N,N-Di-(2-Ethylhexyl)-amino Isostearamide

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

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)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

mixed population of activated sewage sludge micro-organisms was obtained on 09 September 2019 from the aeration stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK, which treats predominantly domestic sewage.

The activated sewage sludge sample was washed twice by settlement and re-suspension in mineral medium to remove any excessive amounts of Dissolved Organic Carbon (DOC) that may have been present. The washed sample was then maintained on continuous aeration in the laboratory at a temperature of approximately 21 ºC and used on the day of collection. Determination of the suspended solids level of the activated sewage sludge was carried out by filtering a sample (100 mL) of the washed activated sewage sludge by suction through pre-weighed Whatman GF/A filter paper* using a Buchner funnel. Filtration was then continued for a further 3 minutes after rinsing the filter three successive times with 10 mL of deionized reverse osmosis water. The filter paper was then dried in an oven at approximately 105 ºC for at least 1-Hour and allowed to cool before weighing. This process was repeated until a constant weight was attained. The suspended solids concentration was equal to 4.0 g/L prior to use.

Duration of test (contact time):

ca. 28 d

Initial conc.:

ca. 12.4 mg/L

Based on:

other: 10mg Carbon/L

Parameter followed for biodegradation estimation:

inorg. C analysis

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (inorg. C analysis)

Value:

ca. 9

Sampling time:

28 d

The test item attained 9% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.

Sodium benzoate attained 68% biodegradation after 14 days with greater than 60% degradation being attained in a 10-day window. These results confirmed the suitability of the inoculum and test conditions and satisfied the validation criterion given in the OECD Test Guidelines

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test item attained 9% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.

Executive summary:

The test item attained 9% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.