4-[3-(1-naphthylamino)propyl]morpholine

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:

February 20, 1998 to June 24, 1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to OECD TG 301B, TSCA 796.3260 and in accordance with the Principles of Good Laboratory Practice (GLP)

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: TSCA 796-3260

Deviations:

no

Principles of method if other than guideline:

not applicable

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
not applicable

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Fresh activated sludge was obtained from the municipal waste treatment facility which treats predominantly domestic waste. Viability of the microorganisms was confirmed after inoculation of the test solutions and activity was checked by means of the positive control. The sludge was used on the day it was collected and aerated prior to use. A subsample of the activated sludge was homogenized for 2 minutes with a mechanical blender and then centrifuged for 30 minutes. The supernatant was decanted, pooled and added to each test vessel to provide sufficient volume for a 1% inoculum. Carry-over of sludge solids which could interfere with the measurement of CO2 production were avoided. Viability counts were performed on the supernatant at the start of the test. The inoculum contained 1 x 10(6) colony forming units/ml and 0.9 g/liter total suspended solids.

Duration of test (contact time):

28 d

Initial conc.:

26.4 mg/L

Based on:

test mat.

Initial conc.:

20 mg/L

Based on:

other: theoretical carbon concentration

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

Six test vessels (2.5 L capacity) were required, two for inoculated basal salt medium (BSM, the inoculum blank), one for the inoculated positive control solution, one for the toxicity control and two for the inoculated replicate test solution. Each test vessel was filled with 1235 ml of BSM and 15 ml of the activated sludge supernatant inoculum. This mixture was aerated for approximately 24 hours to purge the system of CO2. To remove CO2, air was passed through a drying column and a CO2 absorption column at the rate of approximately 50-100 ml/min. After the aeration period, 100 ml of 0.0125 M barium hydroxide was introduced into each of three CO2 absorber bottles connected in series to the exit air line of each vessel.
Test substance was added to two of the vessels to begin the test. The test substance was tested at 20 mg/l total carbon. The two test concentrations were prepared by weighing 0.0396 g of test substance and adding it to each replicate test vessel
The inoculum blank contained no test substance received only 250 ml of CO2-free BSM. The positive control, sodium benzoate (Lot # J42705) was prepared by adding 51.5 mg to 250 ml of CO2 purged BSM. This stock solution was then added to the test vessel. The toxicity control was prepared by adding 39.6 mg test substance plus 51.5 mg sodium benzoate ( Lot # J42705) to 250 ml of CO2 purged BSM. This stock solution was then added to the test vessel. The final volume in each test vessel was 1500 ml and each bottle was wrapped in aluminium foil to exclude light. The test was started by bubbling CO2-free air through the solutions at a rate of about 50-100 ml/minute.
The test was perfomed at a target temperature of 22 ± 2 °C and the pH of both BSM and stock solutions were measured at the start of the test and pH measuresd in all test vessels on day 28.

Reference substance:

benzoic acid, sodium salt

Remarks:

J.T. Baker (Lot # J42705)

Preliminary study:

not applicable

Test performance:

The difference of extremes of replicate test substance values was greater than 20% but the test was not repeated because biodegradation was well below 60% (result was 2%). This deviation had no effect on the outcome of the study.

Parameter:

% degradation (CO2 evolution)

Value:

2

Sampling time:

28 d

Remarks on result:

other: Mortrace MP was not readily biodegradable

Details on results:

The positive control, sodium benzoate yielded 64% of the theoretical CO2 during the test demonstratingthe adequacy of the inoculum and the toxicity control allowed 47% biodegradation, indicating that Mortrace MP was not toxic to the activated sludge at the tested concentration. The inoculum blank evolved 17.7 mg CO2/L. No unusual variation in pH was noted in any test vessel. Temperature remained within the acceptable range of 22 ± 2 °C throughout the test. Daily measured aeration flow rates were 60 ml/minute in each test vessel.
More CO2 was evolved from test vessels containing Mortrace MP from the inoculum blank, resulting in 2% biodegradation after subtraction of the blank to correct for background CO2 evolution. The lag phase, 10-day window and the dergadation phase could not be determined. The slope of degradation line was 0.02. Because degradation was less than 60% after 28 dayys, the results indicate that Mortarce MP was not readily biodegradable under the test conditions.

None

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

As degradation observed was less than 60% after 28 days, Mortrace MP was not readily biodegradable under the test conditions.

Executive summary:

The ready biodegradation of Mortrace MP was evalauted as per OECD TG 301B and TSCA 796.3260 using the CO2 evolution test (modified Sturm test).

Fresh activated sludge obtained from the municipal waste treatment facility was used as the source of unacclimated microorganisms for the test. Biodegradability was determined by measuring the amount of CO2 evolved from the chemical over the 28 day period.

The test was performed with a single concentration of test substance 26.4 mg/L whole test substance and the theoretical carbon concentration of this solution was 20 mg/L. This concentration and an inoculum blank were established in duplicate and a single positive control, sodium benzoate was also established at a dissolved organic carbon concentration of 20 mg/L. A single toxicity control containing sodium benzoate and the test substance was also established at a combined dissolved organic carbon concentration of 40 mg/L.

After 28 days, the test substance at a theoretical concentration of 20 mg/L dissolved organic carbon showed 2% biodegradation. Because degradation was less than 60%, Mortrace MP was not readily biodegradable under the test conditions.

Description of key information

Biodegradation was determined for 4-(3-(1-naphthylamino)propyl)morpholine (also known as Mortrace MP) in a Ready Biodegradability test according to OECD 301B: CO₂Evolution (modified Sturn Test). After 28 days, the observed degradation was 2%. Therefore , 4-(3-(1-naphthylamino)propyl)morpholine was not readily biodegradable under the test conditions.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Biodegradation was determined for 4-(3-(1-naphthylamino)propyl)morpholine (also known as Mortrace MP) in a Ready Biodegradability test according to OECD 301B: CO₂Evolution (modified Sturn Test). The test was performed with a single concentration of test substance 26.4 mg/L whole test substance and the theoretical carbon concentration of this solution was 20 mg/L. This concentration and an inoculum blank were established in duplicate and a single positive control, sodium benzoate was also established at a dissolved organic carbon concentration of 20 mg/L. A single toxicity control containing sodium benzoate and the test substance was also established at a combined dissolved organic carbon concentration of 40 mg/L. After 28 days, the test substance at a theoretical concentration of 20 mg/L dissolved organic carbon showed 2% biodegradation. Therefore 4-(3-(1-naphthylamino)propyl)morpholine was not readily biodegradable.