D-Glucitol, 1-deoxy-1-(methylamino)-, N-[C18-C18 (unsaturated) acyl] derivs.

Biodegradation in soil

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-10-27 to 2015-11-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study, no deficiencies

Qualifier:

according to guideline

Guideline:

OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)

Deviations:

yes

Remarks:

The soil was stored at 6 ± 2 °C instead of 4 ± 2 °C due to organizational reasons.

GLP compliance:

yes

Test type:

laboratory

Radiolabelling:

yes

Oxygen conditions:

aerobic

Soil classification:

DIN 19863 (Deutsche Industrie-Norm)

Year:

2015

Soil no.:

#1

Soil type:

other: Lufa soil 2.2: Loamy sand

% Clay:

8.3

% Silt:

16.9

% Sand:

79.2

% Org. C:

1

pH:

5.4

CEC:

9.7 other: meq/100 g

Bulk density (g/cm³):

1.218

Soil no.:

#2

Soil type:

other: Lufa soil 2.3: Silty sand

% Clay:

6.6

% Silt:

35.9

% Sand:

57.6

% Org. C:

0.51

pH:

5.7

CEC:

7.5 other: meq/100 g

Bulk density (g/cm³):

1.329

Soil no.:

#3

Soil type:

other: Lufa soil 2.4: clay loam

% Clay:

26.2

% Silt:

45.6

% Sand:

28.2

% Org. C:

2.1

pH:

7.3

CEC:

33 other: meq/100 g

Bulk density (g/cm³):

1.265

Soil no.:

#4

Soil type:

other: Lufa soil 5M: Loamy sand

% Clay:

11.1

% Silt:

35.3

% Sand:

53.5

% Org. C:

0.97

pH:

7.3

CEC:

17.4 other: meq/100 g

Bulk density (g/cm³):

1.264

Details on soil characteristics:

Soil type
4 different standard soils (LUFA 2.2, 2.3, 2.4 and 5M, field fresh sampled) representing a range of relevant soils. The soils vary in their organic carbon content, pH, clay content and microbial biomass.

Origin
LANDWIRTSCHAFTLICHE UNTERSUCHUNGS- UND FORSCHUNGSANSTALT SPEYER (LUFA), Obere Langgasse 40, 67346 Speyer, Germany.

Soil handling The soils were manually cleared of large objects and then sieved to a particle size of 2 mm (carried out by LUFA Speyer).
The WHCmax and the pH-value were determined (carried out by LUFA Speyer).
The soil moisture content was determined.  

Soil storage The soil was stored at 6 ± 2 °C: soil 2.2 for 19 days, soil 5M for 34 days, soil 2.4 for 401 days and soil 2.3 for 42 days.

Preincubation
The soil moisture content was adjusted to 42 - 45 % of its WHCmax with demineralised water after receipt.
The soil was preincubated at room temperature (ca. 20 °C) for 5 d (soil 2.4), 7 d (soil 2.2 and 2.3) and 22 d (soil 2.4) before application of the respective soil, to allow germination and removal of seeds and to guarantee a temperature adaptation of the microorganisms.
The soil was checked for a detectable microbial biomass (result in terms of percentage of total organic carbon).

Soil site 2.2: Hanhofen, Großer Striet, Nr. 585, Rheinland-Pfalz,
Germany
2.3: Offenbach, Rechts der Landauer Str., Nr. 826/7,
Rheinland- Pfalz, Germany
2.4: Leimersheim, Hoher Weg, Nr. 3138, Rheinland-Pfalz,
Germany
5M: Mechtersheim, In der Speyerer Hohl Nr. 977, Rheinland-
Pfalz, Germany

Soil History (Crop Rotation and Fertilisation)
Soil 2.2 2.3 2.4 5M
Cultures in year
2015 meadow uncultivated meadow with apple trees meadow
2014 meadow uncultivated meadow with apple trees meadow
2013 meadow uncultivated meadow with apple trees meadow
2012 meadow uncultivated meadow with apple trees meadow
2011 meadow uncultivated meadow with apple trees meadow
Fertilisation in year
2015 none none none none
2014 2000 kg/ha CaO
833 kg/ha MgO (2014-12-15) 3500 kg/ha CaO (2014-06-05)
3500 kg/ha CaO (2014-09-24)
1463 kg/ha MgO (2014-12-15) none none
2013 none none none none
2012 none none none none
2011 none none none none

Soil No.:

#1

Duration:

42 d

Soil No.:

#2

Duration:

19 d

Soil No.:

#3

Duration:

21 d

Soil No.:

#4

Duration:

20 d

Soil No.:

#1

Initial conc.:

2.33 other: kBq/g soil DW

Based on:

test mat.

Soil No.:

#2

Initial conc.:

2.33 other: kBq/g soil DW

Based on:

test mat.

Soil No.:

#3

Initial conc.:

2.33 other: kBq/g soil DW

Based on:

test mat.

Soil No.:

#4

Initial conc.:

2.33 other: kBq/g soil DW

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

radiochem. meas.

Soil No.:

#1

Temp.:

20 +/- 2 °C

Humidity:

16.3 %

Microbial biomass:

2.8 % of org. C

Soil No.:

#2

Temp.:

20 +/- 2 °C

Humidity:

11.8 %

Microbial biomass:

4.53 % of org. C

Soil No.:

#3

Temp.:

20 +/- 2 °C

Humidity:

16.9 %

Microbial biomass:

2.97 % of org. C

Soil No.:

#4

Temp.:

20 +/- 2 °C

Humidity:

14.6 %

Microbial biomass:

2.11 % of org. C

Details on experimental conditions:

Test Groups
TEST ITEM N-[1-14C]Oleoyl-N-methylglucamine
Nominal test item concentration
2.33 kBq/g soil DW (116.5 kBq/Replicate) corresponding to 1000 µg/kg soil DW
Working solution of labelled test item
37 MBq in 10 mL methanol (nominal), 3.59 MBq / ml Methanol (actual)
Solvent for application
Ultrapure water

CONTROL Soil samples, incubated under the same aerobic conditions as the treated soil samples.
These samples were used for biomass measurements at start and end of the definite study.
REFERENCE ITEM No reference item is recommended for this test according to the guideline.

Test Procedures
Application
1.18 mL (soil 2.2) and 0.91 mL (soil 2.3, 2.4, 5M) of the working solution were given in the respective volume of ultrapure water for adjusting the % of MWHC. Afterwards the aqueous solution of the test item was applied on the surface of each soil. Immediately after that the soils were mixed carefully (for 5 min.) to insure a homogeneous distribution of the test item in the soil. Subsequently samples for combustion and LSC analysis were taken to check the homogeneous distribution of the test item (see chapter 12.4). Afterwards the soils were distributed to the test replicates.

Application Conditions of the Soil
Lufa Soil 2.2 2.3 2.4 5M
Maximal water holding capacity (MWHC)* [g/100 g soil DW] 43.5 35.4 43.8 40.0
Dry Weight (DW) before application [g/100 g soil] 83.7 88.2 83.1 85.4
Nominal test item concentration in soil [kBq/g soil DW] 2.33
Actual concentration of stock solution [MBq/10 mL] 35.9
Total applied soil amount
Control [kg DW] 0.5 0.5 0.5 0.5
corresponding to [kg] 0.538 0.801 0.602 0.588
Test item [kg DW] 1.8 1.4 1.4 1.4
corresponding to [kg] 2.151 1.587 1.685 1.647
Applied volume of water to adjust the DW
Control [mL] 10.01) 9.01) 8.01) 8.0)
Test item [mL] 39.82 25.1 21.1 21.1
Volume of test item stock solution for total soil amount [mL] 1.18 0.54 0.91 0.91
Soil amount per test item replicate
(corresponding to 50 g DW) [g] 60.9 57.6 61.0 59.6
Soil amount per control replicate
(corresponding to 200 g DW) [g] 243.6 230.4 243.9 238.4
% of MWHC after application % 50 43 50 46.6
Dry Weight (DW) after application % 82.1 86.8 82.0 84.2
*) data provided by LUFA SPEYER
DW = dry weight

Frequency of application The application was carried out once at exposure day 0 for each soil type.

Test duration
Soil 2.2: 42 days
Soil 2.3: 19 days
Soil 2.4: 21 days
Soil 5M: 20 days

Test vessels
Due to the fast transformation and 14CO2 formation, separate test replicates were prepared for 14CO2determination and soil extraction (determination of transformation and NER).
250 mL, biometer type flasks with gas outlet and connected with appropriate traps for volatile transformation products and 14CO2to determine the mineralization.
250 mL, biometer type flasks with funnel filled with soda lime to trap 14CO2. These replicates were used for soil extraction and determination of transformation and NER.
500 mL, biometer type flasks for the controls

Volatile traps
Crimped headspace bottles containing 30 mL ethylene glycol were used for trapping volatile organic transformation products. Crimped bottles containing 30 mL 1 mol/L aqueous sodium hydroxide were used for trapping 14CO2.

Replicates
Two replicates per sampling interval for each soil treated with test item were tested.
Individual flasks were prepared for each sampling time. In total 24 test item replicates for the soil 2.3, 2.4 and 5M and 32 test item replicates for soil 2.2 and 2 controls were prepared for each soil. At test start 4 subsamples (soil 5M 5 subsamples) of the total applied soil amount were analysed.

Soil amount per replicate
Test item replicates: 50 g soil DW
Control replicates: 200 g soil DW
 
Incubation
All replicates were incubated at 20 ± 2 °C in the dark. Aerobic conditions (exchange of air) were maintained by diffusion from the headspace and ambient atmosphere (replicates for extraction) and continuously aeration (replicates for 14CO2 measurement), respectively.

Temperature
Nominal: 20 ± 2 °C
Actual: 20 ± 2 °C, mean 21.2 °C

Soil moisture content
At the beginning of the test (application of the respective soil) the soils were adjusted to 43 - 50 % of the maximum water holding capacity. Losses by evaporation were checked at least in two-week intervals.


Type and Frequency of Measurements and Observations
Sampling
To confirm the homogeneous distribution of the test item in the soil, directly after application sub-samples of the soil were analyzed by LSC after combustion of the soil.
2 test item replicates were sacrificed at each sampling time. At test start 4 subsamples of the total applied soil amount were analysed.

Frequency of measurements
Sampling for determination of the transformation rate was carried out directly after application and at 6 additional sampling points. The sampling points were chosen in such a way that the pattern of decline of the test item could be established.

Sampling Times
Soil Number of Samplings Sampling Times
2.2 9 0 h, 5 h, 1, 2, 3, 4, 7, 17 and 42 days
2.3 6 0, 1, 2, 5, 12 and 19 days
2.4 6 0, 1, 2, 4, 7 and 21 days
5M 6 0, 1, 2, 3, 9 and 20 days

Test item The radioactivity of the extracts was determined by LSC.

14CO2
The replicates for 14CO2 determination were acidified with phosphoric acid at the respective sampling time and aeration were continued for at least a further 24 h to collect the 14CO2 in the NaOH traps. The traps were analysed for 14CO2 and volatile transformation products by LSC.

14C-Activity
The residual 14C-activity (as % of applied radioactivity) in the soil (after extraction, for details see section 11) was determined by LSC.

NER
The non-extractable residues (NER) as % of the applied radioactivity were determined by LSC after combustion of the extracted soil.

Soil organic matter (humus) fractionation of the non-extractable residues were done at test end to characterize the radioactivity bound to the humic and fulvic acids as well as to the humin fraction of the soil.

Soil moisture
Soil moisture content was checked periodically by weighing of the incubation flasks and adjusting with sterile-filtered demineralized water if necessary. Care was taken, to avoid any losses of volatile degradation products during moisture addition.

Biomass activity
To check the biomass activity glucose induced respiration rates of the controls were determined at test start and test end (see below).

Incubation temperature
The incubation temperature was documented continuously.
 
Measurement of glucose induced respiration rates
The soil of each replicate was mixed with a sufficient amount of glucose (4000 mg/kg) to produce an immediate maximum respiratory response. 200 g soil dry weight were filled into 500 mL glass flasks and closed with OXITOP® sensors. CO2 was adsorbed by soda lime deposited in the headspace. Due to the adsorption of CO2 and the oxygen uptake by the soil the pressure in the glass flasks was reduced and measured. Based on the change of pressure the evolved CO2 and thus the consumed O2 was calculated. Incubation took place for 24 h in the dark at 20 ± 2°C. The pressure was measured 360 times in 24 hours after glucose supplement.

Soil No.:

#1

% Recovery:

112.8

St. dev.:

11

Soil No.:

#2

% Recovery:

110.5

St. dev.:

10.3

Soil No.:

#3

% Recovery:

120.7

St. dev.:

12.9

Soil No.:

#4

% Recovery:

112.6

St. dev.:

5.5

Soil No.:

#1

% Degr.:

98.1

Parameter:

CO2 evolution

Sampling time:

42 d

Soil No.:

#1

% Degr.:

94.4

Parameter:

radiochem. meas.

Sampling time:

42 d

Soil No.:

#2

% Degr.:

85.5

Parameter:

CO2 evolution

Sampling time:

19 d

Soil No.:

#2

% Degr.:

95.3

Parameter:

radiochem. meas.

Sampling time:

19 d

Soil No.:

#3

% Degr.:

106

Parameter:

CO2 evolution

Sampling time:

21 d

Soil No.:

#3

% Degr.:

95.4

Parameter:

radiochem. meas.

Sampling time:

21 d

Soil No.:

#4

% Degr.:

85.1

Parameter:

CO2 evolution

Sampling time:

20 d

Soil No.:

#4

% Degr.:

96.9

Parameter:

radiochem. meas.

Sampling time:

20 d

Soil No.:

#1

DT50:

0.59 d

Type:

other: First-Order Multi-Compartment model (FOMC)

Remarks on result:

other: DT90 = 8.8 d (Dissipation)

Soil No.:

#2

DT50:

0.53 d

Type:

other: First-Order Multi-Compartment model (FOMC)

Remarks on result:

other: DT90 = 4.5 d (Dissipation)

Soil No.:

#3

DT50:

0.36 d

Type:

other: First-Order Multi-Compartment model (FOMC)

Remarks on result:

other: DT90 = 3.5 d (Dissipation)

Soil No.:

#4

DT50:

1 d

Type:

other: First-Order Multi-Compartment model (FOMC)

Remarks on result:

other: DT90 = 3.7 d (Dissipation)

Soil No.:

#1

DT50:

2.6 d

Type:

other: First-Order Multi-Compartment model (FOMC)

Remarks on result:

other: DT90 = 22.2 d (Mineralisation)

Soil No.:

#2

DT50:

2.5 d

Type:

other: First-Order Multi-Compartment model (FOMC)

Remarks on result:

other: DT90 = 37.3 d (Mineralisation)

Soil No.:

#3

DT50:

1.3 d

Type:

other: First-Order Multi-Compartment model (FOMC)

Remarks on result:

other: DT90 = 15.6 d (Mineralisation)

Soil No.:

#4

DT50:

1.8 d

Type:

other: First-Order Multi-Compartment model (FOMC)

Remarks on result:

other: DT90 = 22.9 d (Mineralisation)

Transformation products:

not measured

Details on results:

Transformation of N-[1-14C]Oleoyl-N-methylglucamine

N-[1-14C]Oleoyl-N-methylglucamine was fast degraded in all 4 soils.
The extractable fraction of N-[1-14C]Oleoyl-N-methylglucamine decreased fast. Even directly after application the extractable 14C-resiudes were only in the range 47.9 - 84.6 % of the applied N-[1-14C]Oleoyl-N-methylglucamine (measured as total 14C). At the end of the respective incubation period the extractable radioactivity decreased to 3.1 – 5.6 %.
The evolved 14CO2 increased steadily during the study and reached 85.1 – 106 % at the of the respective incubation period.
No radioactivity (all samples < LOQ) was determined in the ethylene glycol traps, indicating that no volatile transformation products were formed.
The formation of NER reached a maximum of 33.7 – 56.7 % 1-2 days after application. Within the study duration, the NER decreased steadily and reached 24.7 – 30.1 % at test end.
The amount of NER corresponds with the high mineralisation, and can be explained by irreversible binding and incorporation of transformation products in bacterial biomass. 

Distribution of Total AR and Mass Balance for Soil 2.2
Exposure Day Soil Extract Non-Extractable Residues (NER) CO2 Mass Balance
% of AR % of AR % of AR % of AR
Repl. mv mv mv mv
0 (1 h)* 4# 64.7 46.8 37.1 38.0 _ 101.8 103.0
(10.3) 38.1 (48.4)
(45.5) 39.4 (84.9)
66.9 37.4 104.3
0 (5 h) 4# 69.7 65.1 32.6 33.6 _
102.3 98.7
64.3 32.4 96.7
61.3 36.1 97.4
65.0 33.3 98.3
1 1 41.5 41.0 41.5 39.6 28.9 29.3 112.3 109.9
2 40.4 37.5 29.7 107.5
2 1 24.8 25.4 41.0 40.8 48.4 49.8 115.6 115.9
2 25.9 40.6 51.1 116.3
3 1 18.6 18.7 36.1 36.4 53.0 51.7 106.4 106.8
2 18.7 36.7 50.5 107.2
4 1 14.5 14.9 36.0 35.6 56.3 57.2 107.8 107.7
2 15.2 35.2 58.0 107.6
7 1 10.6 10.6 34.2 34.7 77.5 68.1 112.9 113.4
2 10.7 35.1 58.8 113.9
17 1 9.8 8.9 28.2 28.2 97.4 93.3 131.3 130.4
2 8.0 28.2 89.3 129.5
42 1 5.6 5.6 26.6 26.0 91.2 98.1 130.2 129.7
2 5.6 25.5 105.0 129.2
AR = Applied Radioactivity
mv = mean values
# 4 subsamples of the total applied soil batch
* directly after application, processing time for ASE extraction taken into account
( ) = Outlier, not included in calculations
- = not analysed
 
Distribution of Total AR and Mass Balance for Soil 2.3
Exposure Day Soil Extract Non-Extractable Residues (NER) CO2 Mass Balance
% of AR % of AR % of AR % of AR
Repl. mv mv mv mv
0 (1 h)* 4# 49.2 65.4 33.9 28.3 _ 83.1 93.8
63.1 34.0 97.2
87.5 17.3 104.8
61.9 28.0 90.0
1 1 31.6 35.6 48.4 44.2 33.6 34.4 114.4 115.1
2 41.5 40.0 35.2 115.8
2 1 16.7 16.6 43.7 44.5 40.5 43.3 103.7 104.4
2 16.6 45.2 46.2 105.2
5 1 9.1 7.7 38.6 40.0 60.4 61.7 109.4 109.4
2 6.3 41.4 63.0 109.4
12 1 6.4 6.6 32.5 32.2 81.0 81.1 120.0 120.0
2 6.8 32.0 81.3 119.9
19 1 4.7 4.7 30.9 30.1 85.0 85.5 121.2 120.3
2 4.7 29.3 86.0 119.5
AR = Applied Radioactivity
mv = mean values
# 4 subsamples of the total applied soil batch
* directly after application, processing time for ASE extraction taken into account
- = not analysed

Distribution of Total AR and Mass Balance for Soil 2.4
Exposure Day Soil Extract Non-Extractable Residues (NER) CO2 Mass Balance
% of AR % of AR % of AR % of AR
Repl. mv mv mv mv
0 (1 h)* 4# 49.7 47.9 58.8 53.8 _ 108.5 101.7
54.5 60.3 114.7
43.7 44.5 88.2
43.5 51.7 95.2
1 1 26.9 27.2 45.1 56.7 49.1 46.6 118.6 130.5
2 27.6 68.2 44.1 142.4
2 1 16.5 15.1 53.7 51.6 66.4 60.7 130.9 127.5
2 13.8 49.5 55.1 124.1
4 1 8.1 9.3 29.3 34.1 74.0 66.7 104.2 110.2
2 10.5 39.0 59.4 116.2
7 1 4.1 4.1 30.8 31.5 77.0 83.5 118.5 119.1
2 4.0 32.1 90.1 119.7
21 1 4.5 4.6 24.9 24.7 115.9 106.0 135.5 135.4
2 4.8 24.5 96.2 135.3
AR = Applied Radioactivity
mv = mean values
# 4 subsamples of the total applied soil batch
* directly after application, processing time for ASE extraction taken into account
- = not analysed
 
Distribution of Total AR and Mass Balance for Soil 5M
Exposure Day Soil Extract Non-Extractable Residues (NER) CO2 Mass Balance
% of AR % of AR % of AR % of AR
Repl. mv mv mv mv
0 (1 h)* 5# 82.5 84.6 8.5 20.3 _ 91.0 104.8
85.2 11.3 96.5
77.4 24.8 102.2
82.5 17.1 99.6
95.2 39.6 134.8
1 1 50.2 54.3 26.4 28.5 33.5 35.9 112.4 118.7
2 58.5 30.6 38.2 124.9
2 1 27.9 25.6 35.0 33.3 51.3 53.0 116.0 111.9
2 23.3 31.6 54.7 107.9
3 1 12.6 12.2 34.2 33.7 58.7 61.6 108.5 107.5
2 11.7 33.2 64.5 106.5
9 1 6.0 5.3 26.2 27.1 78.7 84.6 116.7 117.0
2 4.7 28.0 90.6 117.2
20 1 3.2 3.1 28.4 27.5 86.9 85.1 116.8 115.7
2 3.1 26.5 83.4 114.7
AR = Applied Radioactivity
mv = mean values
# 5 subsamples of the total applied soil batch
* directly after application, processing time for ASE extraction taken into account
- = not analysed

 
Characterization of Non-Extractable Residues
The residues from the ASE extractions from last sampling of each soil were submitted to organic matter fractionation in order to measure the radioactivity bound to the humic and fulvic acids as well as to the humin fraction of the soil.
The distribution of the radioactivity was comparable for all 4 soils. The majority of the non-extractable radioactivity was bound to the immobile humins (approx. 15 % of AR). Furthermore comparable amounts were bound to the soluble fractions of fulvic acids (3.2 – 5.5 %) and humic acids (2.1 – 4.9 %).

Soil Organic Matter Fractionation
Soil
2.2 2.3 2.4 5M
% of AR % of AR % of AR % of AR
Repl. Repl. Repl. Repl.
1 2 1 2 1 2 1 2
Remaining non-extractable residues in soil after ASE extraction 26.6 25.5 30.9 29.3 24.9 24.5 28.4 26.5
Fulvic acids
Soluble fraction at low pH 3.2 3.3 5.0 5.5 3.0 3.0 3.6 3.4
Humic acids
Soluble fraction at high pH 3.5 4.9 3.6 2.1 2.4 2.8 4.2 4.0
Humin
Insoluble fraction 10.9 12.3 15.4 14.7 15.3 14.9 15.0 15.5
Total 17.6 20.5 23.9 22.3 20.6 20.7 22.8 22.9

Microbial Biomass
The microbial biomass activity of the control replicates was determined for all soils at the respective application day and at the end of the definite study by measurement of the glucose induced respiration rates. The results are given in Table 6.

Soil 2.2, 2.4 and 5M had a comparable biomass concentration, whereas the biomass concentration of soil 2.3 was slightly higher. The resulting biomass activity was comparable for soil 2.2, 2.3 and soil 5M, whereas the biomass activity of soil 2.4 was approx. 2 fold higher.
The biomass activity decreased only slightly during the course of the study, and was > 1 % of the organic carbon throughout the study.


Microbial Biomass Activity of the Controls
Soil Study SR Biomass
day mgO2/(kgDW) % of org. C
2.2 0 240.3 2.80
45 213.6 2.49
2.3 0 198.0 4.53
22 147.9 3.38
2.4 0 535.0 2.97
24 505.8 2.81
5M A 175.4 2.11
30 168.0 2.02
SR = Soil Respiration Rate

Kinetic Analysis

The kinetic evaluations were done based on the FOCUS guidance documenton estimating persistence and degradation kinetics⁽⁴⁾.

The kinetic models were chosen based on the following criteria:

·        Visual assessment of the fitted and observed data versus time

·        Visual assessment of the residuals

·        Estimation of the error percentage at which thec²-test was passed

 

The transformation of N-[1 -14C]Oleoyl-N-methylglucamine (overall dissipation) as well as the mineralization (dissipation to¹⁴CO₂) showed a fast initial decrease followed by a slower decline. Therefore a bi-phasic kinetic model (FOMC: First-Order Multi-Compartment model) was used for the kinetic analysis.

 

The calculated DT₅₀values for the dissipation ofN-[1-14C]Oleoyl-N-methylglucaminewere ≤ 1.0 day. For mineralization the calculated DT₅₀values were in the range 1.3 – 2.6 days.

Data for Kinetic Evaluations: Dissipation ofN-[1-14C]Oleoyl-N-methylglucamine

Soil
2.2				2.3				2.4				5M
Study		Replicate			Study		Replicate			Study		Replicate			Study		Replicate
Day		1		2		Day		1		2		Day		1		2		Day		1		2
0		100.0		100.0		0		100.0		100.0		0		100.0		100.0		0		100.0		100.0
1		41.5		40.4		1		31.6		41.5		1		26.9		27.6		1		50.2		58.5
2		24.8		25.9		2		16.7		16.6		2		16.5		13.8		2		27.9		23.3
3		18.6		18.7		5		9.1		6.3		4		8.1		10.5		3		12.6		11.7
4		14.5		15.2		12		6.4		6.8		7		4.1		4.0		9		6.0		4.7
7		10.6		10.7		19		4.7		4.7		21		4.5		4.8		20		3.2		3.1
17		9.8		8.0
42		5.6		5.6

Table15:            Data for Kinetic Evaluations: Dissipation due to Mineralisation of N-[1-14C]Oleoyl-N-methylglucamine

Soil
2.2				2.3				2.4				5M
Study		Replicate			Study		Replicate			Study		Replicate			Study		Replicate
Day		1		2		Day		1		2		Day		1		2		Day		1		2
0		100.0		100.0		0		100.0		100.0		0		100.0		100.0		0		100.0		100.0
1		71.1		70.3		1		66.4		64.8		1		50.9		55.9		1		66.5		61.8
2		51.6		48.9		2		59.5		53.8		2		33.6		44.9		2		48.7		45.3
3		47.0		49.5		5		39.6		37.0		4		26.0		40.6		3		41.3		35.5
4		43.7		42.0		12		19.0		18.7		7		23.0		9.9		9		21.3		9.4
7		22.5		41.2		19		15.0		14.0		21		0.0		3.8		20		13.1		16.6
17		2.6		10.7
42		8.8		0.0

Kinetic Datafor Dissipation ofN-[1-14C]Oleoyl-N-methylglucamine

Endpoint / Statistic	Soil	Soil	Soil	Soil
	2.2	2.3	2.4	5M
Model	Bi-phasic (FOMC)	Bi-phasic (FOMC)	Bi-phasic (FOMC)	Bi-phasic (FOMC)
C0 (% of applied radioactivity)	100 (fixed)	100 (fixed)	100 (fixed)	100 (fixed)
a(1/d)	0.708 ± 0.147	1.068 ± 0.312	0.939 ± 0.223	11.664 ± 14.188
Initial value for fitting	1.0	1.0	1.2	10
b(1/d)	0.354 ± 0.176	0.583 ± 0.311	0.332 ± 0.174	16.919 ± 21.196
Initial value for fitting	0.5	0.6	0.5	20
c^2error	5.1	6.6	3.8	6.9
r^2	0.9683	0.9849	0.9876	0.9902
DTXvalues in days
DT50	0.59	0.53	0.36	1.0
DT90	8.8	4.5	3.5	3.7

 

Kinetic Data for Mineralisation ofN-[1-14C]Oleoyl-N-methylglucamine

Endpoint / Statistic	Soil	Soil	Soil	Soil
	2.2	2.3	2.4	5M
Model	Bi-exponential (FOMC)	Bi-exponential (FOMC)	Bi-exponential (FOMC)	Bi-exponential (FOMC)
C0 (% of applied radioactivity)	100 (fixed)	100 (fixed)	100 (fixed)	100 (fixed)
a(1/d)	1.040 ± 0.325	0.703 ± 0.217	0.802 ± 0.292	0.773 ± 0.237
Initial value for fitting	0.5	0.5	0.5	0.5
b(1/d)	2.725 ± 1.314	1.467 ± 0.815	0.939 ± 0.634	1.227 ± 0.659
Initial value for fitting	1.5	1.0	1.5	1.5
c^2error	7.1	3.9	7.7	4.0
r^2	0.9428	0.9356	0.9268	0.9485
DTXvalues in days
DT50	2.6	2.5	1.3	1.8
DT90	22.2	37.3	15.6	22.9

 

Conclusions:

The test item N-[1-14C]Oleoyl-N-methylglucamine was fast degraded in all 4 soils.

The extractable fraction of N-[1-14C]Oleoyl-N-methylglucamine decreased fast. Even directly after application the extractable fraction was only in the range 47.9 - 84.6 % of the applied N-[1-14C]Oleoyl-N-methylglucamine (measured as total 14C).

The dominant transformation/dissipation process of N-[1-14C]Oleoyl-N-methylglucamine was mineralization, accompanied by the formation of non-extractable residues (NER).
The amount of NER corresponds with the high mineralisation, and can be explained by irreversible binding and incorporation of transformation products in bacterial biomass.

The calculated DT50 values for the dissipation of N-[1-14C]Oleoyl-N-methylglucamine were ≤ 1.0 day. For mineralization the calculated DT50 values were in the range 1.3 – 2.6 days.

Executive summary:

The aerobic transformation of N-[1-14C]Oleoyl-N-methylglucamine, batch no. not specified) in 4 different natural soils was determinedover a test period of 120 days according to OECD guideline 307. The study was conducted from 2015-10-12 to 2015-11-27 at Dr.U.Noack-Laboratorien, 31157 Sarstedt, Germany.

  

Principle of the Study

The aerobic transformation/dissipation of N-[1-14C]Oleoyl-N-methylglucamine in 4 different soils was investigated. Aerobic transformation encompasses the biotic or abiotic transformation reactions of the test item including mineralisation (CO₂formation) and formation of bound residues (non-extractable residues (NER)).

Four different standard soils (LUFA 2.2, 2.3, 2.4 and 5M, field fresh sampled), varying in their organic carbon content, pH, clay content, cation exchange capacity and microbial biomass, were treated withN-[1-14C]Oleoyl-N-methylglucamine. Soil samples wereincubated in the dark under aerobic conditions for up to 42 days under controlled laboratory conditions.

After appropriate time intervals soil samples were extracted and analyzed for residual radioactivity. The mineralization was determined by trapping and analysis of the evolved¹⁴CO₂. NER were determined after combustion of the extracted soil samples. The radioactivity of the soil extracts, the extracted soil and evolved¹⁴CO₂was determined by LSC.

 

The transformation of N-[1-14C]Oleoyl-N-methylglucamine (overall dissipation) as well as the mineralization (dissipation to¹⁴CO₂) showed a fast initial decrease followed by a slower decline. Therefore the DT₅₀and DT₉₀, the disappearance time within the test item concentration is reduced by 50 % and 90 %, respectively, was calculated with a First-Order Multi-Compartment model (FOMC).

The microbial biomass activity was determined by the glucoseinduced respiration rates.

Results

Microbial Activity

Soil 2.2, 2.4 and 5M had a comparable biomass concentration, whereas the biomass concentration of soil 2.3 was slightly higher. The resulting biomass activity was comparable for soil 2.2, 2.3 and soil 5M, whereas the biomass activity of soil 2.4 was approx. 2 fold higher.

The biomass activity decreased only slightly during the course of the study, and was > 1 % of the organic carbon throughout the study.

 

Mass Balance

At test start the mass balance was in the range 93.8 – 104.8 % for all 4 soils.

Within the study duration the mass balance increased and was > 110 % (up to 135.4 %) at most sampling times.

Due to the calculation of the mass balance from separate replicates,¹⁴CO₂is overvalued in the mass balance calculations.¹⁴CO₂was determined from the replicates for mineralization, but due to the fast mineralization significant amounts of¹⁴CO₂might be associated with bacterial biomass and contribute to the fraction of NER as well.

The higher mass balance had no influence of the calculation of the DT_xvalues. 

 

Transformation ofN-[1-14C]Oleoyl-N-methylglucamine

N-[1-14C]Oleoyl-N-methylglucamine was fast degraded in all 4 soils.

The extractable fraction of N-[1-14C]Oleoyl-N-methylglucamine decreased fast. Even directly after application the extractable¹⁴C-resiudes were only in the range 47.9 - 84.6 % of the appliedN-[1-14C]Oleoyl-N-methylglucamine(measured as total¹⁴C). At the end of the respective incubation period the extractable radioactivity decreased to 3.1 – 5.6 %.

 

The evolved¹⁴CO₂increased steadily during the study and reached 85.1 – 106 % at the of the respective incubation period.

 

No radioactivity (all samples < LOQ) was determined in the ethylene glycol traps, indicating that no volatile transformation products were formed.

 

The formation of NER reached a maximum of 33.7 – 56.7 % 1-2 days after application. Within the study duration, the NER decreased steadily and reached 24.7 – 30.1 % at test end.

The amount of NER corresponds with the high mineralisation, and can be explained by irreversible binding and incorporation of transformation products in bacterial biomass.

 

The results of the organic matter fractionation were comparable for all 4 soils. The majority of the non-extractable radioactivity was bound to the immobile humins (approx. 15 % of AR). Furthermore comparable amounts were bound to the soluble fractions offulvic acids (3.2 – 5.5 %) and humic acids (2.1 – 4.9 %).

Mineralisation and Volatile Transformation Products

The¹⁴CO₂formation started almost immediately after application in all 4 soils. The mineralization progressed steadily and was > 80 % for all soils at test end.

 

Kinetic Data

The transformation ofN-[1-14C]Oleoyl-N-methylglucaminefollowed single first order (SFO) kinetics in all 4 soils.

DT_xvalues forDissipation and Mineralisation

Endpoint		Soil
		2.2		2.3		2.4		5M
DTXvalues in days
Dissipation
DT50		0.59		0.53		0.36		1.0
DT90		8.8		4.5		3.5		3.7
Mineralisation
DT50		2.6		2.5		1.3		1.8
DT90		22.2		37.3		15.6		22.9

Description of key information

The test item N-[1-14C]Oleoyl-N-methylglucamine was fast degraded in all 4 soils.

 

The extractable fraction of N-[1-14C]Oleoyl-N-methylglucamine decreased fast. Even directly after application the extractable fraction was only in the range 47.9 - 84.6 % of the applied N-[1-14C]Oleoyl-N-methylglucamine (measured as total 14C).

 

The dominant transformation/dissipation process of N-[1-14C]Oleoyl-N-methylglucamine was mineralization, accompanied by the formation of non-extractable residues (NER).

The amount of NER corresponds with the high mineralisation, and can be explained by irreversible binding and incorporation of transformation products in bacterial biomass.

 

The calculated DT50 values for the dissipation of N-[1-14C]Oleoyl-N-methylglucamine were ≤ 1.0 day. For mineralization the calculated DT50 values were in the range 1.3 – 2.6 days.

Key value for chemical safety assessment

Half-life in soil:

2.6 d

at the temperature of:

20 °C