1-Propanamine, 3-(C9-11-isoalkyloxy) derivs., C10-rich

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:

16-9-2009 - 21-10-2009

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)

Deviations:

yes

Remarks:

acceptable deviations

Principles of method if other than guideline:

Two minor deviations from the guidelines of the Closed Bottle test were introduced; 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), b) humic acid (2.0 mg/L) was added to reduce the toxicity of the test substance in the test.

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Secondary activated sludge (16-09-2009) was obtained from the wastewater treatment plant Nieuwgraaf in Duiven, The Netherlands.
This plant is an activated sludge plant treating predominantly domestic wastewater. The activated sludge was preconditioned to reduce
the endogenous respiration rates. To this end, 400 mg Dry Weight (DW)/L of activated sludge was aerated for one week.
The sludge was diluted in the BOD bottles (van Ginkel and Stroo, 1992).

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:

Test bottles
The test was performed in 0.30 L BOD (biological oxygen demand) bottles with glass stoppers.

Nutrients and stock solutions
Deionized water used in the Closed Bottle test contained per liter of water with 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. Ammonium chloride was omitted from the medium to prevent nitrification. Sodium acetate and
the test substance were added to the bottles using stock solutions of 1.0 g/L.

Test procedures
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 inoculum, 10 bottles containing inoculum and 2.0 mg/L humic acid, 10 bottles containing inoculum, test substance and
humic acid (2.0 mg/L), and 6 bottles containing sodium acetate and inoculum. 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.

Calculation of the results

Calculation of endogenous respiration
The endogenous respiration (oxygen depletion in the control) was calculated as follows;
Oxygen depletion (endogenous respiration) (mg/L) = Mc (day 0) - Mc (day 28)
Mc is the mean oxygen level in the control bottle inoculated with activated sludge.

Calculation of the theoretical oxygen demand (ThOD)
The ThODs of 1-propanamine, 3-(isodecyloxy)-, and sodium acetate were calculated from their molecular formulae and molecular weights
The calculated theoretical oxygen demand of 1-propanamine, 3-(isodecyloxy)- is 2.8 mg/mg.
The theoretical oxygen demand of sodium acetate is 0.8 mg/mg.

Calculation of the biochemical oxygen demand (BOD)
Provided that the oxygen concentrations in all bottles at the start of the test were equal, the amounts of oxygen consumed in test and reference
compound bottles were calculated as follows:
Oxygen consumptionn (mg/L) by test substance = Mch - Mt
Oxygen consumptionn (mg/L) by reference compound = Mc - Ma
Mc or ch = the mean oxygen level in the control bottles inoculated with activated sludge n days after the start of the test (C). The control of
the test substance contained humic acid (CH).
Mt or a = the mean oxygen concentration in the bottles containing the test compound (t) or the reference compound, sodium acetate (a),
and inoculated with activated sludge n-days after the start of the test.
The biological oxygen demand (BOD) mg/mg of the test compound and sodium acetate was calculated by dividing the oxygen consumption by the
concentration of the test substance and sodium acetate in the closed bottle, respectively.

Calculation of the biodegradation percentages
The biodegradation was calculated as the ratio of the biochemical oxygen demand (BOD) to the theoretical oxygen demand (ThOD).

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

68

Sampling time:

28 d

Remarks on result:

other: in the presence of humic acid

Details on results:

Toxicity
Inhibition of the degradation of a well-degradable compound, e.g. sodium acetate by the test compound in the Closed Bottle test was not determined because possible toxicity of 1-propanamine, 3-(isodecyloxy)- to microorganisms degrading acetate is not relevant. Humic acid was added to the
bottles with 1-propanamine, 3-(isodecyloxy)- because this substance may be toxic to the competent bacteria. Inhibition of the endogenous
respiration of the inoculum by the test substance in the presence of humic acid was not observed. Therefore, no inhibition of the biodegradation due to the "high" initial concentration of the test compound is expected.

Test conditions
The pH of the media was 7.0 at the start of the test. The pH of the medium at day 28 was 7.1 (control), 7.0 (control with humic acid) and 6.8 (test).
Temperatures were within the prescribed temperature range of 22 to 24°C.

Validity criteria fulfilled:

yes

Remarks:

endogenous respiration of 1.3 mg/L; differences between replicates at day 28 < 20%; sodium acetate was degraded 76% after 14 days.; oxygen concentrations >0.5 mg/L in all bottles during the test period.

Interpretation of results:

readily biodegradable

Conclusions:

1-Propanamine, 3-(isodecyloxy)- is oxidised 68% at day 28 in the Closed Bottle test , and should therefore be classified as readily biodegradable.
1-Propanamine, 3-(isodecyloxy)- is a surfactant. Surfactants are chemicals in which a hydrophilic group is linked to a hydrophobic moiety.
Biodegradation of both moieties of surfactants requires the concerted action of at least two microorganisms as a single organism usually lacks the
full complement of enzymatic capabilities (van Ginkel, 1996). In ready biodegradability tests, the two moieties of fatty amine derivatives are degraded sequentially. The biodegradation of the two moieties of 1-propanamine, 3-(isodecyloxy)- may be fully in line with the 10-day window criterion when
judged as separate chemicals whereas the sum of the biodegradation curves is not. The biodegradation curve of
1-propanamine, 3-(isodecyloxy)- should therefore not be used to assess a 10-day effect.
Test performed under GLP according guidelines with (minor) acceptable deviations, meeting all validity criteria

Executive summary:

In order to assess the biotic degradation, the result of a test investigating the biodegradability of 1 -Propanamine, 3 -(isodecyloxy) was performed. There will be no difference between the biodegradation rate in the aquatic environment of an amine and it´s acetate it is therefore justified to perform a read across. The test performed allows the biodegradability to be measured in an aerobic aqueous medium. The ready biodegradability was determined in the Closed Bottle test performed according to slightly modified OECD, EU and ISO Test Guidelines, and in compliance with the OECD principles of Good Laboratory Practice.

1-Propanamine, 3-(isodecyloxy)- did not cause a reduction in the endogenous respiration in the presence of humic acid. The test substance is therefore considered to be non-inhibitory to the inoculum. 1-Propanamine, 3-(isodecyloxy)- was oxidised 68% at day 28 in the Closed Bottle test. Hence this substance should be classified as readily biodegradable.

The test is valid as shown by an endogenous respiration of 1.3 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded 76% of its theoretical oxygen demand after 14 days. Finally, the most important criterion was met by oxygen concentrations >0.5 mg/L in all bottles during the test period.

Description of key information

The test substance  was oxidised by 68% after 28d in the Closed Bottle test.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

In order to assess the biotic degradation, a ready biodegradability test was performed which allowed the biodegradability to be measured in aerobic aqueous media. The study was performed with a Closed Bottle Test (CBT, according to OECD TG 301D) with 3-((C9-11-iso-,C10-rich)alkyloxy)propan-1-amine.

The ready biodegradability was determined in a slightly modified Closed Bottle Test (OECD TG 301D) in compliance with GLP. Ammonium chloride was omitted from the medium to prevent oxygen consumption due to nitrification (omission did not result in nitrogen limitation as shown by the biodegradation of the reference compound). Humic acid (2.0 mg/L) was added to reduce the toxicity of the test substance to the micro-organisms.

 

3-((C9-11-iso-,C10-rich)alkyloxy)propan-1-amine did not cause a reduction in the endogenous respiration in the presence of humic acid. The test substance is therefore considered to be non-inhibitory to the inoculum. 3-((C9-11-iso-,C10-rich)alkyloxy)propan-1 -amine was oxidised 68% at day 28 in the Closed Bottle test. Hence this compound should be classified as readily biodegradable.

The test is valid as shown by an endogenous respiration of 1.4 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded 76% of its theoretical oxygen demand after 14 days. Finally, the most important criterion was met by oxygen concentrations >0.5 mg/L in all bottles during the test period.

1-Propanamine, 3 -(isodecyloxy)- is a surfactant. Surfactants are chemicals in which a hydrophilic group is linked to a hydrophobic moiety. Biodegradation of both moieties of surfactants requires the concerted action of at least two microorganisms as a single organism usually lacks the full complement of enzymatic capabilities (van Ginkel, 1996). In ready biodegradability tests, the two moieties of fatty amine derivatives are degraded sequentially.The biodegradation of the two moieties of 1-propanamine, 3-(isodecyloxy)- may be fully in line with the 10-day window criterion when judged as separate chemicals whereas the sum of the biodegradation curves is not. The biodegradation curve of 1-propanamine, 3-(isodecyloxy)- should therefore not be used to assess a 10-day window effect.

It can be concluded that the substance fulfills the criterion for readily biodegradability based on the results of the OECD301D study (GLP, reliability 1).