Poly(oxy-1,2-ethanediyl), α-[2-(dide- cylmethylammonio)ethyl]- .omega.- hydroxy-, propanoate (salt) (Bardap 26)

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)

GLP compliance:

yes

Test type:

laboratory

Test material

Test material information

Constituent 1

Reference substance name:

bis(decyl)(2-hydroxyethyl)methylazanium propanoate

EC Number:

619-057-3

Cas Number:

94667-33-1

Molecular formula:

C29 H62 N O4 . C3 H5 O2

IUPAC Name:

bis(decyl)(2-hydroxyethyl)methylazanium propanoate

Radiolabelling:

yes

Study design

Oxygen conditions:

aerobic/anaerobic

Soil classification:

USDA (US Department of Agriculture)

Soil properties

Soil properties 1

Soil no.:

#1

Soil type:

sand

% Clay:

1.7

% Silt:

11.4

% Sand:

86.9

% Org. C:

0.69

pH:

4.75

CEC:

3.5 meq/100 g soil d.w.

Soil properties 2

Soil no.:

#2

Soil type:

loamy sand

% Clay:

7.5

% Silt:

13.7

% Sand:

78.8

% Org. C:

1.61

pH:

5.9

CEC:

7.6 meq/100 g soil d.w.

Soil properties 3

Soil no.:

#3

Soil type:

sandy loam

% Clay:

4.7

% Silt:

35.8

% Sand:

59.5

% Org. C:

0.73

pH:

6.41

CEC:

6.5 meq/100 g soil d.w.

Soil properties 4

Soil no.:

#4

Soil type:

loam

% Clay:

26.7

% Silt:

42.2

% Sand:

31.1

% Org. C:

1.92

pH:

7.39

CEC:

20.6 meq/100 g soil d.w.

Parameter followed for biodegradation estimation:

radiochem. meas.

Details on experimental conditions:

For the test system 100 g soil (dry weight) for each sample were used. The biological activity of the soils was checked directly after treatment and at the end of incubation.
All-glass test vessels (300 mL) were filled between 3 and 4 Nov 2016 with 100 g soil (dry substance) and moisturized to 53% WHC on 4 Nov 2016. The soil was stored at 20 °C from the filling date and allowed to equilibrate for at least three days before application.
The flasks were incubated under aerobic conditions, by using an air flow-through system. The system was kept moist with a trap filled with dist. H2O in front of every sample. Each flask was connected to two NaOH traps (2 M, 60 mL) to capture the carbon dioxide and one Tenax® trap for organic volatiles. The first in row NaOH traps were changed on 38 d and 70 d of incubation after a colour change of the phenolphthalein occurred in some samples. Microbial Biomass was determined at the arrival, the start and at the end of the study in samples treated with the same amount of solvent as the treated samples.
Duplicate samples for each test system were worked-up per sampling interval. The entire soil per flask was extracted three times under ambient conditions, followed by a single (until sampling interval 30d) or a triple (beginning with sampling interval 45d) extraction under hot conditions in a microwave oven. A last extraction was performed with acetone under ambient conditions. Extracts with > 5% of AR were combined (at least first three extracts were combined). The combined extracts were analysed for [N-methyl-14C] Bardap 26 and possible transformation products with high performance liquid chromatography (radio-HPLC).

Results and discussion

Half-life / dissipation time of parent compound

Half-life / dissipation time of parent compound 1

Key result

Soil No.:

#1

DT50:

14.6 d

Type:

not specified

Temp.:

20 °C

Half-life / dissipation time of parent compound 2

Key result

Soil No.:

#1

DT50:

28.1 d

Type:

not specified

Temp.:

12 °C

Half-life / dissipation time of parent compound 3

Key result

Soil No.:

#2

DT50:

10.9 d

Type:

not specified

Temp.:

20 °C

Half-life / dissipation time of parent compound 4

Key result

Soil No.:

#2

DT50:

20.7 d

Type:

not specified

Temp.:

12 °C

Half-life / dissipation time of parent compound 5

Key result

Soil No.:

#3

DT50:

16.3 d

Type:

not specified

Temp.:

20 °C

Half-life / dissipation time of parent compound 6

Key result

Soil No.:

#3

DT50:

30.9 d

Type:

not specified

Temp.:

12 °C

Half-life / dissipation time of parent compound 7

Key result

Soil No.:

#4

DT50:

27.6 d

Type:

not specified

Temp.:

20 °C

Half-life / dissipation time of parent compound 8

Key result

Soil No.:

#4

DT50:

52.3 d

Type:

not specified

Temp.:

12 °C

Transformation products:

yes

Remarks:

See attached Robust Study Summary

Identity of transformation products

No.:

#1

Reference

Reference substance name:

Unnamed

IUPAC name:

dioxomethane

Inventory number:

InventoryMultipleMappingImpl [inventoryEntryValue=EC 204-696-9]

CAS number:

124-38-9

Details on transformation products:

With HPLC method 1 (reverse-phase HPLC) the signal M1 was found up to 42.4%, 21.1%, 22.1 % and 7.3% of AR in the soils Lufa 2.1, Lufa 2.2, Lufa 2.3 and Lufa 2.4, respectively.
HILIC HPLC was used to separate possible metabolites associated with M1 resulting in a separation of one major (M1a) and several minor metabolites (H1-H12 – see section 4.6 for example found in lufa 2.1). The major metabolite M1a reached up to 29.4% and 12.7% of AR in the soils Lufa 2.1 and Lufa 2.2, respectively.
Up to 12 minor transformation products occurred during the incubation period whereas two (H6 and H10) did exceed 5% of AR but less than 10% AR. The identification of the structure for H6 was possible.

Applicant's summary and conclusion

Conclusions:

[N-methyl-14C]Bardap 26 degraded under aerobic laboratory conditions, with a typical half-live of 14.6, 10.8, 16.2 and 28.2 days in soil extracts for the soils Lufa 2.1, Lufa 2.2, Lufa 2.3 and Lufa 2.4, respectively.
Metabolite M1a reached up to 29.4% and 12.7% AR in the soils Lufa 2.1 and Lufa 2.2, respectively. Metabolites H6 and H10 were observed at higher than 5% AR but less than 10% AR during the study.
H6 was identified but it was not possible to identify H10.
Up to 12 minor transformation products occurred during the incubation period.

Executive summary:

The mean recoveries for the soils Lufa 2.1, 2.2, 2.3 and 2.4 were within the range of 90.8% – 101.2; 91.0% – 100.4%; 92.3 – 106.3% and 91.9% – 98.4% of the applied radioactivity (AR), respectively (satisfying required recovery range for radiolabelled test item).

The radioactivity in the soil extract of Lufa 2.1, 2.2, 2.3 and 2.4 decreased to a minimum of 37.4%; 13.8%; 16.2% and 10.5% of AR after 120 days of treatment, respectively. However, the amount of total carbon dioxide formed during the study was found in the four soils up to 44.1%, 68.9%, 70.2% and 74.3% of AR after 120 days of incubation.

The amount of non-extractable radioactive residues in the soils ranged between 0.4%  52.5%, 0.8%  48.1%, 0.4%  44.9% and 4.2%  28.4% of AR after 30 days of incubation, respectively, and decreased to values of 11.5%, 11.7%, 9.6% and 13.6% of AR after 120 days of incubation.

The microbial biomass for the soils Lufa 2.1, Lufa 2.2, Lufa 2.3 and Lufa 2.4 was measured at the start and at the end of the study was in the range of 2.2 – 13.7, 19.5 – 32.1, 8.4 – 32.9 and 34.6 – 56.6 mg C/ 100 g dry weight, respectively.

According to Irmer (2017, amended 2019), the DT50 ranged between 10.8-28.2 days and DT90 between 35.9-93.6 days, with a single-first order kinetics assigned as best fit to the data (see table A7.2.1-3 for summary of kinetics).

According to Patterson (2019a), the DT50 ranged between 10.9-27.6 days and DT90 between 36.2-91.7 days, with a single first order kinetics assigned as best fit to the data (see summary table 7.2.1-18 and detailed tables 7.2.1-19- 7.2.1-22).