Extract of fava d'anta, obtained from the fruits of Dimorphandra mollis (Leguminosae) by solvent extraction

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

Study period:

16.03.2021-20.04.2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): A sample of activated sludge was taken from the aeration tank of Sewage Treatment Plant ”Czajka” , Warsaw, receiving predominantly domestic sewage
- Preparation of inoculum for exposure: Pre-conditioning consisted of 7 days aeration of activated sludge at the test temperature of 22 ± 1ºC.
- Pretreatment: The coarse particles were removed
- Concentration of sludge: 5.10 mg/L
- Water filtered: no

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Remarks:

53.0 mg/l of organic carbon

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: test item, 100 mg/L; inoculum, 30 mg/L SS; P, 116 mg/L; N 1.3 mg/L; Na, 86 mg/L; K, 122 mg/L; Mg, 2.2 mg/L; Ca, 9.9 mg/L; Fe 0.05-0.1 mg/L.
- Water: The deionized water was taken from Milipore set. The measured value of water TOC was 2.019 mgC/l of organic carbon
- Test temperature: 22±1ºC
- pH: 7.4±0.2
- pH adjusted: no
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes
- Volume of test solution in flask, V: 164 mL

TEST SYSTEM
- Number of culture flasks/concentration: Triplicates. Flasks #7 (a1*), 8 (a2*) and 9 (a3*) containing test item (COD equals 141 mgO2/l) and inoculum 30 mg/l SS.
- Measuring equipment: Readings from apparatus (closed WTW OxiTop OC 110 respirometer).
- Details of trap for CO2 and volatile organics if used: potassium hydroxide solution.

SAMPLING
- Sampling frequency: O2 uptake data were read out every 112 min during the 28-day test (40 320 min that is 360 readings) and were recorded and stored in the measuring heads of the sample bottles.
- Sampling method: Readings from apparatus (closed WTW OxiTop OC 110 respirometer).

CONTROL AND BLANK SYSTEM
- Inoculum blank: Flasks #1 (b1*), 2 (b2*) and 3 (b3*) containing only inoculum 30 mg/l SS.
- Toxicity control: Flasks #10 (tox1*) and 11 (tox2*) containing test item, reference item at the same concentrations as in the individual solutions and inoculum 30 mg/l SS.
- Procedure control: Flasks #4 (w1*), 5 (w2*) and 6 (w3*) containing reference item (sodium acetate 100 mg/l) and inoculum 30 mg/SS.

STATISTICAL METHODS:
The calculations and the graphs were performed using SigmaP lot 9.0 software of SYSTAT Software, Inc., USA purchased from GAMBIT CoiS ltd, Poland.

Reference substance:

acetic acid, sodium salt

Remarks:

CHEMPUR, purity p.a. 99.7%

Key result

Parameter:

% degradation (O2 consumption)

Value:

87.5

Sampling time:

28 d

Details on results:

The test item attained 87.5 ± 0.4% of biodegradation as BOD/COD. The reference item reached 74.8 ± 7.8% of biodegradation and the level for ready biodegradability by 5 days. In a toxicity test the biodegradation was equal to 69.4% in 14 days. The oxygen uptake of the inoculum blank was equal to 26.3 mg/l in 28 days. In the toxicity test, containing both the test item and a reference item, 69.4% of biodegradation (based on COD) occurred in 14 days. The pH values of test item flasks were inside the range 7.45-7.68

Results with reference substance:

The reference item reached 74.8 ± 7.8% of biodegradation and the level for ready biodegradability by 5 days

Table 2. Sample oxygen uptake: biodegradability.

		time, days
		1	3	5	7	9	12	14	16	18	21	23	25		28
Test item O2 uptake, mg/l	a1	6.1	40.1	51.8	60.9	67.9	81.3	87.5	91.5	94.4	102.2	104.7	107.4		113.7
	a2	5.5	39.3	51.8	64.0	74.9	87.7	93.7	99.1	101.8	107.4	109.0	110.4		114.4
	a3	6.3	41.9	53.9	62.7	70.5	80.2	82.5	84.7	85.7	87.5	87.2	86.2		86.3
	am. avg	5.8	39.7	51.8	62.4	71.4	84.5	90.6	95.3	98.1	104.8	106.9	108.9		114.0
Blank test O2 uptake, mg/l	b1	3.0	9.4	11.5	13.2	15.5	17.0	17.8	19.1	21.0	22.8	24.5	26.3		28.0
	b2	5.9	10.5	11.4	14.7	15.3	16.7	18.2	20.8	20.3	21.8	22.4	24.4		23.9
	b3	4.3	9.2	8.5	13.1	15.2	15.6	17.2	18.4	20.4	22.3	24.5	27.3		26.8
	bm avg	4.4	9.7	10.5	13.7	15.3	16.4	17.7	19.4	20.6	22.3	23.8	26.0		26.3
Reference item O2 uptake, mg/l	w1	34.7	48.0	53.6	60.6	63.5	68.1	70.4	71.4	72.7	75.8	78.0	80.0		80.3
	w2	17.1	53.2	67.4	75.2	79.4	86.2	87.2	90.4	93.1	95.8	96.2	99.1		101.3
	w3	16.9	50.1	61.9	67.8	73.4	78.0	80.2	81.7	82.7	84.9	86.8	87.3		88.9
	wm.avg	25.8	49.1	57.8	64.2	68.5	73.1	75.3	76.5	77.7	80.3	82.4	83.6		84.6
Toxicity control O2 uptake, mg/l	tox1	26.1	61.8	84.6	115.2	129.4	141.2	148.7	162.4	169.8	180.5	186.5	190.7		196.7
	tox2	21.4	55.0	73.9	93.1	107.8	124.6	134.3	142.8	152.4	160.4	166.5	168.6		174.4
	tox.avg	23.8	58.4	79.3	104.1	118.6	132.9	141.5	152.6	161.1	170.4	176.5	179.6		185.6
Corrected test item O2 uptake, mg/l	a1 - bm	1.7	30.4	41.4	47.2	52.6	64.9	69.8	72.1	73.8	79.8	80.9	81.4		87.4
	a2 - bm	1.1	29.6	41.4	50.3	59.5	71.3	76.0	79.7	81.2	85.1	85.2	84.4		88.1
	a3 - bm	-	-	-	-	-	-	-	-	-	-	-	-		-
Reference item % degradation ThOD = 0.78 mgO2/mg C = 100 mg/l	R1 (w1)	38.8	49.2	55.3	60.2	61.8	66.2	67.5	66.6	66.8	68.6	69.4	69.2		69.3
	R2 (w2)	-	-	-	-	-	-	-	-	-	-	-	-		-
	R3 (w3)	16.0	51.9	66.0	69.4	74.4	79.0	80.0	79.8	79.6	80.2	80.8	78.6		80.3
	Ravg	27.4	50.5	60.7	64.8	68.1	72.6	73.8	73.2	73.2	74.4	75.1	73.9		74.8±7.8
Test item % degradation COD = 141 mgO2/l	R1 (a1)	1.7	30.4	41.2	47.1	52.4	64.7	69.6	71.8	73.6	79.6	80.7		81.2		87.2
	R2 (a2)	1.1	29.5	41.2	50.2	59.4	71.1	75.8	79.4	80.9	84.8	84.9		84.2		87.8
	R3 (a3)	-	-	-	-	-	-	-	-	-	-	-		-		-
	Raavg	1.4	29.9	41.2	48.6	55.9	67.9	72.7	75.6	77.3	82.2	82.8		82.7		87.5±0.4
Toxicity test % degradation	R1 (tox1)	12.2	29.2	41.6	56.9	64.0	70.0	73.5	80.2	83.7	88.7	91.3		92.4		95.6
	R2 (tox2)	9.5	25.4	35.6	44.6	51.9	60.7	65.4	69.2	73.9	77.5	80.0		80.0		83.1
	Rtoxavg	10.9	27.3	38.6	50.7	57.9	65.3	69.4	74.7	78.8	83.1	85.6		86.2		89.4±8.8

 

Table 3. The pH values of test flasks

flask #	1	2	3	4	5	6	7	8	9	10	11
	Inoculum blank			Reference item			Test item			Toxicity test
initial	7.37	7.41	7.44	7.44	7.46	7.46	7.45	7.45	7.46	7.44	7.43
final	7.43	7.42	7.32	9.26	8.93	8.91	7.68	7.59	7.51	8.38	8.45

Validity criteria fulfilled:

yes

Remarks:

See "overall remarks".

Interpretation of results:

readily biodegradable

Conclusions:

The test item attained 87.5% biodegradation after 28 days and reached 60% COD within the 10 day window. Thus, the test item can be deemed as readily biodegradable.

Executive summary:

A 28-day ready aerobic biodegradability test was performed on the test item, following OECD guideline 301 F, under GLP conditions. Activated sludge from the aeration tank of a sewage treatment plant, receiving predominantly domestic sewage, served as inoculum.  100 mg/L of test item was incubated with activated sludge (30 mg/L SS) and incubated under aerobic conditions in a closed respirometer flask at constant temperature (22±1ºC) for 28 days. A blank test, a procedure test with reference substance (sodium acetate) and a toxicity test were run in parallel. In the toxicity test, containing both the test item and a reference item, on the 14th test day the biodegradation (based on COD) attained 69.4%. Thus, the test item is not inhibitory. ll the validiity criiteria for this study were met. At the 28th day of the test, the test item attained 87.5% of biodegradation. As 60% of COD was achieved in the 10-day window, the test item is considered as readily biodegradable.

Description of key information

Key study. Method according to OECD 301F, GLP study. The test item attained 87.5% biodegradation after 28 days and reached 60% COD within the 10 day window. Thus, the test item can be deemed as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

A 28-day ready aerobic biodegradability test was performed on the test item, following OECD guideline 301 F, under GLP conditions. Activated sludge from the aeration tank of a sewage treatment plant, receiving predominantly domestic sewage, served as inoculum.  100 mg/L of test item was incubated with activated sludge (30 mg/L SS) and incubated under aerobic conditions in a closed respirometer flask at constant temperature (22±1ºC) for 28 days. A blank test, a procedure test with reference substance (sodium acetate) and a toxicity test were run in parallel. In the toxicity test, containing both the test item and a reference item, on the 14th test day the biodegradation (based on COD) attained 69.4%. Thus, the test item is not inhibitory. At the 28th day of the test, the test item attained 87.5% of biodegradation. As 60% of COD was achieved in the 10-day window, the test item is considered as readily biodegradable.