Miristalkonium chloride

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

January, 2005

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

Refer to section 13 for details on the read-across justification. The study with the read across substance is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

>106 CFU/mL; consisting of micro-organisms in mud collected from Station Epuration Wavre 2nd Stage, a household water treating plant

Duration of test (contact time):

28 d

Initial conc.:

5 other: mgC/L

Based on:

test mat.

Details on study design:

Test conditions:
- Test temperature: 22 ± 2°C
- pH: 7.3 at start and 7.8 at the end of study
- Aeration of dilution water: Air free from carbon dioxide was passed through the solutions using a flow of 50 to 100 mL/min
- Continuous darkness: Yes
- Other: Total organic carbon content: 62.8%
Test system:
- Culturing apparatus: 3-litre flasks mounted with an aeration tube on a magnetic stirrer
- Details of trap for CO2 and volatile organics if used: the CO2 produced in each flask was precipitated with Ba(OH2). The amount of CO2 produced was determined by titration.

Reference substance:

benzoic acid, sodium salt

Remarks:

20 mgC/L

Key result

Parameter:

% degradation (CO2 evolution)

Value:

95.5

Sampling time:

28 d

Details on results:

- The biodegradability in the test flask was determined to be 95.5% after 28 days (See Table 1 under 'Any other information on results inc. tables).
- The CO2 production in the blank (inoculum control) was 39.2 mg. The pH measured at the start and end of the test period was 7.3 and 7.8, respectively. The temperature throughout the test ranged from 20.8 to 21.4°C.

Results with reference substance:

The biodegradability in the reference flask was determined to be 88.9% after 28 days (See Table 1 under 'Any other information on results inc. tables).

Table 1. Biodegradability values:

Day	Reference substance		Test substance
	% CO2Produced	% CO2 Total	% CO2Produced	% CO2 Total
0	0.00	0.00	0.0	0.0
1	14.16	14.16	1.2	1.2
3	28.54	42.69	1.0	2.2
6	21.20	63.89	9.5	11.6
8	8.77	72.67	16.0	27.7
10	3.72	76.39	20.2	47.9
13	3.26	79.65	17.4	65.3
15	2.53	82.18	7.5	72.8
17	1.47	83.65	5.1	77.9
20	2.31	85.95	3.9	81.8
22	1.15	87.11	1.6	83.5
24	0.25	87.36	4.4	87.8
28	0.16	87.52	1.8	89.6
29	1.35	88.87	5.8	95.5

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Based on the results of read across substance study, the test substance can also be considered to be readily biodegradable.

Executive summary:

A study was conducted to determine the biodegradation of the read across substance, C12-16 ADBAC, in water according to OECD Guideline 301B (CO2 evolution test). Flasks containing inoculum from a household water-treating plant dosed with the equivalent of 5 mg C/L test or 20 mg C/L reference substances were maintained for 28 d. Biodegradability was calculated from the released CO2 over time in the test and reference flasks compared to the blank control (a flask prepared without test or reference substance). CO2 production in the blank (inoculum control) was 39.2 mg. Biodegradability in the reference flask was determined to be 88.9% after 28 d. Under the test conditions, the biodegradation of the test substance in water was determined to be 95.5% after 28 d (CO2 evolution). The test substance was considered to be readily biodegradable (van Dievoet, 2005). Based on the results of read across substance study, the test substance can also be considered to be readily biodegradable.

Description of key information

Based on the results of read across substance study, the test substance, C14 ADBAC, can also be considered to be readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

A study was conducted to determine the biodegradation of the read across substance, C12-16 ADBAC, in water according to OECD Guideline 301B (CO2 evolution test). Flasks containing inoculum from a household water-treating plant dosed with the equivalent of 5 mg C/L test or 20 mg C/L reference substances were maintained for 28 d. Biodegradability was calculated from the released CO2 over time in the test and reference flasks compared to the blank control (a flask prepared without test or reference substance). CO2 production in the blank (inoculum control) was 39.2 mg. Biodegradability in the reference flask was determined to be 88.9% after 28 d. Under the test conditions, the biodegradation of the test substance in water was determined to be 95.5% after 28 d (CO2 evolution) and the test substance was considered to be readily biodegradable (van Dievoet, 2005). Based on the results of read across substance study, the test substance, C14 ADBAC, can also be considered to be readily biodegradable.