cis-2,6-dimethylmorpholine

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study. No guideline followed, however, the method is similar to aerobic degradation part as described in the OECD 307.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)

GLP compliance:

yes (incl. QA statement)

Test type:

laboratory

Test material

Test material information

Constituent 1

Reference substance name:

14C-Dimethylmorpholine

IUPAC Name:

14C-Dimethylmorpholine

Constituent 2

Reference substance name:

cis-2,6-dimethylmorpholine

EC Number:

229-353-0

EC Name:

cis-2,6-dimethylmorpholine

Cas Number:

6485-55-8

Molecular formula:

C6 H13 N O

IUPAC Name:

2,6-dimethylmorpholine

Radiolabelling:

yes

Study design

Oxygen conditions:

aerobic

Soil classification:

USDA (US Department of Agriculture)

Soil properties

Soil no.:

#1

Soil type:

sandy loam

% Clay:

11.58

% Silt:

21.19

% Sand:

67.23

% Org. C:

2.2

pH:

7.1

CEC:

13.9

Duration of test (contact time)

Soil No.:

#1

Duration:

120 d

Initial test substance concentration

Soil No.:

#1

Initial conc.:

0.2 mg/kg soil d.w.

Based on:

test mat.

Parameter followed for biodegradation estimation:

radiochem. meas.

Experimental conditions

Soil No.:

#1

Temp.:

20 °C

Humidity:

40 % of water holding capacity

Details on experimental conditions:

EXPERIMENTAL DESIGN
- Soil preincubation conditions (duration): 9 days, aerobic conditions, darkness
- Soil condition: fresh
- Soil (g/replicate): 50 g d.w.
- No. of replication treatments: duplicate samples
- Test apparatus (Type/material/volume): 250 ml Dreschel Bottles
- Details of traps for CO2 and organic volatile, if any: 1.) ethyl digol, 2.) 1M aqueous potassium hydroxide solution and phenolphthalein indicator, 3.) ethanolamine/2-ethoxyethanol (1:3)

Test material application
- Volume of test solution used/treatment: 100 µl containing 0.01 mg free base
- Application method: dissolved in acetonitril, evenly applied on soil surface, gentle agitation

Any indication of the test material adsorbing to the walls of the test apparatus: no

Experimental conditions
- Moisture maintenance method: addition of water if necessary
- Continuous darkness: Yes

OXYGEN CONDITIONS
- Methods used to create the aerobic conditions: continuous air flow at 60 ml/min

SUPPLEMENTARY EXPERIMENTS:

SAMPLING DETAILS
- Sampling intervals: immediately after application, after 2, 7, 14, 30, 58, 90 and 120 days

Results and discussion

Material (mass) balance

Soil No.:

#1

% Recovery:

101.9

St. dev.:

3.5

% Degradation

Soil No.:

#1

% Degr.:

50

Parameter:

radiochem. meas.

Sampling time:

149 d

Half-life / dissipation time of parent compound

Soil No.:

#1

DT50:

149 d

Type:

(pseudo-)first order (= half-life)

Transformation products:

no

Evaporation of parent compound:

yes

Volatile metabolites:

yes

Residues:

yes

Applicant's summary and conclusion

Conclusions:

Cis-2,6-dimethylmorpholine was only slowly degraded in soil under aerobic conditions with a DT50 of 149 days.