24,5% at d 28)

Interpretation of results:

readily biodegradable

Conclusions:

According OECD guideline 301F, test item is readily biodegradable in the test.

Executive summary:

The Ready Biodegradability of test item was determined by the Manometric Respirometry Test. The test item is readily biodegradable in the test for the period of 28 days. Control solutions with inoculum and the reference item, sodium benzoate, together with a toxicity control were used for validation purposes. The test item attained, 83.3 %  biodegradation after 28 days and satisfied the 10-days window validation criterion. The test item is readily biodegradable according to OECD guideline 301 F. It was reported in the study report that the maximum value of relative deviation between the two replicates was 14,8% (less than the validity criteria of 20%) but this relative deviation was calculated with the mean of replicates. If we consider the difference of extremes of replicate values (like mentioned in the OECD Guideline), and not the mean value, the deviation is >20% (21,5% at d14 and 24,5% at d28). But as the substance is well readily biodegradable and that we have another study showing the same conclusion, this study is reliable with restrictions.

 

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Test dates: Jun. 21-22 to Dec. 21, 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

Inspected on: 11-15 October 2004; Signed on: 28 July 2007

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

- Source of inoculum/activated sludge: aeration tank of RWZl, Zonhoven (Belgium) dealing with domestic sewage.

Upon arrival at the laboratory, the liquor was sieved through a 0.5 mm sieve in order to remove large particles and aerated for 4 hours before the -start of the test. The pH of the liquor was 7.00. Then the liquor was homogenised and allowed to settle for 30-60 minutes. The clear supernatant was decanted to provide sufficient volume for a 1 % inoculum in each carboy.

Duration of test (contact time):

28 d

Initial conc.:

15 mg/L

Based on:

ThCO2

Remarks:

163 mg

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

activated sludge, domestic, adapted

- Source of inoculum/activated sludge: aeration tank of RWZl, Zonhoven (Belgium) dealing with domestic sewage.

Upon arrival at the laboratory, the liquor was sieved through a 0.5 mm sieve in order to remove large particles and aerated for 4 hours before the -start of the test. The pH of the liquor was 7.00. Then the liquor was homogenised and allowed to settle for 30-60 minutes. The clear supernatant was decanted to provide sufficient volume for a 1 % inoculum in each carboy.

TEST CONDITIONS
- Composition of medium:
Mineral stock solutions were prepared as follows:
Phosphate solution:
KH2PO4: 8.50 g/L
K2HPO4: 21.75 g/L
Na2HPO4: 26.64 g/L
NH4Cl: 0.50 g/L
CaCl2 2H2O: 36.40 g/L
MgSO4 7H2O: 22.50 g/L
FeCl3 6H2O: 0.25 g/L

The mineral medium contained the following amounts of stock solution per litre High quality water.
- 10 ml of the phosphate solution;
- 1 ml of the CaCl2.2H2O solution;
- 1 ml of the MgSO4.7H2O solution;
- 1 ml of the FeCl3.6H2O solution.

- Test temperature: 21 to 26 °C
- pH: 6.82 - 7.47
- pH adjusted: no
- Aeration of dilution water: CO2-free air
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 5 L brown glass vessels with aeration tubes.
- Number of culture flasks/concentration: 2
- Measuring equipment: TOC analysers: Element Analyser EA 1112 and Shimadzu TOC-VCPN
- Details of trap for CO2 and volatile organics if used: a 1 L glass vessel containing 700 mL 0.0125 M Ba(OH)2.8H2O is connected in series between a pressurised air source and a carboy. Air is sparged through the scrubbing solutions at a constant rate.

CONTROL AND BLANK SYSTEM
- Control: 531 ml High quality water
- Reference: 15 mg/L final carbon (Sodium benzoate); 30 ml + 501 ml High quality water
- Toxicity control: 0.0626 mg of test item + 30 mg/L final carbon (Sodium benzoate); 30 ml + 501 ml High quality water

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

83

Sampling time:

28 d

 Control vessels

The total CO₂production in the control inoculums at the end of the test was ≤ 7.05 mg/L and did not exceed 70 mg/L medium.

 

Reference item

Biodegradation (% of ThCO₂) of the reference item was 67% after 5 days and increased to 100% by day 22. The test therefore fulfilled the necessary criteria (> 60% biodegradation by day 14).

5 days	biodegradation (% of ThCO2)	67 %
28 days (end of the test)	biodegradation (% of ThCO2)	100 %

 

Toxicity control

The biodegradation of the toxicity control was > 25 % after 14 days, indicating that test item had no inhibitory effect on the micro-organisms in the test.

10 days	biodegradation (% of ThCO2)	76 %
28 days (end of the test)	biodegradation (% of ThCO2)	83 %

 

Test item

The following results were obtained for the ready biodegradability of the test item, based on mg CO₂produced with respect to the ThCO₂.

10-day window	1. biodegradation (% of ThCO2)	day 0 (test day 3):	21 %
		day 7 (test day 10) *:	73 %
	2. biodegradation (% of ThCO2)	day 0 (test day 3):	18 %
		day 7 (test day 10) *:	73 %
28 days (end of the (test)	1. biodegradation (% of ThCO2)		83 %
	2. biodegradation (% of ThCO2)		83 %

*: No measurement was done on day 10 of the 10-day window, but on day 7 already > 60% biodegradation occurred.

The difference between the degradation results of the replicates with test item was 60% at the end of the test (due to the low degradation results).

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

According OECD guideline 301B, test item is readily biodegradable or had no inhibitory effect on the micro-organisms in the test.

Executive summary:

The Ready Biodegradability of test item was determined in an aerobic, inoculated aqueous medium, aerated with CO2-free air at a controled rate in the dark.  Degradation was followed over 28 days by determinaton of the CO2 production, in relation to the theoretical CO2 that could have been produced, based on the carbon content of the test item. Control solutions with inoculum and the reference item, sodium benzoate, together with a toxicity control were used for validation purposes. The test item attained, 83 %  biodegradation after 28 days and satisfied the 10-days window validation criterion. The test item is readily biodegradable according to OECD guideline 301 B.

Description of key information

OECD Guideline 301B, EGLP, Key study, validity 1:

83% biodegradation after 28 days within the 10d window

Readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

To assess the biodegradation potential of the registered substance, two experimental studies are available.

 

One study (Lisec, 2005), assessed as the key study, was performed on the registered substance to assess the ready biodegradability of the test item in an aerobic aqueous medium, according to OECD Guideline 301B performed under GLP (with statement included in the report). The Ready Biodegradability of test item was determined in an aerobic, inoculated aqueous medium, aerated with CO2-free air at a controled rate in the dark. Degradation was followed over 28 days by determinaton of the CO2 production, in relation to the theoretical CO2 that could have been produced, based on the carbon content of the test item. Control solutions with inoculum and the reference item, sodium benzoate, together with a toxicity control were used for validation purposes. The test item attained, 83 %  biodegradation after 28 days and satisfied the 10-days window validation criterion. The test item is readily biodegradable according to OECD guideline 301 B.

 

The second study (Guangdong, 2013) was also performed on the registered substance but according to the manometric respirometry method. Control solutions with inoculum and the reference item, sodium benzoate, together with a toxicity control were used for validation purposes. The test item attained, 83.3 %  biodegradation after 28 days and satisfied the 10-days window validation criterion. The test item is readily biodegradable according to OECD guideline 301 F. It was reported in the study report that the maximum value of relative deviation between the two replicates was 14,8% (less than the validity criteria of 20%) but this relative deviation was calculated with the mean of replicates. If we consider the difference of extremes of replicate values (like mentioned in the OECD Guideline), and not the mean value, the deviation is >20% (21,5% at d14 and 24,5% at d28). But as the substance is well readily biodegradable and that we have another study showing the same conclusion, this study is reliable with restrictions.