Dimethyldioctylammonium chloride

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:

27 June to 26 July 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1992

Deviations:

yes

Remarks:

Ammonium chloride omitted from medium to prevent oxygen consumption due to nitrification

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Version / remarks:

1992

Qualifier:

equivalent or similar to guideline

Guideline:

ISO 10707 Water quality - Evaluation in an aqueous medium of the "ultimate" aerobic biodegradability of organic compounds - Method by analysis of biochemical oxygen demand (closed bottle test)

Version / remarks:

1994

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Supplied by Akzo Nobel Surface Chemistry
- Purity: 97.9%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Ambient temperature, in the dark
- Stability under test conditions: No data

Oxygen conditions:

aerobic

Inoculum or test system:

natural water: freshwater

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): River water from River Rhine near Heveadorp, The Netherlands
- Storage conditions: Aerated
- Storage length: 7 days
- Preparation of inoculum for exposure: Particles removed by sedimentation

Duration of test (contact time):

<= 28 d

Initial conc.:

<= 2 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

Oxygen depletion

Details on study design:

TEST CONDITIONS
- Composition of medium: Per litre; 8.5 mg KH2PO4, 21.75 mg K2HPO4, 33.3 mg Na2HPO4.2H2O, 22.5 mg MgSO4.7H2O, 27.5 mg CaCl2, 0.25 mg FeCl3.6H2O
- Additional substrate: No
- Test temperature: 22 to 24oC
- pH: 7.8 to 7.9
- pH adjusted: No
- Suspended solids concentration of inoculum: <2.0 mg/L (dry weight)
- Continuous darkness: Yes

TEST SYSTEM
- Culturing apparatus: 0.3L BOD bottles with glass stoppers
- Number of culture flasks/concentration: 10 bottles (sacrificial) for blank and test substance, 6 bottles for reference substance
- Measuring equipment: WTW TrioXmatic EO 200 oxygen electrode and WTW OXI 530 meter
- Test performed in open system: No

SAMPLING
- Sampling frequency: Days 0, 7, 14, 21 and 28
- Sampling method: Removal of duplicate bottles for DO analysis
- Sample storage before analysis: No data

CONTROL AND BLANK SYSTEM
- Inoculum blank: 10 bottles (sacrificial)
- Abiotic sterile control: Not applicable
- Reference substance: 6 bottles (sacrificial)

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

>= 33

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

45

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

59

Sampling time:

21 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

73

Sampling time:

28 d

Details on results:

Test substance achieved 73% degradation after 28 days but did not meet 10-day window

Results with reference substance:

Sodium acetate attained 75% degradation after 14 days confirming the suitability of hthe inoculum and test conditions

Time (days)	Oxygen consumption (mg/L)		Biodegradation (%)
	Test substance	Reference substance	Test substance	Reference substance
0	0.0	0.0	0	0
7	1.9	3.6	33	69
14	2.5	3.9	45	75
21	3.3	-	59	-
28	4.1	-	73	-

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

The test substance was >70% degraded after 28 days and can be considered readily biodegradable under the conditions of the test

Executive summary:

The ready biodegradability of the test substance, dioctylmethylammonium chloride, was assessed in a GLP-compliant test to internationally accepted test guidelines. The test followed OECD 301D (closed bottle) test guidelines and involved a 2.0 mg/L nominal concentration of the test substance being incubated in full closed bottles in the dark at a constant temperature together with a small number of micro-organisms obtained from natural river water. Degradation was determined by analysis of dissolved oxygen over a 28 -day period. The test included a reference substance, sodium acetate, to confirm the viability of the test inoculum.

The test substance showed 33, 45, 59 and 73% degradation after 7, 14, 21 and 28 days, respectively. The reference substance showed 75% degradation after 14 days.

The test substance is classified as readily biodegradable under the conditions of the test, although did not pass the 10-day window.

Description of key information

A reliable OECD 301D test guideline study (Klimisch 1) to determine the ready biodegradability for the test substance, dimethyldioctylammonium chloride (C8DAQ), measured 73% degradation after 28 days. The test substance is classified as readily biodegradable under the conditions of the test. The test validity criteria were met and there were no significant deviations noted to affect the integrity of the study, however the 10-day window was not met. This study is considered acceptable and satisfies the guideline requirements for a biodegradation in water screening test.

A reliable OECD 301B test guideline study (Klimisch 1) to determine the ready biodegradability for the read across substance, N,N-Didecyl-N,N-dimethylammonium carbonate (DDACarbonate) (NOACK, 2007), measured 10 % biodegradation (beginning of biodegradation) after 5 days and the pass level of 60 % after 12 days. The second test item replicate reached the 10 % level after 4 days and the pass level of 60 % after 10 days. At test end a biodegradation rate of 99 % was reached. The positive control and toxicity controls both passed the test criteria, demonstrating the test system was functioning well and the test substance was not toxic to the microorganisms. The results indicate the test substance is readily biodegradable.

Another reliable OECD 301B test guideline study (Klimisch 1) to determine the ready biodegradability for the read across substance, N,N-Didecyl-N,N-dimethylammonium carbonate (DDACarbonate) (NOACK, 2008). Again, the positive control and toxicity controls both passed the test criteria, with percentage degradation of the positive control reaching the pass level of 60 % after 6 days, with 81 % after 14 days. In the toxicity control containing both test and reference item a biodegradation rate of 62 % occurred within 14 days and came to 97 % after 28 days. In the test vessels, the 10 % level (beginning of biodegradation) was reached after 11 days and the pass level of 60 % after 19 days. The mean biodegradation came to 96 % after 28 days.

In addition, four reliable studies are available for the read across substance (DDAC). A reliable study by Clariant (1992) included two separate experiments, one conducted according to OECD 301A (Die away test) and the other conducted according to OECD 302B guidelines (inherent biodegradability, Zahn Wellens). Activated sludge from a sewage treatment plant was used for the OECD 302B test, which after 28 days, was used as pre-adapted sludge for the Die-away study. In the Zahn-Wellens Test elimination of DDAC after 28 days was 95.5 % (related to 3 h-value). In the DOC Die-Away Test the maximum degradation was 90 % and fulfilled the 10-day window criteria. A further reliable study was carried out by Wildlife (1996) according to OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) using DDAC. The results of this study indicated that both un-complexed and test substance complexed to bentonite clay were biodegradable when exposed to unacclimated microorganisms obtained from a receiving system representative of a site where these test substances may be expected to be discharged. Degradation of 77.5 % was attained for non-complexed test substance after 28 days, and slightly lower when DDAC was complexed with clay. A further Wildlife study (2001) conducted not according to guidelines, in which activated sludge pre-exposed to non-labelled DDAC, was exposed to radiolabelled DDAC for a 28 days period and the DDAC (plus metabolites) in the different phases (sludge, water and mineralisation) were measured. 14CO2 production reached 71.82 % at Day 1, 88.36 % at Day 7, and 93.30 % at Day 28, with low amounts of DDAC or metabolites measured in the sludge or water phases. The fourth study on DDAC by ABC Laboratories (1993) was conducted according to the EPA OPTS 796.3100 guideline, using a mix of inoculum from soil, activated sludge and influent sewage. Degradation of 80.92% was attained after 28 days.

The study on the C8DAQ is considered the key study, which indicates the test substance is readily biodegradable, although it did not pass the 10-day window. The two additional studies on the read-across substance DDACarbonate and the four additional studies on the read-across substance DDAC all supported this finding. Many of these studies also indicated the substance achieved the 10 -day window.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable but failing 10-day window