Amines, N-(C16-18 and C18-unsatd. alkyl)-N,N',N'-trimethyltrimethylenedi-

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:

13-04-2016 - 12-05-2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD 301D study conducted under GLP conditions

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

Ammonium chloride was omitted from the medium to prevent oxygen consumption due to nitrification. River water instead of an effluent/extract/mixture was used as inoculum.

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

other: River Water

Details on inoculum:

River water was sampled from the Rhine near Heveadorp, The Netherlands (07-04-2016). The nearest plant (Arnhem-Zuid) treating domestic wastewater biologically was 3 km upstream. The river water was aerated for 7 days before use to reduce the endogenous respiration. River water without particles was used as inoculum. The particles were removed by sedimentation after 1 day while moderately aerating.

Duration of test (contact time):

28 d

Initial conc.:

2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

The Closed Bottle test was performed according to the study plan. The study plan was developed from ISO Test Guidelines (1994). Use was made of 10 bottles containing only river water, 10 bottles containing only river water with test substance 6 bottles containing river water and sodium acetate, 6 bottles containing river water, sodium acetate and test substance. The concentrations of the test substance, and sodium acetate in the bottles were 2.0 and 6.7 mg/L, respectively. Each of the prepared solutions was dispensed into the respective group of BOD bottles so that all bottles were completely filled without air bubbles. The zero time bottles were immediately analyzed for dissolved oxygen using an oxygen electrode. The remaining bottles were closed and incubated in the dark. Two duplicate bottles of all series were withdrawn for analyses of the dissolved oxygen concentration at day 7, 14, 21, and 28.

Key result

Parameter:

% degradation (O2 consumption)

Value:

73

Sampling time:

28 d

Details on results:

N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine was biodegraded by 73% at day 28 in the Closed Bottle test. Poor water solubility of organic compounds affects the biodegradation kinetics because of slow desorption and dissolution rates of the test substance present at high concentrations. The biodegradation curves of poorly-water soluble substances are linear instead of the anticipated S-shape. It should be noted that under environmental conditions N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine will be present in the environment at very low concentrations. The poor water solubility of N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine is therefore the reason for not applying the time window as pass/fail criterion (Battersby, 2000; Richterich and Steber, 2001). Hence N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine should therefore be classified as readily biodegradable.

Results with reference substance:

The biodegradation percentage of the reference compound, sodium acetate, at day 14 was 78%.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

A valid study performed acccording to the guidelines with only a minor deviations;
a) ammonium chloride was omitted from the medium to prevent oxygen consumption due to nitrification (omission does not result in nitrogen limitation as shown by the biodegradation of the reference compound), and b) river water instead of an effluent/extract/mixture was used as inoculum.

Executive summary:

N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine was biodegraded by 73% at day 28 in the Closed Bottle test. Poor water solubility of organic compounds affects the biodegradation kinetics because of slow desorption and dissolution rates of the test substance present at high concentrations. The biodegradation curves of poorly-water soluble substances are linear instead of the anticipated S-shape. It should be noted that under environmental conditions N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine will be present in the environment at very low concentrations. The poor water solubility of N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine is therefore the reason for not applying the time window as pass/fail criterion (Battersby, 2000; Richterich and Steber, 2001). Hence N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine should therefore be classified as readily biodegradable.

Description of key information

One OECD 301D study has been performed under GLP conditions. The substance was degraded to 73% at day 28 and is therefore readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

One OECD 301D test was performed under GLP conditions. N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine (CAS no 1275611-65-8) was biodegraded by 73% at day 28 in the Closed Bottle test. Poor water solubility of organic compounds affects the biodegradation kinetics because of slow desorption and dissolution rates of the test substance present at relatively high concentrations. The biodegradation curves of poorly-water soluble substances are linear instead of the anticipated S-shape. It should be noted that under environmental conditions N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine will be present in the environment at very low concentrations. The poor water solubility of N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine and the fact that the substance is a UVCB are the reasons for not applying the time window as pass/fail criterion (Battersby, 2000; Richterich and Steber, 2001). Hence N-C16-18-alkyl-(evennumbered, C18 unsaturated) trimethylpropane-1,3-diamine should therefore be classified as readily biodegradable.