2-{2-[(2-ethylhexyl)oxy]ethoxy}ethyl prop-2-enoate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted between 18 August 2015 and 16 September 2015.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: 1= Reliable without restriction o GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-{2-[(2-ethylhexyl)oxy]ethoxy}ethyl prop-2-enoate

Cas Number:

117646-83-0

Molecular formula:

C15H28O4

IUPAC Name:

2-{2-[(2-ethylhexyl)oxy]ethoxy}ethyl prop-2-enoate

Test material form:

other: liquid

Details on test material:

Identification:
M120

Physical state/Appearance:
clear colorless liquid

Batch:
NC-5635-01

Purity:
99.4%

Expiry Date:
5 December 2015

Storage Conditions:
room temperature in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

10 other: mg carbon/L

Based on:

DOC

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

69

Sampling time:

28 d

Any other information on results incl. tables

Definitive Test

Inorganic carbon values for the test item, procedure control, toxicity control and inoculum control vessels at each analysis occasion,

Percentage biodegradation values of the test and reference items and the toxicity control, and Total and Inorganic Carbon values in the culture vessels on Day 0 are all given in the tables below.

Validation Criteria

The total CO₂evolution in the inoculum control vessels on Day 28 was 35.98 mg/L and therefore satisfied the validation criterion given in the OECD Test Guidelines.

 

The IC content of the test item suspension in the mineral medium at the start of the test (see Table 3) was below 5% of the TC content and hence satisfied the validation criterion given in the OECD Test Guidelines.

 

The difference between the values for CO₂production at the end of the test for the replicate vessels was <20% and hence satisfied the validation criterion given in the OECD Test Guidelines.

Biodegradation

Acidification of the test vessels on Day 28 followed by the final analyses on Day 29 was conducted according to thethods specified in the Test Guidelines. This acidification effectively kills the micro-organisms present and drives off any dissolved CO₂present in the test vessels. Therefore any additional CO₂detected in the Day 29 samples originated from dissolved CO₂that was present in the test vessels on Day 28 and hence the biodegradation value calculated from the Day 29 analyses is taken as being the final biodegradation value for the test item.

 

The results of the inorganic carbon analysis of samples from the first absorber vessels on Day 29 showed a decrease in all replicate vessels with the exception of test item replicate 2 and the toxicity control vessel. This decrease was considered to be due to sampling/analytical variation. 

 

Inorganic carbon analysis of the samples from the second absorber vessels on Day 29 confirmed that no significant carry-over of CO₂into the second absorber vessels occurred.

 

The test item attained 69% biodegradation after 28 days. Under the strict terms and conditions of OECD Guideline No. 301B the test item cannot be considered to be readily biodegradable as the test item failed to satisfy the 10-Day window validation criterion, whereby 60% biodegradation must be attained within 10 days of the biodegradation exceeding 10%. However, the test item has exhibited the potential for rapid biodegradation.

 

The toxicity control attained 70% biodegradation after 14 days and 105% biodegradation after 28 days thereby confirming that the test item did not exhibit an inhibitory effect on the sewage treatment micro-organisms used in the test. Biodegradation values in excess of 100% were considered to be due to sampling/analytical variation. 

 

Sodium benzoate attained 65% biodegradation after 14 days and 74% biodegradation after 28 days thereby confirming the suitability of the inoculum and test conditions. 

Inorganic Carbon Values on Each Analysis Occasion

Day	Inorganic Carbon (mg IC)
	Inoculum Control				Procedure Control				Test Item				Toxicity Control
	R1		R2		R1		R2		R1		R2		R1
	Abs1	Abs 2	Abs 1	Abs 2	Abs 1	Abs 2	Abs 1	Abs 2	Abs 1	Abs 2	Abs 1	Abs 2	Abs 1	Abs 2
0	1.28	1.05	1.05	1.05	1.40	0.93	1.17	0.93	1.05	1.05	1.05	1.17	1.05	1.05
2	7.66	-	8.35	-	2.44	-	23.66	-	9.40	-	10.79	-	32.13	-
6	12.34	-	11.65	-	28.83	-	33.45	-	18.45	-	16.95	-	49.82	-
8	15.02	-	14.79	-	29.58	-	38.18	-	21.79	-	29.81	-	60.09	-
10	13.23	-	16.53	-	35.00	-	36.82	-	27.93	-	37.51	-	64.07	-
14	21.08	-	18.70	-	39.44	-	39.10	-	33.89	-	39.33	-	61.77	-
21	23.55	-	23.21	-	45.97	-	49.12	-	47.77	-	42.59	-	71.99	-
28	30.24	-	28.67	-	49.84	-	54.10	-	50.29	-	48.38	-	83.89	-
29	24.38	1.51	27.50	1.51	48.21	1.63	47.76	1.51	42.42	1.51	50.10	2.44	88.81	1.74

R1 – R2= Replicates 1 and 2

Abs= CO2 absorber vessels

Percentage Biodegradation Values

Day	% Biodegradation
	Procedure Control	Test Item	Toxicity Control
0	0	0	0
2	17	7	40
6	64	19	63
8	63	36	75
10	70	59	82
14	65	56	70
21	81	73	81
28	75	66	91
29*	74	69	105

* Day 29 values corrected to include any carry-over of CO2 detected in Absorber 2

Total and Inorganic Carbon Values in the Culture Vessels on Day 0

Test vessel	Total Carbon* (mg/L)	Inorganic Carbon* (mg/L)	IC Content (% of TC)
Test Item 10 mg C/L R1	9.26**	-0.53	0
Test Item 10 mg C/L R2	9.47**	-0.29	0

R1 – R2 = Replicates 1 and 2

*Corrected for control values. Negative values are due to measured concentrations being less than control values

**Total carbon value given is the sum of the TC value obtained from analysis and the nominal TC contribution of the test item

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

The test item attained 69% biodegradation after 28 days. Under the strict terms and conditions of OECD Guideline No. 301B the test item cannot be considered to be readily biodegradable as the test item failed to satisfy the 10-Day window validation criterion, whereby 60% biodegradation must be attained within 10 days of the biodegradation exceeding 10%. However, the test item has exhibited the potential for rapid biodegradation.