1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-C12-14 acyl derivs., hydroxides, inner salts

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:

19 May 1995 to 16 June 1995

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic (adaptation not specified)

Details on inoculum:

Inoculum consisted of a mixed population of sewage sludge treatment microorganisms from the secondary treatment stage of the Severn Trent Water plc sewage treatment plant at Belper, Derbyshire, treating predominantly domestic sewage.

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Test concentrations:
a) Inoculated culture medium,
b) 3 mg/L sodium benzoate with inoculum
c) 10 mg/L test material with inoculum
d) Toxicity control 10 mg/L test material plus 1.5 mg/L sodium benzoate with inoculum

Test media a-d were inoculated with activated sludge effluent at the rate of 1 drop of inoculum per litre.


Data Evaluation:

The dissolved oxygen depletion for each replicate flask for the test and standard materials was calculated as follows:
Oxygen depletion = (Mt0 – Mtx) – (Mb0 – Mb0) mg O2/L

Where
Mt0 = value in the test flask at time 0
Mtx = value in the test flask at time x
Mb0 = mean inoculated control flasks value at time 0
Mb0 = mean inoculated control flasks value at time x

The oxygen depletion for the blank was calculated as follows:
Inoculated control oxygen depletion = Mb0 – Mbx

The percentage degradation for each replicate flask for the test and standard materials was calculated as follows:
% degradation = (oxygen depletion / (concentration of test material x COD)) x 100

Mean % degradation = (% degradation of replicate 1 + % degradation of replicate 2) / 2

Nitrate and nitrite analysis was performed on the test solutions at each sampling occasion in order to correct the oxygen depletion values for any oxygen consumption due ti nitrification that may have occurred. Oxygen consumed by nitrification was calculated from the changes in nitrite and nitrate concentration as follows:
O2 consumption due to nitrification = ± 3.43 x change in nitrite concentration + 4.57 x increase in nitrate concentration
Thus
O2 consumption due to carbon oxidation = total consumption – consumption due to nitrification

The oxygen consumption due to carbon oxidation was then compared to the COD to calculate % degradation.

Reference substance:

benzoic acid, sodium salt

Preliminary study:

N/A

Test performance:

The toxicity control, containing both Betadet SHR and sodium benzoate, attained 87% degradation after 28 days, confirming that Betadet SHR was not toxic to the sewage treatment microorganisms used in the study.

Key result

Parameter:

% degradation (O2 consumption)

Value:

94

Sampling time:

28 d

Details on results:

Dissolved oxygen measurements for the test and standard material solutions, together with the controls on 0, 3, 6, 9, 12, 15, 21 and 28 days are given in Table 1. Oxygen depletion values due to nitrification are given in Table 2. Oxygen depletion values and percentage degradation values (% of COD) are given in Table 3. Percentage degradation values are presented graphically in Figure 1.

Betadet SHR attained 94% degradation after 28 days and therefore can be considered readily biodegradable according to OECD Guideline 301D. No oxygen depletion due to nitrification was observed during the course of the study. Degradation of Betadet SHR was 25% on day 6 and 77% on day 12 of the study, thereby satisfying the 10-day window validation criterion given in the OECD Guidelines.

Results with reference substance:

Sodium benzoate attained 93% degradation after 28 days, thereby confirming the suitability of the test method and culture conditions.

Table 1: Dissolved oxygen measurements from a Closed Bottle biodegradation test with Betadet SHR 

Test series		Dissolved Oxygen (mg O2/L)
		Day
		0	3	6	9	12	15	21	28
(a)      Culture medium with inoculum	R1	8.90	8.70	8.50	8.30	8.10	7.90	7.90	7.90
	R2	8.90	8.80	8.50	8.35	8.00	7.95	7.90	7.95
(b)      Standard material, sodium benzoate (3 mg/L) with inoculum	R1	8.90	5.50	4.60	4.10	3.85	3.20	3.20	3.25
	R2	8.90	5.40	4.50	4.05	3.90	3.40	3.30	3.25
(c)       Test material, Betadet SHR (10 mg/L) with inoculum	R1	8.90	8.75	7.50	6.20	4.50	3.70	3.70	3.70
	R2	8.90	8.70	7.30	6.30	4.70	3.90	3.85	3.70
(d)      Test material, Betadet SHR (10 mg/L) plus sodium benzoate (1.5 mg/L) with inoculum	R1	8.90	7.40	6.30	4.90	3.70	2.05	2.00	1.80
	R2	8.90	7.10	6.15	5.10	3.60	2.00	2.00	1.85

R1 and R2 = Replicates 1 and 2

 

 

 Table 2: Oxygen depletion due to nitrification from a Closed Bottle biodegradation test with Betadet SHR 

Test series		Dissolved Oxygen (mg O2/L)
		Day
		0	3	6	9	12	15	21	28
(a)      Culture medium with inoculum	R1	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	R2	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
(b)      Test material, Betadet SHR (10 mg/L) with inoculum	R1	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	R2	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
(c)       Test material, Betadet SHR (10 mg/L) plus sodium benzoate (1.5 mg/L) with inoculum	R1	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	R2	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00

R1 and R2 = Replicates 1 and 2

  

  

Table 3: Oxygen Depletion and Mean percentage biodegradation values from a Closed Bottle Biodegradation Test with Betadet SHR 

Test series			Dissolved Oxygen (mg O2/L)
			Day
			3	6	9	12	15	21	28
(a)      Culture medium with inoculum	Mean O2depletion (mg O2/L)*		0.150	0.400	0.575	0.850	0.975	1.000	0.975
(b)      Standard material, sodium benzoate (3 mg/L) with inoculum	O2depletion (mg O2/L)	R1	3.250	3.900	4.225	4.200	4.725	4.700	4.675
		R2	3.250	4.000	4.275	4.150	4.525	4.600	4.675
	% degradation (mean)		66	79	85	84	92	93	93
(c)       Test material, Betadet SHR (10 mg/L) with inoculum	O2depletion (mg O2/L)	R1	0.000	1.000	2.125	3.550	4.225	4.200	4.225
		R2	0.050	1.200	2.025	3.350	4.025	4.050	4.225
	% degradation (mean)		1	25	46	77	92	92	94
(d)      Test material, Betadet SHR (10 mg/L) plus sodium benzoate (1.5 mg/L) with inoculum	O2depletion (mg O2/L)	R1	1.350	2.200	2.425	4.350	5.875	5.900	6.125
		R2	1.650	2.350	3.225	4.450	5.925	5.900	6.075
	% degradation (mean)		22	33	48	63	85	84	87

R1 and R2 = Replicates 1 and 2

* Corrected for oxygen depletion due to nitrification

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Betadet SHR achieved 94% degradation after 28 days, satisfying the 10-day window, and is therefore considered readily biodegradable.

Executive summary:

An OECD 301D (Ready Biodegradability: Closed Bottle Test) study was conducted using the test substance Betadet SHR. Results demonstrate that the test substance can be considered to be readily biodegradable, given that the substance attained 94% degradation after 28 days whilst meeting the 10-day window (showing 25% degradation on day 6 and 77% degradation on day 12 of the study).  

 

The reference substance, sodium benzoate, attained 93% degradation after 28 days, thereby confirming the suitability of the test method and culture conditions. Furthermore, the toxicity control, attained 87% degradation after 28 days, confirming that Betadet SHR was not toxic to the sewage treatment microorganisms used in the study. As such, the study is considered to be valid.

Description of key information

An OECD 301D (Ready Biodegradability: Closed Bottle Test) study was conducted using the test substance Betadet SHR. Results demonstrate that the test substance can be considered to be readily biodegradable, given that the substance attained 94% degradation after 28 days whilst meeting the 10-day window (showing 25% degradation on day 6 and 77% degradation on day 12 of the study).  

 

The reference substance, sodium benzoate, attained 93% degradation after 28 days, thereby confirming the suitability of the test method and culture conditions. Furthermore, the toxicity control, attained 87% degradation after 28 days, confirming that Betadet SHR was not toxic to the sewage treatment microorganisms used in the study. As such, the study is considered to be valid.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater