Dimethyl[3-[(1-oxooctadecyl)amino]propyl][2-oxo-2-(tetradecyloxy)ethyl]ammonium 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:

Experimental start date: 24 Apr 2017 - experimental completion date: 02 Jun 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted July 17, 1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
The freshly obtained sludge was used immediately. The concentration of suspended solids was determined to be 3.5 g/L in the concentrated sludge. Before use, the sludge was allowed to settle (30 minutes) and the supernatant liquid was used as inoculum at the amount of 10 mL/L of mineral medium.

Duration of test (contact time):

42 d

Initial conc.:

22.5 mg/L

Based on:

test mat.

Remarks:

The test item was tested in duplicate: 2-L bottle A: 45.2 mg and 2-L bottle B: 44.7 mg, corresponding to a target of 12 mg TOC/L.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Test duration:
- 28 days for the inoculum blank and test item (last CO2measurement on day 29).
- 14 days for the positive and toxicity control (last CO2 measurement on day 15).
Test vessels: 2 litre brown coloured glass bottles.
Pre-incubation medium: The day before the start of the test (day -1) mineral components, Milli-RO water (ca. 80% of final volume) and
inoculum (1% of final volume) were added to each bottle. This mixture was aerated with synthetic CO2-free air overnight to purge the system of CO2.
Type and number of bottles: 2 bottles for each for of test item suspension:or blank with inoculum; 1 bottle for the Positive control: containing reference item and inoculum or the toxicity control containing reference item with test item and inoculum
Preparation: At the start of the test (day 0), test and reference item were added to the bottles containing the microbial organisms and mineral components. The volumes of suspensions were made up to 2 litres with Milli-RO water, resulting in the mineral medium described before. Three CO2-absorbers (bottles filled with 100 mL 0.0125 M Ba(OH)2) were connected in series to the exit airline of each test bottle.
Determination of CO2:
The CO2 produced in each test bottle reacted with the barium hydroxide in the gas scrubbing bottle and precipitated out as barium carbonate. The amount of CO2 produced was determined by titrating the remaining Ba(OH)2 with 0.05 M standardized HCl (1:20 dilution from 1 M HCl (Titrisol® ampoule), Merck, Darmstadt, Germany). Test item titrations were made on day 1, 4, 6, 8, 11, 13, 15, 18, 20, 25 and 28.
On the penultimate day, the pH of respective test suspensions was measured and 1 mL of concentrated HCl (37%, Merck) was added to the bottles of the inoculum blank and test suspension. The bottles were aerated overnight to drive off CO2 present in the test suspension.
The final titration was made on day 15 for positive and toxicity control, and on day 29 for the remaining vessels.

Reference substance:

acetic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Remarks:

Based on measurements of two separate bottles.

Value:

74

St. dev.:

3

Sampling time:

28 d

Results with reference substance:

> 80% within 15 days.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Remarks:

k1st order = 0.0173x, R² = 0.9703

Conclusions:

Quaternium-70 was readily biodegradable under the conditions of the modified Sturm test presently performed. This conclusion holds true for the test article as a whole as well as the test item corrected for propylene glycol.

Description of key information

Quaternium-70 was readily biodegradable under the conditions of a modified Sturm test (OECD 301B) performed under GLP.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The conclusion of ready biodegradability holds true for the test article as a whole as well as the test item corrected for propylene glycol.