Ethyl formate

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:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

other: Respirometric test

Principles of method if other than guideline:

Biodegradation study was conducted according to respirometric test for evaluating the percentage biodegradability of test chemical.

GLP compliance:

not specified

Oxygen conditions:

not specified

Inoculum or test system:

activated sludge, adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Test inoculum activated sludge (adapted) was obtained from biological sewage treatment plants.

Duration of test (contact time):

8 d

Initial conc.:

395 mg/L

Based on:

other: Org. C

Parameter followed for biodegradation estimation:

TOC removal

Parameter followed for biodegradation estimation:

other: BOD

Parameter:

other: BOD

Value:

69

Sampling time:

8 d

Remarks on result:

other: Other details not known

Parameter:

% degradation (TOC removal)

Value:

86

Sampling time:

8 d

Remarks on result:

other: Other details not known

Details on results:

Test substance undergoes 69 and 86% degradation by BOD and TOC removal parameter in 8 days, respectively.

Parameter:

BOD5

Value:

760 mg O2/g test mat.

Parameter:

COD

Value:

1 090 mg O2/g test mat.

Parameter:

BOD5*100/COD

Value:

>= 60

Remarks on result:

other: BOD5*100/COD = >60%

1. Eliminability from the water:

Eliminations degree	Rating	Experimental method	Analysis-method
˃60%	Well biodegradable	Respirometric test	BOD of the measured COD

 

With proper introduction into adapted biological sewage treatment plants, no disturbances of the degrading activity of the activated sludge are to be expected.

 

Remarks/Observations: COD = 1090 mg/g

                                              BOD5 = 760 mg/g

2. Behaviour in sewage treatment plants

Sample –Ethyl formate

Trial date –1/3/18

No. –3245

Approach date –01 March, 1978

Z. V. –0.9

 

Verd. P	FI. No.	Beginning O2 mg/l	End O2 mg/l	Z = A - E	1000/P (Z-ZV) + ZV	Individual value	Mean value	Remarks
6.5	309	88
	193		30		738
	49		30	57	738
10	277	88
	142		14	74	650
	242		09	719	720	6	707
15	264	88
	424		01
	438		01

3. Result of test chemical

Date: 25/4/78

Test material    : Ethyl formate

 

Activated sludge-Concentrations           a. original – 28 g TS/l

Activated sludge-Origin:VKA                  b. Test approach – 0.2 g TS/l

 

		Blank value	Reference value	Toxic – approach		Reduction - approach
Approach No.		1	2	3	4	5	6
Test material (mg TOC/l)		-	-	5	50	5	50
Test material (mg/l)		-	-	12	123	12	123
Total– TOC (mg/l)		-	50	55	100	5	50
After 24 hr	BOD (mg/l)	0	50	70	75	10	35
	Difference in BOD (%)	-	50	140	150	-	-
	O2 / l	-	-	4	0.5	2	0.7
After 168 hr = 7 days	BOD (mg/l)	30	155	180	260	50	155
	Difference in BOD (%)	-	155 100%	116	168	-	-
	O2 / l	-	-	5	2	4	2.5

Degradation curve (Total value or reference value deducted)

Time (d)	1	2	3	4	5	6	7	8	9	10	11	12	13	14
No. : 1 BOD mg/l	0	0	10				30
No. : 2 BOD mg/l	50	85	110				155
No. : 3 BOD mg/l	20	20	20				85
No. : 4 BOD mg/l	25	80	80				105
No. : 5 BSB mg/l	10	20	15				80
No. : 6 BOD mg/l	35	100	110				02

 

Parameter	Beginning	End	Elimination (%)
TOC mg/l	50	7	86
TOD mg/l	21

 

Biological degradation:

 

✓ well X Moderate   X Difficult to Degrade   X No statement possible

 

Beginning: 1 d
End: 2 d

 

 

Biological effect:

 

X Inhibitory

✓ Promoting

X No effect

4. Respirometric-degrading test

Date: 27/2/73

Test substance:Ethyl formate

Prod. no.:04837

Approach	TOC		TOD
	mg/l	mg/g	mg/l	mg/g
Approach
Beginning	75		65
End	31		63
Reduction (%)	54		3

O2-consumption (mg/l)

Time	Blank	No. of replicates		1+2/2 – blank	%BOD
		1	2
1d	22	7	10	-13
3d	53	15	5	-43
5d	79	49	43	-33
6d	89	72	74	-16
8d	93	84	87	-8

 

*Parameter specific (TOC, TOD, COD, BODth)

Degradability:

Well

Moderate (20%)

Difficult to degrade (0-20%)

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

The test item undergoes 69 and 86% degradation by BOD and TOC removal parameter after 8 days. in the test condition. Thus, the test item was considered to be readily biodegradable.

Executive summary:

Biodegradation study was conducted according to respiromteric test for evaluating the percentage biodegradability of test chemical. Activated sludge (adapted) obtained from biological sewage treatment plants was used as a test inoculum. The concentration of test item used for the study was 395 mg/L based on org. C. % degradation was calculated using the values of BOD and COD for test item. The BOD5 value of test chemical was observed to be 760 mgO2/mg. COD was calculated as 1090 mgO2/mg. Accordingly, The % degradation of the test item after 8 days of incubation according to respiromteric test was determined to be 69 and 86% degradation by BOD and TOC removal parameter. Based on the results, the test chemical, under the test conditions, was considered to be readily biodegradable in nature.

Description of key information

28-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test item (Experimental study report, 2018). 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. The concentration of test and reference item (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 item and reference item. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 76.5%. Degradation of Sodium Benzoate exceeds 45.18% on 7 days & 70.48% 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 1.51 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 77.48%. Based on the results, the test item, under the test conditions, was 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 for the test chemical and supporting study for its structurally and functionally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from study report (2018), 28-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test item (Experimental study report, 2018). 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. The concentration of test and reference item (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 item and reference item. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 76.5%. Degradation of Sodium Benzoate exceeds 45.18% on 7 days & 70.48% 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 1.51 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 77.48%. Based on the results, the test item, under the test conditions, was considered to be readily biodegradable in nature.

In a supporting study, biodegradation experiment was conducted according to respiromteric test for evaluating the percentage biodegradability of test chemical (Study report, 1987). Activated sludge (adapted) obtained from biological sewage treatment plants was used as a test inoculum. The concentration of test item used for the study was 395 mg/L based on org. C. % degradation was calculated using the values of BOD and COD for test item. The BOD5 value of test chemical was observed to be 760 mgO2/mg. COD was calculated as 1090 mgO2/mg. Accordingly, The % degradation of the test item after 8 days of incubation according to respiromteric test was determined to be 69 and 86% degradation by BOD and TOC removal parameter. Based on the results, the test chemical, under the test conditions, was considered to be readily biodegradable in nature.

In an another supporting study (from peer reviewed journal, handbook, authoritative databases and secondary source), biodegradation experiment was conducted for 10 days for evaluating the percentage biodegradability of test chemical. The study was performed under aerobic conditions at a temperature of 20°C, respectively. The inoculum used for the study was sewage seed which has been acclimated for one year to the tested substance. Initial test substance conc. used in the study was 200-1000 mg/L, respectively. The biodegradation is measured after one day in an oxidation unit with non-flocculants growth activated sludge. The percentage degradation of test chemical was determined to be 30% by BOD parameter after 10 days. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

 

Another biodegradability of test chemical was estimated using the BIODEG linear and non-linear model (E. Rorije et. al., 1997). The models have been applied are Quantitative Structure-Activity Relationships. Two models are fitted to the judgement of an evaluation of various different biodegradation rates of chemical. This include the one using linear regression and other using a form of non-linear fitting. These models used 36 fragments as descriptors with the molecular weight of the molecule as an added descriptor, and are fitted on the evaluated biodegradation data of a series of 295 compounds. The output of the models, x, is the number that should be interpreted as x < 0.5 (=0) (Chemical biodegrades slowly or not at all) or x > 0.5 (=1) (Chemical biodegrades fast), respectively. These tests typically produce ‘biodegradable’ (1) or ‘non-biodegradable’ (0) as a result. The application of the models has been automated, the BIODEG models are incorporated in the PC-based program. As the biodegradability prediction of test chemical by the BIODEG models comes out to be 1, test chemical is estimated to be readily biodegradable in nature.

 

For the test chemical, biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I) under aerobic conditions. Activated sludge was used as a test inoculums for the study. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of test substance was determined to be 94, 100 and 97% by BOD, GC and TOC removal parameter in 28 days. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

 

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